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Sample records for interspecific gene flow1

  1. Chapter 2: Genetic Variability in Nuclear Ribosomal and Chloroplast DNA in Utah (Juniperus Osteosperma) and Western (J. Occidentalis) Juniper (Cupressaceae): Evidence for Interspecific Gene Flow1

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    Terry, Randall G.; Tausch, Robin J.; Nowak, Robert S.

    1998-02-14

    Early studies of evolutionary change in chloroplast DNA indicated limited variability within species. This finding has been attributed to relatively low rates of sequence evolution and has been maintained as justification for the lack of intraspecific sampling in studies examining, relationships at the species level and above. However, documentation of intraspecific variation in cpDNA has become increasingly common and has been attributed in many cases to ''chloroplast capture'' following genetic exchange across species boundaries. Rleseberg and Wendel (1993) list 37 cases of proposed hybridization in plants that include intraspecific variation in cpDNA, 24 (65%) of which they considered to be probable instances of introgression. Rieseberg (1995) suspected that a review of the literature at that time would reveal over 100 cases of intraspecific variation in CPDNA that could be attributed to hybridization and introgression. That intraspecific variation in cpDNA is potentially indicative of hybridization is founded on the expectation that slowly evolving loci or genomes will produce greater molecular variation between than within species. In cases where a species is polymorphic for CPDNA and at least one of the molecular variants is diagnostic for a second species, interspecific hybridization is a plausible explanation. Incongruence between relationships suggested by cpDNA variation and those supported by other types of data (e.g., morphology or molecular data from an additional locus) provides additional support for introgression. One aspect of hybridization in both animals and plants that has become increasingly evident is incongruence in the phylogenetic and geographic distribution of cytoplasmic and nuclear markers. In most cases cytoplasmic introgression appears to be more pervasive than nuclear exchange. This discordance appears attributable to several factors including differences in the mutation rate, number of effective alleles, and modes

  2. Interspecific and interploidal gene flow in Central European Arabidopsis (Brassicaceae

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    Jørgensen Marte H

    2011-11-01

    Full Text Available Abstract Background Effects of polyploidisation on gene flow between natural populations are little known. Central European diploid and tetraploid populations of Arabidopsis arenosa and A. lyrata are here used to study interspecific and interploidal gene flow, using a combination of nuclear and plastid markers. Results Ploidal levels were confirmed by flow cytometry. Network analyses clearly separated diploids according to species. Tetraploids and diploids were highly intermingled within species, and some tetraploids intermingled with the other species, as well. Isolation with migration analyses suggested interspecific introgression from tetraploid A. arenosa to tetraploid A. lyrata and vice versa, and some interploidal gene flow, which was unidirectional from diploid to tetraploid in A. arenosa and bidirectional in A. lyrata. Conclusions Interspecific genetic isolation at diploid level combined with introgression at tetraploid level indicates that polyploidy may buffer against negative consequences of interspecific hybridisation. The role of introgression in polyploid systems may, however, differ between plant species, and even within the small genus Arabidopsis, we find very different evolutionary fates when it comes to introgression.

  3. Interspecific gene flow and maintenance of species integrity in oaks

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    Oliver Gailing

    2014-07-01

    Full Text Available Oak species show a wide variation in morphological and physiological characters, and species boundaries between closely related species are often not clear-cut. Still, despite frequent interspecific gene flow, oaks maintain distinct morphological and physiological adaptations. In sympatric stands, spatial distribution of species with different ecological requirements is not random but constrained by soil and other microenvironmental factors. Pre-zygotic isolation (e.g. cross incompatibilities, asynchrony in flowering, pollen competition and post-zygotic isolation (divergent selection contribute to the maintenance of species integrity in sympatric oak stands. The antagonistic effects of interspecific gene flow and divergent selection are reflected in the low genetic differentiation between hybridizing oak species at most genomic regions interspersed by regions with signatures of divergent selection (outlier regions. In the near future, the availability of high-density genetic linkage maps anchored to scaffolds of a sequenced Q. robur genome will allow to characterize the underlying genes in these outlier regions and their putative role in reproductive isolation between species. Reciprocal transplant experiments of seedlings between parental environments can be used to characterize selection on outlier genes. High transferability of gene-based markers will enable comparative outlier screens in different oak species.

  4. Interspecific studies of circadian genes period and timeless in Drosophila.

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    Noreen, Shumaila; Pegoraro, Mirko; Nouroz, Faisal; Tauber, Eran; Kyriacou, Charalambos P

    2018-03-30

    The level of rescue of clock function in genetically arrhythmic Drosophila melanogaster hosts using interspecific clock gene transformation was used to study the putative intermolecular coevolution between interacting clock proteins. Among them PER and TIM are the two important negative regulators of the circadian clock feedback loop. We transformed either the D. pseudoobscura per or tim transgenes into the corresponding arrhythmic D. melanogaster mutant (per01 or tim01) and observed >50% rhythmicity but the period of activity rhythm was either longer (D. pseudoobscura-per) or shorter than 24 h (D. pseudoobscura-tim) compared to controls. By introducing both transgenes simultaneously into double mutants, we observed that the period of the activity rhythm was rescued by the pair of hemizygous transgenes (~24 h). These flies also showed a more optimal level of temperature compensation for the period. Under LD 12:12 these flies have a D. pseudoobscura like activity profile with the absence of morning anticipation as well as a very prominent earlier evening peak of activity rhythm. These observation are consistent with the view that TIM and PER form a heterospecific coevolved module at least for the circadian period of activity rhythms. However the strength of rhythmicity was reduced by having both transgenes present, so while evidence for a coevolution between PER and TIM is observed for some characters it is not for others. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  5. Carotenoid accumulation and carotenogenic gene expression during fruit development in novel interspecific inbred squash lines and their parents.

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    Nakkanong, Korakot; Yang, Jing Hua; Zhang, Ming Fang

    2012-06-13

    Carotenoid levels and composition during squash fruit development were compared in Cucurbita moschata , Cucurbita maxima , and two lines of their interspecific inbred lines, namely, Maxchata1 and Maxchata2. Eight genes associated with carotenoid biosynthesis were analyzed by quantitative RT-PCR. The two squash species and their interspecific inbred lines exhibited different qualitative and quantitative carotenoid profiles and regulatory mechanisms. C. moschata had the lowest total carotenoid content and mainly accumulated α-carotene and β-carotene, as expected in a fruit with pale-orange flesh. Low carotenoid content in this species was probably due to the comparatively low expression of all genes investigated, especially PSY1 gene, compared to the other squashes. The predominant carotenoids in C. maxima were violaxanthin and lutein, which produced a corresponding yellow flesh color in mature fruit. The relationship between the expression of the CHYB and ZEP genes may result in almost equal concentrations of violaxanthin and lutein in C. maxima at fruit ripening. In contrast, their interspecific inbred lines principally accumulated lutein and β-carotene, leading to orange flesh color. The PSY1 gene exhibited higher expression levels at earlier stages of fruit development in the Maxchata lines, potentially triggering the increased carotenoid accumulation seen in these fruits. Likewise, the higher transcription level of CHYB gene observed in the two interspecific inbred lines might be correlated with high lutein in these hybrids. However, this study could not explain the observed β-carotene accumulation on the basis of gene expression.

  6. Intra and Interspecific Variations of Gene Expression Levels in Yeast Are Largely Neutral: (Nei Lecture, SMBE 2016, Gold Coast).

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    Yang, Jian-Rong; Maclean, Calum J; Park, Chungoo; Zhao, Huabin; Zhang, Jianzhi

    2017-09-01

    It is commonly, although not universally, accepted that most intra and interspecific genome sequence variations are more or less neutral, whereas a large fraction of organism-level phenotypic variations are adaptive. Gene expression levels are molecular phenotypes that bridge the gap between genotypes and corresponding organism-level phenotypes. Yet, it is unknown whether natural variations in gene expression levels are mostly neutral or adaptive. Here we address this fundamental question by genome-wide profiling and comparison of gene expression levels in nine yeast strains belonging to three closely related Saccharomyces species and originating from five different ecological environments. We find that the transcriptome-based clustering of the nine strains approximates the genome sequence-based phylogeny irrespective of their ecological environments. Remarkably, only ∼0.5% of genes exhibit similar expression levels among strains from a common ecological environment, no greater than that among strains with comparable phylogenetic relationships but different environments. These and other observations strongly suggest that most intra and interspecific variations in yeast gene expression levels result from the accumulation of random mutations rather than environmental adaptations. This finding has profound implications for understanding the driving force of gene expression evolution, genetic basis of phenotypic adaptation, and general role of stochasticity in evolution. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  7. Development and bin mapping of gene-associated interspecific SNPs for cotton (Gossypium hirsutum L.) introgression breeding efforts.

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    Hulse-Kemp, Amanda M; Ashrafi, Hamid; Zheng, Xiuting; Wang, Fei; Hoegenauer, Kevin A; Maeda, Andrea B V; Yang, S Samuel; Stoffel, Kevin; Matvienko, Marta; Clemons, Kimberly; Udall, Joshua A; Van Deynze, Allen; Jones, Don C; Stelly, David M

    2014-10-30

    Cotton (Gossypium spp.) is the largest producer of natural fibers for textile and is an important crop worldwide. Crop production is comprised primarily of G. hirsutum L., an allotetraploid. However, elite cultivars express very small amounts of variation due to the species monophyletic origin, domestication and further bottlenecks due to selection. Conversely, wild cotton species harbor extensive genetic diversity of prospective utility to improve many beneficial agronomic traits, fiber characteristics, and resistance to disease and drought. Introgression of traits from wild species can provide a natural way to incorporate advantageous traits through breeding to generate higher-producing cotton cultivars and more sustainable production systems. Interspecific introgression efforts by conventional methods are very time-consuming and costly, but can be expedited using marker-assisted selection. Using transcriptome sequencing we have developed the first gene-associated single nucleotide polymorphism (SNP) markers for wild cotton species G. tomentosum, G. mustelinum, G. armourianum and G. longicalyx. Markers were also developed for a secondary cultivated species G. barbadense cv. 3-79. A total of 62,832 non-redundant SNP markers were developed from the five wild species which can be utilized for interspecific germplasm introgression into cultivated G. hirsutum and are directly associated with genes. Over 500 of the G. barbadense markers have been validated by whole-genome radiation hybrid mapping. Overall 1,060 SNPs from the five different species have been screened and shown to produce acceptable genotyping assays. This large set of 62,832 SNPs relative to cultivated G. hirsutum will allow for the first high-density mapping of genes from five wild species that affect traits of interest, including beneficial agronomic and fiber characteristics. Upon mapping, the markers can be utilized for marker-assisted introgression of new germplasm into cultivated cotton and in

  8. Advances in interspecific pregnancy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Interspecific pregnancy in which the conceptus and female carrying the pregnancy are of different species is a key step to interspecific cloning. Cloning endangered animals by interspecific pregnancy is such a highlight catching people's eyes nowadays. In this article, the history of interspecific pregnancy, the methods for establishment of interspecific pregnancy, the corresponding theories, barriers and applied prospects are reviewed.``

  9. An interspecific fungal hybrid reveals cross-kingdom rules for allopolyploid gene expression patterns.

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    Murray P Cox

    2014-03-01

    Full Text Available Polyploidy, a state in which the chromosome complement has undergone an increase, is a major force in evolution. Understanding the consequences of polyploidy has received much attention, and allopolyploids, which result from the union of two different parental genomes, are of particular interest because they must overcome a suite of biological responses to this merger, known as "genome shock." A key question is what happens to gene expression of the two gene copies following allopolyploidization, but until recently the tools to answer this question on a genome-wide basis were lacking. Here we utilize high throughput transcriptome sequencing to produce the first genome-wide picture of gene expression response to allopolyploidy in fungi. A novel pipeline for assigning sequence reads to the gene copies was used to quantify their expression in a fungal allopolyploid. We find that the transcriptional response to allopolyploidy is predominantly conservative: both copies of most genes are retained; over half the genes inherit parental gene expression patterns; and parental differential expression is often lost in the allopolyploid. Strikingly, the patterns of gene expression change are highly concordant with the genome-wide expression results of a cotton allopolyploid. The very different nature of these two allopolyploids implies a conserved, eukaryote-wide transcriptional response to genome merger. We provide evidence that the transcriptional responses we observe are mostly driven by intrinsic differences between the regulatory systems in the parent species, and from this propose a mechanistic model in which the cross-kingdom conservation in transcriptional response reflects conservation of the mutational processes underlying eukaryotic gene regulatory evolution. This work provides a platform to develop a universal understanding of gene expression response to allopolyploidy and suggests that allopolyploids are an exceptional system to investigate gene

  10. Microdiversification of a Pelagic Polynucleobacter Species Is Mainly Driven by Acquisition of Genomic Islands from a Partially Interspecific Gene Pool

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    Schmidt, Johanna; Jezberová, Jitka; Koll, Ulrike; Hahn, Martin W.

    2016-01-01

    ABSTRACT Microdiversification of a planktonic freshwater bacterium was studied by comparing 37 Polynucleobacter asymbioticus strains obtained from three geographically separated sites in the Austrian Alps. Genome comparison of nine strains revealed a core genome of 1.8 Mb, representing 81% of the average genome size. Seventy-five percent of the remaining flexible genome is clustered in genomic islands (GIs). Twenty-four genomic positions could be identified where GIs are potentially located. These positions are occupied strain specifically from a set of 28 GI variants, classified according to similarities in their gene content. One variant, present in 62% of the isolates, encodes a pathway for the degradation of aromatic compounds, and another, found in 78% of the strains, contains an operon for nitrate assimilation. Both variants were shown in ecophysiological tests to be functional, thus providing the potential for microniche partitioning. In addition, detected interspecific horizontal exchange of GIs indicates a large gene pool accessible to Polynucleobacter species. In contrast to core genes, GIs are spread more successfully across spatially separated freshwater habitats. The mobility and functional diversity of GIs allow for rapid evolution, which may be a key aspect for the ubiquitous occurrence of Polynucleobacter bacteria. IMPORTANCE Assessing the ecological relevance of bacterial diversity is a key challenge for current microbial ecology. The polyphasic approach which was applied in this study, including targeted isolation of strains, genome analysis, and ecophysiological tests, is crucial for the linkage of genetic and ecological knowledge. Particularly great importance is attached to the high number of closely related strains which were investigated, represented by genome-wide average nucleotide identities (ANI) larger than 97%. The extent of functional diversification found on this narrow phylogenetic scale is compelling. Moreover, the transfer of

  11. A single gene causes an interspecific difference in pigmentation in Drosophila.

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    Ahmed-Braimah, Yasir H; Sweigart, Andrea L

    2015-05-01

    The genetic basis of species differences remains understudied. Studies in insects have contributed significantly to our understanding of morphological evolution. Pigmentation traits in particular have received a great deal of attention and several genes in the insect pigmentation pathway have been implicated in inter- and intraspecific differences. Nonetheless, much remains unknown about many of the genes in this pathway and their potential role in understudied taxa. Here we genetically analyze the puparium color difference between members of the virilis group of Drosophila. The puparium of Drosophila virilis is black, while those of D. americana, D. novamexicana, and D. lummei are brown. We used a series of backcross hybrid populations between D. americana and D. virilis to map the genomic interval responsible for the difference between this species pair. First, we show that the pupal case color difference is caused by a single Mendelizing factor, which we ultimately map to an ∼11-kb region on chromosome 5. The mapped interval includes only the first exon and regulatory region(s) of the dopamine N-acetyltransferase gene (Dat). This gene encodes an enzyme that is known to play a part in the insect pigmentation pathway. Second, we show that this gene is highly expressed at the onset of pupation in light brown taxa (D. americana and D. novamexicana) relative to D. virilis, but not in the dark brown D. lummei. Finally, we examine the role of Dat in adult pigmentation between D. americana (heavily melanized) and D. novamexicana (lightly melanized) and find no discernible effect of this gene in adults. Our results demonstrate that a single gene is entirely or almost entirely responsible for a morphological difference between species. Copyright © 2015 by the Genetics Society of America.

  12. Cheetah interspecific SCNT followed by embryo aggregation improves in vitro development but not pluripotent gene expression.

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    Moro, L N; Hiriart, M I; Buemo, C; Jarazo, J; Sestelo, A; Veraguas, D; Rodriguez-Alvarez, L; Salamone, D F

    2015-07-01

    The aim of this study was to evaluate the capacity of domestic cat (Dc, Felis silvestris) oocytes to reprogram the nucleus of cheetah (Ch, Acinonyx jubatus) cells by interspecies SCNT (iSCNT), by using embryo aggregation. Dc oocytes were in vitro matured and subjected to zona pellucida free (ZP-free) SCNT or iSCNT, depending on whether the nucleus donor cell was of Dc or Ch respectively. ZP-free reconstructed embryos were then cultured in microwells individually (Dc1X and Ch1X groups) or in couples (Dc2X and Ch2X groups). Embryo aggregation improved in vitro development obtaining 27.4, 47.7, 16.7 and 28.3% of blastocyst rates in the Dc1X, Dc2X, Ch1X and Ch2X groups, respectively (P<0.05). Moreover, aggregation improved the morphological quality of blastocysts from the Dc2X over the Dc1X group. Gene expression analysis revealed that Ch1X and Ch2X blastocysts had significantly lower relative expression of OCT4, CDX2 and NANOG than the Dc1X, Dc2X and IVF control groups. The OCT4, NANOG, SOX2 and CDX2 genes were overexpressed in Dc1X blastocysts, but the relative expression of these four genes decreased in the Dc2X, reaching similar relative levels to those of Dc IVF blastocysts. In conclusion, Ch blastocysts were produced using Dc oocytes, but with lower relative expression of pluripotent and trophoblastic genes, indicating that nuclear reprogramming could be still incomplete. Despite this, embryo aggregation improved the development of Ch and Dc embryos, and normalized Dc gene expression, which suggests that this strategy could improve full-term developmental efficiency of cat and feline iSCNT embryos. © 2015 Society for Reproduction and Fertility.

  13. Genetic dissection of growth, wood basic density and gene expression in interspecific backcrosses of Eucalyptus grandis and E. urophylla

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    2012-01-01

    Background F1 hybrid clones of Eucalyptus grandis and E. urophylla are widely grown for pulp and paper production in tropical and subtropical regions. Volume growth and wood quality are priority objectives in Eucalyptus tree improvement. The molecular basis of quantitative variation and trait expression in eucalypt hybrids, however, remains largely unknown. The recent availability of a draft genome sequence (http://www.phytozome.net) and genome-wide genotyping platforms, combined with high levels of genetic variation and high linkage disequilibrium in hybrid crosses, greatly facilitate the detection of quantitative trait loci (QTLs) as well as underlying candidate genes for growth and wood property traits. In this study, we used Diversity Arrays Technology markers to assess the genetic architecture of volume growth (diameter at breast height, DBH) and wood basic density in four-year-old progeny of an interspecific backcross pedigree of E. grandis and E. urophylla. In addition, we used Illumina RNA-Seq expression profiling in the E. urophylla backcross family to identify cis- and trans-acting polymorphisms (eQTLs) affecting transcript abundance of genes underlying QTLs for wood basic density. Results A total of five QTLs for DBH and 12 for wood basic density were identified in the two backcross families. Individual QTLs for DBH and wood basic density explained 3.1 to 12.2% of phenotypic variation. Candidate genes underlying QTLs for wood basic density on linkage groups 8 and 9 were found to share trans-acting eQTLs located on linkage groups 4 and 10, which in turn coincided with QTLs for wood basic density suggesting that these QTLs represent segregating components of an underlying transcriptional network. Conclusion This is the first demonstration of the use of next-generation expression profiling to quantify transcript abundance in a segregating tree population and identify candidate genes potentially affecting wood property variation. The QTLs identified in this

  14. Efficient procedure for transferring specific human genes into Chinese hamster cell mutants: interspecific transfer of the human genes encoding leucyl- and asparaginyl-tRNA synthetases

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    Cirullo, R.E.; Dana, S.; Wasmuth, J.J.

    1983-01-01

    A simple and efficient procedure for transferring specific human genes into mutant Chinese hamster ovary cell recipients has been developed that does not rely on using calcium phosphate-precipitated high-molecular-weight DNA. Interspecific cell hybrids between human leukocytes and temperature-sensitive Chinese hamster cell mutants with either a thermolabile leucyl-tRNA synthetase or a thermolabile asparaginyl-tRNA synthetase were used as the starting material in these experiments. These hybrids contain only one or a few human chromosomes and require expression of the appropriate human aminoacyl-tRNA synthetase gene to grow at 39 degrees C. Hybrids were exposed to very high doses of gamma-irradiation to extensively fragment the chromosomes and re-fused immediately to the original temperature-sensitive Chinese hamster mutant, and secondary hybrids were isolated at 39 degrees C. Secondary hybrids, which had retained small fragments of the human genome containing the selected gene, were subjected to another round of irradiation, refusion, and selection at 39 degrees C to reduce the amount of human DNA even further. Using this procedure, Chinese hamster cell lines have been constructed that express the human genes encoding either asparaginyl- or leucyl-tRNA synthetase, yet less than 0.1% of their DNA is derived from the human genome, as quantitated by a sensitive dot-blot nucleic acid hybridization procedure

  15. Interspecific exchange of avian influenza virus genes in Alaska: The influence of trans-hemispheric migratory tendency and breeding ground sympatry

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    Pearce, John M.; Reeves, A.B.; Ramey, A.M.; Hupp, J.W.; Ip, Hon S.; Bertram, M.; Petrula, M.J.; Scotton, B.D.; Trust, K.A.; Meixell, B.W.; Runstadler, J.A.

    2011-01-01

    The movement and transmission of avian influenza viral strains via wild migratory birds may vary by host species as a result of migratory tendency and sympatry with other infected individuals. To examine the roles of host migratory tendency and species sympatry on the movement of Eurasian low-pathogenic avian influenza (LPAI) genes into North America, we characterized migratory patterns and LPAI viral genomic variation in mallards (Anas platyrhynchos) of Alaska in comparison with LPAI diversity of northern pintails (Anas acuta). A 50-year band-recovery data set suggests that unlike northern pintails, mallards rarely make trans-hemispheric migrations between Alaska and Eurasia. Concordantly, fewer (14.5%) of 62 LPAI isolates from mallards contained Eurasian gene segments compared to those from 97 northern pintails (35%), a species with greater inter-continental migratory tendency. Aerial survey and banding data suggest that mallards and northern pintails are largely sympatric throughout Alaska during the breeding season, promoting opportunities for interspecific transmission. Comparisons of full-genome isolates confirmed near-complete genetic homology (>99.5%) of seven viruses between mallards and northern pintails. This study found viral segments of Eurasian lineage at a higher frequency in mallards than previous studies, suggesting transmission from other avian species migrating inter-hemispherically or the common occurrence of endemic Alaskan viruses containing segments of Eurasian origin. We conclude that mallards are unlikely to transfer Asian-origin viruses directly to North America via Alaska but that they are likely infected with Asian-origin viruses via interspecific transfer from species with regular migrations to the Eastern Hemisphere.

  16. Differential expression of photosynthesis-related genes in pentaploid interspecific hybrid and its decaploid of Fragaria spp.

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    Wang, Tao; Huang, Dongya; Chen, Baoyu; Mao, Nini; Qiao, Yushan; Ji, Muxiang

    2018-03-01

    Polyploidization always induces a series of changes in genome, transcriptome and epigenetics, of which changes in gene expression are the immediate causes of genotype alterations of polyploid plants. In our previous study on strawberry polyploidization, genes related to photosynthesis were found to undergo changes in gene expression and DNA methylation. Therefore, we chose 11 genes that were closely related to plant photosynthesis and analysed their expression during strawberry hybridization and chromosome doubling. Most genes of pentaploids showed expression levels between parents and were more similar to F. × ananassa. Gene expression levels of decaploids were higher than those of pentaploids and F. × ananassa. Different types of photosynthesis-related genes responded differently to hybridization and chromosome doubling. Chloroplast genes and regulatory genes showed complex responses. Structural genes of the photosynthetic system were expressed at a constant level and displayed a clear dosage effect. The methylation levels of one CG site on SIGE, which regulates expression of chloroplast genes, were negatively correlated with gene expression. In pentaploids and decaploids, more transcripts were from F. × ananassa than from F. viridis. The ratio of transcripts from from F. × ananassa to those from F. viridis was close to the ratio (4:1) of the genome of F. × ananassa to that of F. viridis in pentaploids and decaploids, but there were also some exceptions with obvious deviation.

  17. [Interspecific polymorphism of the glucosyltransferase domain of the sucrose synthase gene in the genus Malus and related species of Rosaceae].

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    Boris, K V; Kochieva, E Z; Kudryavtsev, A M

    2014-12-01

    The sequences that encode the main functional glucosyltransferase domain of sucrose synthase genes have been identified for the first time in 14 species of the genus Malus and related species of the family Rosaceae, and their polymorphism was investigated. Single nucleotide substitutions leading to amino acid substitutions in the protein sequence, including the conservative transmembrane motif sequence common to all sucrose synthase genes of higher plants, were detected in the studied sequences.

  18. Chromosomal rearrangements and gene flow over time in an inter-specific hybrid zone of the Sorex araneus group.

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    Yannic, G; Basset, P; Hausser, J

    2009-06-01

    Most hybrid zones have existed for hundreds or thousands of years but have generally been observed for only a short time period. Studies extending over periods long enough to track evolutionary changes in the zones or assess the ultimate outcome of hybridization are scarce. Here, we describe the evolution over time of the level of genetic isolation between two karyotypically different species of shrews (Sorex araneus and Sorex antinorii) at a hybrid zone located in the Swiss Alps. We first evaluated hybrid zone movement by contrasting patterns of gene flow and changes in cline parameters (centre and width) using 24 microsatellite loci, between two periods separated by 10 years apart. Additionally, we tested the role of chromosomal rearrangements on gene flow by analysing microsatellite loci located on both rearranged and common chromosomes to both species. We did not detect any movement of the hybrid zone during the period analysed, suggesting that the zone is a typical tension zone. However, the gene flow was significantly lower among the rearranged than the common chromosomes for the second period, whereas the difference was only marginally significant for the first period. This further supports the role of chromosomal rearrangements on gene flow between these taxa.

  19. Global gene expression profiling related to temperature-sensitive growth abnormalities in interspecific crosses between tetraploid wheat and Aegilops tauschii.

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    Ryusuke Matsuda

    Full Text Available Triploid wheat hybrids between tetraploid wheat and Aegilops tauschii sometimes show abnormal growth phenotypes, and the growth abnormalities inhibit generation of wheat synthetic hexaploids. In type II necrosis, one of the growth abnormalities, necrotic cell death accompanied by marked growth repression occurs only under low temperature conditions. At normal temperature, the type II necrosis lines show grass-clump dwarfism with no necrotic symptoms, excess tillers, severe dwarfism and delayed flowering. Here, we report comparative expression analyses to elucidate the molecular mechanisms of the temperature-dependent phenotypic plasticity in the triploid wheat hybrids. We compared gene and small RNA expression profiles in crown tissues to characterize the temperature-dependent phenotypic plasticity. No up-regulation of defense-related genes was observed under the normal temperature, and down-regulation of wheat APETALA1-like MADS-box genes, considered to act as flowering promoters, was found in the grass-clump dwarf lines. Some microRNAs, including miR156, were up-regulated, whereas the levels of transcripts of the miR156 target genes SPLs, known to inhibit tiller and branch number, were reduced in crown tissues of the grass-clump dwarf lines at the normal temperature. Unusual expression of the miR156/SPLs module could explain the grass-clump dwarf phenotype. Dramatic alteration of gene expression profiles, including miRNA levels, in crown tissues is associated with the temperature-dependent phenotypic plasticity in type II necrosis/grass-clump dwarf wheat hybrids.

  20. Interspecific proteomic comparisons reveal ash phloem genes potentially involved in constitutive resistance to the emerald ash borer.

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    Whitehill, Justin G A; Popova-Butler, Alexandra; Green-Church, Kari B; Koch, Jennifer L; Herms, Daniel A; Bonello, Pierluigi

    2011-01-01

    The emerald ash borer (Agrilus planipennis) is an invasive wood-boring beetle that has killed millions of ash trees since its accidental introduction to North America. All North American ash species (Fraxinus spp.) that emerald ash borer has encountered so far are susceptible, while an Asian species, Manchurian ash (F. mandshurica), which shares an evolutionary history with emerald ash borer, is resistant. Phylogenetic evidence places North American black ash (F. nigra) and Manchurian ash in the same clade and section, yet black ash is highly susceptible to the emerald ash borer. This contrast provides an opportunity to compare the genetic traits of the two species and identify those with a potential role in defense/resistance. We used Difference Gel Electrophoresis (DIGE) to compare the phloem proteomes of resistant Manchurian to susceptible black, green, and white ash. Differentially expressed proteins associated with the resistant Manchurian ash when compared to the susceptible ash species were identified using nano-LC-MS/MS and putative identities assigned. Proteomic differences were strongly associated with the phylogenetic relationships among the four species. Proteins identified in Manchurian ash potentially associated with its resistance to emerald ash borer include a PR-10 protein, an aspartic protease, a phenylcoumaran benzylic ether reductase (PCBER), and a thylakoid-bound ascorbate peroxidase. Discovery of resistance-related proteins in Asian species will inform approaches in which resistance genes can be introgressed into North American ash species. The generation of resistant North American ash genotypes can be used in forest ecosystem restoration and urban plantings following the wake of the emerald ash borer invasion.

  1. Comprehensive search for intra- and inter-specific sequence polymorphisms among coding envelope genes of retroviral origin found in the human genome: genes and pseudogenes

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    Vasilescu Alexandre

    2005-09-01

    Full Text Available Abstract Background The human genome carries a high load of proviral-like sequences, called Human Endogenous Retroviruses (HERVs, which are the genomic traces of ancient infections by active retroviruses. These elements are in most cases defective, but open reading frames can still be found for the retroviral envelope gene, with sixteen such genes identified so far. Several of them are conserved during primate evolution, having possibly been co-opted by their host for a physiological role. Results To characterize further their status, we presently sequenced 12 of these genes from a panel of 91 Caucasian individuals. Genomic analyses reveal strong sequence conservation (only two non synonymous Single Nucleotide Polymorphisms [SNPs] for the two HERV-W and HERV-FRD envelope genes, i.e. for the two genes specifically expressed in the placenta and possibly involved in syncytiotrophoblast formation. We further show – using an ex vivo fusion assay for each allelic form – that none of these SNPs impairs the fusogenic function. The other envelope proteins disclose variable polymorphisms, with the occurrence of a stop codon and/or frameshift for most – but not all – of them. Moreover, the sequence conservation analysis of the orthologous genes that can be found in primates shows that three env genes have been maintained in a fully coding state throughout evolution including envW and envFRD. Conclusion Altogether, the present study strongly suggests that some but not all envelope encoding sequences are bona fide genes. It also provides new tools to elucidate the possible role of endogenous envelope proteins as susceptibility factors in a number of pathologies where HERVs have been suspected to be involved.

  2. Transcriptome profiling in conifers and the PiceaGenExpress database show patterns of diversification within gene families and interspecific conservation in vascular gene expression

    Directory of Open Access Journals (Sweden)

    Raherison Elie

    2012-08-01

    Full Text Available Abstract Background Conifers have very large genomes (13 to 30 Gigabases that are mostly uncharacterized although extensive cDNA resources have recently become available. This report presents a global overview of transcriptome variation in a conifer tree and documents conservation and diversity of gene expression patterns among major vegetative tissues. Results An oligonucleotide microarray was developed from Picea glauca and P. sitchensis cDNA datasets. It represents 23,853 unique genes and was shown to be suitable for transcriptome profiling in several species. A comparison of secondary xylem and phelloderm tissues showed that preferential expression in these vascular tissues was highly conserved among Picea spp. RNA-Sequencing strongly confirmed tissue preferential expression and provided a robust validation of the microarray design. A small database of transcription profiles called PiceaGenExpress was developed from over 150 hybridizations spanning eight major tissue types. In total, transcripts were detected for 92% of the genes on the microarray, in at least one tissue. Non-annotated genes were predominantly expressed at low levels in fewer tissues than genes of known or predicted function. Diversity of expression within gene families may be rapidly assessed from PiceaGenExpress. In conifer trees, dehydrins and late embryogenesis abundant (LEA osmotic regulation proteins occur in large gene families compared to angiosperms. Strong contrasts and low diversity was observed in the dehydrin family, while diverse patterns suggested a greater degree of diversification among LEAs. Conclusion Together, the oligonucleotide microarray and the PiceaGenExpress database represent the first resource of this kind for gymnosperm plants. The spruce transcriptome analysis reported here is expected to accelerate genetic studies in the large and important group comprised of conifer trees.

  3. Some results of applied interspecific hybridization in sunflower breeding

    International Nuclear Information System (INIS)

    Tsvetkova, F.

    1976-01-01

    Investigations on the interspecific hybridization in sunflower, aimed at developing a diversified initial selection material, were carried out Wild species of the diploid, tetraploid and hexaploid groups, varieties, hybrids, and selfed-lines of cultivated sunflower were used for crossings. To overcome incrossability between the species and sterility in the hybrids the method of f;cilitating of crossability by mutual gra'fting and gamma-rays treatment of seeds and pollen were applied. Results showed that: 1. By the method of interspecific hybridization forms might be produced resistant to more important diseases. 2. Interspecific hybridization in combination with other methods of selection might produce varieties and hybrids with a complex of valuable qualities. 3. Crossings between wild species and cultivated sunflower gave progenies with gene rale sterility. 4. The species H.tuberosus, H.scaberimus, H.arωphylus and H.lenticularis possess genes of full fertility restoration. (author)

  4. Construction of an EST-SSR-based interspecific transcriptome ...

    Indian Academy of Sciences (India)

    Construction of an EST-SSR-based interspecific transcriptome linkage map of fibre development in cotton. CHUANXIANG LIU, DAOJUN YUAN and ZHONGXU LIN. ∗. National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan),. Huazhong Agricultural University, Wuhan ...

  5. Antioxidant enzymatic activities and gene expression associated with heat tolerance in the stems and roots of two cucurbit species ("Cucurbita maxima" and "Cucurbita moschata") and their interspecific inbred line "Maxchata".

    Science.gov (United States)

    Ara, Neelam; Nakkanong, Korakot; Lv, Wenhui; Yang, Jinghua; Hu, Zhongyuan; Zhang, Mingfang

    2013-12-10

    The elucidation of heat tolerance mechanisms is required to combat the challenges of global warming. This study aimed to determine the antioxidant enzyme responses to heat stress, at the enzymatic activity and gene expression levels, and to investigate the antioxidative alterations associated with heat tolerance in the stems and roots of squashes using three genotypes differing in heat tolerance. Plants of heat-tolerant "C. moschata", thermolabile "C. maxima" and moderately heat-tolerant interspecific inbred line "Maxchata" genotypes were exposed to moderate (37 °C) and severe (42 °C) heat shocks. "C. moschata" exhibited comparatively little oxidative damage, with the lowest hydrogen peroxide (H2O2), superoxide (O2(-)) and malondialdehyde (MDA) contents in the roots compared to stems, followed by "Maxchata". The enzyme activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) were found to be increased with heat stress in tolerant genotypes. The significant inductions of FeSOD, MnSOD, APX2, CAT1 and CAT3 isoforms in tolerant genotypes suggested their participation in heat tolerance. The differential isoform patterns of SOD, APX and CAT between stems and roots also indicated their tissue specificity. Furthermore, despite the sequence similarity of the studied antioxidant genes among "C. maxima" and "Maxchata", most of these genes were highly induced under heat stress in "Maxchata", which contributed to its heat tolerance. This phenomenon also indicated the involvement of other unknown genetic and/or epigenetic factors in controlling the expression of these antioxidant genes in squashes, which demands further exploration.

  6. Antioxidant Enzymatic Activities and Gene Expression Associated with Heat Tolerance in the Stems and Roots of Two Cucurbit Species (“Cucurbita maxima” and “Cucurbita moschata”) and Their Interspecific Inbred Line “Maxchata”

    Science.gov (United States)

    Ara, Neelam; Nakkanong, Korakot; Lv, Wenhui; Yang, Jinghua; Hu, Zhongyuan; Zhang, Mingfang

    2013-01-01

    The elucidation of heat tolerance mechanisms is required to combat the challenges of global warming. This study aimed to determine the antioxidant enzyme responses to heat stress, at the enzymatic activity and gene expression levels, and to investigate the antioxidative alterations associated with heat tolerance in the stems and roots of squashes using three genotypes differing in heat tolerance. Plants of heat-tolerant “C. moschata”, thermolabile “C. maxima” and moderately heat-tolerant interspecific inbred line “Maxchata” genotypes were exposed to moderate (37 °C) and severe (42 °C) heat shocks. “C. moschata” exhibited comparatively little oxidative damage, with the lowest hydrogen peroxide (H2O2), superoxide (O2−) and malondialdehyde (MDA) contents in the roots compared to stems, followed by “Maxchata”. The enzyme activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) were found to be increased with heat stress in tolerant genotypes. The significant inductions of FeSOD, MnSOD, APX2, CAT1 and CAT3 isoforms in tolerant genotypes suggested their participation in heat tolerance. The differential isoform patterns of SOD, APX and CAT between stems and roots also indicated their tissue specificity. Furthermore, despite the sequence similarity of the studied antioxidant genes among “C. maxima” and “Maxchata”, most of these genes were highly induced under heat stress in “Maxchata”, which contributed to its heat tolerance. This phenomenon also indicated the involvement of other unknown genetic and/or epigenetic factors in controlling the expression of these antioxidant genes in squashes, which demands further exploration. PMID:24336062

  7. Antioxidant Enzymatic Activities and Gene Expression Associated with Heat Tolerance in the Stems and Roots of Two Cucurbit Species (“Cucurbita maxima” and “Cucurbita moschata” and Their Interspecific Inbred Line “Maxchata”

    Directory of Open Access Journals (Sweden)

    Neelam Ara

    2013-12-01

    Full Text Available The elucidation of heat tolerance mechanisms is required to combat the challenges of global warming. This study aimed to determine the antioxidant enzyme responses to heat stress, at the enzymatic activity and gene expression levels, and to investigate the antioxidative alterations associated with heat tolerance in the stems and roots of squashes using three genotypes differing in heat tolerance. Plants of heat-tolerant “C. moschata”, thermolabile “C. maxima” and moderately heat-tolerant interspecific inbred line “Maxchata” genotypes were exposed to moderate (37 °C and severe (42 °C heat shocks. “C. moschata” exhibited comparatively little oxidative damage, with the lowest hydrogen peroxide (H2O2, superoxide (O2− and malondialdehyde (MDA contents in the roots compared to stems, followed by “Maxchata”. The enzyme activities of superoxide dismutase (SOD, ascorbate peroxidase (APX, catalase (CAT and peroxidase (POD were found to be increased with heat stress in tolerant genotypes. The significant inductions of FeSOD, MnSOD, APX2, CAT1 and CAT3 isoforms in tolerant genotypes suggested their participation in heat tolerance. The differential isoform patterns of SOD, APX and CAT between stems and roots also indicated their tissue specificity. Furthermore, despite the sequence similarity of the studied antioxidant genes among “C. maxima” and “Maxchata”, most of these genes were highly induced under heat stress in “Maxchata”, which contributed to its heat tolerance. This phenomenon also indicated the involvement of other unknown genetic and/or epigenetic factors in controlling the expression of these antioxidant genes in squashes, which demands further exploration.

  8. Evolutionary disarmament in interspecific competition.

    Science.gov (United States)

    Kisdi, E; Geritz, S A

    2001-12-22

    Competitive asymmetry, which is the advantage of having a larger body or stronger weaponry than a contestant, drives spectacular evolutionary arms races in intraspecific competition. Similar asymmetries are well documented in interspecific competition, yet they seldom lead to exaggerated traits. Here we demonstrate that two species with substantially different size may undergo parallel coevolution towards a smaller size under the same ecological conditions where a single species would exhibit an evolutionary arms race. We show that disarmament occurs for a wide range of parameters in an ecologically explicit model of competition for a single shared resource; disarmament also occurs in a simple Lotka-Volterra competition model. A key property of both models is the interplay between evolutionary dynamics and population density. The mechanism does not rely on very specific features of the model. Thus, evolutionary disarmament may be widespread and may help to explain the lack of interspecific arms races.

  9. Assembly of 500,000 inter-specific catfish expressed sequence tags and large scale gene-associated marker development for whole genome association studies

    Energy Technology Data Exchange (ETDEWEB)

    Catfish Genome Consortium; Wang, Shaolin; Peatman, Eric; Abernathy, Jason; Waldbieser, Geoff; Lindquist, Erika; Richardson, Paul; Lucas, Susan; Wang, Mei; Li, Ping; Thimmapuram, Jyothi; Liu, Lei; Vullaganti, Deepika; Kucuktas, Huseyin; Murdock, Christopher; Small, Brian C; Wilson, Melanie; Liu, Hong; Jiang, Yanliang; Lee, Yoona; Chen, Fei; Lu, Jianguo; Wang, Wenqi; Xu, Peng; Somridhivej, Benjaporn; Baoprasertkul, Puttharat; Quilang, Jonas; Sha, Zhenxia; Bao, Baolong; Wang, Yaping; Wang, Qun; Takano, Tomokazu; Nandi, Samiran; Liu, Shikai; Wong, Lilian; Kaltenboeck, Ludmilla; Quiniou, Sylvie; Bengten, Eva; Miller, Norman; Trant, John; Rokhsar, Daniel; Liu, Zhanjiang

    2010-03-23

    Background-Through the Community Sequencing Program, a catfish EST sequencing project was carried out through a collaboration between the catfish research community and the Department of Energy's Joint Genome Institute. Prior to this project, only a limited EST resource from catfish was available for the purpose of SNP identification. Results-A total of 438,321 quality ESTs were generated from 8 channel catfish (Ictalurus punctatus) and 4 blue catfish (Ictalurus furcatus) libraries, bringing the number of catfish ESTs to nearly 500,000. Assembly of all catfish ESTs resulted in 45,306 contigs and 66,272 singletons. Over 35percent of the unique sequences had significant similarities to known genes, allowing the identification of 14,776 unique genes in catfish. Over 300,000 putative SNPs have been identified, of which approximately 48,000 are high-quality SNPs identified from contigs with at least four sequences and the minor allele presence of at least two sequences in the contig. The EST resource should be valuable for identification of microsatellites, genome annotation, large-scale expression analysis, and comparative genome analysis. Conclusions-This project generated a large EST resource for catfish that captured the majority of the catfish transcriptome. The parallel analysis of ESTs from two closely related Ictalurid catfishes should also provide powerful means for the evaluation of ancient and recent gene duplications, and for the development of high-density microarrays in catfish. The inter- and intra-specific SNPs identified from all catfish EST dataset assembly will greatly benefit the catfish introgression breeding program and whole genome association studies.

  10. Interspecific variations in the gastrointestinal microbiota in penguins

    OpenAIRE

    Dewar, Meagan L; Arnould, John P Y; Dann, Peter; Trathan, Phil; Groscolas, Rene; Smith, Stuart

    2013-01-01

    Despite the enormous amount of data available on the importance of the gastrointestinal (GI) microbiota in vertebrate (especially mammals), information on the GI microbiota of seabirds remains incomplete. As with many seabirds, penguins have a unique digestive physiology that enables them to store large reserves of adipose tissue, protein, and lipids. This study used quantitative real-time polymerase chain reaction (qPCR) and 16S rRNA gene pyrosequencing to characterize the interspecific vari...

  11. Drosophila interspecific hybrids phenocopy piRNA-pathway mutants.

    Directory of Open Access Journals (Sweden)

    Erin S Kelleher

    Full Text Available The Piwi-interacting RNA (piRNA pathway defends the germline of animals from the deleterious activity of selfish transposable elements (TEs through small-RNA mediated silencing. Adaptation to novel invasive TEs is proposed to occur by incorporating their sequences into the piRNA pool that females produce and deposit into their eggs, which then propagates immunity against specific TEs to future generations. In support of this model, the F1 offspring of crosses between strains of the same Drosophila species sometimes suffer from germline derepression of paternally inherited TE families, caused by a failure of the maternal strain to produce the piRNAs necessary for their regulation. However, many protein components of the Drosophila piRNA pathway exhibit signatures of positive selection, suggesting that they also contribute to the evolution of host genome defense. Here we investigate piRNA pathway function and TE regulation in the F1 hybrids of interspecific crosses between D. melanogaster and D. simulans and compare them with intraspecific control crosses of D. melanogaster. We confirm previous reports showing that intraspecific crosses are characterized by derepression of paternally inherited TE families that are rare or absent from the maternal genome and piRNA pool, consistent with the role of maternally deposited piRNAs in shaping TE silencing. In contrast to the intraspecific cross, we discover that interspecific hybrids are characterized by widespread derepression of both maternally and paternally inherited TE families. Furthermore, the pattern of derepression of TE families in interspecific hybrids cannot be attributed to their paucity or absence from the piRNA pool of the maternal species. Rather, we demonstrate that interspecific hybrids closely resemble piRNA effector-protein mutants in both TE misregulation and aberrant piRNA production. We suggest that TE derepression in interspecific hybrids largely reflects adaptive divergence of pi

  12. Interspecific Hybridization within Ornamental Plants

    DEFF Research Database (Denmark)

    Kuligowska, Katarzyna

    commercially important genera of ornamental plants: Kalanchoë and Hibiscus. The nature of hybridization barriers hampering hybrid production was investigated during pre- and post-fertilization stages. For each genus the interspecific crosses of Kalanchoë species and Hibiscus species, abnormal germination...... and growth of pollen tubes, as well as lower frequencies of pollen tubes were observed in specific cross-combinations. Post-fertilization barriers related to endosperm development and hybrid incompatibility were also observed in Kalanchoë and Hibiscus genus, respectively. Qualitative and quantitative...

  13. Introgression in interspecific hybrids of lily

    NARCIS (Netherlands)

    Tuyl, van J.M.; Maas, I.W.G.M.; Lim, K.B.

    2002-01-01

    In order to introduce new desirable characters into the cultivar assortment of lily a range of interspecific crossing barriers has to be overcome. By using various pollination and embryo rescue techniques pre- and postfertilization barriers were overcome and a range of wide interspecific lily

  14. Interspecific hybridization of flower bulbs: a review

    NARCIS (Netherlands)

    Tuyl, van J.M.

    1997-01-01

    In order to introduce new characters such as resistances, flower shape and colour, from wild species into the cultivar assortment of lily it is necessary to overcome interspecific crossing barriers.. Several techniques have been used for wide interspecific lily crosses with species and cultivars

  15. Interspecific Competition Underlying Mutualistic Networks

    Science.gov (United States)

    Maeng, Seong Eun; Lee, Jae Woo; Lee, Deok-Sun

    2012-03-01

    Multiple classes of interactions may exist affecting one another in a given system. For the mutualistic networks of plants and pollinating animals, it has been known that the degree distribution is broad but often deviates from power-law form more significantly for plants than animals. To illuminate the origin of such asymmetry, we study a model network in which links are assigned under generalized preferential-selection rules between two groups of nodes and find the sensitive dependence of the resulting connectivity pattern on the model parameters. The nonlinearity of preferential selection can come from interspecific interactions among animals and among plants. The model-based analysis of real-world mutualistic networks suggests that a new animal determines its partners not only by their abundance but also under the competition with existing animal species, which leads to the stretched-exponential degree distributions of plants.

  16. Interspecific Hybridisation in Campanula

    DEFF Research Database (Denmark)

    Röper, Anna Catharina

    In the present thesis, economically important Campanula species were selected for interspecific hybridisation to increase the genetic viability in plant breeding material. To reach this goal, ovule culture was established as an embryo rescue technique to overcome post-fertilisation barriers...... had an influence on the number of ovules and germination success in some cross combinations. In the second research part interspecific hybrids obtained from ovule culture were genotypically and phenotypically characterised by AFLP analysis, flow cytometry and biometrical parameters. Hybridity...

  17. An RNA-seq transcriptome analysis of floral buds of an interspecific Brassica hybrid between B. carinata and B. napus.

    Science.gov (United States)

    Chu, Pu; Liu, Huijuan; Yang, Qing; Wang, Yankun; Yan, Guixia; Guan, Rongzhan

    2014-12-01

    Interspecific hybridizations promote gene transfer between species and play an important role in plant speciation and crop improvement. However, hybrid sterility that commonly found in the first generation of hybrids hinders the utilization of interspecific hybridization. The combination of divergent parental genomes can create extensive transcriptome variations, and to determine these gene expression alterations and their effects on hybrids, an interspecific Brassica hybrid of B. carinata × B. napus was generated. Scanning electron microscopy analysis indicated that some of the hybrid pollen grains were irregular in shape and exhibited abnormal exine patterns compared with those from the parents. Using the Illumina HiSeq 2000 platform, 39,598, 32,403 and 42,208 genes were identified in flower buds of B. carinata cv. W29, B. napus cv. Zhongshuang 11 and their hybrids, respectively. The differentially expressed genes were significantly enriched in pollen wall assembly, pollen exine formation, pollen development, pollen tube growth, pollination, gene transcription, macromolecule methylation and translation, which might be associated with impaired fertility in the F1 hybrid. These results will shed light on the mechanisms underlying the low fertility of the interspecific hybrids and expand our knowledge of interspecific hybridization.

  18. Molecular markers unravel intraspecific and interspecific genetic ...

    Indian Academy of Sciences (India)

    [Kotwal S., Dhar M. K., Kour B., Raj K. and Kaul S. 2013 Molecular markers unravel intraspecific and interspecific genetic variability in ... of bowel problems including chronic constipation, amoebic ..... while to select parents from accessions, Pov80 and Pov79 ... nology (DBT), Govt. of India, for financial assistance in the form.

  19. Interspecific nest use by aridland birds

    Science.gov (United States)

    Deborah M. Finch

    1982-01-01

    Nest holes drilled by woodpeckers (Picidae) are frequently used by secondary cavity-nesting species, but interspecific use of open and domed nests is less well known. Nests constructed by many southwestern desert birds last longer than one year (pers. obs.) and are consequently reused by the same pair (e.g., Abert's Towhees [Pipilo aberti], pers. obs.) or by other...

  20. Synthesis and characterization of interspecific trigenomic hybrids ...

    African Journals Online (AJOL)

    Jane

    2011-09-28

    Sep 28, 2011 ... Interspecific reciprocal crosses between three cultivated Brassica ... environmental conditions, which impacts the qualitative and quantitative crop and oil production to a greater extent. ... Brassica rapa L. (2n= 20, AA) (Nanda Kumar et al., 1991; ... breeding potential for the crop brassicas as a trigenomic.

  1. Asymmetric interspecific territorial competition over food resources ...

    African Journals Online (AJOL)

    The rock-dwelling cichlids in Lake Malawi comprise the most diverse freshwater fish community in the world. Individuals frequently interact with heterospecifics through feeding territoriality. Underwater observations and experiments were conducted to examine interspecific variation in the frequencies of territorial behaviour ...

  2. Molecular profiling of interspecific lowland rice populations derived ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-03

    Dec 3, 2008 ... Molecular profiling of interspecific lowland rice populations ... Both cluster and principal component analyses revealed two major groups ...... simulations. Theor ... inheritance, chromosomal location, and population dynamics.

  3. Obtaining of interspecific hybrids for pea introgressive breeding

    Directory of Open Access Journals (Sweden)

    Sergey Vasilevich Bobkov

    2015-09-01

    Full Text Available Background. Overcoming of reproductive isolation, identification and transfer of agronomic value genes from wild relatives into cultivated pea genomes is an important task for pea introgressive breeding. Materials and methods. Reciprocal hybridization of cultivated pea with wide set of P. fulvum accessions was conducted. Identification of hybrids was carried out with use of biochemical and morphological markers. Identification of unique protein was conducted with use of electrophoretic spectra of mature seeds. Results. Pea interspecific hybrids were obtained in two reciprocal directions of crosses. Cross efficiency in Р. sativum × P. fulvum and P. fulvum × Р. sativum combinations was 36 % and 7 %, respectively. All tested seeds in crosses Р. sativum × P. fulvum were hybrids. Crosses in direction P. fulvum × Р. sativum led to formation of puny seeds restricted in embryo growth. Protein markers of one seed derived in cross P. fulvum × Р. sativum proved its hybrid nature. Morphological markers demonstrated that plant derived from another cross was also a hybrid. Culture of immature embryos was developed for recovering plants in interspecific crosses. Morphogenic calli and regenerated plants were obtained in culture of immature embryos P. fulvum (И592589 × Р. sativum (Aest. Identification of unique protein 7 of P. fulvum was conducted. Inheritance of that protein was proved as monogenic dominant. Conclusion. Efficiency of hybridization in combination P. fulvum × Р. sativum was significantly less in compare to reciprocal one. All products of that cross combination were tested as hybrids. Unique protein 7 of P. fulvum was revealed as a result of mature seed electrophoretic spectra analysis. Inheritance of that protein was determined as monogenic dominant.

  4. Comparative intra-and inter-specific sexual organ reciprocity in four distylous Primula species in the Himalaya-Hengduan Mountains.

    Science.gov (United States)

    Li, Hai-Dong; Ren, Zong-Xin; Zhou, Wei; Bernhardt, Peter; Zhao, Yan-Hui; Wu, Zhi-Kun; Li, De-Zhu; Wang, Hong

    2018-04-23

    Distyly is a mechanism promoting cross-pollination within a balanced polymorphism. Numerous studies show that the degree of inter-morph sexual organ reciprocity (SOR) within species relates to its pollen-mediated gene flow. Similarly, a lower inter-specific SOR should promote inter-specific isolation when congeners are sympatric, co-blooming, and share pollinators. In this comparative study, we address the significance of SOR at both intra- and inter-specific levels. Seventeen allopatric and eight sympatric populations representing four Primula species (P. anisodora, P. beesiana, P. bulleyana and P. poissonii) native to the Himalaya-Hengduan Mountains were measured for eight floral traits in both long- and short-styled morphs. GLMM and spatial overlap methods were used to compare intra- and inter-specific SOR. While floral morphology differed among four Primula species. SOR within species was generally higher than between species, but species pairs P. poissonii / P. anisodora and P. beesiana / P. bulleyana, the SOR was high at both intra- and inter-specific levels. We didn't detect a significant variation in intra-specific SOR or inter-specific SOR when compare allopatric vs. sympatric populations for all species studied. As intra-specific SOR increased, disassortative mating may be promoted. As inter-specific SOR decreased, inter-specific isolation between co-flowering species pairs also may increase. Hybridization between congeners occurred when inter-specific SOR increased in sympatric populations was confirmed in two species pairs, P. poissonii / P. anisodora and P. beesiana / P. bulleyana. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  5. Backcrosses in interspecific hybridization in sunflower

    Directory of Open Access Journals (Sweden)

    Atlagić Jovanka

    2003-01-01

    Full Text Available When incorporating desirable traits (resistance to causal agents of various diseases from the wild relatives into the cultivated sunflower, some undesirable ones are introduced too (branching, small head diameter, low oil content, etc. To overcome this problem, backcrosses (F1 interspecific hybrids x cultivated sunflower are used, although very often desirable traits are lost in the process. Cytological analysis (meiosis and pollen viability and molecular markers (RAPD were used to estimate what portion of the parental species genome was present in (be interspecific hybrids of the F1 and BC1F1 generations. The results showed that the percentage of irregularities at meiosis increased from F1 to BC1F1 gen. They also indicated the presence of aneuploids and sterility in the cross between the hexaploid species H.rigidus and cultivated sunflower. The genetic distance between the parents was 83%, that between H.rigidus and the F1 hybrid 54 61%, and that between H.annuus and F1 hybrid 70-76%. In the BC1F1 generation, the genetic distance from Hannuus decreased to 58-66% and that from H.rigidus increased to 69-76%.

  6. Interspecific lily hybrids: a promise for the future

    NARCIS (Netherlands)

    Tuyl, van J.M.; Chi, H.S.; Kronenburg-van de Ven, van B.C.E.; Meijer, B.

    1997-01-01

    In order to introduce new characters such as resistances, flower shape and colour, from wild species into the cultivar assortment of lily it is necessary to overcome interspecific crossing barriers.. Several techniques have been used for wide interspecific lily crosses with species and cultivars

  7. Interspecific hybrids between Paspalum plicatulum and P. oteroi: a key tool for forage breeding

    Directory of Open Access Journals (Sweden)

    Patricia Elda Novo

    2016-08-01

    Full Text Available ABSTRACT Grama-tio-pedro (Paspalum oteroi Swallen is a rare stoloniferous grass of the Plicatula group of Paspalum, well adapted to continuous grazing in areas subject to seasonal flooding in the Pantanal region, in central western Brazil. The species is a facultative apomictic (asexual reproduction by seed tetraploid, sporadically cultivated on Pantanal farms, propagated either by cuttings or seed. Due to its potential for extensive cultivation and forage quality, Grama-tio-pedro appears as a candidate for genetic improvement within the Plicatula group through plant breeding. We used a colchicine-induced sexual autotetraploid genotype of P. plicatulum Michx. to obtain interspecific hybrids using the apomictic species, P. oteroi, as pollen donor. The very similar meiotic chromosome behavior observed in both parents, with main quadrivalent and bivalent associations, suggested that P. oteroi is a natural autotetraploid. The hybrids showed less irregular meiotic behavior with fewer quadrivalents and more bivalents than either parent. Fertility among interspecific hybrids varied from complete sterility in some of them to seed productions in others that were approximately twice as much as for either parent. The great variability of seed set performance may well be a drastic genetic consequence of joining two homologous chromosome sets of P. plicatulum together with two homologous sets of P. oteroi that, in turn, have some homeology between them. Most hybrids reproduce by sexual means, thus, they could be used as female parents in backcrosses and in crosses with other species of the Plicatula group for interspecific gene transferring in breeding programs.

  8. Interspecific bacterial interactions are reflected in multispecies biofilm spatial organization

    Directory of Open Access Journals (Sweden)

    Wenzheng Liu

    2016-08-01

    Full Text Available Interspecies interactions are essential for the persistence and development of any kind of complex community, and microbial biofilms are no exception. Multispecies biofilms are structured and spatially defined communities that have received much attention due to their omnipresence in natural environments. Species residing in these complex bacterial communities usually interact both intra- and interspecifically. Such interactions are considered to not only be fundamental in shaping overall biomass and the spatial distribution of cells residing in multispecies biofilms, but also to result in coordinated regulation of gene expression in the different species present. These communal interactions often lead to emergent properties in biofilms, such as enhanced tolerance against antibiotics, host immune responses and other stresses, which have been shown to provide benefits to all biofilm members not only the enabling sub-populations. However, the specific molecular mechanisms of cellular processes affecting spatial organization, and vice versa, are poorly understood and very complex to unravel. Therefore, detailed description of the spatial organization of individual bacterial cells in multispecies communities can be an alternative strategy to reveal the nature of interspecies interactions of constituent species. Closing the gap between visual observation and biological processes may become crucial for resolving biofilm related problems, which is of utmost importance to environmental, industrial, and clinical implications. This review briefly presents the state of the art of studying interspecies interactions and spatial organization of multispecies communities, aiming to support theoretical and practical arguments for further advancement of this field.

  9. Evolutionary and Ecological Consequences of Interspecific Hybridization in Cladocerans

    NARCIS (Netherlands)

    Schwenk, K.; Spaak, P.

    1995-01-01

    The evolutionary process of interspecific hybridization in cladocerans is reviewed based on ecological and population genetic data. The evolutionary consequences of hybridization, biogeographic patterns and fitness comparisons are analyzed within the conceptual framework of theories on

  10. Meiotic behaviour in three interspecific three-way hybrids between ...

    Indian Academy of Sciences (India)

    The meiotic behaviour of three three-way interspecific promising hybrids (H17, H27, and H34) was evaluated. ... Arrangement of parental genomes in distinct ... vanna due to its physiological tolerance to low fertility acid ... nomic evaluations.

  11. Prairie dogs increase fitness by killing interspecific competitors.

    Science.gov (United States)

    Hoogland, John L; Brown, Charles R

    2016-03-30

    Interspecific competition commonly selects for divergence in ecology, morphology or physiology, but direct observation of interspecific competition under natural conditions is difficult. Herbivorous white-tailed prairie dogs (Cynomys leucurus) employ an unusual strategy to reduce interspecific competition: they kill, but do not consume, herbivorous Wyoming ground squirrels (Urocitellus elegans) encountered in the prairie dog territories. Results from a 6-year study in Colorado, USA, revealed that interspecific killing of ground squirrels by prairie dogs was common, involving 47 different killers; 19 prairie dogs were serial killers in the same or consecutive years, and 30% of female prairie dogs killed at least one ground squirrel over their lifetimes. Females that killed ground squirrels had significantly higher annual and lifetime fitness than non-killers, probably because of decreased interspecific competition for vegetation. Our results document the first case of interspecific killing of competing individuals unrelated to predation (IK) among herbivorous mammals in the wild, and show that IK enhances fitness for animals living under natural conditions. © 2016 The Author(s).

  12. Unified theory of interspecific allometric scaling

    International Nuclear Information System (INIS)

    Silva, Jafferson K L da; Barbosa, Lauro A; Silva, Paulo Roberto

    2007-01-01

    A general simple theory for the interspecific allometric scaling is developed in the d + 1-dimensional space (d biological lengths and a physiological time) of metabolic states of organisms. It is assumed that natural selection shaped the metabolic states in such a way that the mass and energy d + 1-densities are size-invariant quantities (independent of body mass). The different metabolic states (basal and maximum) are described by considering that the biological lengths and the physiological time are related by different transport processes of energy and mass. In the basal metabolism, transportation occurs by ballistic and diffusion processes. In d = 3, the 3/4 law occurs if the ballistic movement is the dominant process, while the 2/3 law appears when both transport processes are equivalent. Accelerated movement during the biological time is related to the maximum aerobic sustained metabolism, which is characterized by the scaling exponent 2d/(2d + 1) (6/7 in d = 3). The results are in good agreement with empirical data and a verifiable empirical prediction about the aorta blood velocity in maximum metabolic rate conditions is made. (fast track communication)

  13. Interspecific variations in the gastrointestinal microbiota in penguins.

    Science.gov (United States)

    Dewar, Meagan L; Arnould, John P Y; Dann, Peter; Trathan, Phil; Groscolas, Rene; Smith, Stuart

    2013-02-01

    Despite the enormous amount of data available on the importance of the gastrointestinal (GI) microbiota in vertebrate (especially mammals), information on the GI microbiota of seabirds remains incomplete. As with many seabirds, penguins have a unique digestive physiology that enables them to store large reserves of adipose tissue, protein, and lipids. This study used quantitative real-time polymerase chain reaction (qPCR) and 16S rRNA gene pyrosequencing to characterize the interspecific variations of the GI microbiota of four penguin species: the king, gentoo, macaroni, and little penguin. The qPCR results indicated that there were significant differences in the abundance of the major phyla Firmicutes, Bacteroides, Actinobacteria, and Proteobacteria. A total of 132,340, 18,336, 6324, and 4826 near full-length 16S rRNA gene sequences were amplified from fecal samples collected from king, gentoo, macaroni, and little penguins, respectively. A total of 13 phyla were identified with Firmicutes, Bacteroidetes, Proteobacteria, and Fusobacteria dominating the composition; however, there were major differences in the relative abundance of the phyla. In addition, this study documented the presence of known human pathogens, such as Campylobacter, Helicobacter, Prevotella, Veillonella, Erysipelotrichaceae, Neisseria, and Mycoplasma. However, their role in disease in penguins remains unknown. To our knowledge, this is the first study to provide an in-depth investigation of the GI microbiota of penguins. © 2013 The Authors. Published by Blackwell Publishing Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

  14. Barriers to gene flow in interspecific hybridization in Fuchsia L ...

    Indian Academy of Sciences (India)

    from the poor pollen germination on the stigma to arrested pollen tube ..... stored in 70% ethanol until required. The pistils ... A total of 1495 flowers were pollinated in 125 combinations. (including ... 'Gartenmeister Bonstedt' as the female parent. Despite ... centage of unfilled seeds ranged from 30 per cent to 71 per cent. In ...

  15. Experimental evolution of protozoan traits in response to interspecific competition.

    Science.gov (United States)

    terHorst, C P

    2011-01-01

    Decades of experiments have demonstrated the ecological effect of competition, but experimental evidence for competitive effects on trait evolution is rare. I measured the evolution of six protozoan traits in response to competitors from the inquiline community of pitcher plants. Replicate populations of Colpoda, a ciliated protozoan, were allowed to evolve in response to intra- and interspecific competition for 20 days (approximately 100 generations), before traits were measured in two common garden environments. Populations that evolved with interspecific competition had smaller cell sizes, produced fewer cysts and had higher population growth rates relative to populations grown in monoculture. The presence of interspecific competitors led to differential lineage sorting, most likely by increasing the strength of selection. These results are the first to demonstrate protozoan evolution in response to competition and may have implications for species coexistence in this system. © 2010 The Author. Journal of Evolutionary Biology © 2010 European Society For Evolutionary Biology.

  16. Interspecific RNA interference of SHOOT MERISTEMLESS-like disrupts Cuscuta pentagona plant parasitism.

    Science.gov (United States)

    Alakonya, Amos; Kumar, Ravi; Koenig, Daniel; Kimura, Seisuke; Townsley, Brad; Runo, Steven; Garces, Helena M; Kang, Julie; Yanez, Andrea; David-Schwartz, Rakefet; Machuka, Jesse; Sinha, Neelima

    2012-07-01

    Infection of crop species by parasitic plants is a major agricultural hindrance resulting in substantial crop losses worldwide. Parasitic plants establish vascular connections with the host plant via structures termed haustoria, which allow acquisition of water and nutrients, often to the detriment of the infected host. Despite the agricultural impact of parasitic plants, the molecular and developmental processes by which host/parasitic interactions are established are not well understood. Here, we examine the development and subsequent establishment of haustorial connections by the parasite dodder (Cuscuta pentagona) on tobacco (Nicotiana tabacum) plants. Formation of haustoria in dodder is accompanied by upregulation of dodder KNOTTED-like homeobox transcription factors, including SHOOT MERISTEMLESS-like (STM). We demonstrate interspecific silencing of a STM gene in dodder driven by a vascular-specific promoter in transgenic host plants and find that this silencing disrupts dodder growth. The reduced efficacy of dodder infection on STM RNA interference transgenics results from defects in haustorial connection, development, and establishment. Identification of transgene-specific small RNAs in the parasite, coupled with reduced parasite fecundity and increased growth of the infected host, demonstrates the efficacy of interspecific small RNA-mediated silencing of parasite genes. This technology has the potential to be an effective method of biological control of plant parasite infection.

  17. GENETIC DIVERSITY OF INTERSPECIFIC HYBRIDS OF THE GENUS ALLIUM L.

    Directory of Open Access Journals (Sweden)

    V. S. Romanov

    2018-01-01

    Full Text Available Selection based on interspecific hybridization of fundamentally new plant forms with a unique combination of genetic material allows expanding the scope of genotypic and phenotypic variability. In this work the comparative analysis of plants of interspecific hybrids of genus Allium L. from various inbred descendants of combinations of crossing of species A. cepa х A. vavilovii and A. cepa х A. fistulosum on selection traits is carried out.Forms were identified: by mass of the bulb more than 100 g; with contrasting coloration of dry cover scales bulbs; by the index of the shape of the bulb; on the resistance to peronosporosis of plants of the first year of vegetation and seed plants; by the number of arrows; height of the arrow; on seed production with a sufficiently high percentage of fertile plants. Plants of interspecific hybrids of onions formed bulbs weighing from 20 to 120 g, with white, golden-yellow, dark golden-yellow, brownish and dark purple color of dry covering scales of a bulb. Plants of interspecific hybrids of onions were flat and round-flat shape of the bulb with the frequency of symptoms ranging from 6.9 to 93.3% and from 11.7 to 93.3%. In a phytopathological evaluation of interspecific hybrids of onions the first year of vegetation identified plants with resistance to downy mildew is from 0 to 4.0 points. Was studied the frequency of occurrence of plants in the progenies weight, colour, bulb type, number, height of the seedstalk, seed productivity and resistance to downy mildew. The increase of genetic diversity in onion plants obtained on the basis of interspecific hybridization, backcrossing and inbreeding is shown.

  18. Genetic Linkage Map Construction and QTL Analysis of Two Interspecific Reproductive Isolation Traits in Sponge Gourd.

    Science.gov (United States)

    Wu, Haibin; He, Xiaoli; Gong, Hao; Luo, Shaobo; Li, Mingzhu; Chen, Junqiu; Zhang, Changyuan; Yu, Ting; Huang, Wangping; Luo, Jianning

    2016-01-01

    The hybrids between Luffa acutangula (L.) Roxb. and L.cylindrica (L.) Roem. have strong heterosis effects. However, some reproductive isolation traits hindered their normal hybridization and fructification, which was mainly caused by the flowering time and hybrid pollen sterility. In order to study the genetic basis of two interspecific reproductive isolation traits, we constructed a genetic linkage map using an F2 population derived from a cross between S1174 [L. acutangula (L.) Roxb.] and 93075 [L. cylindrica (L.) Roem.]. The map spans 1436.12 CentiMorgans (cM), with an average of 8.11 cM among markers, and consists of 177 EST-SSR markers distributed in 14 linkage groups (LG) with an average of 102.58 cM per LG. Meanwhile, we conducted colinearity analysis between the sequences of EST-SSR markers and the genomic sequences of cucumber, melon and watermelon. On the basis of genetic linkage map, we conducted QTL mapping of two reproductive isolation traits in sponge gourd, which were the flowering time and hybrid male sterility. Two putative QTLs associated with flowering time (FT) were both detected on LG 1. The accumulated contribution of these two QTLs explained 38.07% of the total phenotypic variance (PV), and each QTL explained 15.36 and 22.71% of the PV respectively. Four QTLs for pollen fertility (PF) were identified on LG 1 (qPF1.1 and qPF1.2), LG 3 (qPF3) and LG 7 (qPF7), respectively. The percentage of PF explained by these QTLs varied from 2.91 to 16.79%, and all together the four QTLs accounted for 39.98% of the total PV. Our newly developed EST-SSR markers and linkage map are very useful for gene mapping, comparative genomics and molecular marker-assisted breeding. These QTLs for interspecific reproductive isolation will also contribute to the cloning of genes relating to interspecific reproductive isolation and the utilization of interspecific heterosis in sponge gourd in further studies.

  19. Genetic Identification of Hyalodaphnia Species and Interspecific Hybrids

    NARCIS (Netherlands)

    Billiones, R.; Brehm, G.M.; Klee, J.; Schwenk, K.

    2004-01-01

    Species of the genus Daphnia, in particular the subgenus Hyalodaphnia, represent a taxonomically problematic group due to their phenotypic plasticity, local races and the formation of interspecific hybrids and backcrosses. In this study, we present a genetic approach utilising nuclear DNA to

  20. Sex-specific asymmetry in eye development in interspecific hybrids ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 94; Issue 3. Sex-specific asymmetry in eye development in interspecific hybrids in the Drosophila bipectinata species complex. Bashisth N. Singh Parul Banerjee. Research Note Volume 94 Issue 3 September 2015 pp 493-495 ...

  1. Quantitative trait loci mapping for stomatal traits in interspecific ...

    Indian Academy of Sciences (India)

    Dr.YASODHA

    seedling raising, field planting and maintenance of the mapping population. ... tereticornis and production of interspecific hybrids displaying hybrid vigour in terms of .... A total of 114, 115 and 129 SSR, ISSR and SRAP markers were generated .... stomatal traits with yield and adaptability would help to improve productivity of ...

  2. Evaluation of interspecific DNA variability in poplars using AFLP and ...

    African Journals Online (AJOL)

    The objective of this paper was to examine interspecific DNA variation in poplars using AFLP and SSR markers. The AFLP and SSR markers polymorphism and its power of discrimination were determined within 13 genotypes of different genetic background (clones, cultivars, hybrids) of two sections (Aigeiros and ...

  3. Species delimitation and interspecific relationships of the genus Orychophragmus (Brassicaceae inferred from whole chloroplast genomes

    Directory of Open Access Journals (Sweden)

    Huan Hu

    2016-12-01

    Full Text Available IntroductionIt is rather difficult to delimit recently diverged species and construct their interspecific relationships because of insufficient informative variations of sampled DNA fragments (Schluter, 2000; Arnold, 2006. The genome-scale sequence variations were found to increase the phylogenetic resolutions of both high- and low-taxonomic groups (e.g., Yoder et al., 2013; Lamichhaney et al., 2015. It is still expensive to collect nuclear genome variations between species for most none-model genera without the reference genome. However, chloroplast genomes (plastome are relatively easy to be assembled to examine interspecific relationships for phylogenetic analyses, especially in addressing unresolved relationship at low taxonomic levels (Wu et al., 2010; Nock et al., 2011; Yang et al., 2013; Huang et al., 2014; Carbonell-Caballero et al., 2015. Plastomes are haploid with maternal inheritance in most angiosperms (Corriveau and Coleman, 1988; Zhang and Liu, 2003; Hagemann, 2004 and are highly conservative in gene order and genome structure with rare recombinations (Jansen et al., 2007; Moore et al., 2010. In this study, we aimed to examine species delimitation and interspecific relationships in Orychophragmus through assembling chloroplast genomes of multiple individuals of tentatively delimited species (Hu et al., 2015a. Orychophragmus is a small genus in the mustard family (Brassicaceae, Cruciferae distributed in northern, central, and southeastern China (Zhou et al., 2001. Its plants have been widely cultivated as ornamentals, vegetables, or source of seed oil (Sun et al., 2011. Despite controversial species delimitations in the genus (Zhou et al., 1987; Tan et al., 1998; Wu and Zhao, 2003; Al-Shehbaz and Yang, 2000; Zhou et al., 2001; Sun et al., 2012, our recent study based on nuclear (nr ITS sequence variations suggested the recognition of seven species (Hu et al., 2015a. Orychophragmus is sister to Sinalliaria, which is a genus endemic

  4. DEVELOPMENT AND COMPREHENSIVE ASSESSMENT OF BULBOUS FORMS OF INTERSPECIFIC HYBRIDS OF ONION ALLIUM CEPA x A. FISTULOSUM

    Directory of Open Access Journals (Sweden)

    V. S. Romanov

    2016-01-01

    Full Text Available One of the way of increasing of genetic variability of onion (Allium cepa L. is the interspecific hybridization. Development of onion interspecific hybrids consists of the study of initial breeding forms, its heterogeneity, ways of crossing and pollination, overcoming of outbreeding problem, sterility and weak fertility of the hybrids of first and next generations, specifics of hybrid’s seeds development, identification and selection of recombinant forms with breeding valuable traits. The stages of development of the bulbous forms of interspecific hybrids of onion are presented in the article. The study was conducted in the “All-Russian Scientific Research Institute of vegetable breeding and seed production” of the Moscow region. The plants of inbreed progenies I1-5 from BC1-2F5 of bulb forms of interspecific hybrids A. cepa х A. Fistulosum as well as the parental forms were analyzed. The breeding and phytopathological assessment of recombinant forms of onion interspecific hybrids was done for qualitative and quantitative traits and for resistance to downy mildew. Using the individual selection for quality and quantity traits, it was found that the forms, whose traits were not undergo the inbreeding depression because of the higher homozygosity can be used for development of linear initial material for breeding for heterosis. The forms with the inbreeding depression have to be used for crossbreeding. Along with increasing of homozygosity, the new modified genotypes appear because of potential variability and genes recombination. It allows to make the purposive selection of recombinant forms for valuable traits. The selected onion forms from inbreed progenies of I1-5 from BC1-2F5 which have bulbs of flat and well-rounded-flat shape are characterized by high resistance to downy mildew and bulbs with good storage ability. The selection process of the recombinant forms from progenies of onion interspecific hybrids obtained based on repeated

  5. Interspecific introgression and changes in population structure in a flatfish species complex after the Prestige accident

    International Nuclear Information System (INIS)

    Crego-Prieto, V.; Danancher, D.; Campo, D.; Perez, J.; Garcia-Vazquez, E.; Roca, A.

    2013-01-01

    Highlights: • Impact of Prestige oil spill was studied on two sympatric megrim fish populations. • Samples before and nine years after the accident were genetically analyzed. • A large proportion of post-F1 interspecific hybrids was found in the polluted area. • Both species’ population structure was altered by introgression of foreign alleles. • The spillage likely promoted a hybrid zone for Lepidorhombus in the areas affected. -- Abstract: Oil spills cause aggressive impacts on marine ecosystems affecting immense areas and the species inhabiting them. If wastes are not cleaned up properly, the remnants may affect local populations for a long time. This work focuses on the long-term impacts of the Prestige spillage that occurred off Galician coast (Spain) in November 2002. Model species were two sympatric flatfish, the megrims Lepidorhombus whiffiagonis and Lepidorhombus boscii. Samples obtained before and nine years after the Prestige accident from affected and unaffected areas were genotyped for six hypervariable nuclear markers and for the mitochondrial D-loop sequence. The results revealed a high proportion of post-F1 interspecific hybrids in the area affected, and also increased intraspecific population differentiation likely due to such localized introgression of foreign genes. These changes suggest the appearance of a hybrid zone following the accident and emphasize the need of paying special attention to potential evolutionary impacts of oil spills

  6. TAI vacuolar invertase orthologs: the interspecific variability in tomato plants (Solanum section Lycopersicon).

    Science.gov (United States)

    Slugina, M A; Shchennikova, A V; Kochieva, E Z

    2017-10-01

    Understanding the genetic mechanisms underlying carbohydrate metabolism can promote the development of biotechnological advances in fruit plants. The flesh tomato fruit represents an ideal system for examining the role of sucrose cleavage enzymes in fruit development, and wild tomato species differing in storage sugars serve as an excellent research material for this purpose. Plant vacuolar invertase is a key enzyme of sucrose metabolism in the sink organs. In the present study, we identified complete gene sequences encoding the TAI vacuolar invertase in 11 wild and one cultivated tomato accessions of the Solanum section Lycopersicon. The average level of interspecific polymorphism in TAI genes was 8.58%; however, in the green-fruited tomatoes, the TAI genes contained 100 times more SNPs than those in the red-fruited accessions. The TAI proteins demonstrated 8% variability, whereas the red-fruited species had none. A TAI-based phylogenetic tree revealed two main clusters containing self-compatible and self-incompatible species, which concurs with the previous crossability-based division and demonstrates that the TAI genes reflect the evolutionary relationships between the red- and green-fruited tomatoes. Furthermore, we detected differential expression patterns of the TAI genes in the fruits of wild and cultivated tomatoes, which corresponded to sugar composition. The polymorphism analysis of the TAI acid invertases of Solanum section Lycopersicon species will contribute to the understanding of the genetic potential of TAI genes to impact tomato breeding through genetic engineering of the carbohydrate composition in the fruit.

  7. New lager yeast strains generated by interspecific hybridization.

    Science.gov (United States)

    Krogerus, Kristoffer; Magalhães, Frederico; Vidgren, Virve; Gibson, Brian

    2015-05-01

    The interspecific hybrid Saccharomyces pastorianus is the most commonly used yeast in brewery fermentations worldwide. Here, we generated de novo lager yeast hybrids by mating a domesticated and strongly flocculent Saccharomyces cerevisiae ale strain with the Saccharomyces eubayanus type strain. The hybrids were characterized with respect to the parent strains in a wort fermentation performed at temperatures typical for lager brewing (12 °C). The resulting beers were analysed for sugar and aroma compounds, while the yeasts were tested for their flocculation ability and α-glucoside transport capability. These hybrids inherited beneficial properties from both parent strains (cryotolerance, maltotriose utilization and strong flocculation) and showed apparent hybrid vigour, fermenting faster and producing beer with higher alcohol content (5.6 vs 4.5 % ABV) than the parents. Results suggest that interspecific hybridization is suitable for production of novel non-GM lager yeast strains with unique properties and will help in elucidating the evolutionary history of industrial lager yeast.

  8. Production of interspecific Campanula hybrids by ovule culture

    DEFF Research Database (Denmark)

    Röper, A. C.; Lütken, H.; Christensen, B.

    2015-01-01

    The Campanula genus comprises several economically important ornamental plants species. Wide hybridisation is a method to increase phenotypic variability, but is limited due to interspecies hybridisation barriers. In this study we investigated whether ovule culture could be used to increase....... With this study, a protocol for ovule culture was established and the usefulness of ovule culture to obtain interspecific hybrids of selected Campanula species was demonstrated....

  9. Predators induce interspecific herbivore competition for food in refuge space

    OpenAIRE

    Pallini, A.; Janssen, A.; Sabelis, M.W.

    1998-01-01

    Resource competition among herbivorous arthropods has long been viewed as unimportant because herbivore populations are controlled by predators. Although recently resurrected as an organizing force in arthropod communities on plants, there is still general agreement that resource competition among herbivores is reduced by predators. Here we show the reverse: predators induce interspecific resource competi-tion among herbivores. We found that thrips larvae (Frankliniella occidentalis) use the ...

  10. Erosion of interspecific reproductive barriers resulting from hatchery supplementation of rainbow trout sympatric with cutthroat trout.

    Science.gov (United States)

    Docker, Margaret F; Dale, Angie; Heath, Daniel D

    2003-12-01

    The frequency of hybridization between cutthroat (Onchorhynchus clarki clarki) and rainbow (O. mykiss irideus) trout from coastal habitats in British Columbia, Canada, was examined in seven populations where the two species are sympatric with no history of rainbow trout stocking and compared with areas where native rainbow trout populations have been supplemented with hatchery fish (three populations). Four nuclear markers were used to identify each species and interspecific hybrids and one mitochondrial marker showed the direction of gene exchange between species. The frequency of hybrids was significantly higher (Fisher exact test, P < 0.001) in river systems where hatchery rainbow trout have been introduced (50.6% hybrids) than in populations where the two species naturally co-occur without supplementation (9.9% hybrids).

  11. Interspecific Plastome Recombination Reflects Ancient Reticulate Evolution in Picea (Pinaceae).

    Science.gov (United States)

    Sullivan, Alexis R; Schiffthaler, Bastian; Thompson, Stacey Lee; Street, Nathaniel R; Wang, Xiao-Ru

    2017-07-01

    Plastid sequences are a cornerstone in plant systematic studies and key aspects of their evolution, such as uniparental inheritance and absent recombination, are often treated as axioms. While exceptions to these assumptions can profoundly influence evolutionary inference, detecting them can require extensive sampling, abundant sequence data, and detailed testing. Using advancements in high-throughput sequencing, we analyzed the whole plastomes of 65 accessions of Picea, a genus of ∼35 coniferous forest tree species, to test for deviations from canonical plastome evolution. Using complementary hypothesis and data-driven tests, we found evidence for chimeric plastomes generated by interspecific hybridization and recombination in the clade comprising Norway spruce (P. abies) and 10 other species. Support for interspecific recombination remained after controlling for sequence saturation, positive selection, and potential alignment artifacts. These results reconcile previous conflicting plastid-based phylogenies and strengthen the mounting evidence of reticulate evolution in Picea. Given the relatively high frequency of hybridization and biparental plastid inheritance in plants, we suggest interspecific plastome recombination may be more widespread than currently appreciated and could underlie reported cases of discordant plastid phylogenies. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  12. Interspecific Hybridization May Provide Novel Opportunities for Coral Reef Restoration

    Directory of Open Access Journals (Sweden)

    Wing Yan Chan

    2018-05-01

    Full Text Available Climate change and other anthropogenic disturbances have created an era characterized by the inability of most ecosystems to maintain their original, pristine states, the Anthropocene. Investigating new and innovative strategies that may facilitate ecosystem restoration is thus becoming increasingly important, particularly for coral reefs around the globe which are deteriorating at an alarming rate. The Great Barrier Reef (GBR lost half its coral cover between 1985 and 2012, and experienced back-to-back heat-induced mass bleaching events and high coral mortality in 2016 and 2017. Here we investigate the efficacy of interspecific hybridization as a tool to develop coral stock with enhanced climate resilience. We crossed two Acropora species pairs from the GBR and examined several phenotypic traits over 28 weeks of exposure to ambient and elevated temperature and pCO2. While elevated temperature and pCO2 conditions negatively affected size and survival of both purebreds and hybrids, higher survival and larger recruit size were observed in some of the hybrid offspring groups under both ambient and elevated conditions. Further, interspecific hybrids had high fertilization rates, normal embryonic development, and similar Symbiodinium uptake and photochemical efficiency as purebred offspring. While the fitness of these hybrids in the field and their reproductive and backcrossing potential remain to be investigated, current findings provide proof-of-concept that interspecific hybridization may produce genotypes with enhanced climate resilience, and has the potential to increase the success of coral reef restoration initiatives.

  13. Heterosis and correlation in interspecific and intraspecific hybrids of cotton.

    Science.gov (United States)

    Munir, S; Hussain, S B; Manzoor, H; Quereshi, M K; Zubair, M; Nouman, W; Shehzad, A N; Rasul, S; Manzoor, S A

    2016-06-24

    Interspecific and intraspecific hybrids show varying degrees of heterosis for yield and yield components. Yield-component traits have complex genetic relationships with each other. To determine the relationship of yield-component traits and fiber traits with seed cotton yield, six lines (Bt. CIM-599, CIM-573, MNH-786, CIM-554, BH-167, and GIZA-7) and three test lines (MNH-886, V4, and CIM-557) were crossed in a line x tester mating design. Heterosis was observed for seed cotton yield, fiber traits, and for other yield-component traits. Heterosis in interspecific hybrids for seed cotton yield was more prominent than in intraspecific hybrids. The interspecific hybrid Giza-7 x MNH-886 had the highest heterosis (114.77), while among intraspecific hybrids, CIM-554 x CIM-557 had the highest heterosis (61.29) for seed cotton yield. A major trait contributing to seed cotton yield was bolls/plant followed by boll weight. Correlation studies revealed that bolls/plant, boll weight, lint weight/boll, lint index, seed index, lint/seed, staple length, and staple strength were significantly and positively associated with seed cotton yield. Selection based on boll weight, boll number, lint weight/boll, and lint index will be helpful for improving cotton seed yield.

  14. Interspecific sex in grass smuts and the genetic diversity of their pheromone-receptor system.

    Directory of Open Access Journals (Sweden)

    Ronny Kellner

    2011-12-01

    Full Text Available The grass smuts comprise a speciose group of biotrophic plant parasites, so-called Ustilaginaceae, which are specifically adapted to hosts of sweet grasses, the Poaceae family. Mating takes a central role in their life cycle, as it initiates parasitism by a morphological and physiological transition from saprobic yeast cells to pathogenic filaments. As in other fungi, sexual identity is determined by specific genomic regions encoding allelic variants of a pheromone-receptor (PR system and heterodimerising transcription factors. Both operate in a biphasic mating process that starts with PR-triggered recognition, directed growth of conjugation hyphae, and plasmogamy of compatible mating partners. So far, studies on the PR system of grass smuts revealed diverse interspecific compatibility and mating type determination. However, many questions concerning the specificity and evolutionary origin of the PR system remain unanswered. Combining comparative genetics and biological approaches, we report on the specificity of the PR system and its genetic diversity in 10 species spanning about 100 million years of mating type evolution. We show that three highly syntenic PR alleles are prevalent among members of the Ustilaginaceae, favouring a triallelic determination as the plesiomorphic characteristic of this group. Furthermore, the analysis of PR loci revealed increased genetic diversity of single PR locus genes compared to genes of flanking regions. Performing interspecies sex tests, we detected a high potential for hybridisation that is directly linked to pheromone signalling as known from intraspecies sex. Although the PR system seems to be optimised for intraspecific compatibility, the observed functional plasticity of the PR system increases the potential for interspecific sex, which might allow the hybrid-based genesis of newly combined host specificities.

  15. Interspecific aggression, not interspecific mating, drives character displacement in the wing coloration of male rubyspot damselflies (Hetaerina)

    Science.gov (United States)

    Drury, J. P.; Grether, G. F.

    2014-01-01

    Traits that mediate intraspecific social interactions may overlap in closely related sympatric species, resulting in costly between-species interactions. Such interactions have principally interested investigators studying the evolution of reproductive isolation via reproductive character displacement (RCD) or reinforcement, yet in addition to reproductive interference, interspecific trait overlap can lead to costly between-species aggression. Previous research on rubyspot damselflies (Hetaerina spp.) demonstrated that sympatric shifts in male wing colour patterns and competitor recognition reduce interspecific aggression, supporting the hypothesis that agonistic character displacement (ACD) drove trait shifts. However, a recent theoretical model shows that RCD overshadows ACD if the same male trait is used for both female mate recognition and male competitor recognition. To determine whether female mate recognition is based on male wing coloration in Hetaerina, we conducted a phenotype manipulation experiment. Compared to control males, male H. americana with wings manipulated to resemble a sympatric congener (H. titia) suffered no reduction in mating success. Thus, female mate recognition is not based on species differences in male wing coloration. Experimental males did, however, experience higher interspecific fighting rates and reduced survival compared to controls. These results greatly strengthen the case for ACD and highlight the mechanistic distinction between ACD and RCD. PMID:25339724

  16. Host responses to interspecific brood parasitism: a by-product of adaptations to conspecific parasitism?

    Science.gov (United States)

    Samas, Peter; Hauber, Mark E; Cassey, Phillip; Grim, Tomas

    2014-01-01

    Why have birds evolved the ability to reject eggs? Typically, foreign egg discrimination is interpreted as evidence that interspecific brood parasitism (IP) has selected for the host's ability to recognize and eliminate foreign eggs. Fewer studies explore the alternative hypothesis that rejection of interspecific eggs is a by-product of host defenses, evolved against conspecific parasitism (CP). We performed a large scale study with replication across taxa (two congeneric Turdus thrushes), space (populations), time (breeding seasons), and treatments (three types of experimental eggs), using a consistent design of egg rejection experiments (n = 1057 nests; including controls), in areas with potential IP either present (Europe; native populations) or absent (New Zealand; introduced populations). These comparisons benefited from the known length of allopatry (one and a half centuries), with no gene flow between native and introduced populations, which is rarely available in host-parasite systems. Hosts rejected CP at unusually high rates for passerines (up to 60%). CP rejection rates were higher in populations with higher conspecific breeding densities and no risks of IP, supporting the CP hypothesis. IP rejection rates did not covary geographically with IP risk, contradicting the IP hypothesis. High egg rejection rates were maintained in the relatively long-term isolation from IP despite non-trivial rejection costs and errors. These egg rejection patterns, combined with recent findings that these thrushes are currently unsuitable hosts of the obligate parasitic common cuckoo (Cuculus canorus), are in agreement with the hypothesis that the rejection of IP is a by-product of fine-tuned egg discrimination evolved due to CP. Our study highlights the importance of considering both IP and CP simultaneously as potential drivers in the evolution of egg discrimination, and illustrates how populations introduced to novel ecological contexts can provide critical insights

  17. Development of a set of SSR markers for genetic polymorphism detection and interspecific hybrid jute breeding

    Directory of Open Access Journals (Sweden)

    Dipnarayan Saha

    2017-10-01

    Full Text Available Corchorus capsularis (white jute and C. olitorius (dark jute are the two principal cultivated species of jute that produce natural bast fiber of commercial importance. We have identified 4509 simple sequence repeat (SSR loci from 34,163 unigene sequences of C. capsularis to develop a non-redundant set of 2079 flanking primer pairs. Among the SSRs, trinucleotide repeats were most frequent (60% followed by dinucleotide repeats (37.6%. Annotation of the SSR-containing unigenes revealed their putative functions in various biological and molecular processes, including responses to biotic and abiotic signals. Eighteen expressed gene-derived SSR (eSSR markers were successfully mapped to the existing single-nucleotide polymorphism (SNP linkage map of jute, providing additional anchor points. Amplification of 72% of the 74 randomly selected primer pairs was successful in a panel of 24 jute accessions, comprising five and twelve accessions of C. capsularis and C. olitorius, respectively, and seven wild jute species. Forty-three primer pairs produced an average of 2.7 alleles and 58.1% polymorphism in a panel of 24 jute accessions. The mean PIC value was 0.34 but some markers showed PIC values higher than 0.5, suggesting that these markers can efficiently measure genetic diversity and serve for mapping of quantitative trait loci (QTLs in jute. A primer polymorphism survey with parents of a wide-hybridized population between a cultivated jute and its wild relative revealed their efficacy for interspecific hybrid identification. For ready accessibility of jute eSSR primers, we compiled all information in a user-friendly web database, JuteMarkerdb (http://jutemarkerdb.icar.gov.in/ for the first time in jute. This eSSR resource in jute is expected to be of use in characterization of germplasm, interspecific hybrid and variety identification, and marker-assisted breeding of superior-quality jute.

  18. The mitochondrial genome impacts respiration but not fermentation in interspecific Saccharomyces hybrids.

    Directory of Open Access Journals (Sweden)

    Warren Albertin

    Full Text Available In eukaryotes, mitochondrial DNA (mtDNA has high rate of nucleotide substitution leading to different mitochondrial haplotypes called mitotypes. However, the impact of mitochondrial genetic variant on phenotypic variation has been poorly considered in microorganisms because mtDNA encodes very few genes compared to nuclear DNA, and also because mitochondrial inheritance is not uniparental. Here we propose original material to unravel mitotype impact on phenotype: we produced interspecific hybrids between S. cerevisiae and S. uvarum species, using fully homozygous diploid parental strains. For two different interspecific crosses involving different parental strains, we recovered 10 independent hybrids per cross, and allowed mtDNA fixation after around 80 generations. We developed PCR-based markers for the rapid discrimination of S. cerevisiae and S. uvarum mitochondrial DNA. For both crosses, we were able to isolate fully isogenic hybrids at the nuclear level, yet possessing either S. cerevisiae mtDNA (Sc-mtDNA or S. uvarum mtDNA (Su-mtDNA. Under fermentative conditions, the mitotype has no phenotypic impact on fermentation kinetics and products, which was expected since mtDNA are not necessary for fermentative metabolism. Alternatively, under respiratory conditions, hybrids with Sc-mtDNA have higher population growth performance, associated with higher respiratory rate. Indeed, far from the hypothesis that mtDNA variation is neutral, our work shows that mitochondrial polymorphism can have a strong impact on fitness components and hence on the evolutionary fate of the yeast populations. We hypothesize that under fermentative conditions, hybrids may fix stochastically one or the other mt-DNA, while respiratory environments may increase the probability to fix Sc-mtDNA.

  19. Interspecific variation of ontogeny and skull shape among porpoises (Phocoenidae).

    Science.gov (United States)

    Galatius, Anders; Berta, Annalisa; Frandsen, Marie Schou; Goodall, R Natalie P

    2011-02-01

    All extant members of Phocoenidae (porpoises) have been characterized as pedomorphic based on skeletal characters. To investigate the ontogenetic background for pedomorphosis and assess interspecific differences in ontogeny among phocoenids, samples of the six extant species were compared in terms of development of both epiphyseal and cranial suture fusion. Across all species, full maturity of the vertebral column was rare. Vertebral epiphyseal development did not progress so far in most Phocoena phocoena as in Phocoenoides dalli and Phocoena dioptrica. P. phocoena, Phocoena spinipinnis, Ph. dalli, and P. dioptrica, for which large series were available, were further compared in terms of ontogeny of cranial shape by three-dimensional geometric morphometrics. Ph. dalli and P. dioptrica generally showed further development of cranial sutures than the other species. Postnatal skull shape development was similar for all species studied; the majority of interspecific shape differences are present at parturition. Smaller species had a higher rate of shape development relative to growth in size than Ph. dalli and P. dioptrica, but they still showed less allometric development due to less postnatal growth. Interspecific shape differences indicate phylogenetic relationships similar to that proposed based on morphology or convergent evolution of the two pelagic species, Ph. dalli and P. dioptrica, under the scenarios suggested by recent molecular studies. A shape trend coinciding with habitat preference was detected; in species with pelagic preference the position and orientation of the foramen magnum aligned the skull with the vertebral column; the rostrum showed less ventral inclination, and the facial region was larger and more concave in lateral aspect. Copyright © 2010 Wiley-Liss, Inc.

  20. Coexistence facilitates interspecific biofilm formation in complex microbial communities

    DEFF Research Database (Denmark)

    Madsen, Jonas Stenløkke; Røder, Henriette Lyng; Russel, Jakob

    2016-01-01

    Social interactions in which bacteria respond to one another by modifying their phenotype are central determinants of microbial communities. It is known that interspecific interactions influence the biofilm phenotype of bacteria; a phenotype that is central to the fitness of bacteria. However......, the underlying role of fundamental ecological factors, specifically coexistence and phylogenetic history, in biofilm formation remains unclear. This study examines how social interactions affect biofilm formation in multi-species co-cultures from five diverse environments. We found prevalence of increased...

  1. The genomic distribution of intraspecific and interspecific sequence divergence of human segmental duplications relative to human/chimpanzee chromosomal rearrangements

    Directory of Open Access Journals (Sweden)

    Eichler Evan E

    2008-08-01

    Full Text Available Abstract Background It has been suggested that chromosomal rearrangements harbor the molecular footprint of the biological phenomena which they induce, in the form, for instance, of changes in the sequence divergence rates of linked genes. So far, all the studies of these potential associations have focused on the relationship between structural changes and the rates of evolution of single-copy DNA and have tried to exclude segmental duplications (SDs. This is paradoxical, since SDs are one of the primary forces driving the evolution of structure and function in our genomes and have been linked not only with novel genes acquiring new functions, but also with overall higher DNA sequence divergence and major chromosomal rearrangements. Results Here we take the opposite view and focus on SDs. We analyze several of the features of SDs, including the rates of intraspecific divergence between paralogous copies of human SDs and of interspecific divergence between human SDs and chimpanzee DNA. We study how divergence measures relate to chromosomal rearrangements, while considering other factors that affect evolutionary rates in single copy DNA. Conclusion We find that interspecific SD divergence behaves similarly to divergence of single-copy DNA. In contrast, old and recent paralogous copies of SDs do present different patterns of intraspecific divergence. Also, we show that some relatively recent SDs accumulate in regions that carry inversions in sister lineages.

  2. Interspecific RNA Interference of SHOOT MERISTEMLESS-Like Disrupts Cuscuta pentagona Plant Parasitism[C][W][OA

    Science.gov (United States)

    Alakonya, Amos; Kumar, Ravi; Koenig, Daniel; Kimura, Seisuke; Townsley, Brad; Runo, Steven; Garces, Helena M.; Kang, Julie; Yanez, Andrea; David-Schwartz, Rakefet; Machuka, Jesse; Sinha, Neelima

    2012-01-01

    Infection of crop species by parasitic plants is a major agricultural hindrance resulting in substantial crop losses worldwide. Parasitic plants establish vascular connections with the host plant via structures termed haustoria, which allow acquisition of water and nutrients, often to the detriment of the infected host. Despite the agricultural impact of parasitic plants, the molecular and developmental processes by which host/parasitic interactions are established are not well understood. Here, we examine the development and subsequent establishment of haustorial connections by the parasite dodder (Cuscuta pentagona) on tobacco (Nicotiana tabacum) plants. Formation of haustoria in dodder is accompanied by upregulation of dodder KNOTTED-like homeobox transcription factors, including SHOOT MERISTEMLESS-like (STM). We demonstrate interspecific silencing of a STM gene in dodder driven by a vascular-specific promoter in transgenic host plants and find that this silencing disrupts dodder growth. The reduced efficacy of dodder infection on STM RNA interference transgenics results from defects in haustorial connection, development, and establishment. Identification of transgene-specific small RNAs in the parasite, coupled with reduced parasite fecundity and increased growth of the infected host, demonstrates the efficacy of interspecific small RNA–mediated silencing of parasite genes. This technology has the potential to be an effective method of biological control of plant parasite infection. PMID:22822208

  3. Interspecific hybridization between Crassostrea angulata and C. ariakensis

    Science.gov (United States)

    Yao, Tuo; Zhang, Yuehuan; Yan, Xiwu; Wang, Zhaoping; Li, Dongchun; Su, Jiaqi; Yu, Ruihai

    2015-08-01

    Interspecific hybridization can generate heterosis, which is proven to be a useful tool in selective breeding programs for oyster culture. Crassostrea angulata and C. ariakensis are two important economic shellfish species in China. We conducted 2 × 2 reciprocal crosses to determine whether these two species can cross-fertilize and their hybrids can hatch, survive and perform heterosis. Fertilization was found symmetrical without delay. The rate of fertilization success of C. angulata ♀ × C. ariakensis ♂ was lower than that of C. ariakensis ♀ × C. angulata ♂, and the success rate of both hybridizations was lower than that of two intraspecific crosses each. During the planktonic period, survival rate of the progeny was lower in the hybrid crosses than in the intraspecific crosses. On day 360, mean shell height of the progeny of C. angulata ♀ × C. angulata ♂ was highest, which was followed by that of C. angulata ♀ × C. ariakensis ♂, C. ariakensis ♀ × C. ariakensis ♂ and C. ariakensis ♀ × C. angulata ♂ in a descending order. Morphology of adults produced by the hybrid crosses was similar to that of C. angulata. Both hybrids underwent normal gonad development and produced mature gametes in the mating season. This study provided new insights into the quantitative traits in interspecific crosses of Crassostrea species, thus being of guidance value for selective breeding of oyster.

  4. The pharmacokinetics of xylazine hydrochloride: an interspecific study.

    Science.gov (United States)

    Garcia-Villar, R; Toutain, P L; Alvinerie, M; Ruckebusch, Y

    1981-06-01

    The pharmacokinetic disposition of xylazine hydrochloride is described after both intravenous and intramuscular injection of a single dose, in four domestic species: horse, cattle, sheep and dog, by an original high performance liquid chromatographic technique. Remarkably small interspecific differences are reported. After intravenous administration, systemic half-life (t1/2 beta) ranged between 22 min (sheep) and 50 min (horse) while the distribution phase is transient with half-life (t1/2 alpha) ranging from 1.2 min (cattle) to 5.9 min (horse). The peak level of drug concentration in the plasma is reached after 12-14 min in all the species studied following intramuscular administration. Xylazine bioavailability, as measured by the ratios of the areas under the intravenous and intramuscular plasma concentration versus time curves, ranged from 52% to 90% in dog, 17% to 73% in sheep and 40% to 48% in horse. The low dosage in cattle did not permit calculation. Kinetic data are correlated with clinical data and the origins of interspecific differences are discussed.

  5. Snake co-occurrence patterns are best explained by habitat and hypothesized effects of interspecific interactions

    Science.gov (United States)

    David A. Steen; Christopher J. W. McClure; Jean C. Brock; D. Craig Rudolph; Josh B. Pierce; James R. Lee; W. Jeffrey Humphries; Beau B. Gregory; William B. Sutton; Lora L. Smith; Danna L. Baxley; Dirk J. Stevenson; Craig Guyer

    2014-01-01

    1. Snakes often occur in species-rich assemblages, and sympatry is thought to be facilitated primarily by low diet overlap, not interspecific interactions. 2. We selected, a priori, three species pairs consisting of species that are morphologically and taxonomically similar and may therefore be likely to engage in interspecific, consumptive competition. We then...

  6. Using DNA to describe and quantify interspecific killing of fishers in California

    Science.gov (United States)

    Greta M. Wengert; Mourad W. Gabriel; Sean M. Matthews; J. Mark Higley; Rick A. Sweitzer; Craig. M. Thompson; Kathryn L. Purcell; Reginald H. Barrett; Leslie W. Woods; Rebecca E. Green; Stefan M. Keller; Patricia M. Gaffney; Megan Jones; Benjamin N. Sacks

    2014-01-01

    Interspecific killing is common among carnivores and can have population-level effects on imperiled species. The fisher (Pekania [Martes] pennant) is a rare forest carnivore in western North America and a candidate for listing under the United States Endangered Species Act. Interspecific killing and...

  7. Genetic Confirmation of Mungbean (Vigna radiata) and Mashbean (Vigna mungo) Interspecific Recombinants using Molecular Markers.

    Science.gov (United States)

    Abbas, Ghulam; Hameed, Amjad; Rizwan, Muhammad; Ahsan, Muhammad; Asghar, Muhammad J; Iqbal, Nayyer

    2015-01-01

    Molecular confirmation of interspecific recombinants is essential to overcome the issues like self-pollination, environmental influence, and inadequacy of morphological characteristics during interspecific hybridization. The present study was conducted for genetic confirmation of mungbean (female) and mashbean (male) interspecific crosses using molecular markers. Initially, polymorphic random amplified polymorphic DNA (RAPD), universal rice primers (URP), and simple sequence repeats (SSR) markers differentiating parent genotypes were identified. Recombination in hybrids was confirmed using these polymorphic DNA markers. The NM 2006 × Mash 88 was most successful interspecific cross. Most of true recombinants confirmed by molecular markers were from this cross combination. SSR markers were efficient in detecting genetic variability and recombination with reference to specific chromosomes and particular loci. SSR (RIS) and RAPD identified variability dispersed throughout the genome. In conclusion, DNA based marker assisted selection (MAS) efficiently confirmed the interspecific recombinants. The results provided evidence that MAS can enhance the authenticity of selection in mungbean improvement program.

  8. Interspecific competition of early successional plant species in ex-arable fields as influenced by plant-soil feedback

    OpenAIRE

    Jing, Jingying; Bezemer, T. Martijn; Van der Putten, Wim H.

    2015-01-01

    Plant–soil feedback can affect plants that belong to the same (intraspecific feedback) or different species (interspecific feedback). However, little is known about how intra- and interspecific plant–soil feedbacks influence interspecific plant competition. Here, we used plants and soil from early-stage ex-arable fields to examine how intra- and interspecific plant–soil feedbacks affect the performance of 10 conditioning species and the focal species, Jacobaea vulgaris. Plants were grown alon...

  9. Interspecific competition of early successional plant species in ex-arable fields as influenced by plant–soil feedback

    NARCIS (Netherlands)

    Jing, Y.; Bezemer, T.M.; Putten, van der W.H.

    2015-01-01

    Plant–soil feedback can affect plants that belong to the same (intraspecific feedback) or different species (interspecific feedback). However, little is known about how intra- and interspecific plant–soil feedbacks influence interspecific plant competition. Here, we used plants and soil from

  10. Interspecific competition of early successional plant species in ex-arable fields as influenced by plant-soil feedback

    NARCIS (Netherlands)

    Jing, Jingying; Bezemer, T. Martijn; Van der Putten, Wim H.

    2015-01-01

    Plant–soil feedback can affect plants that belong to the same (intraspecific feedback) or different species (interspecific feedback). However, little is known about how intra- and interspecific plant–soil feedbacks influence interspecific plant competition. Here, we used plants and soil from

  11. Rin4 causes hybrid necrosis and race-specific resistance in an interspecific lettuce hybrid.

    Science.gov (United States)

    Jeuken, Marieke J W; Zhang, Ningwen W; McHale, Leah K; Pelgrom, Koen; den Boer, Erik; Lindhout, Pim; Michelmore, Richard W; Visser, Richard G F; Niks, Rients E

    2009-10-01

    Some inter- and intraspecific crosses may result in reduced viability or sterility in the offspring, often due to genetic incompatibilities resulting from interactions between two or more loci. Hybrid necrosis is a postzygotic genetic incompatibility that is phenotypically manifested as necrotic lesions on the plant. We observed hybrid necrosis in interspecific lettuce (Lactuca sativa and Lactuca saligna) hybrids that correlated with resistance to downy mildew. Segregation analysis revealed a specific allelic combination at two interacting loci to be responsible. The allelic interaction had two consequences: (1) a quantitative temperature-dependent autoimmunity reaction leading to necrotic lesions, lethality, and quantitative resistance to an otherwise virulent race of Bremia lactucae; and (2) a qualitative temperature-independent race-specific resistance to an avirulent race of B. lactucae. We demonstrated by transient expression and silencing experiments that one of the two interacting genes was Rin4. In Arabidopsis thaliana, RIN4 is known to interact with multiple R gene products, and their interactions result in hypersensitive resistance to Pseudomonas syringae. Site-directed mutation studies on the necrosis-eliciting allele of Rin4 in lettuce showed that three residues were critical for hybrid necrosis.

  12. Caffeine inheritance in interspecific hybrids of Coffea arabica x Coffea canephora (Gentianales, Rubiaceae

    Directory of Open Access Journals (Sweden)

    Regina H.G. Priolli

    2008-01-01

    Full Text Available Caffeine inheritance was investigated in F2 and BC1F1 generations between Coffea arabica var. Bourbon Vermelho (BV and Coffea canephora var. Robusta 4x (R4x. The caffeine content of seeds and leaves was determined during 2004 and 2005. Microsatellite loci-markers were used to deduce the meiotic pattern of chromosome pairing of tetraploid interspecific hybrids. Genetic analysis indicated that caffeine content in seeds was quantitatively inherited and controlled by genes with additive effects. The estimates of broad-sense heritability of caffeine content in seeds were high for both generations. In coffee leaves, the caffeine content (BSH from the same populations showed transgressive segregants with enhanced levels and high BSH. Segregation of loci-markers in BC1F1 populations showed that the ratios of the gametes genotype did not differ significantly from those expected assuming random associations and tetrasomic inheritance. The results confirm the existence of distinct mechanisms controlling the caffeine content in seeds and leaves, the gene exchange between the C. arabica BV and C. canephora R4x genomes and favorable conditions for improving caffeine content in this coffee population.

  13. Constitutive type VI secretion system expression gives Vibrio cholerae intra- and interspecific competitive advantages.

    Directory of Open Access Journals (Sweden)

    Daniel Unterweger

    Full Text Available The type VI secretion system (T6SS mediates protein translocation across the cell membrane of Gram-negative bacteria, including Vibrio cholerae - the causative agent of cholera. All V. cholerae strains examined to date harbor gene clusters encoding a T6SS. Structural similarity and sequence homology between components of the T6SS and the T4 bacteriophage cell-puncturing device suggest that the T6SS functions as a contractile molecular syringe to inject effector molecules into prokaryotic and eukaryotic target cells. Regulation of the T6SS is critical. A subset of V. cholerae strains, including the clinical O37 serogroup strain V52, express T6SS constitutively. In contrast, pandemic strains impose tight control that can be genetically disrupted: mutations in the quorum sensing gene luxO and the newly described regulator gene tsrA lead to constitutive T6SS expression in the El Tor strain C6706. In this report, we examined environmental V. cholerae isolates from the Rio Grande with regard to T6SS regulation. Rough V. cholerae lacking O-antigen carried a nonsense mutation in the gene encoding the global T6SS regulator VasH and did not display virulent behavior towards Escherichia coli and other environmental bacteria. In contrast, smooth V. cholerae strains engaged constitutively in type VI-mediated secretion and displayed virulence towards prokaryotes (E. coli and other environmental bacteria and a eukaryote (the social amoeba Dictyostelium discoideum. Furthermore, smooth V. cholerae strains were able to outcompete each other in a T6SS-dependent manner. The work presented here suggests that constitutive T6SS expression provides V. cholerae with an advantage in intraspecific and interspecific competition.

  14. Reproductive characterization of interspecific hybrids among Capsicum species

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo da Silva Monteiro

    2011-01-01

    Full Text Available The objective of this study was the reproductive characterization of Capsicum accessions as well as of interspecifichybrids, based on pollen viability. Hybrids were obtained between Capsicum species. Pollen viability was high in most accessions,indicating that meiosis is normal, resulting in viable pollen grains. The pollen viability of species C. pubescens was the lowest (27%. The interspecific hybrids had varying degrees of pollen viability, from fertile combinations (C. chinense x C. frutescens and C.annuum x C. baccatum to male sterile combinations. Pollen viability also varied within the hybrid combination according toaccessions used in the cross. Results indicate that male sterility is one of the incompatibility barriers among Capsicum species sincehybrids can be established, but may be male sterile.

  15. Interspecific bacterial interactions are reflected in multispecies biofilm spatial organization

    DEFF Research Database (Denmark)

    Liu, Wenzheng; Røder, Henriette Lyng; Madsen, Jonas Stenløkke

    2016-01-01

    not only the enabling sub-populations. However, the specific molecular mechanisms of cellular processes affecting spatial organization, and vice versa, are poorly understood and very complex to unravel. Therefore, detailed description of the spatial organization of individual bacterial cells...... environments. Species residing in these complex bacterial communities usually interact both intra- and interspecifically. Such interactions are considered to not only be fundamental in shaping overall biomass and the spatial distribution of cells residing in multispecies biofilms, but also to result......, industrial, and clinical implications. This review briefly presents the state of the art of studying interspecies interactions and spatial organization of multispecies communities, aiming to support theoretical and practical arguments for further advancement of this field....

  16. DNA Methylation Alterations at 5'-CCGG Sites in the Interspecific and Intraspecific Hybridizations Derived from Brassica rapa and B. napus.

    Directory of Open Access Journals (Sweden)

    Wanshan Xiong

    Full Text Available DNA methylation is an important regulatory mechanism for gene expression that involved in the biological processes of development and differentiation in plants. To investigate the association of DNA methylation with heterosis in Brassica, a set of intraspecific hybrids in Brassica rapa and B. napus and interspecific hybrids between B. rapa and B. napus, together with parental lines, were used to monitor alterations in cytosine methylation at 5'-CCGG sites in seedlings and buds by methylation-sensitive amplification polymorphism analysis. The methylation status of approximately a quarter of the methylation sites changed between seedlings and buds. These alterations were related closely to the genomic structure and heterozygous status among accessions. The methylation status in the majority of DNA methylation sites detected in hybrids was the same as that in at least one of the parental lines in both seedlings and buds. However, the association between patterns of cytosine methylation and heterosis varied among different traits and between tissues in hybrids of Brassica, although a few methylation loci were associated with heterosis. Our data suggest that changes in DNA methylation at 5'-CCGG sites are not associated simply with heterosis in the interspecific and intraspecific hybridizations derived from B. rapa and B. napus.

  17. Naked Mole Rat Induced Pluripotent Stem Cells and Their Contribution to Interspecific Chimera

    Directory of Open Access Journals (Sweden)

    Sang-Goo Lee

    2017-11-01

    Full Text Available Naked mole rats (NMRs are exceptionally long-lived, cancer-resistant rodents. Identifying the defining characteristics of these traits may shed light on aging and cancer mechanisms. Here, we report the generation of induced pluripotent stem cells (iPSCs from NMR fibroblasts and their contribution to mouse-NMR chimeric embryos. Efficient reprogramming could be observed under N2B27+2i conditions. The iPSCs displayed a characteristic morphology, expressed pluripotent markers, formed embryoid bodies, and showed typical differentiation patterns. Interestingly, NMR embryonic fibroblasts and the derived iPSCs had propensity for a tetraploid karyotype and were resistant to forming teratomas, but within mouse blastocysts they contributed to both interspecific placenta and fetus. Gene expression patterns of NMR iPSCs were more similar to those of human than mouse iPSCs. Overall, we uncovered unique features of NMR iPSCs and report a mouse-NMR chimeric model. The iPSCs and associated cell culture systems can be used for a variety of biological and biomedical applications.

  18. Interspecific competition alters natural selection on shade avoidance phenotypes in Impatiens capensis.

    Science.gov (United States)

    McGoey, Brechann V; Stinchcombe, John R

    2009-08-01

    Shade avoidance syndrome is a known adaptive response for Impatiens capensis growing in dense intraspecific competition. However, I. capensis also grow with dominant interspecific competitors in marshes. Here, we compare the I. capensis shade-avoidance phenotypes produced in the absence and presence of heterospecific competitors, as well as selection on those traits. Two treatments were established in a marsh; in one treatment all heterospecifics were removed, while in the other, all competitors remained. We compared morphological traits, light parameters, seed output and, using phenotypic selection analysis, examined directional and nonlinear selection operating in the different competitive treatments. Average phenotypes, light parameters and seed production all varied depending on competitive treatment. Phenotypic selection analyses revealed different directional, disruptive, stabilizing and correlational selection. The disparities seen in both phenotypes and selection between the treatments related to the important differences in elongation timing depending on the presence of heterospecifics, although environmental covariances between traits and fitness could also contribute. Phenotypes produced by I. capensis depend on their competitive environment, and differing selection on shade-avoidance traits between competitive environments could indirectly select for increased plasticity given gene flow between populations in different competitive contexts.

  19. Development and Meiosis of Three Interspecific Hybrids with Cultivated Barley (Hordeum vulgare L.)

    DEFF Research Database (Denmark)

    Von Bothmer, R.; Flink, J.; Linde-Laursen, Ib

    1986-01-01

    The development and meiosis of three interspecific hybrids between cultivated barley (Hordeum vulgare L.) and H. secalinum Schreb., H. tetraploidum Covas, and H. parodii Covas, respectively, were studied. All three hybrid combinations developed very slowly vegetatively. Meiosis of the hybrids...

  20. Phenotypic and Genotypic Analysis of Newly Obtained Interspecific Hybrids in the Campanula Genus.

    Directory of Open Access Journals (Sweden)

    Anna-Catharina Röper

    Full Text Available Interspecific hybridisation creates new phenotypes within several ornamental plant species including the Campanula genus. We have employed phenotypic and genotypic methods to analyse and evaluate interspecific hybridisation among cultivars of four Campanula species, i.e. C. cochleariifolia, C. isophylla, C. medium and C. formanekiana. Hybrids were analysed using amplified fragment length polymorphism (AFLP, flow cytometry and biometrical measurements. Results of correlation matrices demonstrated heterogeneous phenotypes for the parental species, which confirmed our basic premise for new phenotypes of interspecific hybrids. AFLP assays confirmed the hybridity and identified self-pollinated plants. Limitation of flow cytometry analysis detection was observed while detecting the hybridity status of two closely related parents, e.g. C. cochleariiafolia × C. isophylla. Phenotypic characteristics such as shoot habitus and flower colour were strongly influenced by one of the parental species in most crosses. Rooting analysis revealed that inferior rooting quality occurred more often in interspecific hybrids than in the parental species. Only interspecific hybrid lines of C. formanekiana 'White' × C. medium 'Pink' showed a high rooting level. Phenotype analyses demonstrated a separation from the interspecific hybrid lines of C. formanekiana 'White' × C. medium 'Pink' to the other clustered hybrids of C. formanekiana and C. medium. In our study we demonstrated that the use of correlation matrices is a suitable tool for identifying suitable cross material. This study presents a comprehensive overview for analysing newly obtained interspecific hybrids. The chosen methods can be used as guidance for analyses for further interspecific hybrids in Campanula, as well as in other ornamental species.

  1. Obtaining interspecific hybrids, and molecular analysis by microsatellite markers in grapevine

    OpenAIRE

    Mariane Ruzza Schuck; Luiz Antonio Biasi; Ada Michele Mariano; Bernardo Lipski; Summaira Riaz; Michael Andrew Walker

    2011-01-01

    The objective of this work was to assess the potential of interspecific hybridization of Vitis labruscana and Muscadinia rotundifolia by using artificial cross-pollinations. Microsatellite markers were used to confirm interspecific hybridizations and the identity of the parental genotypes. In crosses in which M. rotundifolia was used as the female parent, no true hybrids were obtained. In the reciprocal crosses, 114 seedlings were identified as true V. labruscana x M. rotundifolia hybrids. Se...

  2. [Interspecific interaction between Moina mongolica and Brachionus plicatilis].

    Science.gov (United States)

    Chen, Taoying; Wang, Yan; Huang, Changzhi; Hu, Shiheng; Zhang, Jun

    2004-07-01

    In a laboratory experiment, Moina mongolica and Brachionus plicatilis were polycultured at four relatively inoculating densities, i.e., 0.06/0.30, 0.10/0.30, 0.30/0.30 and 0.60/0.30 (ind x ml(-1)/ind x ml(-1)), while M. mongolica monocultured at 0.06, 0.10, 0.30 and 0.60 ind x ml(-1) and B. plicatilis at 0.30 ind x ml(-1) were used as the control. Interspecific interference did exist between M. mongolica and B. plicatilis when these two species coexisted in a microcosm. In the polycultured microcosms, depressed population density of M. mongolica resulted from the coexistence of B. plicatilis, and M. mongolica maintained at extremely low density. In opposite, M. mongolica had negligibly negative influence on the population of B. plicatilis. Further experiment showed that the mortality of M. mongolica deprived of food for 120 h was 100%, while 90% of B. plicatilis survived after 144 h of food deprivation. The relatively strong capacity of B. plicatilis in tolerating starvation may be one of the important reasons for it wins the competition against M. mongolica.

  3. Motorboat noise disrupts co-operative interspecific interactions.

    Science.gov (United States)

    Nedelec, Sophie L; Mills, Suzanne C; Radford, Andrew N; Beldade, Ricardo; Simpson, Stephen D; Nedelec, Brendan; Côté, Isabelle M

    2017-08-01

    Human-made noise is contributing increasingly to ocean soundscapes. Its physical, physiological and behavioural effects on marine organisms are potentially widespread, but our understanding remains largely limited to intraspecific impacts. Here, we examine how motorboats affect an interspecific cleaning mutualism critical for coral reef fish health, abundance and diversity. We conducted in situ observations of cleaning interactions between bluestreak cleaner wrasses (Labroides dimidiatus) and their fish clients before, during and after repeated, standardised approaches with motorboats. Cleaners inspected clients for longer and were significantly less cooperative during exposure to boat noise, and while motorboat disturbance appeared to have little effect on client behaviour, as evidenced by consistency of visit rates, clientele composition, and use of cleaning incitation signals, clients did not retaliate as expected (i.e., by chasing) in response to increased cheating by cleaners. Our results are consistent with the idea of cognitive impairments due to distraction by both parties. Alternatively, cleaners might be taking advantage of distracted clients to reduce their service quality. To more fully understand the importance of these findings for conservation and management, further studies should elucidate whether the efficacy of ectoparasite removal by cleaners is affected and explore the potential for habituation to boat noise in busy areas.

  4. Interspecific social networks promote information transmission in wild songbirds.

    Science.gov (United States)

    Farine, Damien R; Aplin, Lucy M; Sheldon, Ben C; Hoppitt, William

    2015-03-22

    Understanding the functional links between social structure and population processes is a central aim of evolutionary ecology. Multiple types of interactions can be represented by networks drawn for the same population, such as kinship, dominance or affiliative networks, but the relative importance of alternative networks in modulating population processes may not be clear. We illustrate this problem, and a solution, by developing a framework for testing the importance of different types of association in facilitating the transmission of information. We apply this framework to experimental data from wild songbirds that form mixed-species flocks, recording the arrival (patch discovery) of individuals to novel foraging sites. We tested whether intraspecific and interspecific social networks predicted the spread of information about novel food sites, and found that both contributed to transmission. The likelihood of acquiring information per unit of connection to knowledgeable individuals increased 22-fold for conspecifics, and 12-fold for heterospecifics. We also found that species varied in how much information they produced, suggesting that some species play a keystone role in winter foraging flocks. More generally, these analyses demonstrate that this method provides a powerful approach, using social networks to quantify the relative transmission rates across different social relationships.

  5. Interspecific competition between alien and native congeneric species

    Science.gov (United States)

    Garcia-Serrano, H.; Sans, F. X.; Escarré, J.

    2007-01-01

    A good way to check hypotheses explaining the invasion of ecosystems by exotic plants is to compare alien and native congeneric species. To test the hypothesis that invasive alien plants are more competitive than natives, we designed a replacement series experiment to evaluate interspecific competition between three Senecio species representing the same bushy life form: two alien species ( S. inaequidens and S. pterophorus, both from South Africa) and a native species from the south-east of the Iberian Peninsula and Maghreb ( S. malacitanus). While S. inaequidens is widespread throughout western Europe and is expanding towards the south of Spanish-French border, the geographical distribution of the recently introduced S. pterophorus is still limited to north-eastern Spain. Plants from each species were grown in pure and in mixed cultures with one of their congeners, and water availability was manipulated to evaluate the effects of water stress on competitive abilities. Our results show that the alien S. inaequidens is the most competitive species for all water conditions. The native S. malacitanus is more competitive that the alien S. pterophorus in water stress conditions, but this situation is reversed when water availability is not limiting.

  6. Gene

    Data.gov (United States)

    U.S. Department of Health & Human Services — Gene integrates information from a wide range of species. A record may include nomenclature, Reference Sequences (RefSeqs), maps, pathways, variations, phenotypes,...

  7. Interspecific nest parasitism by chukar on greater sage-grouse

    Science.gov (United States)

    Fearon, Michelle L.; Coates, Peter S.

    2014-01-01

    Nest parasitism occurs when a female bird lays eggs in the nest of another and the host incubates the eggs and may provide some form of parental care for the offspring (Lyon and Eadie 1991). Precocial birds (e.g., Galliformes and Anseriformes) are typically facultative nest parasites of both their own and other species (Lyon and Eadie 1991). This behavior increases a female’s reproductive success when she parasitizes other nests while simultaneously raising her own offspring. Both interspecific and conspecific nest parasitism have been well documented in several families of the order Galliformes, particularly the Phasianidae (Lyon and Eadie 1991, Geffen and Yom-Tov 2001, Krakauer and Kimball 2009). The Chukar (Alectoris chukar) has been widely introduced as a game bird to western North America from Eurasia and is now well established within the Great Basin from northeastern California east to Utah and north to Idaho and Oregon (Christensen 1996). Over much of this range the Chukar occurs with other phasianids, including the native Greater Sage-Grouse (Centrocercus urophasianus), within sagebrush (Artemisia spp.) steppe (Christensen 1996, Schroeder et al. 1999, Connelly et al. 2000). Chukar typically exploit a broader range of habitats than do sage-grouse, but both species use the same species of sagebrush and other shrubs for nesting cover (Christensen 1996, Schroeder et al. 1999). Chukar are known to parasitize nests of other individuals of their own species (Geffen and Yom-Tov 2001), but we are unaware of reported evidence that Chukar may parasitize nests of sage-grouse. Here we describe a case of a Chukar parasitizing a sage-grouse nest in the sagebrush steppe of western Nevada.

  8. Interspecific interactions in phytophagous insects revisited: a quantitative assessment of competition theory.

    Science.gov (United States)

    Kaplan, Ian; Denno, Robert F

    2007-10-01

    The importance of interspecific competition is a highly controversial and unresolved issue for community ecology in general, and for phytophagous insects in particular. Recent advancements, however, in our understanding of indirect (plant- and enemy-mediated) interactions challenge the historical paradigms of competition. Thus, in the context of this rapidly developing field, we re-evaluate the evidence for interspecific competition in phytophagous insects using a meta-analysis of published studies. Our analysis is specifically designed to test the assumptions underlying traditional competition theory, namely that competitive interactions are symmetrical, necessitate spatial and temporal co-occurrence, and increase in intensity as the density, phylogenetic similarity, and niche overlap of competing species increase. Despite finding frequent evidence for competition, we found very little evidence that plant-feeding insects conform to theoretical predictions for interspecific competition. Interactions were highly asymmetrical, similar in magnitude within vs. between feeding guilds (chewers vs. sap-feeders), and were unaffected by the quantity of resources removed (% defoliation). There was mixed support for the effects of phylogeny, spatial/temporal separation, and the relative strength of intra- vs. interspecific competition. Clearly, a new paradigm that accounts for indirect interactions and facilitation is required to describe how interspecific competition contributes to the organization of phytophagous insect communities, and perhaps to other plant and animal communities as well.

  9. Genetic analysis of female mating recognition between Drosophila ananassae and Drosophila pallidosa: application of interspecific mosaic genome lines.

    Science.gov (United States)

    Sawamura, Kyoichi; Zhi, Hua; Setoguchi, Koji; Yamada, Hirokazu; Miyo, Takahiro; Matsuda, Muneo; Oguma, Yuzuru

    2008-06-01

    Drosophila ananassae and Drosophila pallidosa are closely related species that can produce viable and fertile hybrids of both sexes, although strong sexual isolation exists between the two species. Females are thought to discriminate conspecific from heterospecific males based on their courtship songs. The genetic basis of female discrimination behavior was analyzed using isogenic females from interspecific mosaic genome lines that carry homozygous recombinant chromosomes. Multiple regression analysis indicated a highly significant effect of the left arm of chromosome 2 (2L) on the willingness of females to mate with D. ananassae males. Not only 2L but also the left arm of chromosome X (XL) and the right arm of chromosome 3 (3R) had significant effects on the females' willingness to mate with D. pallidosa males. All regions with strong effects on mate choice have chromosome arrangements characterized by species-specific inversions. Heterospecific combinations of 2L and 3R have previously been suggested to cause postzygotic reproductive isolation. Thus, genes involved in premating as well as postmating isolation are located in or near chromosomal inversions. This conclusion is consistent with the recently proposed hypothesis that "speciation genes" accumulate at a higher rate in non-recombining genome regions when species divergence occurs in the presence of gene flow.

  10. Interspecific competition influences the organization of a diverse sessile insect community

    Science.gov (United States)

    Cornelissen, Tatiana; de Carvalho Guimarães, Carla Daniele; Rodrigues Viana, João Paulo; Silva, Bárbara

    2013-10-01

    Interspecific competition has played a major role in determining the effects of species interactions in terrestrial communities and the perception of its role on shaping population dynamics and community structure has changed throughout the years. In this study, we evaluated the existence of interspecific competition in the herbivore community of the dioecious plant Baccharis pseudomyriocephala (Asteraceae), which holds a diverse community of gall-forming insects. Sixty plants were studied and gall richness and abundance among plants were evaluated. To address whether a plant already occupied by a gall species is preferred or avoided by another gall species, null models were used for all 60 plants combined and for male and female plants separately. Our results have shown that the 11 species of gall-formers found on B. pseudomyriocephala co-occur less than expected by chance alone, indicating that interspecific competition might be an important force structuring the insect community in this tropical host plant, regardless of plant gender.

  11. [Effect of habitat and interspecific competition on Apis cerana cerana colony distribution].

    Science.gov (United States)

    Yu, Linsheng; Han, Shengming

    2003-04-01

    Habitat change and interspecific competition were the main factors affecting, Apis cerana cerana colony distribution among Wannan and Wanxi Dabie mountainous areas, Jianghuai area and Huaibei plain. Wannan and Wanxi Dabie mountainous areas were the ideal places for Apis cerana cerana' habitation and propogation, in which, there were integrated natural vegetation, fine ecological condition, abundant nectariferous plants, and Apis cerana cerana had large colony size, wide distribution, high density, no disturbances of natural mating, and was dominant interspecific competition. In Jianghuai area and Huaibei plain, there were small covering of natural vegetation, different degree of degradation of ecological balance, few kinds of nectariferous plants with almost the same blooming periods, natural mating perturbed by Apis mellifera ligustica for Apis cerana cerana, and which was inferior in interspecific competition, colony size sharply decreased, distribution area reduced, and density cut down to a great extent. In Huaibei plain, the negative factors were more conspicuous.

  12. Breeding of lilies and tulips—Interspecific hybridization and genetic background—

    Science.gov (United States)

    Marasek-Ciolakowska, Agnieszka; Nishikawa, Tomotaro; Shea, Daniel J.; Okazaki, Keiichi

    2018-01-01

    Lilies and tulips (Liliaceae family) are economically very important ornamental bulbous plants. Here, we summarize major breeding goals, the role of an integrated method of cut-style pollination and fertilization followed by embryo rescue and mitotic and meiotic polyploidization involved in new assortment development. Both crops have been subjected to extensive interspecific hybridization followed by selection. Additionally, spontaneous polyploidization has played a role in their evolution. In lilies, there is a tendency to replace diploids with polyploid cultivars, whereas in tulip a majority of the cultivars that exist today are still diploid except for triploid Darwin hybrid tulips. The introduction of molecular cytogenetic techniques such as genomic in situ hybridization (GISH) permitted the detailed studies of genome composition in lily and tulip interspecific hybrids and to follow the chromosome inheritance in interspecific crosses. In addition, this review presents the latest information on phylogenetic relationship in lily and tulip and recent developments in molecular mapping using different DNA molecular techniques. PMID:29681746

  13. Influence of Temperature on Intra- and Interspecific Resource Utilization within a Community of Lepidopteran Maize Stemborers.

    Science.gov (United States)

    Ntiri, Eric Siaw; Calatayud, Paul-Andre; Van Den Berg, Johnnie; Schulthess, Fritz; Le Ru, Bruno Pierre

    2016-01-01

    Competition or facilitation characterises intra- and interspecific interactions within communities of species that utilize the same resources. Temperature is an important factor influencing those interactions and eventual outcomes. The noctuid stemborers, Busseola fusca and Sesamia calamistis and the crambid Chilo partellus attack maize in sub-Saharan Africa. They often occur as a community of interacting species in the same field and plant at all elevations. The influence of temperature on the intra- and interspecific interactions among larvae of these species, was studied using potted maize plants exposed to varying temperatures in a greenhouse and artificial stems kept at different constant temperatures (15°C, 20°C, 25°C and 30°C) in an incubator. The experiments involved single- and multi-species infestation treatments. Survival and relative growth rates of each species were assessed. Both intra- and interspecific competitions were observed among all three species. Interspecific competition was stronger between the noctuids and the crambid than between the two noctuids. Temperature affected both survival and relative growth rates of the three species. Particularly at high temperatures, C. partellus was superior in interspecific interactions shown by higher larval survival and relative growth rates. In contrast, low temperatures favoured survival of B. fusca and S. calamistis but affected the relative growth rates of all three species. Survival and relative growth rates of B. fusca and S. calamistis in interspecific interactions did not differ significantly across temperatures. Temperature increase caused by future climate change is likely to confer an advantage on C. partellus over the noctuids in the utilization of resources (crops).

  14. Influence of Temperature on Intra- and Interspecific Resource Utilization within a Community of Lepidopteran Maize Stemborers.

    Directory of Open Access Journals (Sweden)

    Eric Siaw Ntiri

    Full Text Available Competition or facilitation characterises intra- and interspecific interactions within communities of species that utilize the same resources. Temperature is an important factor influencing those interactions and eventual outcomes. The noctuid stemborers, Busseola fusca and Sesamia calamistis and the crambid Chilo partellus attack maize in sub-Saharan Africa. They often occur as a community of interacting species in the same field and plant at all elevations. The influence of temperature on the intra- and interspecific interactions among larvae of these species, was studied using potted maize plants exposed to varying temperatures in a greenhouse and artificial stems kept at different constant temperatures (15°C, 20°C, 25°C and 30°C in an incubator. The experiments involved single- and multi-species infestation treatments. Survival and relative growth rates of each species were assessed. Both intra- and interspecific competitions were observed among all three species. Interspecific competition was stronger between the noctuids and the crambid than between the two noctuids. Temperature affected both survival and relative growth rates of the three species. Particularly at high temperatures, C. partellus was superior in interspecific interactions shown by higher larval survival and relative growth rates. In contrast, low temperatures favoured survival of B. fusca and S. calamistis but affected the relative growth rates of all three species. Survival and relative growth rates of B. fusca and S. calamistis in interspecific interactions did not differ significantly across temperatures. Temperature increase caused by future climate change is likely to confer an advantage on C. partellus over the noctuids in the utilization of resources (crops.

  15. Susceptibility of parent and interspecific Fl hybrid pine trees to tip moth damage in a coastal North Carolina planting

    Science.gov (United States)

    Maxine T. Highsmith; John Frampton; David 0' Malley; James Richmond; Martesa Webb

    2001-01-01

    Tip moth damage arnong families of parent pine species and their interspecific F1 hybrids was quantitatively assessed in a coastal planting in North Carolina. Three slash pine (Pinus elliotti var. elliotti Engelm.), two loblolly pine (Pinus taeda L.), and four interspecific F1 hybrid pine families were used. The...

  16. Pattern of mating preference of interspecific hybrid females and ...

    Indian Academy of Sciences (India)

    however, do not share identical relationships and there are some which are more closely ... of the parental species, if they additively inherited (Tomaru et al. 2004), while, when the ..... Drosophila sechellia and its siblings. Genes Genet. Syst.

  17. Interspecific and intraspecific hybrid Epichloë species symbiotic with the North American native grass Poa alsodes.

    Science.gov (United States)

    Shymanovich, Tatsiana; Charlton, Nikki D; Musso, Ashleigh M; Scheerer, Jonathan; Cech, Nadja B; Faeth, Stanley H; Young, Carolyn A

    2017-01-01

    The endophyte presence and diversity in natural populations of Poa alsodes were evaluated along a latitudinal transect from the southern distribution range in North Carolina to New York. Two distinct Epichloë hybrid taxa were identified from 23 populations. Each taxon could easily be distinguished by polymerase chain reaction (PCR) genotyping with primers designed to mating type genes and alkaloid biosynthesis genes that encode key pathway steps for ergot alkaloids, indole-diterpenes, lolines, and peramine. The most commonly found Epichloë taxon, Poa alsodes Taxonomic Group-1 (PalTG-1), was detected in 22 populations at high infection frequencies (72-100%), with the exception of one population at high elevation (26% infection). The second taxon, PalTG-2, was observed only in five populations in Pennsylvania constituting 12% of infected samples. Phylogenetic analyses placed PalTG-1 as an interspecific hybrid of E. amarillans and E. typhina subsp. poae ancestors, and it is considered a new hybrid species, which the authors name Epichloë alsodes. PalTG-2 is an intraspecific hybrid of two E. typhina subsp. poae ancestors, similar to E. schardlii from the host Cinna arundinacea, which the authors propose as a new variety, Epichloë schardlii var. pennsylvanica. Epichloë alsodes isolates were all mating type MTA MTB and tested positive for dmaW, easC, perA, and some LOL genes, but only the alkaloid N-acetylnorloline was detected in E. alsodes-infected plant material. Epichloë schardlii var. pennsylvanica isolates were all mating type MTB MTB and tested positive for perA, but peramine was not produced. Both E. alsodes and E. schardlii var. pennsylvanica appeared to have complete perA genes, but point mutations were identified in E. alsodes that would render the encoded perA gene nonfunctional.

  18. Combining Ascochyta blight and Botrytis grey mould resistance in chickpea through interspecific hybridization

    Directory of Open Access Journals (Sweden)

    Livinder KAUR

    2013-05-01

    Full Text Available Ascochyta blight (AB caused by Ascochyta rabiei (Pass. Labr. and Botrytis grey mould (BGM caused by Botrytis cinerea (Pers. ex Fr. are important diseases of the aerial plant parts of chickpea in most chickpea growing areas of the world. Although conventional approaches have contributed to reducing disease, the use of new technologies is expected to further reduce losses through these biotic stresses. Reliable screening techniques were developed: ‘field screening technique’ for adult plant screening, ‘cloth chamber technique’ and ‘growth chamber technique’ for the study of races of the pathogen and for segregating generations. Furthermore, the ‘cut twig technique’ for interspecific population for AB and BGM resistance was developed. For introgression of high levels of AB and BGM resistance in cultivated chickpea from wild relatives, accessions of seven annual wild Cicer spp. were evaluated and identified: C. judaicum accessions 185, ILWC 95 and ILWC 61, C. pinnatifidum accessions 188, 199 and ILWC 212 as potential donors. C. pinnatifidum accession188 was crossed with ICCV 96030 and 62 F9 lines resistant to AB and BGM were derived. Of the derived lines, several are being evaluated for agronomic traits and yield parameters while four lines, GL 29029, GL29206, GL29212, GL29081 possessing high degree of resistance were crossed with susceptible high yielding cultivars BG 256 to improve resistance and to undertake molecular studies. Genotyping of F2 populations with SSR markers from the chickpea genome was done to identify markers potentially linked with AB and BGM resistance genes. In preliminary studies, of 120 SSR markers used, six (Ta 2, Ta 110, Ta 139, CaSTMS 7, CaSTMS 24 and Tr 29 were identified with polymorphic bands between resistant derivative lines and the susceptible parent. The study shows that wild species of Cicer are the valuable gene pools of resistance to AB and BGM. The resistant derivative lines generated here can

  19. Rin4 Causes Hybrid Necrosis and Race-Specific Resistance in an Interspecific Lettuce Hybrid[W

    Science.gov (United States)

    Jeuken, Marieke J.W.; Zhang, Ningwen W.; McHale, Leah K.; Pelgrom, Koen; den Boer, Erik; Lindhout, Pim; Michelmore, Richard W.; Visser, Richard G.F.; Niks, Rients E.

    2009-01-01

    Some inter- and intraspecific crosses may result in reduced viability or sterility in the offspring, often due to genetic incompatibilities resulting from interactions between two or more loci. Hybrid necrosis is a postzygotic genetic incompatibility that is phenotypically manifested as necrotic lesions on the plant. We observed hybrid necrosis in interspecific lettuce (Lactuca sativa and Lactuca saligna) hybrids that correlated with resistance to downy mildew. Segregation analysis revealed a specific allelic combination at two interacting loci to be responsible. The allelic interaction had two consequences: (1) a quantitative temperature-dependent autoimmunity reaction leading to necrotic lesions, lethality, and quantitative resistance to an otherwise virulent race of Bremia lactucae; and (2) a qualitative temperature-independent race-specific resistance to an avirulent race of B. lactucae. We demonstrated by transient expression and silencing experiments that one of the two interacting genes was Rin4. In Arabidopsis thaliana, RIN4 is known to interact with multiple R gene products, and their interactions result in hypersensitive resistance to Pseudomonas syringae. Site-directed mutation studies on the necrosis-eliciting allele of Rin4 in lettuce showed that three residues were critical for hybrid necrosis. PMID:19855048

  20. Interspecific competition and protistan grazing affect the coexistence of freshwater betaproteobacterial strains.

    Czech Academy of Sciences Publication Activity Database

    Salcher, Michaela M.; Ewert, C.; Šimek, Karel; Kasalický, Vojtěch; Posch, T.

    2016-01-01

    Roč. 92, č. 2 (2016), fiv156 ISSN 0168-6496 R&D Projects: GA ČR(CZ) GA13-00243S Institutional support: RVO:60077344 Keywords : betaproteobacteria * chemostat * co-cultivation * flagellate-selective bacterivory * interspecific competition * synergistic cooperation Subject RIV: EE - Microbiology, Virology Impact factor: 3.720, year: 2016

  1. Courtship displays of introgressed, interspecific hybrid Nasonia males : Further investigations into the 'grandfather effect'

    NARCIS (Netherlands)

    Beukeboom, L.W.; Assem, J. van den

    Previously, we investigated courtship behaviour of bidirectional, interspecific hybrid males of two species of Nasonia (Beukeboom & van den Assem, 2001). Characteristics of the displays were intermediate between those of the parental species, but at the same time were biased towards the paternal

  2. Abnormal pollen mitoses (PM I and PM II) in an interspecific hybrid ...

    Indian Academy of Sciences (India)

    Unknown

    sporocytes and pollen grains were prepared by squashing and stained with 0.5% propionic carmine. All meiotic phases and stages of pollen development were evaluated. More than 6000 microspores and pollen grains were care- fully analysed. Keywords. Brachiaria decumbens; Brachiaria ruziziensis; interspecific hybrid; ...

  3. Development of inter-specific chromosomes segment substitution libraries (CSSL) in rice

    Science.gov (United States)

    Six libraries of inter-specific Chromosome Segment Substitution Lines (CSSLs) of rice are being developed as pre-breeding materials and genetic stocks. Three accessions of O. rufipogon were selected as donors, based on phylogenetic, geographical and morphological divergence, and crossed with two rec...

  4. Hydrological Conditions Affect the Interspecific Interaction between Two Emergent Wetland Species

    Directory of Open Access Journals (Sweden)

    Jian Zhou

    2018-01-01

    Full Text Available Hydrological conditions determine the distribution of plant species in wetlands, where conditions such as water depth and hydrological fluctuations are expected to affect the interspecific interactions among emergent wetland species. To test such effects, we conducted a greenhouse experiment with three treatment categories, interspecific interaction (mixed culture or monoculture, water depth (10 or 30 cm depth, and hydrological fluctuation (static or fluctuating water level, and two common emergent wetland plant species, Scirpus planiculumis Fr. (Cyperaceae and Phragmites australis var. baiyangdiansis (Gramineae. An increase in the water depth significantly restrained the growth of both S. planiculumis and P. australis, while hydrological fluctuations did not obviously alter the growth of either species. In addition, both water depth and hydrological fluctuations significantly affected the interspecific interaction between these two wetland species. P. australis benefited from interspecific interaction under increasing water depth and hydrological fluctuations, and the RII values were clearly positive for plants grown at a water depth that fluctuated around 30 cm. The results may have some implications for understanding how S. planiculumis and P. australis, as well as wetland communities, respond to the natural variation or human modification of hydrological conditions.

  5. Application of three pollination techniques and of hormone treatments for overcoming interspecific crossing barriers in Tulipa

    NARCIS (Netherlands)

    Creij, van M.G.M.; Kerckhoffs, D.M.F.J.; Tuyl, van J.M.

    1997-01-01

    In tulip, interspecific crossing is restricted by both pre-fertilization and post-fertilization barriers. In order to introduce traits from wild species into the cultivar assortment these barriers must be bypassed. By application of embryo rescue techniques, unique hybrids have been obtained of

  6. High prevalence of biofilm synergy among bacterial soil isolates in cocultures indicates bacterial interspecific cooperation

    DEFF Research Database (Denmark)

    Ren, Dawei; Madsen, Jonas Stenløkke; Sørensen, Søren Johannes

    2015-01-01

    of single-species biofilms, indicating that all the individual strains benefit from inclusion in the multispecies community. Our results show a high prevalence of synergy in biofilm formation in multispecies consortia isolated from a natural bacterial habitat and suggest that interspecific cooperation...

  7. Using Crossmatch tests for serological compatibility assessment intra- and interspecific at dogs and cats

    Directory of Open Access Journals (Sweden)

    Sergiu Adrian Muntean

    2016-11-01

    Conclusions: The intraspecific evaluations revealed a high level of blood compatibility in the case of dogs unsensitivized through previous blood transfusions, yet without excluding the possibility of some atypical sensitivization for clinical interest. Having all the interspecific tests exclusively highly positive, we can not sustain a probable xenotransfusion.

  8. Another account of interspecific aggression involving a Hoary Bat (Lasiurus cinereus)

    Science.gov (United States)

    Alyson F Brokaw; Jeff Clerc; Ted Weller

    2016-01-01

    We observed an incident of interspecific aggression between a male Hoary Bat (Lasiurus cinereus) and a male Silver-haired Bat (Lasionycteris noctivagans). The Silver-haired Bat suffered few external injuries, the most conspicuous of which were a missing lower right canine and small...

  9. Interspecific and locational differences in metal levels in edible fish tissue from Saudi Arabia

    KAUST Repository

    Burger, Joanna; Gochfeld, Michael; Batang, Zenon B.; Mannalamkunnath Alikunhi, Nabeel; Aljahdali, Ramzi; Al-Jebreen, Dalal; Aziz, Mohammed A. M.; Al-Suwailem, Abdulaziz M.

    2014-01-01

    species collected from three fishing sites and a local fish market in Jeddah, Saudi Arabia. We tested the following null hypotheses: (1) there are no interspecific differences in metal levels, (2) there are no differences in metal levels in fishes between

  10. An Assessment of Phylogenetic Tools for Analyzing the Interplay Between Interspecific Interactions and Phenotypic Evolution.

    Science.gov (United States)

    Drury, J P; Grether, G F; Garland, T; Morlon, H

    2018-05-01

    Much ecological and evolutionary theory predicts that interspecific interactions often drive phenotypic diversification and that species phenotypes in turn influence species interactions. Several phylogenetic comparative methods have been developed to assess the importance of such processes in nature; however, the statistical properties of these methods have gone largely untested. Focusing mainly on scenarios of competition between closely-related species, we assess the performance of available comparative approaches for analyzing the interplay between interspecific interactions and species phenotypes. We find that many currently used statistical methods often fail to detect the impact of interspecific interactions on trait evolution, that sister-taxa analyses are particularly unreliable in general, and that recently developed process-based models have more satisfactory statistical properties. Methods for detecting predictors of species interactions are generally more reliable than methods for detecting character displacement. In weighing the strengths and weaknesses of different approaches, we hope to provide a clear guide for empiricists testing hypotheses about the reciprocal effect of interspecific interactions and species phenotypes and to inspire further development of process-based models.

  11. Assemblage Organization in Stream Fishes: Effects of Enviromental Variation and Interspecific Interactions

    Science.gov (United States)

    Gary D. Grossman; Robert E. Ratajczak; Maurice Crawford; Mary C. Freeman

    1998-01-01

    We assessed the relative importance of environmental variation, interspecific competition for space, and predator abundance on assemblage structure and microhabitat use in a stream fish assemblage inhabiting Coweeta Creek, North Carolina, USA. Our study encompassed a l0-yr time span (1983-1992) and included some of the highest and lowest flows in the last 58 years. We...

  12. Interspecific Hybridization between Sesamum indicum L. and Ceratotheca sesamoides Endl

    Directory of Open Access Journals (Sweden)

    Falusi, OA.

    2001-01-01

    Full Text Available Sesamum indicum L. (2n = 26 and Ceratotheca sesamoides Endl. (2n = 32 were crossed to investigate their genomic relations and feasibility of gene exchange. Results showed that crossability between the two species was low. Pollen viability was drastically reduced in the F1 hybrids. This was attributed to meiotic abnormalities such as univalent and multivalent associations, non-disjunction bridges, and presence of fragments and micronuclei. Findings from this study also imply that gene exchange between Sesamum indicum L. and Ceratotheca sesamoides Endl. is possible. The implications of these results in the species evolution are discussed.

  13. Interspecific associations and community structure: A local survey and analysis in a grass community

    Directory of Open Access Journals (Sweden)

    WenJun Zhang

    2014-09-01

    Full Text Available Interspecific associations in the plant community may help to understand the self-organizing assembly and succession of the community. In present study, Pearson correlation, net correlation, Spearman rank correlation, and point correlation were used to detect the interspecific (inter-family associations of grass species (families using the sampling data collected in a grass community of Zhuhai, China. We found that most associations between grass species (families were positive associations. The competition/interference/niche separation between grass species (families was not significant. A lot of pairs of grass species and families with statistically significant interspecific (inter-family associations based on four correlation measures were discovered. Cluster trees for grass species/families were obtained by using cluster analysis. Relationship among positive/negative associations, interspecific relationship and community succession/stability/robustness was discussed. I held that species with significant positive or negative associations are generally keystone species in the community. Although both negative and positive associations occur in the community succession, the adaptation and selection will finally result in the successful coexistence of the species with significant positive associations in the climax community. As the advance of community succession, the significant positive associations increase and maximize in climax community, and the significant negative associations increase to a maximum and then decline into climax community. Dominance of significant positive associations in the climax community means the relative stablility and equilibrium of the community. No significant associations usually account for the majority of possible interspecific associations at each phase of community succession. They guarantee the robustness of community. They are candidates of keystone species. Lose of some existing keystone species might be

  14. Genetical and ultrastructural aspects of self and cross incompatibility in interspecific hybrids between self-compatible Lycopersicum esculentum and self-incompatible L. peruvianum.

    Science.gov (United States)

    De Nettancourt, D; Devreux, M; Laneri, U; Cresti, M; Pacini, E; Sarfatti, G

    1974-01-01

    Cytological and genetical analyses were made of the breeding system of embryo-cultured interspecific tomato hybrids between L. esculentum and L. peruvianum. It was found that fluorescence techniques and electron microscopy allowed a distinction to be made between pollen tubes inhibited by a unilateral incompatibility reaction and pollen tubes inhibited by a self-incompatibility reaction, after self-pollination of the hybrids or after reciprocal crossing between the hybrid and the parental species. The observed differences, if real and reliable, demonstrate that unilateral incompatibility in esculentum pollen tubes is governed by a single gametophytic factor which is either linked or allelic to the S-locus. This finding is discussed with reference to recent reports that unilateral incompatibility is controlled, in peruvianum styles, by a number of different dominant genes and it is concluded that these dominant genes, the S-locus of self-incompatibility and the gametophytic factor regulating the unilateral reaction in esculentum pollen belong to the same linkage group. The strong sterility barriers which prevent practically all backcrosses between the hybrid and the parental species were shown to be independent of the factors regulating stylar incompatibility. L. peruvianum is heterozygous for the sterility genes which prevent fertilization or embryo formation when the interspecific hybrid is crossed, as pistillate parent, to different accessions of L. peruvianum. One peruvianum stock was found which, as a pollinator, was highly cross-fertile with the hybrids.The presence of a concentric endoplasmic reticulum in inhibited pollen tubes was observed to be a constant feature of both the self- and the unilateral incompatibility reactions and was interpreted as an indication that incompatibility might lead to a general cessation of protein synthesis. Although incompatible tubes very much resemble, in this respect, the pollen tubes cultured in vitro, it seems probable, on

  15. Application of DNA RFLP procedures in interspecific gene transfer: The Lr19 translocation of wheat

    International Nuclear Information System (INIS)

    Prins, R.; Marais, G.F.; Marais, A.S.; Pretorius, Z.A.; Janse, B.J.H.

    1998-01-01

    Twenty-nine lines with deletions in the Lr19 ('Indis') translocated chromosome segment were used to physically map Thinopyrum Restriction Fragment Length Polymorphism (RFLP) loci as well as the Sr25 and Sdl loci. The relative distances between marker loci on the translocation were then calculated. The information was then used as an aid to characterize several recombined forms of the translocation. The data confirmed the reported homoeology between the Lr19 segment and chromosome arm 7DL of wheat. Also, it seems that the Lr19 translocation in 'Indis' is very similar to the Lr19 segment in the T4 source and that the former may not derive from Thinopyrum distichum. Near-isogenic lines of the recombined segments were derived and used to study their expression of leaf rust resistance. It became evident that only one potentially useful recombinant was obtained in an earlier attempt to induce allosyndetic pairing between the Lr19 translocation and 7DL of wheat. (author)

  16. Interspecific Hybridization in Pilot Whales and Asymmetric Genetic Introgression in Northern Globicephala melas under the Scenario of Global Warming.

    Science.gov (United States)

    Miralles, Laura; Oremus, Marc; Silva, Mónica A; Planes, Serge; Garcia-Vazquez, Eva

    2016-01-01

    Pilot whales are two cetacean species (Globicephala melas and G. macrorhynchus) whose distributions are correlated with water temperature and partially overlap in some areas like the North Atlantic Ocean. In the context of global warming, distribution range shifts are expected to occur in species affected by temperature. Consequently, a northward displacement of the tropical pilot whale G. macrorynchus is expected, eventually leading to increased secondary contact areas and opportunities for interspecific hybridization. Here, we describe genetic evidences of recurrent hybridization between pilot whales in northeast Atlantic Ocean. Based on mitochondrial DNA sequences and microsatellite loci, asymmetric introgression of G. macrorhynchus genes into G. melas was observed. For the latter species, a significant correlation was found between historical population growth rate estimates and paleotemperature oscillations. Introgressive hybridization, current temperature increases and lower genetic variation in G. melas suggest that this species could be at risk in its northern range. Under increasing environmental and human-mediated stressors in the North Atlantic Ocean, it seems recommendable to develop a conservation program for G. melas.

  17. Population genetic analysis and evidence of inter-specific introgression in Helichrysum armenium and H. rubicundum (Asteraceae

    Directory of Open Access Journals (Sweden)

    Taban Malahat

    2015-01-01

    Full Text Available Helichrysum armenium and H. rubicundum are two medicinally important plants of Iran that are distributed in various regions of the country. They are extensively used by locals as medicinal plants and a great negative selection pressure is applied on them. Therefore, due to importance of these plant species, we performed a population genetic study in both species. For this study, we used 66 randomly collected plants from 24 geographical populations of Helichrysum armenium and H. rubicundu. These species had areas of overlap and contact and we found some intermediate plants that were included in our study too. UPGMA and MDS analyses revealed morphological separation of these closely related species and placed intermediate plants in an intermediate position. ISSR analysis revealed inter-population genetic diversity and K-Means clustering and STRUCTURE analyses revealed populations. Genetic stratification in both species. Genetic difference of the studied populations was not correlated to geographical distance. Triangle plot of Bayesian analysis and NeighborNet plot showed inter-specific gene flow. The studied populations showed plants with 2n = 2x = 14 and 2n = 4x = 28 chromosomes and differed significantly in their meiotic behavior. Therefore, a combination of genetic stratification, and genetic admixture as well as polyploidy and chromosomes structural changes, have played rule in Helichrysum diversification.

  18. Evaluation of reproductive barriers contributes to the development of novel interspecific hybrids in the Kalanchoë genus

    DEFF Research Database (Denmark)

    Kuligowska, Katarzyna; Lütken, Henrik Vlk; Christensen, Brian

    2015-01-01

    BackgroundInterspecific hybridization is a useful tool in ornamental breeding to increase genetic variability and introduce new valuable traits into existing cultivars. The successful formation of interspecific hybrids is frequently limited by the presence of pre- and post-fertilization barriers....... In the present study, we investigated the nature of hybridization barriers occurring in crosses between Kalancho? species and evaluated possibilities of obtaining interspecific hybrids.ResultsThe qualitative and quantitative analyses of pollen tube growth in situ were performed following intra- and interspecific...... pollinations. They revealed occurrence of pre-fertilization barriers associated with inhibition of pollen germination on the stigma and abnormal growth of pollen tubes. Unilateral incongruity related to differences in pistil length was also observed. The pollen quality was identified as a strong factor...

  19. Characterization of F1 interspecific hybrids between wild Helianthus annuus L. populations and cultivated sunflower

    Directory of Open Access Journals (Sweden)

    Terzić Sreten

    2006-01-01

    Full Text Available Phenotype, chromosomes pairing and pollen vitality were compared between parental populations and F1 hybrids of interspecific cross between Helianthus annuus L. and cultivated sunflower. The investigation of the simple sequence repeats (SSR polymorphism was also used to test the hybrid nature of F1 populations. The phenotypic traits of F1 hybrid plants were either closer to the wild species or intermediate. Irregular chromosome pairing was found in only 0 to 10% of meiocytes in the meiosis of F1 hybrid plants. Interspecific crosses were confirmed with SSR markers in all hybrid combinations. Alleles that were not present in parental DNA were frequently observed in F1 hybrids. That is additional evidence that those hybrid combinations were not produced by self-fertilization. The results suggest that SSR markers can be efficiently used for the F1 hybrid characterization in crosses between closely related species, in which, the changes of phenotype, meiosis and pollen vitality are not always significant.

  20. Plant-mediated interspecific horizontal transmission of an intracellular symbiont in insects

    KAUST Repository

    Gonella, Elena

    2015-11-13

    Intracellular reproductive manipulators, such as Candidatus Cardinium and Wolbachia are vertically transmitted to progeny but rarely show co-speciation with the host. In sap-feeding insects, plant tissues have been proposed as alternative horizontal routes of interspecific transmission, but experimental evidence is limited. Here we report results from experiments that show that Cardinium is horizontally transmitted between different phloem sap-feeding insect species through plants. Quantitative PCR and in situ hybridization experiments indicated that the leafhopper Scaphoideus titanus releases Cardinium from its salivary glands during feeding on both artificial media and grapevine leaves. Successional time-course feeding experiments with S. titanus initially fed sugar solutions or small areas of grapevine leaves followed by feeding by the phytoplasma vector Macrosteles quadripunctulatus or the grapevine feeder Empoasca vitis revealed that the symbionts were transmitted to both species. Explaining interspecific horizontal transmission through plants improves our understanding of how symbionts spread, their lifestyle and the symbiont-host intermixed evolutionary pattern.

  1. Does interspecific competition have a moderating effect on Taenia solium transmission dynamics in Southeast Asia?

    Science.gov (United States)

    Conlan, James V; Vongxay, Khamphouth; Fenwick, Stanley; Blacksell, Stuart D; Thompson, R C Andrew

    2009-09-01

    It is well understood that sociocultural practices strongly influence Taenia solium transmission; however, the extent to which interspecific parasite competition moderates Taenia transmission has yet to be determined. This is certainly the case in Southeast Asia where T. solium faces competition in both the definitive host (people) and the intermediate host (pigs). In people, adult worms of T. solium, T. saginata and T. asiatica compete through density-dependent crowding mechanisms. In pigs, metacestodes of T. solium, T. hydatigena and T. asiatica compete through density-dependent immune-mediated interactions. Here, we describe the biological and epidemiological implications of Taenia competition and propose that interspecific competition has a moderating effect on the transmission dynamics of T. solium in the region. Furthermore, we argue that this competitive ecological scenario should be considered in future research and surveillance activities examining T. solium cysticercosis and taeniasis in Southeast Asia.

  2. Gamma irradiation of the interspecific hybrids Gossypium hirsutum L. x G. barbadense L. Part 1

    International Nuclear Information System (INIS)

    Stoilova, A.

    1990-01-01

    The study was aimed at combining the methods of hybridization and experimental mutagenesis and widening the possibilities of interspecific hybridization for successful breeding work. The reaction of interspecific cotton hybrids (G. hirsutum x G. barbadense) to gamma rays in the year of treatment was investigated. Four hybrid combinations resulting from reciprocal crosses between the two species were studied. Seeds of long fibre F 1 plants from each combination were divided in four equal parts (irradiated with 15, 20 and 25 krad and a control). The changes in the main biometrical indices between the control and maximum dose (25 krad) treatment showed that the F 2 hybrids were either resistant or slightly sensitive to irradiation depending on the direction of crossing in respect to growth processes, field germination and survival to the end of vegetation. 3 tabs., 2 figs., 14 refs

  3. Plant-mediated interspecific horizontal transmission of an intracellular symbiont in insects.

    Science.gov (United States)

    Gonella, Elena; Pajoro, Massimo; Marzorati, Massimo; Crotti, Elena; Mandrioli, Mauro; Pontini, Marianna; Bulgari, Daniela; Negri, Ilaria; Sacchi, Luciano; Chouaia, Bessem; Daffonchio, Daniele; Alma, Alberto

    2015-11-13

    Intracellular reproductive manipulators, such as Candidatus Cardinium and Wolbachia are vertically transmitted to progeny but rarely show co-speciation with the host. In sap-feeding insects, plant tissues have been proposed as alternative horizontal routes of interspecific transmission, but experimental evidence is limited. Here we report results from experiments that show that Cardinium is horizontally transmitted between different phloem sap-feeding insect species through plants. Quantitative PCR and in situ hybridization experiments indicated that the leafhopper Scaphoideus titanus releases Cardinium from its salivary glands during feeding on both artificial media and grapevine leaves. Successional time-course feeding experiments with S. titanus initially fed sugar solutions or small areas of grapevine leaves followed by feeding by the phytoplasma vector Macrosteles quadripunctulatus or the grapevine feeder Empoasca vitis revealed that the symbionts were transmitted to both species. Explaining interspecific horizontal transmission through plants improves our understanding of how symbionts spread, their lifestyle and the symbiont-host intermixed evolutionary pattern.

  4. Evaluation of cheetah and leopard spermatozoa developmental capability after interspecific ICSI with domestic cat oocytes.

    Science.gov (United States)

    Moro, L N; Sestelo, A J; Salamone, D F

    2014-08-01

    The ICSI procedure is potentially of great value for felids, and it has not been extensively studied in these species. The objectives of this work were to determine the best conditions for ICSI in the domestic cat (DC) to generate interspecific embryos by injecting cheetah (Ch) and leopard (Leo) spermatozoa. Firstly, DC oocytes were matured with insulin-transferrin-selenium (ITS) or without it (MM) and cultured using atmospheric (21%) or low (5%) oxygen tension after ICSI. The group ITS-5%O2 showed the highest blastocyst rate (p cheetah and leopard spermatozoa were able to generate blastocysts without artificial activation, which suggests that developmental capacity of wild felid spermatozoa can be evaluated by interspecific ICSI. This technique should be used to assist wild felid reproduction. © 2014 Blackwell Verlag GmbH.

  5. Genetic Linkage Map Construction and QTL Analysis of Two Interspecific Reproductive Isolation Traits in Sponge Gourd

    OpenAIRE

    Wu, Haibin; He, Xiaoli; Gong, Hao; Luo, Shaobo; Li, Mingzhu; Chen, Junqiu; Zhang, Changyuan; Yu, Ting; Huang, Wangping; Luo, Jianning

    2016-01-01

    The hybrids between Luffa acutangula (L.) Roxb. and L.cylindrica (L.) Roem. have strong heterosis effects. However, some reproductive isolation traits hindered their normal hybridization and fructification, which was mainly caused by the flowering time and hybrid pollen sterility. In order to study the genetic basis of two interspecific reproductive isolation traits, we constructed a genetic linkage map using an F2 population derived from a cross between S1174 [L. acutangula (L.) Roxb.] and 9...

  6. Meiosis in elephant grass (Pennisetum purpureum), pearl millet (Pennisetum glaucum) (Poaceae, Poales) and their interspecific hybrids

    OpenAIRE

    Techio, Vânia Helena; Davide, Lisete Chamma; Pereira, Antônio Vander

    2006-01-01

    The cultivated and sexually compatible species Pennisetum purpureum (elephant grass, 2n = 4x = 28) and Pennisetum glaucum (pearl millet, 2n = 2x = 14) can undergo hybridization which favors the amplification of their genetic background and the introgression of favorable alleles into breeding programs. The main problem with interspecific hybrids of these species is infertility due to triploidy (2n = 3x = 21). This study describes meiosis in elephant grass x pearl millet hybrids and their proge...

  7. Phenology of the oil palm interspecific hybrid Elaeis oleifera × Elaeis guineensis

    Directory of Open Access Journals (Sweden)

    Paola Hormaza

    2012-01-01

    Full Text Available Oil palm is one of the most important oil crops in the world. Because of its high productivity and perennial nature, it has been expanding quickly. Commercial plantations consist mostly of the African palm E. guineensis Jacq. However, producers in Latin America are increasingly planting the O × G interspecific hybrid, a cross between African palm (E. guineensis and the American palm (E. oleifera (Kunth Cortés. This interspecific hybrid has emerged as a promising solution to diseases such as the bud rot of oil palm because of the apparent partial resistance of this genotype to the disease. This work studied and described the phenology of the O × G interspecific hybrid. The phenology stages were coded using the BBCH scale. The scale for the phenophases was defined using a three-digit code. Due to the nature of the palm, no descriptions were used for stage two (formation of side shoots/tillering and stage four (development of harvestable vegetative plant parts or vegetative reproductive organs because these stages do not apply to oil palm. The scale was constructed using germinating seeds, pre-nursery and nursery plants and five year-old palms. For the description of the stem elongation, different age palms of the same O × G hybrid were used. Observations were performed during an 18-month period. Additionally, the interval for the change from one phenology stage to another was determined both in days and degree-days (DD. The interspecific O × G hybrid required 6408 DD from when the spear leaf unfolds until the bunch was ripened and harvested, and 4427.6 DD from leaf unfolding to anthesis.

  8. Species-Specific Effects on Ecosystem Functioning Can Be Altered by Interspecific Interactions.

    Science.gov (United States)

    Clare, David S; Spencer, Matthew; Robinson, Leonie A; Frid, Christopher L J

    2016-01-01

    Biological assemblages are constantly undergoing change, with species being introduced, extirpated and experiencing shifts in their densities. Theory and experimentation suggest that the impacts of such change on ecosystem functioning should be predictable based on the biological traits of the species involved. However, interspecific interactions could alter how species affect functioning, with the strength and sign of interactions potentially depending on environmental context (e.g. homogenous vs. heterogeneous conditions) and the function considered. Here, we assessed how concurrent changes to the densities of two common marine benthic invertebrates, Corophium volutator and Hediste diversicolor, affected the ecological functions of organic matter consumption and benthic-pelagic nutrient flux. Complementary experiments were conducted within homogenous laboratory microcosms and naturally heterogeneous field plots. When the densities of the species were increased within microcosms, interspecific interactions enhanced effects on organic matter consumption and reduced effects on nutrient flux. Trait-based predictions of how each species would affect functioning were only consistently supported when the density of the other species was low. In field plots, increasing the density of either species had a positive effect on organic matter consumption (with no significant interspecific interactions) but no effect on nutrient flux. Our results indicate that species-specific effects on ecosystem functioning can be altered by interspecific interactions, which can be either facilitative (positive) or antagonistic (negative) depending on the function considered. The impacts of biodiversity change may therefore not be predictable based solely on the biological traits of the species involved. Possible explanations for why interactions were detected in microcosms but not in the field are discussed.

  9. Species-Specific Effects on Ecosystem Functioning Can Be Altered by Interspecific Interactions.

    Directory of Open Access Journals (Sweden)

    David S Clare

    Full Text Available Biological assemblages are constantly undergoing change, with species being introduced, extirpated and experiencing shifts in their densities. Theory and experimentation suggest that the impacts of such change on ecosystem functioning should be predictable based on the biological traits of the species involved. However, interspecific interactions could alter how species affect functioning, with the strength and sign of interactions potentially depending on environmental context (e.g. homogenous vs. heterogeneous conditions and the function considered. Here, we assessed how concurrent changes to the densities of two common marine benthic invertebrates, Corophium volutator and Hediste diversicolor, affected the ecological functions of organic matter consumption and benthic-pelagic nutrient flux. Complementary experiments were conducted within homogenous laboratory microcosms and naturally heterogeneous field plots. When the densities of the species were increased within microcosms, interspecific interactions enhanced effects on organic matter consumption and reduced effects on nutrient flux. Trait-based predictions of how each species would affect functioning were only consistently supported when the density of the other species was low. In field plots, increasing the density of either species had a positive effect on organic matter consumption (with no significant interspecific interactions but no effect on nutrient flux. Our results indicate that species-specific effects on ecosystem functioning can be altered by interspecific interactions, which can be either facilitative (positive or antagonistic (negative depending on the function considered. The impacts of biodiversity change may therefore not be predictable based solely on the biological traits of the species involved. Possible explanations for why interactions were detected in microcosms but not in the field are discussed.

  10. Impact of interspecific competition and drought on the allocation of new assimilates in trees.

    Science.gov (United States)

    Hommel, R; Siegwolf, R; Zavadlav, S; Arend, M; Schaub, M; Galiano, L; Haeni, M; Kayler, Z E; Gessler, A

    2016-09-01

    In trees, the interplay between reduced carbon assimilation and the inability to transport carbohydrates to the sites of demand under drought might be one of the mechanisms leading to carbon starvation. However, we largely lack knowledge on how drought effects on new assimilate allocation differ between species with different drought sensitivities and how these effects are modified by interspecific competition. We assessed the fate of (13) C labelled assimilates in above- and belowground plant organs and in root/rhizosphere respired CO2 in saplings of drought-tolerant Norway maple (Acer platanoides) and drought-sensitive European beech (Fagus sylvatica) exposed to moderate drought, either in mono- or mixed culture. While drought reduced stomatal conductance and photosynthesis rates in both species, both maintained assimilate transport belowground. Beech even allocated more new assimilate to the roots under moderate drought compared to non-limited water supply conditions, and this pattern was even more pronounced under interspecific competition. Even though maple was a superior competitor compared to beech under non-limited soil water conditions, as indicated by the changes in above- and belowground biomass of both species in the interspecific competition treatments, we can state that beech was still able to efficiently allocate new assimilate belowground under combined drought and interspecific competition. This might be seen as a strategy to maintain root osmotic potential and to prioritise root functioning. Our results thus show that beech tolerates moderate drought stress plus competition without losing its ability to supply belowground tissues. It remains to be explored in future work if this strategy is also valid during long-term drought exposure. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  11. Inter-specific competitive stress does not affect the magnitude of inbreeding depression

    OpenAIRE

    Willi, Yvonne; Dietrich, Stefan; van Kleunen, Mark; Fischer, Markus

    2007-01-01

    Hypothesis: Stressful inter-specific competition enhances inbreeding depression.Organisms: Creeping spearwort (Ranunculus reptans L.) and its common competitor, thecreeping bentgrass (Agrostis stolonifera L.).Field site: Outdoor common garden experiment at the University of Potsdam.Methods: We collected plants of 12 natural populations of R. reptans differing in mean parental inbreeding coefficient (0.01–0.26). We performed within-population crosses for twogenerations and kept the offspring i...

  12. Weak interspecific interactions in a sagebrush steppe? Conflicting evidence from observations and experiments.

    Science.gov (United States)

    Adler, Peter B; Kleinhesselink, Andrew; Giles, Hooker; Taylor, J Bret; Teller, Brittany; Ellner, Stephen P

    2018-04-28

    Stable coexistence requires intraspecific limitations to be stronger than interspecific limitations. The greater the difference between intra- and interspecific limitations, the more stable the coexistence, and the weaker the competitive release any species should experience following removal of competitors. We conducted a removal experiment to test whether a previously estimated model, showing surprisingly weak interspecific competition for four dominant species in a sagebrush steppe, accurately predicts competitive release. Our treatments were 1) removal of all perennial grasses and 2) removal of the dominant shrub, Artemisia tripartita. We regressed survival, growth and recruitment on the locations, sizes, and species identities of neighboring plants, along with an indicator variable for removal treatment. If our "baseline" regression model, which accounts for local plant-plant interactions, accurately explains the observed responses to removals, then the removal coefficient should be non-significant. For survival, the removal coefficients were never significantly different from zero, and only A. tripartita showed a (negative) response to removals at the recruitment stage. For growth, the removal treatment effect was significant and positive for two species, Poa secunda and Pseudoroegneria spicata, indicating that the baseline model underestimated interspecific competition. For all three grass species, population models based on the vital rate regressions that included removal effects projected 1.4 to 3-fold increases in equilibrium population size relative to the baseline model (no removal effects). However, we found no evidence of higher response to removal in quadrats with higher pretreatment cover of A. tripartita, or by plants experiencing higher pre-treatment crowding by A. tripartita, raising questions about the mechanisms driving the positive response to removal. While our results show the value of combining observations with a simple removal experiment

  13. Interspecific Transmission of Double-Stranded RNA and Hypovirulence from Sclerotinia sclerotiorum to S. minor.

    Science.gov (United States)

    Melzer, M S; Ikeda, S S; Boland, G J

    2002-07-01

    ABSTRACT Interspecific transmission of a hypovirulence-associated double-stranded RNA (dsRNA) and hypovirulent phenotype was attempted from hypovirulent isolate Ss275 of Sclerotinia sclerotiorum to five virulent isolates of S. minor. dsRNA and the hypovirulent phenotype were successfully transmitted to one of the five isolates, Sm10. Three putative converted isolates of Sm10 were slow growing and developed atypical colony morphologies characteristic of the hypovirulent phenotype. These isolates were assayed for virulence and produced significantly smaller lesions than isolate Sm10 on detached leaves of Romaine lettuce. One of these putative converted isolates, designated Sm10T, was tested to confirm interspecific transmission of dsRNA. In northern hybridizations, dsRNA isolated from Sm10T hybridized with a digoxigenin-labeled cDNA probe prepared from dsRNA isolated from Ss275. Random amplified polymorphic DNA analysis confirmed that isolate Sm10T was derived from Sm10 and not from Ss275 or a hybrid of the two species. The dsRNA and hypovirulent phenotype were subsequently transmitted intraspecifically from Sm10T to Sm8. To our knowledge, this is the first report of interspecific transmission of dsRNA and an associated hypovirulent phenotype between fungal plant pathogens by hyphal anastomosis.

  14. Stabilization process in Saccharomyces intra and interspecific hybrids in fermentative conditions.

    Science.gov (United States)

    Pérez-Través, Laura; Lopes, Christian A; Barrio, Eladio; Querol, Amparo

    2014-12-01

    We evaluated the genetic stabilization of artificial intra- (Saccharomyces cerevisiae) and interspecific (S. cerevisiae × S. kudriavzevii) hybrids under wine fermentative conditions. Large-scale transitions in genome size and genome reorganizations were observed during this process. Interspecific hybrids seem to need fewer generations to reach genetic stability than intraspecific hybrids. The largest number of molecular patterns recovered among the derived clones was observed for intraspecific hybrids, particularly for those obtained by rare-mating. Molecular marker analyses revealed that unstable clones could change during the industrial process to obtain active dry yeast. When no changes in molecular markers and ploidy were observed after this process, no changes in genetic composition were confirmed by comparative genome hybridization, considering the clone as a stable hybrid. According to our results, under these conditions, fermentation steps 3 and 5 (30-50 generations) would suffice to obtain genetically stable interspecific and intraspecific hybrids, respectively. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

  15. A large set of newly created interspecific Saccharomyces hybrids increases aromatic diversity in lager beers.

    Science.gov (United States)

    Mertens, Stijn; Steensels, Jan; Saels, Veerle; De Rouck, Gert; Aerts, Guido; Verstrepen, Kevin J

    2015-12-01

    Lager beer is the most consumed alcoholic beverage in the world. Its production process is marked by a fermentation conducted at low (8 to 15°C) temperatures and by the use of Saccharomyces pastorianus, an interspecific hybrid between Saccharomyces cerevisiae and the cold-tolerant Saccharomyces eubayanus. Recent whole-genome-sequencing efforts revealed that the currently available lager yeasts belong to one of only two archetypes, "Saaz" and "Frohberg." This limited genetic variation likely reflects that all lager yeasts descend from only two separate interspecific hybridization events, which may also explain the relatively limited aromatic diversity between the available lager beer yeasts compared to, for example, wine and ale beer yeasts. In this study, 31 novel interspecific yeast hybrids were developed, resulting from large-scale robot-assisted selection and breeding between carefully selected strains of S. cerevisiae (six strains) and S. eubayanus (two strains). Interestingly, many of the resulting hybrids showed a broader temperature tolerance than their parental strains and reference S. pastorianus yeasts. Moreover, they combined a high fermentation capacity with a desirable aroma profile in laboratory-scale lager beer fermentations, thereby successfully enriching the currently available lager yeast biodiversity. Pilot-scale trials further confirmed the industrial potential of these hybrids and identified one strain, hybrid H29, which combines a fast fermentation, high attenuation, and the production of a complex, desirable fruity aroma. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  16. Interspecific variation in tree seedlings establishment in canopy gaps in relation to tree density

    Energy Technology Data Exchange (ETDEWEB)

    Reader, R.J.; Bonser, S.P.; Duralia, T.E.; Bricker, B.D. [Guelph Univ., ON (Canada). Dept. of Botany

    1995-10-01

    We tested whether interspecific variation in tree seedling establishment in canopy gaps was significantly related to interspecific variation in tree density, for seven deciduous forest tree species (Quercus alba, Hamamelis virginiana, Acer rubrum, Sassafras albidum, Quercus rubra, Prunus serotina, Ostrya virginiana). For each species, seedling establishment was calculated as the difference in seedling density before experimental gap creation versus three years after gap creation. In each of the six experimentally-created gap types (33% or 66% removal of tree basal area from 0.01ha, 0.05ha or 0.20ha patches), differences in seedling establishment among species were significantly related to differences in their density in the tree canopy. A regression model with log{sub e} tree density as the independent variable accounted for between 93% and 98% of interspecific variation in seedling establishment. Our results provide empirical support for models of tree dynamics in gaps that assume seedling establishment depends on canopy tree density. 17 refs, 1 fig, 3 tabs

  17. Obtaining interspecific hybrids, and molecular analysis by microsatellite markers in grapevine

    Directory of Open Access Journals (Sweden)

    Mariane Ruzza Schuck

    2011-11-01

    Full Text Available The objective of this work was to assess the potential of interspecific hybridization of Vitis labruscana and Muscadinia rotundifolia by using artificial cross-pollinations. Microsatellite markers were used to confirm interspecific hybridizations and the identity of the parental genotypes. In crosses in which M. rotundifolia was used as the female parent, no true hybrids were obtained. In the reciprocal crosses, 114 seedlings were identified as true V. labruscana x M. rotundifolia hybrids. Self pollination occurred in direct and in reciprocal crosses. The crossings between 'Bordo' x 'Carlos', 'Magnolia', 'Regale' and' Roanoke', and between' Isabel' x 'Bountiful', 'Carlos', 'Magnolia', 'Regale' and 'Roanoke' were confirmed. The 15 markers evaluated showed that two M. rotundifolia parental genotypes had the same fingerprint profile, indicating a like lyplanting error. The success of hybridization depends mainly on the species and on the cultivar used as the female parent. Microsatellite markers are efficient to confirm the paternity of interspecific F1 hybrids and to determine the correct identity of M. rotundifolia cultivars.

  18. Comparison of food hoarding of two sympatric rodent species under interspecific competition.

    Science.gov (United States)

    Zhang, Yi-Feng; Tong, Lei; Ji, Wei-Hong; Lu, Ji-Qi

    2013-01-01

    Competition can greatly affect the food hoarding strategies of rodents and the fate of seeds hoarded. In order to understand the influence of interspecific competition on food caching behavior of sympatric rodents, we investigated food hoarding patterns of two sympatric rodent species, buff-breasted rat (Rattus flavipectus) and Chinese white-bellied rat (Niviventor confucianus), and compared their responses and adjustment in hoarding behavior under interspecific competition. The results showed that: (1) the buff-breasted rat larder hoarded seeds only, while Chinese white-bellied rat hoarded seeds in both larder and scatter forms; (2) two species of rodents both larder hoarded more seeds when competitors were present; and (3) the Chinese white-bellied rats adjusted their seed hoarding from scatter to larder when competitors were introduced, which reduced the seed availability. Therefore, we concluded that rodents would adjust their food hoarding strategy when interspecific competitors were present, and this may produce a different effect on the fate of seeds and the recruitment of plants. This article is part of a Special Issue entitled: insert SI title. Copyright © 2012. Published by Elsevier B.V.

  19. Species composition and interspecific association of plants in primary succession of Mount Merapi, Indonesia

    Directory of Open Access Journals (Sweden)

    SUTOMO

    2011-10-01

    Full Text Available Sutomo, Faradila D, Putri LSE (2011 Species composition and interspecific association of plants in primary succession of Mount Merapi, Indonesia. Biodiversitas 12: 212-217. Primary succession refers to the establishment of plant species and subsequent changes in composition following major disturbance such as volcanic activity. The study of succession may assist in recognizing the possible effects of species interactions (i.e. facilitation or inhibition. The barren landscapes created by volcanic disturbance on Mount Merapi, Java, Indonesia, provide excellent opportunities to study primary succession. Fifty-six species belonging to 26 families were recorded in the five nuées ardentes deposits. The highest number of species belonged to the Asteraceae, then Poaceae, followed by Fabaceae and Rubiaceae. In Mount Merapi primary succession, the ecosystem may be developing with time as indicated by the increase in the number of species associations. The number of positive associations was generally higher than the number of negative associations, except in the 2001 deposit where it was equal. Native and alien invasive species had different patterns of interspecific associations. This research demonstrates that in primary succession sites on Mount Merapi, positive interspecific association increased as time progressed, which may support the view that facilitation is more prominent in a severely disturbed habitat as compared to competition.

  20. Simple Sequence Repeat (SSR Genetic Linkage Map of D Genome Diploid Cotton Derived from an Interspecific Cross between Gossypium davidsonii and Gossypium klotzschianum

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    Joy Nyangasi Kirungu

    2018-01-01

    Full Text Available The challenge in tetraploid cotton cultivars is the narrow genetic base and therefore, the bottleneck is how to obtain interspecific hybrids and introduce the germplasm directly from wild cotton to elite cultivars. Construction of genetic maps has provided insight into understanding the genome structure, interrelationships between organisms in relation to evolution, and discovery of genes that carry important agronomic traits in plants. In this study, we generated an interspecific hybrid between two wild diploid cottons, Gossypium davidsonii and Gossypium klotzschianum, and genotyped 188 F2:3 populations in order to develop a genetic map. We screened 12,560 SWU Simple Sequence Repeat (SSR primers and obtained 1000 polymorphic markers which accounted for only 8%. A total of 928 polymorphic primers were successfully scored and only 728 were effectively linked across the 13 chromosomes, but with an asymmetrical distribution. The map length was 1480.23 cM, with an average length of 2.182 cM between adjacent markers. A high percentage of the markers on the map developed, and for the physical map of G. raimondii, exhibited highly significant collinearity, with two types of duplication. High level of segregation distortion was observed. A total of 27 key genes were identified with diverse roles in plant hormone signaling, development, and defense reactions. The achievement of developing the F2:3 population and its genetic map constructions may be a landmark in establishing a new tool for the genetic improvement of cultivars from wild plants in cotton. Our map had an increased recombination length compared to other maps developed from other D genome cotton species.

  1. Genotyping by sequencing reveals the interspecific C. maxima / C. reticulata admixture along the genomes of modern citrus varieties of mandarins, tangors, tangelos, orangelos and grapefruits.

    Science.gov (United States)

    Oueslati, Amel; Salhi-Hannachi, Amel; Luro, François; Vignes, Hélène; Mournet, Pierre; Ollitrault, Patrick

    2017-01-01

    The mandarin horticultural group is an important component of world citrus production for the fresh fruit market. This group formerly classified as C. reticulata is highly polymorphic and recent molecular studies have suggested that numerous cultivated mandarins were introgressed by C. maxima (the pummelos). C. maxima and C. reticulata are also the ancestors of sweet and sour oranges, grapefruit, and therefore of all the "small citrus" modern varieties (mandarins, tangors, tangelos) derived from sexual hybridization between these horticultural groups. Recently, NGS technologies have greatly modified how plant evolution and genomic structure are analyzed, moving from phylogenetics to phylogenomics. The objective of this work was to develop a workflow for phylogenomic inference from Genotyping By Sequencing (GBS) data and to analyze the interspecific admixture along the nine citrus chromosomes for horticultural groups and recent varieties resulting from the combination of the C. reticulata and C. maxima gene pools. A GBS library was established from 55 citrus varieties, using the ApekI restriction enzyme and selective PCR to improve the read depth. Diagnostic polymorphisms (DPs) of C. reticulata/C. maxima differentiation were identified and used to decipher the phylogenomic structure of the 55 varieties. The GBS approach was powerful and revealed 30,289 SNPs and 8,794 Indels with 12.6% of missing data. 11,133 DPs were selected covering the nine chromosomes with a higher density in genic regions. GBS combined with the detection of DPs was powerful for deciphering the "phylogenomic karyotypes" of cultivars derived from admixture of the two ancestral species after a limited number of interspecific recombinations. All the mandarins, mandarin hybrids, tangelos and tangors analyzed displayed introgression of C. maxima in different parts of the genome. C. reticulata/C. maxima admixture should be a major component of the high phenotypic variability of this germplasm opening

  2. Interspecific in vitro assay for the chimera-forming ability of human pluripotent stem cells.

    Science.gov (United States)

    Masaki, Hideki; Kato-Itoh, Megumi; Umino, Ayumi; Sato, Hideyuki; Hamanaka, Sanae; Kobayashi, Toshihiro; Yamaguchi, Tomoyuki; Nishimura, Ken; Ohtaka, Manami; Nakanishi, Mahito; Nakauchi, Hiromitsu

    2015-09-15

    Functional assay limitations are an emerging issue in characterizing human pluripotent stem cells (PSCs). With rodent PSCs, chimera formation using pre-implantation embryos is the gold-standard assay of pluripotency (competence of progeny to differentiate into all three germ layers). In human PSCs (hPSCs), however, this can only be monitored via teratoma formation or in vitro differentiation, as ethical concerns preclude generation of human-human or human-animal chimeras. To circumvent this issue, we developed a functional assay utilizing interspecific blastocyst injection and in vitro culture (interspecies in vitro chimera assay) that enables the development and observation of embryos up to headfold stage. The assay uses mouse pre-implantation embryos and rat, monkey and human PSCs to create interspecies chimeras cultured in vitro to the early egg-cylinder stage. Intra- and interspecific chimera assays with rodent PSC lines were performed to confirm the consistency of results in vitro and in vivo. The behavior of chimeras developed in vitro appeared to recapitulate that of chimeras developed in vivo; that is, PSC-derived cells survived and were integrated into the epiblast of egg-cylinder-stage embryos. This indicates that the interspecific in vitro chimera assay is useful in evaluating the chimera-forming ability of rodent PSCs. However, when human induced PSCs (both conventional and naïve-like types) were injected into mouse embryos and cultured, some human cells survived but were segregated; unlike epiblast-stage rodent PSCs, they never integrated into the epiblast of egg-cylinder-stage embryos. These data suggest that the mouse-human interspecies in vitro chimera assay does not accurately reflect the early developmental potential/process of hPSCs. The use of evolutionarily more closely related species as host embryos might be necessary to evaluate the developmental potency of hPSCs. © 2015. Published by The Company of Biologists Ltd.

  3. Interspecific competition between entomopathogenic nematodes (Steinernema is modified by their bacterial symbionts (Xenorhabdus

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    Pages Sylvie

    2006-09-01

    Full Text Available Abstract Background Symbioses between invertebrates and prokaryotes are biological systems of particular interest in order to study the evolution of mutualism. The symbioses between the entomopathogenic nematodes Steinernema and their bacterial symbiont Xenorhabdus are very tractable model systems. Previous studies demonstrated (i a highly specialized relationship between each strain of nematodes and its naturally associated bacterial strain and (ii that mutualism plays a role in several important life history traits of each partner such as access to insect host resources, dispersal and protection against various biotic and abiotic factors. The goal of the present study was to address the question of the impact of Xenorhabdus symbionts on the progression and outcome of interspecific competition between individuals belonging to different Steinernema species. For this, we monitored experimental interspecific competition between (i two nematode species: S. carpocapsae and S. scapterisci and (ii their respective symbionts: X. nematophila and X. innexi within an experimental insect-host (Galleria mellonella. Three conditions of competition between nematodes were tested: (i infection of insects with aposymbiotic IJs (i.e. without symbiont of both species (ii infection of insects with aposymbiotic IJs of both species in presence of variable proportion of their two Xenorhabdus symbionts and (iii infection of insects with symbiotic IJs (i.e. naturally associated with their symbionts of both species. Results We found that both the progression and the outcome of interspecific competition between entomopathogenic nematodes were influenced by their bacterial symbionts. Thus, the results obtained with aposymbiotic nematodes were totally opposite to those obtained with symbiotic nematodes. Moreover, the experimental introduction of different ratios of Xenorhabdus symbionts in the insect-host during competition between Steinernema modified the proportion of

  4. [Niche and interspecific association of the dominant fish in the south coastal waters of Wenzhou, China].

    Science.gov (United States)

    Dong, Jing Rui; Shui, Bo Nian; Hu, Cheng Ye; Shui, Yu Yue; DU, Xiao; Tian, Kuo

    2017-05-18

    The studies about the niche and interspecific association in China were mainly focused on the plants, birds and marine animals, and seldom on fish. Based on the fishery resources survey in spring (May) and autumn (September) in 2015, the associations among major fish species in south coastal waters of Wenzhou were investigated. The methods including niche breadth, niche overlap, variance ratio (VR), Χ 2 -test, association coefficient (AC), percentage of co-occurrence (PC) and point correlation coefficients (Ф) were used. The results showed that 47 fish species were identified, including 9 orders, 27 families and 41 genera. Four species were dominant species and 9 were important species, which together accounted for 17%. The niche breadth cluster analysis demonstrated two clearly identifiable ecological niches. The first one referred to wide niche that included Harpodon nehereus, Collichthys lucidus, Engraulis japonicas, Pampus echinogaster, Argyrosomus argentatus, Polynemus sextarius, Decapterus maruadsi and Trichiurus haumela, and the second one was narrow niche that included Muraenesox cinereus, Amblychaeturichthys hexanema, Cunoglossus robustus, Pseudosciaena polyactis and Ilisha elongate. The niche overlap value of the main fish was 0-0.90, indicating that there was difference in the resource utilization among the species. The ecological niche widths of C. robustus and M. cinereus were narrow, and the overlap values were high. This indicated that there was competition between these two species. The VR analysis revealed significant positive correlation among the main fish species. In view of the advantages of Ф value, which could reduce the impact of the analysis results of Χ 2 -test, AC and PC to the interspecific association, the Ф value method was selected in this study, and the association of 63 couples were positive. Both the interspecific association and ecological niche had different degrees of correlation with the stability of community structure

  5. The responses of crop - wild Brassica hybrids to simulated herbivory and interspecific competition: implications for transgene introgression.

    Science.gov (United States)

    Sutherland, Jamie P; Justinova, Lenka; Poppy, Guy M

    2006-01-01

    Brassica rapa grows as a wild and weedy species throughout the world and is the most likely recipient of transgenes from GM oilseed rape. For transgene introgression to occur, the critical step which must be realized, is the formation of an F1 hybrid. Concerns exist that hybrid populations could be more vigorous and competitive compared to the parental species. This study examines the effect of simulated herbivory and interspecific competition on the vegetative and reproductive performance of non-transgenic F1 hybrids and their parental lines. Several vegetative and reproductive performance measures were used to determine the effect of simulated herbivory and competition on the Brassica lines, including leaf length and biomass for herbivory and seedling height and biomass for competition. For defoliation experiments, B. rapa showed little response in terms of leaf length but B. napus and the F1 hybrid responded negatively. Brassica rapa showed elevated biomass responses, but B. napus and the hybrid demonstrated negative responses to defoliation. Defoliation at the cotyledon stage had a slight effect upon final biomass with the F1 hybrid performing significantly worse than B. napus, although seed counts were not significantly different. For the series of competition experiments, hybrids seemed to be more similar to B. rapa in terms of early seedling growth and reproductive measures. The underperformance of hybrid plants when challenged by herbivory and competition, could potentially decrease survivorship and explain the rarity of hybrids in field surveys. However, should transgene introgression occur, the dynamics of hybrids could change radically thus increasing the risk of gene flow from a transgenic oilseed rape crop to the wild recipient.

  6. Native intra- and inter-specific reactions may cause the paradox of pest control with harvesting.

    Science.gov (United States)

    Seno, Hiromi

    2010-05-01

    We analyse a general time-discrete mathematical model of host-parasite population dynamics with harvesting, in which the host can be regarded as a pest. We harvest a portion of the host population at a moment in each year. Our model involves the density effect on the host population. We investigate the condition in which the harvesting of the host results in a paradoxical increase of its equilibrium population size. Our results imply that for a family of pest-enemy systems, the paradox of pest control could be caused essentially by the interspecific relationship and the intraspecific density effect.

  7. Cell wall metabolism and hexose allocation contribute to biomass accumulation in high yielding extreme segregants of a Saccharum interspecific F2 population.

    Science.gov (United States)

    Wai, Ching Man; Zhang, Jisen; Jones, Tyler C; Nagai, Chifumi; Ming, Ray

    2017-10-11

    Sugarcane is an emerging dual-purpose biofuel crop for energy and sugar production, owing to its rapid growth rate, high sucrose storage in the stems, and high lignocellulosic yield. It has the highest biomass production reaching 1.9 billion tonnes in 2014 worldwide. To improve sugarcane biomass accumulation, we developed an interspecific cross between Saccharum officinarum 'LA Purple' and Saccharum robustum 'MOL5829'. Selected F1 individuals were self-pollinated to generate a transgressive F2 population with a wide range of biomass yield. Leaf and stem internodes of fourteen high biomass and eight low biomass F2 extreme segregants were used for RNA-seq to decipher the molecular mechanism of rapid plant growth and dry weight accumulation. Gene Ontology terms involved in cell wall metabolism and carbohydrate catabolism were enriched among 3274 differentially expressed genes between high and low biomass groups. Up-regulation of cellulose metabolism, pectin degradation and lignin biosynthesis genes were observed in the high biomass group, in conjunction with higher transcript levels of callose metabolic genes and the cell wall loosening enzyme expansin. Furthermore, UDP-glucose biosynthesis and sucrose conversion genes were differentially expressed between the two groups. A positive correlation between stem glucose, but not sucrose, levels and dry weight was detected. We thus postulated that the high biomass sugarcane plants rapidly convert sucrose to UDP-glucose, which is the building block of cell wall polymers and callose, in order to maintain the rapid plant growth. The gene interaction of cell wall metabolism, hexose allocation and cell division contributes to biomass yield.

  8. Sexual imprinting misguides species recognition in a facultative interspecific brood parasite.

    Science.gov (United States)

    Sorenson, Michael D; Hauber, Mark E; Derrickson, Scott R

    2010-10-22

    Sexual reproduction relies on the recognition of conspecifics for breeding. Most experiments in birds have implicated a critical role for early social learning in directing subsequent courtship behaviours and mating decisions. This classical view of avian sexual imprinting is challenged, however, by studies of megapodes and obligate brood parasites, species in which reliable recognition is achieved despite the lack of early experience with conspecifics. By rearing males with either conspecific or heterospecific brood mates, we experimentally tested the effect of early social experience on the association preferences and courtship behaviours of two sympatrically breeding ducks. We predicted that redheads (Aythya americana), which are facultative interspecific brood parasites, would show a diminished effect of early social environment on subsequent courtship preferences when compared with their host and congener, the canvasback (Aythya valisineria). Contrary to expectations, cross-fostered males of both species courted heterospecific females and preferred them in spatial association tests, whereas control males courted and associated with conspecific females. These results imply that ontogenetic constraints on species recognition may be a general impediment to the initial evolution of interspecific brood parasitism in birds. Under more natural conditions, a variety of mechanisms may mitigate or counteract the effects of early imprinting for redheads reared in canvasback broods.

  9. Epigenetic patterns newly established after interspecific hybridization in natural populations of Solanum

    Science.gov (United States)

    Cara, Nicolás; Marfil, Carlos F; Masuelli, Ricardo W

    2013-01-01

    Interspecific hybridization is known for triggering genetic and epigenetic changes, such as modifications on DNA methylation patterns and impact on phenotypic plasticity and ecological adaptation. Wild potatoes (Solanum, section Petota) are adapted to multiple habitats along the Andes, and natural hybridizations have proven to be a common feature among species of this group. Solanum × rechei, a recently formed hybrid that grows sympatrically with the parental species S. kurtzianum and S. microdontum, represents an ideal model for studying the ecologically and evolutionary importance of hybridization in generating of epigenetic variability. Genetic and epigenetic variability and their correlation with morphological variation were investigated in wild and ex situ conserved populations of these three wild potato species using amplified fragment length polymorphism (AFLP) and methylation-sensitive amplified polymorphism (MSAP) techniques. We observed that novel methylation patterns doubled the number of novel genetic patterns in the hybrid and that the morphological variability measured on 30 characters had a higher correlation with the epigenetic than with the genetic variability. Statistical comparison of methylation levels suggested that the interspecific hybridization induces genome demethylation in the hybrids. A Bayesian analysis of the genetic data reveled the hybrid nature of S. × rechei, with genotypes displaying high levels of admixture with the parental species, while the epigenetic information assigned S. × rechei to its own cluster with low admixture. These findings suggested that after the hybridization event, a novel epigenetic pattern was rapidly established, which might influence the phenotypic plasticity and adaptation of the hybrid to new environments. PMID:24198938

  10. Interspecific variation in egg testosterone levels: implications for the evolution of bird song.

    Science.gov (United States)

    Garamszegi, L Z; Biard, C; Eens, M; Møller, A P; Saino, N

    2007-05-01

    Although interspecific variation in maternal effects via testosterone levels can be mediated by natural selection, little is known about the evolutionary consequences of egg testosterone for sexual selection. However, two nonexclusive evolutionary hypotheses predict an interspecific relationship between egg testosterone levels and the elaboration of sexual traits. First, maternal investment may be particularly enhanced in sexually selected species, which should generate a positive relationship. Secondly, high prenatal testosterone levels may constrain the development of sexual characters, which should result in a negative relationship. Here we investigated these hypotheses by exploring the relationship between yolk testosterone levels and features of song in a phylogenetic study of 36 passerine species. We found that song duration and syllable repertoire size were significantly negatively related to testosterone levels in the egg, even if potentially confounding factors were held constant. These relationships imply that high testosterone levels during early development of songs may be detrimental, thus supporting the developmental constraints hypothesis. By contrast, we found significant evidence that song-post exposure relative to the height of the vegetation is positively related to egg testosterone levels. These results support the hypothesis that high levels of maternal testosterone have evolved in species with intense sexual selection acting on the location of song-posts. We found nonsignificant effects for intersong interval and song type repertoire size, which may suggest that none of the above hypothesis apply to these traits, or they act simultaneously and have opposing effects.

  11. Genetic evidence for intra- and interspecific slavery in honey ants (genus Myrmecocystus).

    Science.gov (United States)

    Kronauer, D J C; Gadau, J; Hölldobler, B

    2003-04-22

    The New World honey ant species Myrmecocystus mimicus is well known for its highly stereotyped territorial tournaments, and for the raids on conspecific nests that can lead to intraspecific slavery. Our results from mitochondrial and nuclear markers show that the raided brood emerges in the raiding colony and is subsequently incorporated into the colony's worker force. We also found enslaved conspecifics in a second honey ant species, M. depilis, the sister taxon of M. mimicus, which occurs in sympatry with M. mimicus at the study site. Colonies of this species furthermore contained raided M. mimicus workers. Both species have an effective mating frequency that is not significantly different from 1. This study provides genetic evidence for facultative intra- and interspecific slavery in the genus Myrmecocystus. Slavery in ants has evolved repeatedly and supposedly by different means. We propose that, in honey ants, secondary contact between two closely related species that both exhibit intraspecific slavery gave rise to an early form of facultative interspecific slavery.

  12. Interspecific introgression in cetaceans: DNA markers reveal post-F1 status of a pilot whale.

    Directory of Open Access Journals (Sweden)

    Laura Miralles

    Full Text Available Visual species identification of cetacean strandings is difficult, especially when dead specimens are degraded and/or species are morphologically similar. The two recognised pilot whale species (Globicephala melas and Globicephala macrorhynchus are sympatric in the North Atlantic Ocean. These species are very similar in external appearance and their morphometric characteristics partially overlap; thus visual identification is not always reliable. Genetic species identification ensures correct identification of specimens. Here we have employed one mitochondrial (D-Loop region and eight nuclear loci (microsatellites as genetic markers to identify six stranded pilot whales found in Galicia (Northwest Spain, one of them of ambiguous phenotype. DNA analyses yielded positive amplification of all loci and enabled species identification. Nuclear microsatellite DNA genotypes revealed mixed ancestry for one individual, identified as a post-F1 interspecific hybrid employing two different Bayesian methods. From the mitochondrial sequence the maternal species was Globicephala melas. This is the first hybrid documented between Globicephala melas and G. macrorhynchus, and the first post-F1 hybrid genetically identified between cetaceans, revealing interspecific genetic introgression in marine mammals. We propose to add nuclear loci to genetic databases for cetacean species identification in order to detect hybrid individuals.

  13. Genomic Characterization of Interspecific Hybrids and an Admixture Population Derived from Panicum amarum × P. virgatum

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    Christopher Heffelfinger

    2015-07-01

    Full Text Available Switchgrass ( L. and its relatives are regarded as top bioenergy crop candidates; however, one critical barrier is the introduction of useful genetic diversity and the development of new cultivars and hybrids. Combining genomes from related cultivars and species provides an opportunity to introduce new traits. In switchgrass, a breeding advantage would be achieved by combining the genomes of intervarietal ecotypes or interspecific hybrids. The recovery of wide crosses, however, is often tedious and may involve complicated embryo rescue and numerous backcrosses. Here, we demonstrate a straightforward approach to wide crosses involving the use of a selectable transgene for recovery of interspecific [ cv. Alamo × Ell var or Atlantic Coastal Panicgrass (ACP] F hybrids followed by backcrossing to generate a nontransgenic admixture population. A nontransgenic herbicide-sensitive (HbS admixture population of 83 FBC progeny was analyzed by genotyping-by-sequencing (GBS to characterize local ancestry, parental contribution, and patterns of recombination. These results demonstrate a widely applicable breeding strategy that makes use of transgenic selectable resistance to identify and recover true hybrids.

  14. The cytology, isozyme, HPLC fingerprint, and interspecific hybridization studies of genus epimedium (berberidaceae).

    Science.gov (United States)

    Wang, Lin-Jiao; Sheng, Mao-Yin

    2013-01-01

    104 samples from 27 accessions belonging to 12 species of genus Epimedium were studied on the basis of cytology observation, POD (i.e., peroxide) isozyme, high performance liquid chromatography (i.e., HPLC) fingerprint, and interspecific hybridization. The cytology observation showed karyotypes of twelve species studied; all are 2A symmetry type of Stebbins standard and similar to each other, and except for karyotype of E. leptorrhizum which is 2n = 2x = 8m (2SAT) + 4sm, the rest are 2n = 2x = 6m (2SAT) + 6sm. Chromosomes C-banding of barrenwort species varies, with 15 to 22 bands, consisting of centromeric bands, intercalary bands, terminal bands, and middle satellite bands. Results of POD isozyme showed that the zymographs vary greatly and sixteen bands were detected in the eleven species, and each species has its own characteristic bands different from the others. Studies on the HPLC fingerprint showed that the HPLC fingerprint of different species has characteristic peaks, divided into two regions (retention time 10 min). Results of interspecific hybridization showed that crosses of any combination among seven species studied are successful and the rates of grain set vary greatly. Based on these results, the system and phylogeny of this genus were inferred.

  15. Social phenotype extended to communities: expanded multilevel social selection analysis reveals fitness consequences of interspecific interactions.

    Science.gov (United States)

    Campobello, Daniela; Hare, James F; Sarà, Maurizio

    2015-04-01

    In social species, fitness consequences are associated with both individual and social phenotypes. Social selection analysis has quantified the contribution of conspecific social traits to individual fitness. There has been no attempt, however, to apply a social selection approach to quantify the fitness implications of heterospecific social phenotypes. Here, we propose a novel social selection based approach integrating the role of all social interactions at the community level. We extended multilevel selection analysis by including a term accounting for the group phenotype of heterospecifics. We analyzed nest activity as a model social trait common to two species, the lesser kestrel (Falco naumanni) and jackdaw (Corvus monedula), nesting in either single- or mixed-species colonies. By recording reproductive outcome as a measure of relative fitness, our results reveal an asymmetric system wherein only jackdaw breeding performance was affected by the activity phenotypes of both conspecific and heterospecific neighbors. Our model incorporating heterospecific social phenotypes is applicable to animal communities where interacting species share a common social trait, thus allowing an assessment of the selection pressure imposed by interspecific interactions in nature. Finally, we discuss the potential role of ecological limitations accounting for random or preferential assortments among interspecific social phenotypes, and the implications of such processes to community evolution. © 2015 The Author(s).

  16. Arbuscular common mycorrhizal networks mediate intra- and interspecific interactions of two prairie grasses.

    Science.gov (United States)

    Weremijewicz, Joanna; da Silveira Lobo O'Reilly Sternberg, Leonel; Janos, David P

    2018-01-01

    Arbuscular mycorrhizal fungi form extensive common mycorrhizal networks (CMNs) that may interconnect neighboring root systems of the same or different plant species, thereby potentially influencing the distribution of limiting mineral nutrients among plants. We examined how CMNs affected intra- and interspecific interactions within and between populations of Andropogon gerardii, a highly mycorrhiza dependent, dominant prairie grass and Elymus canadensis, a moderately dependent, subordinate prairie species. We grew A. gerardii and E. canadensis alone and intermixed in microcosms, with individual root systems isolated, but either interconnected by CMNs or with CMNs severed weekly. CMNs, which provided access to a large soil volume, improved survival of both A. gerardii and E. canadensis, but intensified intraspecific competition for A. gerardii. When mixed with E. canadensis, A. gerardii overyielded aboveground biomass in the presence of intact CMNs but not when CMNs were severed, suggesting that A. gerardii with intact CMNs most benefitted from weaker interspecific than intraspecific interactions across CMNs. CMNs improved manganese uptake by both species, with the largest plants receiving the most manganese. Enhanced growth in consequence of improved mineral nutrition led to large E. canadensis in intact CMNs experiencing water-stress, as indicated by 13 C isotope abundance. Our findings suggest that in prairie plant communities, CMNs may influence mineral nutrient distribution, water relations, within-species size hierarchies, and between-species interactions.

  17. Testing spatial theories of plant coexistence: no consistent differences in intra- and interspecific interaction distances.

    Science.gov (United States)

    Vogt, Deborah R; Murrell, David J; Stoll, Peter

    2010-01-01

    Plants stand still and interact with their immediate neighbors. Theory has shown that the distances over which these interactions occur may have important consequences for population and community dynamics. In particular, if intraspecific competition occurs over longer distances than interspecific competition (heteromyopia), coexistence can be promoted. We examined how intraspecific and interspecific competition scales with neighbor distance in a target-neighbor greenhouse competition experiment. Individuals from co-occurring forbs from calcareous grasslands were grown in isolation and with single conspecific or heterospecific neighbors at distances of 5, 10, or 15 cm (Plantago lanceolata vs. Plantago media and Hieracium pilosella vs. Prunella grandiflora). Neighbor effects were strong and declined with distance. Interaction distances varied greatly within and between species, but we found no evidence for heteromyopia. Instead, neighbor identity effects were mostly explained by relative size differences between target and neighbor. We found a complex interaction between final neighbor size and identity such that neighbor identity may become important only as the neighbor becomes very large compared with the target individual. Our results suggest that species-specific size differences between neighboring individuals determine both the strength of competitive interactions and the distance over which these interactions occur.

  18. Interspecific competition and the structure of bird guilds in boreal Europe: the importance of doing fieldwork in the right season.

    Science.gov (United States)

    Oksanen, L

    1987-12-01

    Bird studies have gained a central role in the debate on the importance of interspecific competition in nature. Thus, the negative results reported from a breeding bird community in a North American shrubsteppe area have created ripples throughout community ecology. However, the set of coexisting breeding birds might be an inappropriate operational definition of a bird community, because the intensity of interspecific competition can be expected to peak in autumn-winter. A review of North European data on wintering birds suggests that the case for the competition theory remains strong when bird communities are defined on the basis of winter coexistence. Copyright © 1987. Published by Elsevier Ltd.

  19. Induction of Tetraploid Male Sterile Tagetes erecta by Colchicine Treatment and Its Application for Interspecific Hybridization

    Directory of Open Access Journals (Sweden)

    Yanhong He

    2016-09-01

    Full Text Available Tagetes erecta is an annual multifunctional plant which can be cultivated under a broad range of climatic conditions. Polyploidization and interspecific hybridization are applied to facilitate breeding cultivars of T. erecta with improved ornamental qualities. Colchicine treatment to the germinating seeds was proved to be a useful tool for chromosome doubling of the male sterile two-type line ‘M525AB’, with the resulting frequency of polyploid seedlings ranging from 88.89% (following 0.05% w/v colchicine applied for a 3–6 h exposure period to a maximum of 100.00% (following 0.1% for 3–6 h, or 0.2% for 3 h. Morphological observation, stomatal size and density analysis, flow cytometric analysis and chromosome counting were conducted to identify the tetraploid plants. Distinctive morphological changes were observed in a notable proportion of polyploid plants. The colchicine-treated polyploid T. erecta plants showed dwarfed and more robust growth, thicker, larger and greener leaves, larger inflorescences and florets. The mutant plants identified through morphological observation all aligned as polyploid plants, thus morphological observation could be an effective method for the detection of polyploidy. The polyploid plants had significant larger stomata size over the abaxial leaf surface, whereas the density of stomata distribution was remarkably reduced. The survival rate of tetraploid cuttings (i.e. 38% was greatly reduced compared to that of diploid plants. The fertility of tetraploid plants was also decreased, as shown by cross-pollination yields. Interspecific hybridizations between colchicine-induced tetraploid plants of a male sterile T. erecta line and the naturally tetraploid fully fertile Tagetes patula species resulted in hybrid progeny. Most of these hybrids displayed the dwarfed growth stature and compact, larger-flower morphology which is the typical ideotype of herbaceous flowers. Thus, polyploidization may be employed

  20. Evidence for the Emergence of New Rice Types of Interspecific Hybrid Origin in West African Farmers' Fields

    NARCIS (Netherlands)

    Nuijten, H.A.C.P.; Treuren, van R.; Struik, P.C.; Mokuwa, G.A.; Okry, F.; Teeken, B.W.E.; Richards, P.

    2009-01-01

    In West Africa two rice species (Oryza glaberrima Steud. and Oryza sativa L.) co-exist. Although originally it was thought that interspecific hybridization is impossible without biotechnological methods, progenies of hybridization appear to occur in farmer fields. AFLP analysis was used to assess

  1. Introducing a new breed of wine yeast: interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast and Saccharomyces mikatae.

    Science.gov (United States)

    Bellon, Jennifer R; Schmid, Frank; Capone, Dimitra L; Dunn, Barbara L; Chambers, Paul J

    2013-01-01

    Interspecific hybrids are commonplace in agriculture and horticulture; bread wheat and grapefruit are but two examples. The benefits derived from interspecific hybridisation include the potential of generating advantageous transgressive phenotypes. This paper describes the generation of a new breed of wine yeast by interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast strain and Saccharomyces mikatae, a species hitherto not associated with industrial fermentation environs. While commercially available wine yeast strains provide consistent and reliable fermentations, wines produced using single inocula are thought to lack the sensory complexity and rounded palate structure obtained from spontaneous fermentations. In contrast, interspecific yeast hybrids have the potential to deliver increased complexity to wine sensory properties and alternative wine styles through the formation of novel, and wider ranging, yeast volatile fermentation metabolite profiles, whilst maintaining the robustness of the wine yeast parent. Screening of newly generated hybrids from a cross between a S. cerevisiae wine yeast and S. mikatae (closely-related but ecologically distant members of the Saccharomyces sensu stricto clade), has identified progeny with robust fermentation properties and winemaking potential. Chemical analysis showed that, relative to the S. cerevisiae wine yeast parent, hybrids produced wines with different concentrations of volatile metabolites that are known to contribute to wine flavour and aroma, including flavour compounds associated with non-Saccharomyces species. The new S. cerevisiae x S. mikatae hybrids have the potential to produce complex wines akin to products of spontaneous fermentation while giving winemakers the safeguard of an inoculated ferment.

  2. Somatic embryogenesis from corolla tubes of interspecific amphiploids between cultivated sunflower (Helianthus annuus L.) and its wild species

    Science.gov (United States)

    Somatic embryogenesis in vitro provides an efficient means of plant multiplication, facilitating sunflower improvement and germplasm innovation. In the present study, using interspecific amphiploids (2n=4x=68) between cultivated sunflower and wild perennial Helianthus species as explant donors, soma...

  3. Introducing a new breed of wine yeast: interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast and Saccharomyces mikatae.

    Directory of Open Access Journals (Sweden)

    Jennifer R Bellon

    Full Text Available Interspecific hybrids are commonplace in agriculture and horticulture; bread wheat and grapefruit are but two examples. The benefits derived from interspecific hybridisation include the potential of generating advantageous transgressive phenotypes. This paper describes the generation of a new breed of wine yeast by interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast strain and Saccharomyces mikatae, a species hitherto not associated with industrial fermentation environs. While commercially available wine yeast strains provide consistent and reliable fermentations, wines produced using single inocula are thought to lack the sensory complexity and rounded palate structure obtained from spontaneous fermentations. In contrast, interspecific yeast hybrids have the potential to deliver increased complexity to wine sensory properties and alternative wine styles through the formation of novel, and wider ranging, yeast volatile fermentation metabolite profiles, whilst maintaining the robustness of the wine yeast parent. Screening of newly generated hybrids from a cross between a S. cerevisiae wine yeast and S. mikatae (closely-related but ecologically distant members of the Saccharomyces sensu stricto clade, has identified progeny with robust fermentation properties and winemaking potential. Chemical analysis showed that, relative to the S. cerevisiae wine yeast parent, hybrids produced wines with different concentrations of volatile metabolites that are known to contribute to wine flavour and aroma, including flavour compounds associated with non-Saccharomyces species. The new S. cerevisiae x S. mikatae hybrids have the potential to produce complex wines akin to products of spontaneous fermentation while giving winemakers the safeguard of an inoculated ferment.

  4. Introducing a New Breed of Wine Yeast: Interspecific Hybridisation between a Commercial Saccharomyces cerevisiae Wine Yeast and Saccharomyces mikatae

    Science.gov (United States)

    Bellon, Jennifer R.; Schmid, Frank; Capone, Dimitra L.; Dunn, Barbara L.; Chambers, Paul J.

    2013-01-01

    Interspecific hybrids are commonplace in agriculture and horticulture; bread wheat and grapefruit are but two examples. The benefits derived from interspecific hybridisation include the potential of generating advantageous transgressive phenotypes. This paper describes the generation of a new breed of wine yeast by interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast strain and Saccharomyces mikatae, a species hitherto not associated with industrial fermentation environs. While commercially available wine yeast strains provide consistent and reliable fermentations, wines produced using single inocula are thought to lack the sensory complexity and rounded palate structure obtained from spontaneous fermentations. In contrast, interspecific yeast hybrids have the potential to deliver increased complexity to wine sensory properties and alternative wine styles through the formation of novel, and wider ranging, yeast volatile fermentation metabolite profiles, whilst maintaining the robustness of the wine yeast parent. Screening of newly generated hybrids from a cross between a S. cerevisiae wine yeast and S. mikatae (closely-related but ecologically distant members of the Saccharomyces sensu stricto clade), has identified progeny with robust fermentation properties and winemaking potential. Chemical analysis showed that, relative to the S. cerevisiae wine yeast parent, hybrids produced wines with different concentrations of volatile metabolites that are known to contribute to wine flavour and aroma, including flavour compounds associated with non-Saccharomyces species. The new S. cerevisiae x S. mikatae hybrids have the potential to produce complex wines akin to products of spontaneous fermentation while giving winemakers the safeguard of an inoculated ferment. PMID:23614011

  5. (S)-(+)-Ipsdienol: Interspecific Inhibition of Ips latidens (LeConte) by Ips pini (Say) (Coleoptera: Scolytidae)

    Science.gov (United States)

    Daniel R. Miller; John H. Borden

    1992-01-01

    In south-central British Columbia, the attraction of Ips latidens (LeConte) to its pheromone, ipsenol, was inhibited by (S)-(+)-ipsdienol, a pheromone for I. pini (Say). (R)-(-)-Ipsdienol had no effect on I. latidens. (S)-(+)-lpsdienol probably plays a role in interspecific communication between the two species...

  6. Abnormal spindle orientation during microsporogenesis in an interspecific Brachiaria (Gramineae hybrid

    Directory of Open Access Journals (Sweden)

    Andréa Beatriz Mendes-Bonato

    2006-01-01

    Full Text Available This paper reports a case of abnormal spindle orientation during microsporogenesis in an interspecific hybrid of the tropical grass Brachiaria. In the affected plant, prophase I was normal. In metaphase I, bivalents were regularly co-oriented but distantly positioned and spread over the equatorial plate. In anaphase I, chromosomes failed to converge into focused poles due to parallel spindle fibers. As a consequence, in telophase I, an elongated nucleus or several micronuclei were observed in each pole. In the second division, the behavior was the same, leading to polyads with several micronuclei. A total of 40% of meiotic products were affected. The use of this hybrid in production systems needing good-quality seeds is discussed.

  7. Embryogenic calli induced in interspecific (Elaeis guineensis x E. oleifera hybrid zygotic embryos

    Directory of Open Access Journals (Sweden)

    Paula Cristina da Silva Angelo

    2009-01-01

    Full Text Available The hybridization between oil palm (Elaeis guineensis and caiaué (E. oleifera plants is directed to obtainprogenies presenting high yields like oil palm but with reduced shoot height and resistance to lethal yellowing like caiaué.Cloning F1, BC1 and BC2 progenies can make the replication of selection trials easier. The objective of this work was to inducesomatic embryogenesis in interspecific zygotic embryos collected 100 days after pollination. Three progenies were cultivatedin an induction medium developed for Tenera (E. guineensis tp. dura x pisifera embryos. The number of embryos bearing calliand germinating was recorded and submitted to the Z test. Calli were weighted and submitted to histological analysis.Progenies differed in the number of embryos presenting plumules and calli simultaneously. By the ninth month, the apices ofincompletely developed somatic embryos were observed protruding from the surfaces of nodular calli. Highly embryogenicand friable secondary calli producing globular somatic embryos were not observed.

  8. First report of interspecific facultative social parasitism in the paper wasp genus Mischocyttarus Saussure (Hymenoptera, Vespidae

    Directory of Open Access Journals (Sweden)

    Thiago S. Montagna

    2012-06-01

    Full Text Available First report of interspecific facultative social parasitism in the paper wasp genus Mischocyttarus Saussure (Hymenoptera, Vespidae. Parasitism of colonies of the social wasp Mischocyttarus cerberus Ducke, 1918 by females of Mischocyttarus consimilis Zikán, 1949 was observed in a rural area of Dourados, state of Mato Grosso do Sul, Brazil. In all monitored cases, the invasion occurred in the pre-emergence colony stage, generally by a single female of M. consimilis. The period of establishment of the foreign female in the host colony was marked by antagonistic behaviors between the host female and the invasive. In general, the architecture of the parasitized nest was modified from the typical architecture of the host species nest.

  9. Gamma irradiation of the interspecific hybrids Gossypium hirsutum L. x G. barbadense L. Part 1

    International Nuclear Information System (INIS)

    Stoilova, A.

    1990-01-01

    The aim of the investigation is to combine the methods of hybridization and experimental mutagenesis and to widen the possibilities of interspecific hybridization for successful breeding work. Four hybrid combinations resulting from reciprocal crosses between the two species were studied. Seeds of long fibre F 1 plants from each combination were devided in four equal parts, three of which were irradiated with doses 15, 20 and 25 krad and one remained as control. The complex radiosensitivity evaluation of the four hybrid combinations investigated was based on the changes in the main biometrical indices comparing the control with 25 krad treatment and showed that the F 2 hybrids were either resistant or slightly sensitive to irradiation depending on the direction of crossing in respect to growth process, field germination and survival to the end of vegetation. 2 figs., 3 tabs., 14 refs

  10. Phenology and interspecific association of Forficula auricularia and Forficula pubescens in apple orchards

    Directory of Open Access Journals (Sweden)

    Jaume Lordan

    2015-03-01

    Full Text Available The European earwig Forficula auricularia L. (Dermaptera: Forficulidae has been widely studied as a key predator of pests in temperate regions, but its phenology and behavior may differ in warmer areas such as the Mediterranean. Here we assessed the phenology, aggregation, and interspecific association of F. auricularia and Forficula pubescens Gené, the only two species found consistently in both ground and canopy shelters in Mediterranean apple orchards. In addition to F. auricularia and F. pubescens, three other earwig species, namely Labidura riparia Pallas, Nala lividipes Dufour and Euborellia moesta Gené, were found occasionally. The mature stages of F. auricularia were observed mainly from May to November in tree shelters and immature ones from October to June in ground shelters. Adult individuals of F. pubescens were observed year-round and nymph instars were detected from April to June in ground as well as in tree shelters. The suitability of the current degree-days models for temperate regions was evaluated for the prediction of European earwig phenology in a Mediterranean climate. Regarding interspecific association, F. auricularia and F. pubescens co-occurred in canopies without apparent competition. This study provides useful weekly data about the phenology of the two earwig species throughout the year that can be used to detect the key periods during which to enhance their populations in pip fruit orchards or to control them in stone fruit crops. Furthermore, our results are of relevance for the development of new phenological models of earwigs in Mediterranean areas where nymphs hibernate, a feature that makes current models inaccurate.

  11. Spatial distribution and interspecific associations of tree species in a tropical seasonal rain forest of China.

    Directory of Open Access Journals (Sweden)

    Guoyu Lan

    Full Text Available Studying the spatial pattern and interspecific associations of plant species may provide valuable insights into processes and mechanisms that maintain species coexistence. Point pattern analysis was used to analyze the spatial distribution patterns of twenty dominant tree species, their interspecific spatial associations and changes across life stages in a 20-ha permanent plot of seasonal tropical rainforest in Xishuangbanna, China, to test mechanisms maintaining species coexistence. Torus-translation tests were used to quantify positive or negative associations of the species to topographic habitats. The results showed: (1 fourteen of the twenty tree species were negatively (or positively associated with one or two of the topographic variables, which evidences that the niche contributes to the spatial pattern of these species. (2 Most saplings of the study species showed a significantly clumped distribution at small scales (0-10 m which was lost at larger scales (10-30 m. (3 The degree of spatial clumping deceases from saplings, to poles, to adults indicates that density-dependent mortality of the offspring is ubiquitous in species. (4 It is notable that a high number of positive small-scale interactions were found among the twenty species. For saplings, 42.6% of all combinations of species pairs showed positive associations at neighborhood scales up to five meters, but only 38.4% were negative. For poles and adults, positive associations at these distances still made up 45.5% and 29.5%, respectively. In conclusion, there is considerable evidence for the presence of positive interactions among the tree species, which suggests that species herd protection may occur in our plot. In addition, niche assembly and limited dispersal (likely contribute to the spatial patterns of tree species in the tropical seasonal rain forest in Xishuangbanna, China.

  12. Environmental determinism, and not interspecific competition, drives morphological variability in Australasian warblers (Acanthizidae).

    Science.gov (United States)

    García-Navas, Vicente; Rodríguez-Rey, Marta; Marki, Petter Z; Christidis, Les

    2018-04-01

    Interspecific competition is thought to play a key role in determining the coexistence of closely related species within adaptive radiations. Competition for ecological resources can lead to different outcomes from character displacement to, ultimately, competitive exclusion. Accordingly, divergent natural selection should disfavor those species that are the most similar to their competitor in resource use, thereby increasing morphological disparity. Here, we examined ecomorphological variability within an Australo-Papuan bird radiation, the Acanthizidae, which include both allopatric and sympatric complexes. In addition, we investigated whether morphological similarities between species are related to environmental factors at fine scale (foraging niche) and/or large scale (climate). Contrary to that predicted by the competition hypothesis, we did not find a significant correlation between the morphological similarities found between species and their degree of range overlap. Comparative modeling based on both a priori and data-driven identification of selective regimes suggested that foraging niche is a poor predictor of morphological variability in acanthizids. By contrast, our results indicate that climatic conditions were an important factor in the formation of morphological variation. We found a significant negative correlation between species scores for PC1 (positively associated to tarsus length and tail length) and both temperature and precipitation, whereas PC2 (positively associated to bill length and wing length) correlated positively with precipitation. In addition, we found that species inhabiting the same region are closer to each other in morphospace than to species outside that region regardless of genus to which they belong or its foraging strategy. Our results indicate that the conservative body form of acanthizids is one that can work under a wide variety of environments (an all-purpose morphology), and the observed interspecific similarity is

  13. Phenology and interspecific association of Forficula auricularia and Forficula pubescens in apple orchards

    Energy Technology Data Exchange (ETDEWEB)

    Lordan, J.; Alegre, S.; Moerkens, R.; Sarasúa, M.J.; Alins, G.

    2015-07-01

    The European earwig Forficula auricularia L. (Dermaptera: Forficulidae) has been widely studied as a key predator of pests in temperate regions, but its phenology and behavior may differ in warmer areas such as the Mediterranean. Here we assessed the phenology, aggregation, and interspecific association of F. auricularia and Forficula pubescens Gené, the only two species found consistently in both ground and canopy shelters in Mediterranean apple orchards. In addition to F. auricularia and F. pubescens, three other earwig species, namely Labidura riparia Pallas, Nala lividipes Dufour and Euborellia moesta Gené, were found occasionally. The mature stages of F. auricularia were observed mainly from May to November in tree shelters and immature ones from October to June in ground shelters. Adult individuals of F. pubescens were observed year-round and nymph instars were detected from April to June in ground as well as in tree shelters. The suitability of the current degree-days models for temperate regions was evaluated for the prediction of European earwig phenology in a Mediterranean climate. Regarding interspecific association, F. auricularia and F. pubescens co-occurred in canopies without apparent competition. This study provides useful weekly data about the phenology of the two earwig species throughout the year that can be used to detect the key periods during which to enhance their populations in pip fruit orchards or to control them in stone fruit crops. Furthermore, our results are of relevance for the development of new phenological models of earwigs in Mediterranean areas where nymphs hibernate, a feature that makes current models inaccurate. (Author)

  14. Interspecific semantic alarm call recognition in the solitary Sahamalaza sportive lemur, Lepilemur sahamalazensis.

    Directory of Open Access Journals (Sweden)

    Melanie Seiler

    Full Text Available As alarm calls indicate the presence of predators, the correct interpretation of alarm calls, including those of other species, is essential for predator avoidance. Conversely, communication calls of other species might indicate the perceived absence of a predator and hence allow a reduction in vigilance. This "eavesdropping" was demonstrated in birds and mammals, including lemur species. Interspecific communication between taxonomic groups has so far been reported in some reptiles and mammals, including three primate species. So far, neither semantic nor interspecific communication has been tested in a solitary and nocturnal lemur species. The aim of this study was to investigate if the nocturnal and solitary Sahamalaza sportive lemur, Lepilemur sahamalazensis, is able to access semantic information of sympatric species. During the day, this species faces the risk of falling prey to aerial and terrestrial predators and therefore shows high levels of vigilance. We presented alarm calls of the crested coua, the Madagascar magpie-robin and aerial, terrestrial and agitation alarm calls of the blue-eyed black lemur to 19 individual Sahamalaza sportive lemurs resting in tree holes. Songs of both bird species' and contact calls of the blue-eyed black lemur were used as a control. After alarm calls of crested coua, Madagascar magpie-robin and aerial alarm of the blue-eyed black lemur, the lemurs scanned up and their vigilance increased significantly. After presentation of terrestrial alarm and agitation calls of the blue-eyed black lemur, the animals did not show significant changes in scanning direction or in the duration of vigilance. Sportive lemur vigilance decreased after playbacks of songs of the bird species and contact calls of blue-eyed black lemurs. Our results indicate that the Sahamalaza sportive lemur is capable of using information on predator presence as well as predator type of different sympatric species, using their referential

  15. Interspecific variation in the tetradactyl manus of modern tapirs (Perissodactyla: Tapirus) exposed using geometric morphometrics.

    Science.gov (United States)

    MacLaren, Jamie A; Nauwelaerts, Sandra

    2017-11-01

    The distal forelimb (autopodium) of quadrupedal mammals is a key morphological unit involved in locomotion, body support, and interaction with the substrate. The manus of the tapir (Perissodactyla: Tapirus) is unique within modern perissodactyls, as it retains the plesiomorphic tetradactyl (four-toed) condition also exhibited by basal equids and rhinoceroses. Tapirs are known to exhibit anatomical mesaxonic symmetry in the manus, although interspecific differences and biomechanical mesaxony have yet to be rigorously tested. Here, we investigate variation in the manus morphology of four modern tapir species (Tapirus indicus, Tapirus bairdii, Tapirus pinchaque, and Tapirus terrestris) using a geometric morphometric approach. Autopodial bones were laser scanned to capture surface shape and morphology was quantified using 3D-landmark analysis. Landmarks were aligned using Generalised Procrustes Analysis, with discriminant function and partial least square analyses performed on aligned coordinate data to identify features that significantly separate tapir species. Overall, our results support the previously held hypothesis that T. indicus is morphologically separate from neotropical tapirs; however, previous conclusions regarding function from morphological differences are shown to require reassessment. We find evidence indicating that T. bairdii exhibits reduced reliance on the lateral fifth digit compared to other tapirs. Morphometric assessment of the metacarpophalangeal joint and the morphology of the distal facets of the lunate lend evidence toward high loading on the lateral digits of both the large T. indicus (large body mass) and the small, long limbed T. pinchaque (ground impact). Our results support other recent studies on T. pinchaque, suggesting subtle but important adaptations to a compliant but inclined habitat. In conclusion, we demonstrate further evidence that the modern tapir forelimb is a variable locomotor unit with a range of interspecific features

  16. Climate as possible reproductive barrier in Pinus radiata (D. Don interspecific hybridisation

    Directory of Open Access Journals (Sweden)

    Hannél Ham

    2017-12-01

    Full Text Available Historically, interspecific hybridisation with Pinus radiata D. Don had limited success. The effect of environmental conditions and position of pollination bags in the tree were investigated as possible hybridisation barriers. The study was conducted in a P. radiata seed orchard in the Southern Cape (South Africa. Field data were compared to the climatic conditions at natural and commercial provenances of seven Mesoamerican Pinus species identified as possible hybrid partners. In vitro pollen studies were used to confirm whether interspecific crosses with P. radiata might be feasible within predefined climatic parameters. The temperature ranges for both top and northern side of P. radiata pine trees in the seed orchard was similar to the natural distribution of P. radiata, P. elliottii Engelm. and P. taeda L. in the USA. Results suggested that pollen of P. elliottii and P. taeda might be more suited to result in the successful pollination of P. radiata than the other Mesoamerican pine species tested in this study.  Furthermore, the combination of minimum temperature and precipitation also showed a closer correlation to successful hybridisation with P. radiata for both P. elliotii and P. taeda. However, pollen tube elongation studies did not support these results, suggesting that mean temperature might not be the only determining factor of hybridisation success. Three circadian temperature models that mimic natural conditions were developed for Karatara and Sabie (Tweefontein, Witklip and Spitskop.  These models will be tested in future in vitro studies to further evaluate temperature fluctuations between day and night regimes as a possible reproductive barrier limiting hybridisation success between P. radiata and other Mesoamerican pine species.

  17. PROPAGATION OF KHAYA ANTHOTHECA: INTERSPECIFIC GRAFTING WITH SWIETENIA MACROPHYLLA AND AIR LAYERING

    Directory of Open Access Journals (Sweden)

    Joamir Barbosa Filho

    2016-12-01

    Full Text Available Swietenia macrophylla yields high-quality wood; however, its vulnerability to extinction coupled with challenges for its cultivation have brought attention to its replacement for alternative species such as the Khaya anthotheca. The species has been recently introduced to South America, with potential for the production of high-quality wood. However, limited background on breeding and efficient strategies for its vegetative propagation exist. Here, we achieved significant results with the application of cleft grafting and air layering for the propagation of K. anthotheca plants grown from seeds. First, we analyzed the compatibility of scions and rootstocks for intraspecific and interspecific cleft grafting combinations of K. anthotheca and S. macrophylla. Second, air layering was performed in K. anthotheca seedlings irrigated with three nutrient solution (100%, 50% and 25% of the initial concentration of nutrients combined with the application of indole-3-butyric acid (IBA to evaluate adventitious rooting. From cleft grafting, we achieved an overall graft compatibility and survival of 48% after 200 days. However, the interspecific combination of S. macrophylla (scion and K. anthotheca (rootstock implicated in no compatibility, while the reciprocal resulted in 52% of compatibility. Through air layering, the irrigation with the nutrient solution with at least 50% of the nutrients concentration and with IBA (3.0 or 8.0 g.L-1 resulted in the best adventitious rooting. Overall, we recommend cleft grafting, except for the combination S. macrophylla(scion and K. anthotheca (rootstock, with no compatibility. Air layering might also be useful for the propagation of K. anthotheca genotypes in breeding programs.

  18. Interspecific differences between D. pulex and D. magna in tolerance to cyanobacteria with protease inhibitors.

    Directory of Open Access Journals (Sweden)

    Christian J Kuster

    Full Text Available It is known that cyanobacteria negatively affect herbivores due to their production of toxins such as protease inhibitors. In the present study we investigated potential interspecific differences between two major herbivores, Daphnia magna and Daphnia pulex, in terms of their tolerance to cyanobacteria with protease inhibitors. Seven clones each of D. magna and of D. pulex were isolated from different habitats in Europe and North America. To test for interspecific differences in the daphnids' tolerance to cyanobacteria, their somatic and population growth rates were determined for each D. magna and D. pulex clone after exposure to varying concentrations of two Microcystis aeruginosa strains. The M. aeruginosa strains NIVA and PCC(- contained either chymotrypsin or trypsin inhibitors, but no microcystins. Mean somatic and population growth rates on a diet with 20% NIVA were significantly more reduced in D. pulex than in D. magna. On a diet with 10% PCC(-, the population growth of D. pulex was significantly more reduced than that of D. magna. This indicates that D. magna is more tolerant to cyanobacteria with protease inhibitors than D. pulex. The reduction of growth rates was possibly caused by an interference of cyanobacterial inhibitors with proteases in the gut of Daphnia, as many other conceivable factors, which might have been able to explain the reduced growth, could be excluded as causal factors. Protease assays revealed that the sensitivities of chymotrypsins and trypsins to cyanobacterial protease inhibitors did not differ between D. magna and D. pulex. However, D. magna exhibited a 2.3-fold higher specific chymotrypsin activity than D. pulex, which explains the observed higher tolerance to cyanobacterial protease inhibitors of D. magna. The present study suggests that D. magna may control the development of cyanobacterial blooms more efficiently than D. pulex due to differences in their tolerance to cyanobacteria with protease

  19. Interspecific reciprocity explains mobbing behaviour of the breeding chaffinches, Fringilla coelebs.

    Science.gov (United States)

    Krams, Indrikis; Krama, Tatjana

    2002-01-01

    When prey animals discover a predator close by, they mob it while uttering characteristic sounds that attract other prey individuals to the vicinity. Mobbing causes a predator to vacate its immediate foraging area, which gives an opportunity for prey individuals to continue their interrupted daily activity. Besides the increased benefits, mobbing behaviour also has its costs owing to injuries or death. The initiator of mobbing may be at increased risk of predation by attracting the predator's attention, especially if not joined by other neighbouring prey individuals. Communities of breeding birds have always been considered as temporal aggregations. Since an altruist could not prevent cheaters from exploiting its altruism in an anonymous community, this excluded any possibility of explaining mobbing behaviour in terms of reciprocal altruism. However, sedentary birds may have become acquainted since the previous non-breeding season. Migrant birds, forming anonymous communities at the beginning of the breeding season, may also develop closer social ties during the course of the breeding season. We tested whether a male chaffinch, a migrant bird, would initiate active harassment of a predator both at the beginning of the breeding season and a week later when it has become a member of a non-anonymous multi-species aggregation of sedentary birds. We expected that male chaffinches would be less likely to initiate a mob at the beginning of the breeding season when part of an anonymous multi-species aggregation of migratory birds. However, their mobbing activity should increase as the breeding season advances. Our results support these predictions. Cooperation among individuals belonging to different species in driving the predator away may be explained as interspecific reciprocity based on interspecific recognition and temporal stability of the breeding communities. PMID:12495502

  20. Interspecific and locational differences in metal levels in edible fish tissue from Saudi Arabia

    KAUST Repository

    Burger, Joanna

    2014-07-06

    Metal levels in fish have been extensively studied, but little data currently exists for the Middle East. We examined the levels of metals and metalloids (aluminum, arsenic, copper, manganese, selenium, zinc, and mercury) in the flesh of 13 fish species collected from three fishing sites and a local fish market in Jeddah, Saudi Arabia. We tested the following null hypotheses: (1) there are no interspecific differences in metal levels, (2) there are no differences in metal levels in fishes between market and fishing sites, (3) there are no size-related differences in metal levels, and (4) there are no differences in selenium:mercury molar ratio among different fish species. There were significant interspecific differences in concentrations for all metals. There was an order of magnitude difference in the levels of aluminum, arsenic, mercury, manganese, and selenium, indicating wide variation in potential effects on the fish themselves and on their predators. Fishes from Area II, close to a large commercial port, had the highest levels of arsenic, mercury, and selenium, followed by market fishes. Mercury was positively correlated with body size in 6 of the 13 fish species examined. Mercury was correlated positively with arsenic and selenium, but negatively with aluminum, cobalt, copper, manganese, and zinc. Selenium:mercury molar ratios varied significantly among species, with Carangoides bajad, Cephalopholis argus, Variola louti, and Ephinephelus tauvina having ratios below 10:1. These findings can be used in risk assessments, design of mercury reduction plans, development of fish advisories to protect public health, and future management decision-making.

  1. Mapping of genes for flower-related traits and QTLs for flowering ...

    Indian Academy of Sciences (India)

    Mapping of genes for flower-related traits and QTLs for flowering time in an interspecific population of Gossypium hirsutum × G. darwinii. Shuwen Zhang, Qianqian Lan, Xiang Gao, Biao Yang, Caiping Cai, Tianzhen Zhang and Baoliang Zhou. J. Genet. 95, 197–201. Table 1. Loci composition and recombination distances of ...

  2. Interspecific cross of the Bactrocera dorsalis Complex (Diptera: Tephritidae): How did it happen?

    International Nuclear Information System (INIS)

    Wee, Suk-Ling; Tan, Keng-Hong

    2000-01-01

    consumption, males of B. papayae and B. carambolae produce a common sex pheromonal component, coniferyl alcohol, CF (Nishida et al. 1988a, Nishida et al. 1988b, Tan and Nishida 1996). Therefore, is CF the sole factor that causes the interspecific attraction before copulation can take place? Secondly, will the acquisition of ME enhance the interspecific mating competitiveness? Lastly, do the females (of these species) show preference for their conspecific males or any males that have ingested ME in their diet and vice versa? The objective of the current investigation was to shed some light on these questions

  3. Heavy metals in fish from the Aleutians: Interspecific and locational differences

    International Nuclear Information System (INIS)

    Burger, Joanna; Gochfeld, Michael; Jeitner, Christian; Pittfield, Taryn; Donio, Mark

    2014-01-01

    The objectives of this study were to examine levels of arsenic, cadmium, lead, mercury and selenium in edible tissue of seven species of marine fish collected from several Aleutian islands (in 2004) to determine: (1) interspecific differences, (2) locational differences (among Aleutian Islands), (3) size-related differences in any metal levels within a species, and (4) potential risk to the fish or to predators on the fish, including humans. We also compared metals levels to those of three other fish species previously examined in detail, as well as examining metals in the edible tissue of octopus (Octopus dofleini). Octopus did not have the highest levels of any metal. There were significant interspecific differences in all metal levels among the fish species, although the differences were less than an order of magnitude, except for arsenic (mean of 19,500 ppb in Flathead sole, Hippoglossoides elassodon). Significant intraisland variation occurred among the four sites on Amchitka, but there was not a consistent pattern. There were significant interisland differences for some metals and species. Mercury levels increased significantly with size for several species; lead increased significantly for only one fish species; and cadmium and selenium decreased significantly with size for halibut (Hippoglossus stenolepis). The Alaskan Department of Health and Social Services supports unrestricted consumption of most Alaskan fish species for all people, including pregnant women. Most mean metal concentrations were well below the levels known to adversely affect the fish themselves, or predators that consume them (including humans), except for mercury in three fish species (mean levels just below 0.3 ppm), and arsenic in two fish species. However, even at low mercury levels, people who consume fish almost daily will exceed guideline values from the Centers for Disease Control and the Environmental Protection Agency. - Highlights: • Cadmium, lead, mercury and selenium

  4. Heavy metals in fish from the Aleutians: Interspecific and locational differences

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Joanna, E-mail: burger@biology.rutgers.edu [Division of Life Sciences, Rutgers University, 604 Allison Road, Piscataway, NJ (United States); Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ (United States); Consortium for Risk Evaluation with Stakeholder Participation, Vanderbilt University, Nashville, TN 37235 (United States); Gochfeld, Michael [Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ (United States); Consortium for Risk Evaluation with Stakeholder Participation, Vanderbilt University, Nashville, TN 37235 (United States); Environmental and Occupational Medicine, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854 (United States); Jeitner, Christian; Pittfield, Taryn [Division of Life Sciences, Rutgers University, 604 Allison Road, Piscataway, NJ (United States); Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ (United States); Consortium for Risk Evaluation with Stakeholder Participation, Vanderbilt University, Nashville, TN 37235 (United States); Donio, Mark [Division of Life Sciences, Rutgers University, 604 Allison Road, Piscataway, NJ (United States)

    2014-05-01

    The objectives of this study were to examine levels of arsenic, cadmium, lead, mercury and selenium in edible tissue of seven species of marine fish collected from several Aleutian islands (in 2004) to determine: (1) interspecific differences, (2) locational differences (among Aleutian Islands), (3) size-related differences in any metal levels within a species, and (4) potential risk to the fish or to predators on the fish, including humans. We also compared metals levels to those of three other fish species previously examined in detail, as well as examining metals in the edible tissue of octopus (Octopus dofleini). Octopus did not have the highest levels of any metal. There were significant interspecific differences in all metal levels among the fish species, although the differences were less than an order of magnitude, except for arsenic (mean of 19,500 ppb in Flathead sole, Hippoglossoides elassodon). Significant intraisland variation occurred among the four sites on Amchitka, but there was not a consistent pattern. There were significant interisland differences for some metals and species. Mercury levels increased significantly with size for several species; lead increased significantly for only one fish species; and cadmium and selenium decreased significantly with size for halibut (Hippoglossus stenolepis). The Alaskan Department of Health and Social Services supports unrestricted consumption of most Alaskan fish species for all people, including pregnant women. Most mean metal concentrations were well below the levels known to adversely affect the fish themselves, or predators that consume them (including humans), except for mercury in three fish species (mean levels just below 0.3 ppm), and arsenic in two fish species. However, even at low mercury levels, people who consume fish almost daily will exceed guideline values from the Centers for Disease Control and the Environmental Protection Agency. - Highlights: • Cadmium, lead, mercury and selenium

  5. Parrotfish grazing ability: interspecific differences in relation to jaw-lever mechanics and relative weight of adductor mandibulae on an Okinawan coral reef

    OpenAIRE

    Nanami, Atsushi

    2016-01-01

    Parrotfishes (family Labridae: Scarini) are regarded to have important roles for maintaining the ecosystem balance in coral reefs due to their removal of organic matter and calcic substrates by grazing. The purpose of the present study was to clarify the interspecific differences in grazing ability of five parrotfish species (Chlorurus sordidus, C. bowersi, Scarus rivulatus, S. niger and S. forsteni) in relation to interspecific differences in jaw-lever mechanics and the relative weight of th...

  6. Interspecific competition changes photosynthetic and oxidative stress response of barley and barnyard grass to elevated CO2 and temperature

    OpenAIRE

    Irena Januskaitiene; Jūratė Žaltauskaitė; Austra Dikšaitytė; Gintarė Sujetovienė; Diana Miškelytė; Giedrė Kacienė; Sandra Sakalauskienė; Jurga Miliauskienė; Romualdas Juknys

    2018-01-01

    This work focuses on the investigation of competition interaction between C3 crop barley (Hordeum vulgare L.) and C4 weed barnyard grass (Echinochloa crus-galli L.) at 2 times higher than ambient [CO2] and +4 0C higher ambient temperature climate conditions. It was hypothesized that interspecific competition will change the response of the investigated plants to increased [CO2] and temperature. The obtained results showed that in the current climate conditions, a higher biomass and photosynth...

  7. Niche filtering, not interspecific resource competition, explains the co-occurrence of butterfly species across the Japanese archipelago

    OpenAIRE

    Iwasaki, Takaya; Sato, Yasuhiro; Nakadai, Ryosuke; Hashimoto, Koya

    2017-01-01

    The relevance of interspecific resource competition in the context of community assembly by herbivorous insects is a well-known topic in ecology. Most previous studies focused on local species assemblies, that shared host plants. Few studies evaluated species pairs within a single taxon when investigating the effects of host plant sharing at the regional scale. Herein, we explore the effect of plant sharing on the geographical co-occurrence patterns of 229 butterflies distributed across the J...

  8. Variation in foraging behavior and body mass in broods of Emperor Geese (Chen canagica): Evidence for interspecific density dependence

    Science.gov (United States)

    Schmutz, J.A.; Laing, K.K.

    2002-01-01

    Broods of geese spend time feeding according to availability and quality of food plants, subject to inherent foraging and digestive constraints. We studied behavioral patterns of broods of Emperor Geese (Chen canagica) on the Yukon–Kuskokwim Delta, Alaska, and examined how feeding and alert behavior varied in relation to habitat and goose density. During 1994–1996, time spent feeding by Emperor Goose goslings and adult females was positively related to multispecies goose densities near observation blinds, and not to just Emperor Goose density. Similarly, body mass of Emperor Goose goslings was more strongly related (negatively) to multispecies goose densities than intraspecific densities. A grazing experiment in 1995 indicated that most above ground primary production by Carex subspathacea, a preferred food plant, was consumed by grazing geese. Those results demonstrate that interspecific competition for food occurred, with greatest support for goslings whose behavioral repertoire is limited primarily to feeding, digesting, and resting. Although the more abundant Cackling Canada Geese (Branta canadensis minima) differed from Emperor Geese in their preferred use of habitats during brooding rearing (Schmutz 2001), the two species occurred in equal abundance in habitats preferred by Emperor Goose broods. Thus, Cackling Canada Geese were a numerically significant competitor with Emperor Geese. Comparing these results to an earlier study, time spent feeding by goslings, adult females, and adult males were greater during 1993–1996 than during 1985–1986. During the interval between those studies, densities of Cackling Canada Geese increased two to three times whereas Emperor Goose numbers remained approximately stable, which implies that interspecific competition affected foraging behavior over a long time period. These density-dependent changes in foraging behavior and body mass indicate that interspecific competition affects nutrient acquisition and gosling

  9. Importance of intra- and interspecific plant interactions for the phytomanagement of semiarid mine tailings using the tree species Pinus halepensis.

    Science.gov (United States)

    Martinez-Oró, Duli; Parraga-Aguado, Isabel; Querejeta, Jose Ignacio; Conesa, Héctor M

    2017-11-01

    The objective of this work was to evaluate the effects of plant interactions (intra- and interspecific) on the growth and metal(loid) uptake of the tree species Pinus halepensis to determine its suitability for the phytomanagement of semiarid mine tailings. The pioneer tailings colonizer grass Piptatherum miliaceum was selected for assessing interspecific interactions. The experiment was conducted following a pot experimental design employing mine tailings soil. Pots containing single individuals of P. halepensis or P. miliaceum and pots containing combinations with pines (two pines per pot, or one pine and one grass per pot) were used. The analyses included the determination of plant biomass, foliar element status and stable isotope composition, metal(loid) uptake and its translocation to different plant organs. P. halepensis strongly favoured the growth of P. miliaceum by increasing 9-fold the latter's biomass and alleviating its P limitation. In this interspecific treatment P. halepensis showed a strong N limitation (N/P = 7), which negatively affected its growth, (to about half the biomass of that obtained for the other treatments) and exhibited a significant increase in some metals translocation (especially Cd) into aerial parts. Interestingly, P. miliaceum showed a decrease in the root to leaves translocation factor for most of metals when growing together with pines. The effects of the intraespecific combination on growth and metal uptake in P. halepensis were less relevant than those obtained for the interspecific one. Further research should be focused on testing the behaviour of plant co-cultures under the addition of N or P amendments which could alleviate the negative effects of plant competition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Interspecific interactions between Phragmites australis and Spartina alterniflora along a tidal gradient in the Dongtan wetland, Eastern China.

    Directory of Open Access Journals (Sweden)

    Yue Yuan

    Full Text Available The invasive species Spartina alterniora Loisel was introduced to the eastern coast of China in the 1970s and 1980s for the purposes of land reclamation and the prevention of soil erosion. The resulting interspecific competition had an important influence on the distribution of native vegetation, which makes studying the patterns and mechanisms of the interactions between Spartina alterniora Loisel and the native species Phragmites australis (Cav. Trin ex Steud in this region very important. There have been some researches on the interspecific interactions between P. australis and S. alterniora in the Dongtan wetland of Chongming, east China, most of which has focused on the comparison of their physiological characteristics. In this paper, we conducted a neighbor removal experiment along a tidal gradient to evaluate the relative competitive abilities of the two species by calculating their relative neighbor effect (RNE index. We also looked at the influence of environmental stress and disturbance on the competitive abilities of the two species by comparing interaction strength (I among different tidal zones both for P. australis and S. alterniora. Finally, we measured physiological characteristics of the two species to assess the physiological mechanisms behind their different competitive abilities. Both negative and positive interactions were found between P. australis and S. alterniora along the environmental gradient. When the direction of the competitive intensity index for P. australis and S. alterniora was consistent, the competitive or facilitative effect of S. alterniora on P. australis was stronger than that of P. australis on S. alterniora. The interspecific interactions of P. australis and S. alterniora varied with environmental conditions, as well as with the method used, to measure interspecific interactions.

  11. Molecular phylogeny of the genus Asparagus (Asparagaceae) explains interspecific crossability between the garden asparagus (A. officinalis) and other Asparagus species.

    Science.gov (United States)

    Kubota, Shosei; Konno, Itaru; Kanno, Akira

    2012-02-01

    The genus Asparagus comprises approximately 200 species, some of which are commercially cultivated, such as the garden asparagus (A. officinalis). Many Asparagus species, including A. officinalis, are dioecious and have been grouped into a subgenus distinct from that of hermaphroditic species. Although many interspecific crossings have been attempted to introduce useful traits into A. officinalis, only some of the dioecious species were found to be cross-compatible with A. officinalis. Here, molecular phylogenetic analyses were conducted to determine whether interspecific crossability is proportional to the genetic distance between the crossing pairs and to further clarify the evolutionary history of the Asparagus genus. A clade with all cross-compatible species and no cross-incompatible species was recovered in the phylogenetic tree based on analyses of non-coding cpDNA regions. In addition, a sex-linked marker developed for A. officinalis amplified a male-specific region in all cross-compatible species. The phylogenetic analyses also provided some insights about the evolutionary history of Asparagus; for example, by indicating that the genus had its origin in southern Africa, subsequently spreading throughout the old world through intensive speciation and dispersal. The results also suggest that dioecious species were derived from a single evolutionary transition from hermaphroditism in Asparagus. These findings not only contribute towards the understanding of the evolutionary history of the genus but may also facilitate future interspecific hybridization programs involving Asparagus species.

  12. Interspecific competition changes photosynthetic and oxidative stress response of barley and barnyard grass to elevated CO2 and temperature

    Directory of Open Access Journals (Sweden)

    Irena Januskaitiene

    2018-03-01

    Full Text Available This work focuses on the investigation of competition interaction between C3 crop barley (Hordeum vulgare L. and C4 weed barnyard grass (Echinochloa crus-galli L. at 2 times higher than ambient [CO2] and +4 0C higher ambient temperature climate conditions. It was hypothesized that interspecific competition will change the response of the investigated plants to increased [CO2] and temperature. The obtained results showed that in the current climate conditions, a higher biomass and photosynthetic rate and a lower antioxidant activity were detected for barley grown under interspecific competition effect. While in the warmed climate and under competition conditions opposite results were detected: a higher water use efficiency, a higher photosynthetic performance, a lower dissipated energy flux and a lower antioxidant enzymes activity were detected for barnyard grass plants. This study highlights that in the future climate conditions, barnyard grass will become more efficient in performance of the photosynthetic apparatus and it will suffer from lower oxidative stress caused by interspecific competition as compared to barley.

  13. Body mass of prefledging Emperor Geese Chen canagica: Large-scale effects of interspecific densities and food availability

    Science.gov (United States)

    Lake, B.C.; Schmutz, J.A.; Lindberg, M.S.; Ely, Craig R.; Eldridge, W.D.; Broerman, F.J.

    2008-01-01

    We studied body mass of prefledging Emperor Geese Chen canagica at three locations across the Yukon-Kuskokwim Delta, Alaska, during 1990-2004 to investigate whether large-scale variation in body mass was related to interspecific competition for food. From 1990 to 2004, densities of Cackling Geese Branta hutchinsii minima more than doubled and were c. 2-5?? greater than densities of Emperor Geese, which were relatively constant over time. Body mass of prefledging Emperor Geese was strongly related (negatively) to interspecific densities of geese (combined density of Cackling and Emperor Geese) and positively related to measures of food availability (grazing lawn extent and net above-ground primary productivity (NAPP)). Grazing by geese resulted in consumption of ??? 90% of the NAPP that occurred in grazing lawns during the brood-rearing period, suggesting that density-dependent interspecific competition was from exploitation of common food resources. Efforts to increase the population size of Emperor Geese would benefit from considering competitive interactions among goose species and with forage plants. ?? 2008 The Authors.

  14. Assessment of interspecific interactions in plant communities: an illustration from the cold desert saltbush grasslands of North America

    Science.gov (United States)

    Freeman, Carl D.; Emlen, John M.

    1995-01-01

    Interspecific interactions influence both the productivity and composition of plant communities. Here, we propose new field procedures and analytical approaches for assessing interspecific interactions in nature and apply these procedures to the salt desert shrub grasslands of western Utah. Data were collected from two grazing treatments over a period of 2 years. The proposed equations were fairly consistent across both treatments and years. In addition to illustrating how to assess interspecific interactions within a community, we also develop a new approach for projecting the community composition as a result of some alteration, i.e. increase or decrease in the abundance of one or more species. Results demonstrate competition both within and between plant life-form groups. While introduced annuals were found to depress profoundly the likelihood of perennial plants replacing themselves, perennials had little influence on annuals. Thus, as native perennials die, they are more likely to be replaced by perennials than for the reverse to occur. Our results suggest that unless conditions change, these communities will become increasingly dominated by introduced annuals.

  15. Interspecific variation in the phenology of advertisement calling in a temperate Australian frog community.

    Science.gov (United States)

    Heard, Geoffrey W; Canessa, Stefano; Parris, Kirsten M

    2015-09-01

    Spatial and temporal partitioning of resources underlies the coexistence of species with similar niches. In communities of frogs and toads, the phenology of advertisement calling provides insights into temporal partitioning of reproductive effort and its implications for community dynamics. This study assessed the phenology of advertisement calling in an anuran community from Melbourne, in southern Australia. We collated data from 1432 surveys of 253 sites and used logistic regression to quantify seasonality in the nightly probability of calling and the influence of meteorological variables on this probability for six species of frogs. We found limited overlap in the predicted seasonal peaks of calling among these species. Those shown to have overlapping calling peaks are unlikely to be in direct competition, due to differences in larval ecology (Crinia signifera and Litoria ewingii) or differences in calling behavior and acoustics (Limnodynastes dumerilii and Litoria raniformis). In contrast, closely related and ecologically similar species (Crinia signfera and Crinia parinsignifera;Litoria ewingii and Litoria verreauxii) appear to have staggered seasonal peaks of calling. In combination with interspecific variation in the meteorological correlates of calling, these results may be indicative of temporal partitioning of reproductive activity to facilitate coexistence, as has been reported for tropical and temperate anurans from other parts of the globe.

  16. Meiosis in elephant grass (Pennisetum purpureum, pearl millet (Pennisetum glaucum (Poaceae, Poales and their interspecific hybrids

    Directory of Open Access Journals (Sweden)

    Vânia Helena Techio

    2006-01-01

    Full Text Available The cultivated and sexually compatible species Pennisetum purpureum (elephant grass, 2n = 4x = 28 and Pennisetum glaucum (pearl millet, 2n = 2x = 14 can undergo hybridization which favors the amplification of their genetic background and the introgression of favorable alleles into breeding programs. The main problem with interspecific hybrids of these species is infertility due to triploidy (2n = 3x = 21. This study describes meiosis in elephant grass x pearl millet hybrids and their progenitors. Panicles were prepared according to the conventional protocol for meiotic studies and Alexander’s stain was used for assessing pollen viability. Pearl millet accessions presented regular meiosis with seven bivalents and high pollen viability. For elephant grass, 14 bivalents in diakinesis and metaphase I were observed. The BAG 63 elephant grass accession, derived from tissue culture, presented a high frequency of meiotic abnormalities. The three hybrid accessions presented a high frequency of abnormalities characterized by irregular chromosomal segregation which resulted in the formation of sterile pollen.

  17. Newly generated interspecific wine yeast hybrids introduce flavour and aroma diversity to wines.

    Science.gov (United States)

    Bellon, Jennifer R; Eglinton, Jeffery M; Siebert, Tracey E; Pollnitz, Alan P; Rose, Louisa; de Barros Lopes, Miguel; Chambers, Paul J

    2011-08-01

    Increasingly, winemakers are looking for ways to introduce aroma and flavour diversity to their wines as a means of improving style and increasing product differentiation. While currently available commercial yeast strains produce consistently sound fermentations, there are indications that sensory complexity and improved palate structure are obtained when other species of yeast are active during fermentation. In this study, we explore a strategy to increase the impact of non-Saccharomyces cerevisiae inputs without the risks associated with spontaneous fermentations, through generating interspecific hybrids between a S. cerevisiae wine strain and a second species. For our experiments, we used rare mating to produce hybrids between S. cerevisiae and other closely related yeast of the Saccharomyces sensu stricto complex. These hybrid yeast strains display desirable properties of both parents and produce wines with concentrations of aromatic fermentation products that are different to what is found in wine made using the commercial wine yeast parent. Our results demonstrate, for the first time, that the introduction of genetic material from a non-S. cerevisiae parent into a wine yeast background can impact favourably on the wine flavour and aroma profile of a commercial S. cerevisiae wine yeast.

  18. Identification of interspecific hybrids between loquat (eriobotrya japonica lindl.) and bengal loquat (e. bengalensis hook.)

    International Nuclear Information System (INIS)

    Wang, Y.; Deng, Q.; Zeng, J.; Zhang, J.

    2017-01-01

    Loquat (Eriobotrya japonica Lindl.) is an important subtropical fruit; however, loquat fruitlets are vulnerable to cold injury in winter, which significantly decreases loquat yield in most production regions. In the present study, two loquat cultivars ('Dawuxing' and '4-1-5') and one wild loquat (E. bengalensis Hook., Bengal loquat), were used for interspecific hybridization to produce hybrids with characteristics of spring blooming to avoid cold injury of fruitlets. Hybrid seedlings were derived from direct cross (loquat as female parent and Bengal loquat as male parent) and reciprocal cross. The authenticity of 47 hybrid seedlings was confirmed using inter-simple sequence repeat (ISSR) molecular markers; and leaf morphological characteristics of the hybrid offspring and parents were preliminarily studied and compared. The results suggested that 23 true direct cross hybrids and 12 true reciprocal cross hybrids were obtained, with hybrid authenticity rates of 100 and 50.0%, respectively. Thus, a novel method of distant hybridization for loquat breeding was developed, and with their various genetic and morphological characteristics these hybrids could be valuable germplasms for horticultural use. (author)

  19. Evaluation of wheat genotypes originated from interspecific crossing and gamma radiation

    International Nuclear Information System (INIS)

    Camargo, C.E.O.; Ferreira Filho, A.W.P.; Freitas, J.G.; Tulmann Neto, A.; Pettinelli Junior, A.; Castro, J.L.

    1995-01-01

    Twenty three inbred HEXAPLOID wheat lines were evaluated. They were originated by selections made in populations submitted to gamma radiation (27.5 krad), in the F 4 generation, from the interspecific hybrid between BH-1146 (triticum aestivum L.) and Anhinga S x Winged S (Triticum durum L.) and the cultivars BH-1146 and Yavaros S (T. durum L.) Nine trials were carried out with irrigation and in upland conditions. Several agronomic characteristics were assessed. Under laboratory conditions the genotypes were evaluated with respect to Al toxicity using nutrient solutions. Semi dwarf line 11 and 19, with moderate lodging resistance, medium cycle from emergence to flowering, tolerance to aluminum toxicity, were the most productive. Seven lines showed resistance to the causal agent of mildew, but all genotypes were susceptible to the causal agents of leaf spots. Some of the genotypes could be used in cross breeding as genetic sources for short plant, long head, large number of spikelets per head, large number of grains per head and per spikelet and heavy grains. BH-1146 and seven from the 23 lines were considered the most tolerant to aluminium toxicity, presenting good regrowth after treatment in nutrient solutions with 10 mg/liter of Al +3 . (author). 15 refs., 7 tabs

  20. Meta-analysis of the effects of forest fragmentation on interspecific interactions.

    Science.gov (United States)

    Magrach, Ainhoa; Laurance, William F; Larrinaga, Asier R; Santamaria, Luis

    2014-10-01

    Forest fragmentation dramatically alters species persistence and distribution and affects many ecological interactions among species. Recent studies suggest that mutualisms, such as pollination and seed dispersal, are more sensitive to the negative effects of forest fragmentation than antagonisms, such as predation or herbivory. We applied meta-analytical techniques to evaluate this hypothesis and quantified the relative contributions of different components of the fragmentation process (decreases in fragment size, edge effects, increased isolation, and habitat degradation) to the overall effect. The effects of fragmentation on mutualisms were primarily driven by habitat degradation, edge effects, and fragment isolation, and, as predicted, they were consistently more negative on mutualisms than on antagonisms. For the most studied interaction type, seed dispersal, only certain components of fragmentation had significant (edge effects) or marginally significant (fragment size) effects. Seed size modulated the effect of fragmentation: species with large seeds showed stronger negative impacts of fragmentation via reduced dispersal rates. Our results reveal that different components of the habitat fragmentation process have varying impacts on key mutualisms. We also conclude that antagonistic interactions have been understudied in fragmented landscapes, most of the research has concentrated on particular types of mutualistic interactions such as seed dispersal, and that available studies of interspecific interactions have a strong geographical bias (arising mostly from studies carried out in Brazil, Chile, and the United States). © 2014 Society for Conservation Biology.

  1. Pesticide-mediated interspecific competition between local and invasive thrips pests

    Science.gov (United States)

    Zhao, Xueyin; Reitz, Stuart R.; Yuan, Huiguo; Lei, Zhongren; Paini, Dean Ronald; Gao, Yulin

    2017-01-01

    Competitive interactions between species can be mitigated or even reversed in the presence of anthropogenic influences. The thrips species Frankliniella occidentalis and Thrips tabaci are highly invasive and damaging agricultural pests throughout the world. Where the species co-occur, one species tends to eventually predominate over the other. Avermectin and beta-cypermethrin are commonly used insecticides to manage thrips in China, and laboratory bioassays demonstrated that F. occidentalis is significantly less susceptible than T. tabaci to these insecticides. In laboratory cage trials in which both species were exposed to insecticide treated cabbage plants, F. occidentalis became the predominant species. In contrast, T. tabaci completely displaced F. occidentalis on plants that were not treated with insecticides. In field trials, the species co-existed on cabbage before insecticide treatments began, but with T. tabaci being the predominant species. Following application of avermectin or beta-cypermethrin, F. occidentalis became the predominant species, while in plots not treated with insecticides, T. tabaci remained the predominant species. These results indicate that T. tabaci is an intrinsically superior competitor to F. occidentalis, but its competitive advantage can be counteracted through differential susceptibilities of the species to insecticides. These results further demonstrate the importance of external factors, such as insecticide applications, in mediating the outcome of interspecific interactions and produce rapid unanticipated shifts in the demographics of pest complexes. PMID:28084404

  2. Interspecific variation of total seed protein in wild rice germplasm using SDS-Page

    International Nuclear Information System (INIS)

    Shah, S.M.A.; Hidayat-ur-Rahman; Abbasi, F.M.; Ashiq, M.; Rabbani, A.M.; Khan, I.A.; Shinwari, Z.K.; Shah, Z.

    2011-01-01

    Variation in seed protein of 14 wild rice species (Oryza spp.) along with cultivated rice species (O. sativa) was studied using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) to assess genetic diversity in the rice germplasm. SDS bands were scored as present (1) or absent (0) for protein sample of each genotype. On the basis of cluster analysis, four clusters were identified at a similarity level of 0.85. O. nivara, O. rufipogon and O. sativa with AA genomes constituted the first cluster. The second cluster comprised O. punctata of BB genome and wild rice species of CC genome i.e., O. rhizomatis and O. officinalis. However, it also contained O. barthii and O. glumaepatula of AA genome. O. australiensis with EE genome, and O. latifolia, O. alta and O. grandiglumis having CCDD genomes comprised the third cluster. The fourth cluster consisted of wild rice species, O. brachyantha with EE genome along with two other wild rice species, O. longistaminata and O. meridionalis of AA genome. Overall, on the basis of total seed protein, the grouping pattern of rice genotypes was mostly compatible with their genome status. The results of the present work depicted considerable interspecific genetic variation in the investigated germplasm for total seed protein. Moreover, the results obtained in this study also suggest that analysis of seed protein can also provide a better understanding of genetic affinity of the germplasm. (author)

  3. Interspecific shared collective decision-making in two forensically important species.

    Science.gov (United States)

    Boulay, Julien; Deneubourg, Jean-Louis; Hédouin, Valéry; Charabidzé, Damien

    2016-02-10

    To date, the study of collective behaviour has mainly focused on intraspecific situations: the collective decision-making of mixed-species groups involving interspecific aggregation-segregation has received little attention. Here, we show that, in both conspecific and heterospecific groups, the larvae of two species (Lucilia sericata and Calliphora vomitoria, calliphorid carrion-feeding flies) were able to make a collective choice. In all groups, the choice was made within a few minutes and persisted throughout the period of the experiment. The monitoring of a focal individual within a group showed that these aggregations were governed by attractive and retentive effects of the group. Furthermore, the similarity observed between the conspecific and heterospecific groups suggested the existence of shared aggregation signals. The group size was found to have a stronger influence than the species of necrophagous larvae. These results should be viewed in relation to the well-known correlation between group size and heat generation. This study provides the first experimental examination of the dynamics of collective decision-making in mixed-species groups of invertebrates, contributing to our understanding of the cooperation-competition phenomenon in animal social groups. © 2016 The Author(s).

  4. Genetic analysis of Vitis interspecific hybrids occurring in vineyards of the Czech Republic

    International Nuclear Information System (INIS)

    Jana, R.; Andrea, S.; Radek, S.; Baranek, M.

    2016-01-01

    SSR analysis of 18 unknown uncultured Vitis genotypes planted in an area mostly dedicated to viticulture in the Czech Republic was performed in this work. The aim of this study was to identify analysed samples by comparing their SSR profiles with described standards and classify their mutual relationships based on their distribution in obtained dendrogram. Results show that 50 percent of unknown genotypes belongs to old American interspecific cultivar Noah and 11 percent belong to another old American cultivar Isabella. The rest of analysed genotypes remain unidentified, but three of them suggest relatedness with Noah cultivar, one genotype shows relatednessto Isabella cultivar. From practical point of view the most interesting ones are three genotypes, which were clearly clustered with the genotypes of cultural varities (botanically V. vinifera L.) used as standard. Based on this it is then possible to assume that those genotypes probably originated from crossing of non-V. vinifera genotype specimen with unknown cultural variety. Potential importance of analysed hybrids for further investigation and breeding, especialy in an eco-friendly viticulture, is also discussed. (author)

  5. Widespread evidence for interspecific mating between Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in nature.

    Science.gov (United States)

    Bargielowski, I E; Lounibos, L P; Shin, D; Smartt, C T; Carrasquilla, M C; Henry, A; Navarro, J C; Paupy, C; Dennett, J A

    2015-12-01

    Aedes aegypti and Aedes albopictus, two important vectors of the dengue and chikungunya viruses to humans, often come in contact in their invasive ranges. In these circumstances, a number of factors are thought to influence their population dynamics, including resource competition among the larval stages, prevailing environmental conditions and reproductive interference in the form of satyrization. As the distribution and abundance of Ae. aegypti and Ae. albopictus have profound epidemiological implications, understanding the competitive interactions that influence these patterns in nature is important. While evidence for resource competition and environmental factors had been gathered from the field, the evidence for reproductive interference, though strongly inferred through laboratory trials, remained sparse (one small-scale field trial). In this paper we demonstrate that low rates (1.12-3.73%) of interspecific mating occur in nature among populations of these species that have co-existed sympatrically from 3 to 150yrs. Finally this report contributes a new species-specific primer set for identifying the paternity of sperm extracted from field collected specimens. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Global warming increases the interspecific competitiveness of the invasive plant alligator weed, Alternanthera philoxeroides.

    Science.gov (United States)

    Wu, Hao; Ismail, Mohannad; Ding, Jianqing

    2017-01-01

    Global warming could accelerate the spread of invasive species to higher latitudes and intensify their effects on native species. Here, we report results of two years of field surveys along a latitudinal gradient (21°N to 31°N) in southern China, to determine the species structure of the invasive plant Alternanthera philoxeroides community. We also performed a replacement series experiment (mono and mixed) to evaluate the effects of elevated temperature on the competitiveness of A. philoxeroides with the native co-occurring species Digitaria sanguinalis. In the field survey, we found that the dominance of A. philoxeroides increased with increasing of latitude gradient while cover of D. sanguinalis decreased. In monospecific plantings, artificial warming reduced the length of D. sanguinalis roots. In mixed plantings, warming reduced both A. philoxeroides abundance and D. sanguinalis stem length when A. philoxeroides was more prevalent in the planting. Warming also significantly reduced D. sanguinalis biomass, but increased that of A. philoxeroides. In addition, elevated temperatures significantly reduced the relative yield (RY) of D. sanguinalis, particularly when A. philoxeroides was planted in higher proportion in the plot. These results suggest that the invasiveness of A. philoxeroides increased with increasing latitude, and that warming may increase the effectiveness of its interspecific competition with D. sanguinalis. Hence, under global warming conditions, the harm to native species from A. philoxeroides would increase at higher latitudes. Our findings are critical for predicting the invasiveness of alien species under climate change. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Climate and foraging mode explain interspecific variation in snake metabolic rates.

    Science.gov (United States)

    Dupoué, Andréaz; Brischoux, François; Lourdais, Olivier

    2017-11-29

    The energy cost of self-maintenance is a critical facet of life-history strategies. Clarifying the determinant of interspecific variation in metabolic rate (MR) at rest is important to understand and predict ecological patterns such as species distributions or responses to climatic changes. We examined variation of MR in snakes, a group characterized by a remarkable diversity of activity rates and a wide distribution. We collated previously published MR data ( n = 491 observations) measured in 90 snake species at different trial temperatures. We tested for the effects of metabolic state (standard MR (SMR) versus resting MR (RMR)), foraging mode (active versus ambush foragers) and climate (temperature and precipitation) while accounting for non-independence owing to phylogeny, body mass and thermal dependence. We found that RMR was 40% higher than SMR, and that active foragers have higher MR than species that ambush their prey. We found that MR was higher in cold environments, supporting the metabolic cold adaptation hypothesis. We also found an additive and positive effect of precipitation on MR suggesting that lower MR in arid environments may decrease dehydration and energetic costs. Altogether, our findings underline the complex influences of climate and foraging mode on MR and emphasize the relevance of these facets to understand the physiological impact of climate change. © 2017 The Author(s).

  8. Interspecific Plant Interactions Reflected in Soil Bacterial Community Structure and Nitrogen Cycling in Primary Succession

    Directory of Open Access Journals (Sweden)

    Joseph E. Knelman

    2018-02-01

    Full Text Available Past research demonstrating the importance plant–microbe interactions as drivers of ecosystem succession has focused on how plants condition soil microbial communities, impacting subsequent plant performance and plant community assembly. These studies, however, largely treat microbial communities as a black box. In this study, we sought to examine how emblematic shifts from early successional Alnus viridus ssp. sinuata (Sitka alder to late successional Picea sitchensis (Sitka spruce in primary succession may be reflected in specific belowground changes in bacterial community structure and nitrogen cycling related to the interaction of these two plants. We examined early successional alder-conditioned soils in a glacial forefield to delineate how alders alter the soil microbial community with increasing dominance. Further, we assessed the impact of late-successional spruce plants on these early successional alder-conditioned microbiomes and related nitrogen cycling through a leachate addition microcosm experiment. We show how increasingly abundant alder select for particular bacterial taxa. Additionally, we found that spruce leachate significantly alters the composition of these microbial communities in large part by driving declines in taxa that are enriched by alder, including bacterial symbionts. We found these effects to be spruce specific, beyond a general leachate effect. Our work also demonstrates a unique influence of spruce on ammonium availability. Such insights bolster theory relating the importance of plant–microbe interactions with late-successional plants and interspecific plant interactions more generally.

  9. Interspecific Plant Interactions Reflected in Soil Bacterial Community Structure and Nitrogen Cycling in Primary Succession.

    Science.gov (United States)

    Knelman, Joseph E; Graham, Emily B; Prevéy, Janet S; Robeson, Michael S; Kelly, Patrick; Hood, Eran; Schmidt, Steve K

    2018-01-01

    Past research demonstrating the importance plant-microbe interactions as drivers of ecosystem succession has focused on how plants condition soil microbial communities, impacting subsequent plant performance and plant community assembly. These studies, however, largely treat microbial communities as a black box. In this study, we sought to examine how emblematic shifts from early successional Alnus viridus ssp. sinuata (Sitka alder) to late successional Picea sitchensis (Sitka spruce) in primary succession may be reflected in specific belowground changes in bacterial community structure and nitrogen cycling related to the interaction of these two plants. We examined early successional alder-conditioned soils in a glacial forefield to delineate how alders alter the soil microbial community with increasing dominance. Further, we assessed the impact of late-successional spruce plants on these early successional alder-conditioned microbiomes and related nitrogen cycling through a leachate addition microcosm experiment. We show how increasingly abundant alder select for particular bacterial taxa. Additionally, we found that spruce leachate significantly alters the composition of these microbial communities in large part by driving declines in taxa that are enriched by alder, including bacterial symbionts. We found these effects to be spruce specific, beyond a general leachate effect. Our work also demonstrates a unique influence of spruce on ammonium availability. Such insights bolster theory relating the importance of plant-microbe interactions with late-successional plants and interspecific plant interactions more generally.

  10. Concentration of trace elements in feathers of three Antarctic penguins: Geographical and interspecific differences

    Energy Technology Data Exchange (ETDEWEB)

    Jerez, Silvia [Area de Toxicologia, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain); Motas, Miguel, E-mail: motas@um.es [Area de Toxicologia, Facultad de Veterinaria, Universidad de Murcia, Campus de Espinardo, 30100 Murcia (Spain); Palacios, Maria Jose; Valera, Francisco [Departamento de Ecologia Funcional y Evolutiva, Estacion Experimental de Zonas Aridas, CSIC, Carretera de Sacramento s/n, 04120 La Canada de San Urbano, Almeria (Spain); Cuervo, Jose Javier; Barbosa, Andres [Departamento de Ecologia Funcional y Evolutiva, Estacion Experimental de Zonas Aridas, CSIC, Carretera de Sacramento s/n, 04120 La Canada de San Urbano, Almeria (Spain); Departamento de Ecologia Evolutiva, Museo Nacional de Ciencias Naturales, CSIC, C/Jose Gutierrez Abascal 2, 28006 Madrid (Spain)

    2011-10-15

    Antarctica is often considered as one of the last pristine regions, but it could be affected by pollution at global and local scale. Concentrations of Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Cd and Pb were determinated by ICP-MS in feathers (n = 207 individuals) of gentoo, chinstrap and Adelie penguin collected in 8 locations throughout the Antarctic Peninsula (2006-2007). The highest levels of several elements were found in samples from King George Island (8.08, 20.29 and 1.76 {mu}g g{sup -1} dw for Cr, Cu and Pb, respectively) and Deception Island (203.13, 3.26 and 164.26 {mu}g g{sup -1} dw for Al, Mn and Fe, respectively), where probably human activities and large-scale transport of pollutants contribute to increase metal levels. Concentrations of Cr, Mn, Cu, Se or Pb, which are similar to others found in different regions of the world, show that some areas in Antarctica are not utterly pristine. - Highlights: > We study levels of trace elements in feathers of Antarctic penguins. > Eight different rookeries throughout the Antarctic Peninsula were sampled. > Interspecific (gentoo, chinstrap, Adelie) and geographical differences were tested. > Relatively high metal levels were found in areas with major human presence. > Penguin feather can be useful for metals monitoring in the Antarctic environment. - Trace element levels in feathers of three penguin species from the Antarctic Peninsula indicate the presence of pollution in certain locations.

  11. Modeling plant interspecific interactions from experiments with perennial crop mixtures to predict optimal combinations.

    Science.gov (United States)

    Halty, Virginia; Valdés, Matías; Tejera, Mauricio; Picasso, Valentín; Fort, Hugo

    2017-12-01

    The contribution of plant species richness to productivity and ecosystem functioning is a longstanding issue in ecology, with relevant implications for both conservation and agriculture. Both experiments and quantitative modeling are fundamental to the design of sustainable agroecosystems and the optimization of crop production. We modeled communities of perennial crop mixtures by using a generalized Lotka-Volterra model, i.e., a model such that the interspecific interactions are more general than purely competitive. We estimated model parameters -carrying capacities and interaction coefficients- from, respectively, the observed biomass of monocultures and bicultures measured in a large diversity experiment of seven perennial forage species in Iowa, United States. The sign and absolute value of the interaction coefficients showed that the biological interactions between species pairs included amensalism, competition, and parasitism (asymmetric positive-negative interaction), with various degrees of intensity. We tested the model fit by simulating the combinations of more than two species and comparing them with the polycultures experimental data. Overall, theoretical predictions are in good agreement with the experiments. Using this model, we also simulated species combinations that were not sown. From all possible mixtures (sown and not sown) we identified which are the most productive species combinations. Our results demonstrate that a combination of experiments and modeling can contribute to the design of sustainable agricultural systems in general and to the optimization of crop production in particular. © 2017 by the Ecological Society of America.

  12. Life span and reproductive cost explain interspecific variation in the optimal onset of reproduction.

    Science.gov (United States)

    Mourocq, Emeline; Bize, Pierre; Bouwhuis, Sandra; Bradley, Russell; Charmantier, Anne; de la Cruz, Carlos; Drobniak, Szymon M; Espie, Richard H M; Herényi, Márton; Hötker, Hermann; Krüger, Oliver; Marzluff, John; Møller, Anders P; Nakagawa, Shinichi; Phillips, Richard A; Radford, Andrew N; Roulin, Alexandre; Török, János; Valencia, Juliana; van de Pol, Martijn; Warkentin, Ian G; Winney, Isabel S; Wood, Andrew G; Griesser, Michael

    2016-02-01

    Fitness can be profoundly influenced by the age at first reproduction (AFR), but to date the AFR-fitness relationship only has been investigated intraspecifically. Here, we investigated the relationship between AFR and average lifetime reproductive success (LRS) across 34 bird species. We assessed differences in the deviation of the Optimal AFR (i.e., the species-specific AFR associated with the highest LRS) from the age at sexual maturity, considering potential effects of life history as well as social and ecological factors. Most individuals adopted the species-specific Optimal AFR and both the mean and Optimal AFR of species correlated positively with life span. Interspecific deviations of the Optimal AFR were associated with indices reflecting a change in LRS or survival as a function of AFR: a delayed AFR was beneficial in species where early AFR was associated with a decrease in subsequent survival or reproductive output. Overall, our results suggest that a delayed onset of reproduction beyond maturity is an optimal strategy explained by a long life span and costs of early reproduction. By providing the first empirical confirmations of key predictions of life-history theory across species, this study contributes to a better understanding of life-history evolution. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  13. Inter-specific coral chimerism: Genetically distinct multicellular structures associated with tissue loss in Montipora capitata

    Science.gov (United States)

    Work, Thierry M.; Forsman, Zac H.; Szabo, Zoltan; Lewis, Teresa D.; Aeby, Greta S.; Toonen, Robert J.

    2011-01-01

    Montipora white syndrome (MWS) results in tissue-loss that is often lethal to Montipora capitata, a major reef building coral that is abundant and dominant in the Hawai'ian Archipelago. Within some MWS-affected colonies in Kane'ohe Bay, Oahu, Hawai'i, we saw unusual motile multicellular structures within gastrovascular canals (hereafter referred to as invasive gastrovascular multicellular structure-IGMS) that were associated with thinning and fragmentation of the basal body wall. IGMS were in significantly greater densities in coral fragments manifesting tissue-loss compared to paired normal fragments. Mesenterial filaments from these colonies yielded typical M. capitata mitochondrial haplotypes (CO1, CR), while IGMS from the same colony consistently yielded distinct haplotypes previously only found in a different Montipora species (Montipora flabellata). Protein profiles showed consistent differences between paired mesenterial filaments and IGMS from the same colonies as did seven microsatellite loci that also exhibited an excess of alleles per locus inconsistent with a single diploid organism. We hypothesize that IGMS are a parasitic cellular lineage resulting from the chimeric fusion between M. capitata and M. flabellata larvae followed by morphological reabsorption of M. flabellata and subsequent formation of cell-lineage parasites. We term this disease Montiporaiasis. Although intra-specific chimerism is common in colonial animals, this is the first suspected inter-specific example and the first associated with tissue loss.

  14. Pesticide-mediated interspecific competition between local and invasive thrips pests.

    Science.gov (United States)

    Zhao, Xueyin; Reitz, Stuart R; Yuan, Huiguo; Lei, Zhongren; Paini, Dean Ronald; Gao, Yulin

    2017-01-13

    Competitive interactions between species can be mitigated or even reversed in the presence of anthropogenic influences. The thrips species Frankliniella occidentalis and Thrips tabaci are highly invasive and damaging agricultural pests throughout the world. Where the species co-occur, one species tends to eventually predominate over the other. Avermectin and beta-cypermethrin are commonly used insecticides to manage thrips in China, and laboratory bioassays demonstrated that F. occidentalis is significantly less susceptible than T. tabaci to these insecticides. In laboratory cage trials in which both species were exposed to insecticide treated cabbage plants, F. occidentalis became the predominant species. In contrast, T. tabaci completely displaced F. occidentalis on plants that were not treated with insecticides. In field trials, the species co-existed on cabbage before insecticide treatments began, but with T. tabaci being the predominant species. Following application of avermectin or beta-cypermethrin, F. occidentalis became the predominant species, while in plots not treated with insecticides, T. tabaci remained the predominant species. These results indicate that T. tabaci is an intrinsically superior competitor to F. occidentalis, but its competitive advantage can be counteracted through differential susceptibilities of the species to insecticides. These results further demonstrate the importance of external factors, such as insecticide applications, in mediating the outcome of interspecific interactions and produce rapid unanticipated shifts in the demographics of pest complexes.

  15. Interspecific competition and allelopathic interaction between Karenia mikimotoi and Dunaliella salina in laboratory culture

    Science.gov (United States)

    He, Dong; Liu, Jiao; Hao, Qiang; Ran, Lihua; Zhou, Bin; Tang, Xuexi

    2016-03-01

    Algal allelopathy is a manifold ecological/physiological phenomenon that is focused on chemical interactions and autotoxicity. We investigated the allelopathic interactions between Karenia mikimotoi and Dunaliella salina in laboratory cultures based on diff erent temperature (15°C, 20°C, and 25°C) and lighting (40, 80, and 160 μmol/(m2·s)) conditions. The growth of D. salina in bi-algae culture (1:1 size/density) was significantly restrained. The results of cell-free filtrate culture indicate that direct cell-tocell contact was not necessary in interspecific competition. Further experimental results demonstrated that allelochemicals released from K. mikimotoi were markedly influenced by both temperature ( P =0.013) and irradiance ( P =0.003), resulting in diff erent growth characteristics of D. salina in filtrate mediums. Compared with the plateau period, K. mikimotoi exudates in the exponential phase had a stronger short-term inhibition effect on D. salina in normal conditions. A clear concentration-dependent relationship was observed in the effect of allelochemicals released from K. mikimotoi with low-promoting and high-repressing effects on D. Salina in a short time-scale. In addition, allelopathic substances remain stable and effective under high temperature and pressure stress. Many flocculent sediments adhering with D. salina cells were observed in all filtrate mediums, while the quantity and color depended on the original culture conditions.

  16. Interspecific competition between Solenopsis invicta and two native ant species, Pheidole fervens and Monomorium chinense.

    Science.gov (United States)

    Chen, Yin-Cheng; Kafle, Lekhnath; Shih, Cheng-Jen

    2011-04-01

    This study was designed to understand the effects of the interspecific competition between red imported fire ant, Solenopsis invicta Buren and two native ant species, Pheidole fervens Smith and Monomorium chinense Santschi, by conducting colony interference and individual confrontation tests under laboratory conditions. The colony interference test showed that both native ant species, owing to their numerical advantage, killed the Solenopsis invicta virus-1 (SINV-1)-infected or healthy queens of S. invicta. Significantly less time was required for M. chinense to kill all SINV-1-infected S. invicta compared with the time required to kill the healthy S. invicta. Compared with healthy S. invicta, SINV-1-infected S. invicta spent a longer time eliminating the P. fervens colonies. In confrontation tests, M. chinense killed a significantly higher number of infected S. invicta minors than they did healthy minors, but the number of S. invicta majors (either infected or healthy) killed was substantially less. This study found that the viral infection weakened the competitive ability of S. invicta and made them prone to be eliminated by M. chinense but not by P. fervens.

  17. Positive selection and propeptide repeats promote rapid interspecific divergence of a gastropod sperm protein.

    Science.gov (United States)

    Hellberg, M E; Moy, G W; Vacquier, V D

    2000-03-01

    Male-specific proteins have increasingly been reported as targets of positive selection and are of special interest because of the role they may play in the evolution of reproductive isolation. We report the rapid interspecific divergence of cDNA encoding a major acrosomal protein of unknown function (TMAP) of sperm from five species of teguline gastropods. A mitochondrial DNA clock (calibrated by congeneric species divided by the Isthmus of Panama) estimates that these five species diverged 2-10 MYA. Inferred amino acid sequences reveal a propeptide that has diverged rapidly between species. The mature protein has diverged faster still due to high nonsynonymous substitution rates (> 25 nonsynonymous substitutions per site per 10(9) years). cDNA encoding the mature protein (89-100 residues) shows evidence of positive selection (Dn/Ds > 1) for 4 of 10 pairwise species comparisons. cDNA and predicted secondary-structure comparisons suggest that TMAP is neither orthologous nor paralogous to abalone lysin, and thus marks a second, phylogenetically independent, protein subject to strong positive selection in free-spawning marine gastropods. In addition, an internal repeat in one species (Tegula aureotincta) produces a duplicated cleavage site which results in two alternatively processed mature proteins differing by nine amino acid residues. Such alternative processing may provide a mechanism for introducing novel amino acid sequence variation at the amino-termini of proteins. Highly divergent TMAP N-termini from two other tegulines (Tegula regina and Norrisia norrisii) may have originated by such a mechanism.

  18. Effects of local adaptation and interspecific competition on species' responses to climate change.

    Science.gov (United States)

    Bocedi, Greta; Atkins, Katherine E; Liao, Jishan; Henry, Roslyn C; Travis, Justin M J; Hellmann, Jessica J

    2013-09-01

    Local adaptation and species interactions have been shown to affect geographic ranges; therefore, we need models of climate impact that include both factors. To identify possible dynamics of species when including these factors, we ran simulations of two competing species using an individual-based, coupled map-lattice model using a linear climatic gradient that varies across latitude and is warmed over time. Reproductive success is governed by an individual's adaptation to local climate as well as its location relative to global constraints. In exploratory experiments varying the strength of adaptation and competition, competition reduces genetic diversity and slows range change, although the two species can coexist in the absence of climate change and shift in the absence of competitors. We also found that one species can drive the other to extinction, sometimes long after climate change ends. Weak selection on local adaptation and poor dispersal ability also caused surfing of cooler-adapted phenotypes from the expanding margin backwards, causing loss of warmer-adapted phenotypes. Finally, geographic ranges can become disjointed, losing centrally-adapted genotypes. These initial results suggest that the interplay between local adaptation and interspecific competition can significantly influence species' responses to climate change, in a way that demands future research. © 2013 New York Academy of Sciences.

  19. Concentration of trace elements in feathers of three Antarctic penguins: Geographical and interspecific differences

    International Nuclear Information System (INIS)

    Jerez, Silvia; Motas, Miguel; Palacios, Maria Jose; Valera, Francisco; Cuervo, Jose Javier; Barbosa, Andres

    2011-01-01

    Antarctica is often considered as one of the last pristine regions, but it could be affected by pollution at global and local scale. Concentrations of Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Cd and Pb were determinated by ICP-MS in feathers (n = 207 individuals) of gentoo, chinstrap and Adelie penguin collected in 8 locations throughout the Antarctic Peninsula (2006-2007). The highest levels of several elements were found in samples from King George Island (8.08, 20.29 and 1.76 μg g -1 dw for Cr, Cu and Pb, respectively) and Deception Island (203.13, 3.26 and 164.26 μg g -1 dw for Al, Mn and Fe, respectively), where probably human activities and large-scale transport of pollutants contribute to increase metal levels. Concentrations of Cr, Mn, Cu, Se or Pb, which are similar to others found in different regions of the world, show that some areas in Antarctica are not utterly pristine. - Highlights: → We study levels of trace elements in feathers of Antarctic penguins. → Eight different rookeries throughout the Antarctic Peninsula were sampled. → Interspecific (gentoo, chinstrap, Adelie) and geographical differences were tested. → Relatively high metal levels were found in areas with major human presence. → Penguin feather can be useful for metals monitoring in the Antarctic environment. - Trace element levels in feathers of three penguin species from the Antarctic Peninsula indicate the presence of pollution in certain locations.

  20. Informational mismatches: a neglected threat of climate change to interspecific interactions

    Directory of Open Access Journals (Sweden)

    Deseada eParejo

    2016-04-01

    Full Text Available Interspecific interactions are deeply affected by the current scenario of climate change. This is because interactions are sensitive to many traits of interacting species as phenology, distribution, behaviour and relative abundances which may be differently influenced by climate change in each species. In this scenario, positive interactions, which require temporal coordination of events of life history of interacting species, could be particularly altered due to differential effects of climate change on phenology, apart from by the effects on abundance and distribution. Hitherto, studies focusing on the effects of climate change on positive biotic interactions are scarce and mainly focused on plant-pollinator interactions. Here I propose that, by inducing informational mismatches, climate change may lead to individuals from competing species relying on heterospecific social information to making mis- or un-informed decisions. The idea is that competing species are valuable sources of social information to each other provided overlap of their activities occurs. However, whenever coordination of events fails, competing species will co-occur at the wrong moment, co-occur only in small numbers or even not co-occur at all and thus they will not be able to access useful or any social information from heterospecifics. In that scenario, interacting species would be mis- or un- informed, and, consequently, decision taking will be impaired, leading to disequilibrium in the community. Throughout the manuscript, I will develop the idea of mismatches of information and illustrate it with some case studies.

  1. Learning and owner-stranger effects on interspecific communication in domestic dogs (Canis familiaris).

    Science.gov (United States)

    Elgier, Angel M; Jakovcevic, Adriana; Mustaca, Alba E; Bentosela, Mariana

    2009-05-01

    Domestic dogs are very successful at following human cues like gazing or pointing to find hidden food in an object choice task. They solve this kind of situation at their first attempts and from early stages of their development and perform better than wolves. Most of the authors proposed that these abilities are a domestication product, and independent from learning processes. There are few systematic studies on the effects of learning on dogs' communicative skills. We aim to evaluate the effect of extinction and reversal learning procedures on the use of the pointing gesture in an object choice task. The results showed that dogs stopped following the pointing cue in the extinction and that they learned to choose the not pointed container in the reversal learning. Results suggest that instrumental learning plays an important role in interspecific communication mechanisms between humans and dogs. In both experiments for half of the subjects the pointer was the owner and for the rest was a stranger. A differential effect was found: extinction was slower but reversal learning was faster when the owner gave the cue. This data indicates that the relationship of the dog with the person who emits the cue influences performance.

  2. SOCIO-PSYCHOLOGICAL EFFECTS OF INTERSPECIFIC INTERACTIONS IN A GROUP “HUMAN - PET”

    Directory of Open Access Journals (Sweden)

    A V Gagarin

    2016-12-01

    Full Text Available The article reveals the features of interspecific interaction “Human - Pet” in aspects of psychology and behaviorism. This direction is shown to be promising in the theoretical and applied aspects. This is significant for the study of individual social activity and human life, as well as social groups. The article identifies the promising areas of the research of such interaction: in the development of family and child-parent relations; in the asocial individual development under the influence of various factors (social and personal; in various directions of media development (social advertising on television and in print, in fiction and film; in socially-significant communicating in social networks (communication through video sharing, etc.. It is shown that this perspective is important for research in education and upbringing. We have come to the conclusion that the problems are of social significance because the direct and/or indirect human contact with natural objects contributes to the development of different spheres of his/her personality (cognitive, communicative, aesthetic, ethical, emotional, volitional.

  3. [Effects of precipitation and interspecific competition on Quercus mongolica and pinus koraiensis seedlings growth].

    Science.gov (United States)

    Wu, Jing-Lian; Wang, Miao; Lin, Fei; Hao, Zhan-Qing; Ji, Lan-Zhu; Liu, Ya-Qin

    2009-02-01

    Aiming at the variation of precipitation pattern caused by global warming, a field simulation experiment was conducted to study the effects of 30% increase (+W) and decrease (-W) of precipitation on the morphology, growth, and biomass partitioning of mono- and mixed cultured seedlings of Quercus mongolica and Pinus koraiensis, the two dominant tree species in temperate broad-leaved Korean pine mixed forest in Changbai Mountains. Comparing with monoculture, mixed culture increased the canopy width and main root length of Q. mongolica seedlings, but decreased the basal diameter, plant height, leaf number, and dry masses of root, stem, leaf and whole plant of P. koraiensis seedlings significantly. Treatment (-W) increased the stem/mass ratio while decreased the main root length of Q. mongolica seedlings, and decreased the main root length, leaf number, dry masses of leaf and whole plant, and leaf/mass ratio, while increased the stem/mass ratio of P. koraiensis seedlings significantly, compared with treatment CK. Treatment (+W) had no significant effect on these indices of the two species. At early growth stage, interspecific competition and precipitation pattern had significant effects on the morphology and growth of the seedlings, and the responses were much stronger for P. koraiensis than for Q. mongolica.

  4. Intra- and interspecific competition between western flower thrips and sweetpotato whitefly.

    Science.gov (United States)

    Wu, Qing-Jun; Hou, Wen-Jie; Li, Fei; Xu, Bao-Yun; Xie, Wen; Wang, Shao-Li; Zhang, You-Jun

    2014-01-01

    The western flower thrips, Frankliniella occidentalis (Pergande), and the sweetpotato whitefly, Bemisia tabaci (Gennadius), are both invasive insect pests and are present in most of the same agricultural crops without a clear dominance of either species. Here, intra- and interspecific competition in B. tabaci and F. occidentalis was determined under controlled experiments. The results showed that intraspecific competition was distinct in F. occidentalis and that the co-occurrence of B. tabaci had a strong effect on F. occidentalis, resulting in a decrease in oviposition. Significant intraspecific competition was found in B. tabaci, and the coexistence of F. occidentalis had limited effect on the oviposition of B. tabaci. In a selective host plant preference experiment, both F. occidentalis and B. tabaci preferred eggplants most, followed by cucumbers and tomatoes. On cucumber plants, B. tabaci was predominant, whereas on eggplant and tomato plants, F. occidentalis and B. tabaci exhibited comparative competitive abilities during the initial stage. However, over time, higher numbers of B. tabaci than that of F. occidentalis were found on the two host plants. Our in vitro and potted plant experiments indicate that B. tabaci is competitively superior to F. occidentalis, which might help to explain their differential distribution patterns in China. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  5. Interspecific competition in plants: how well do current methods answer fundamental questions?

    Science.gov (United States)

    Connolly, J; Wayne, P; Bazzaz, F A

    2001-02-01

    Accurately quantifying and interpreting the processes and outcomes of competition among plants is essential for evaluating theories of plant community organization and evolution. We argue that many current experimental approaches to quantifying competitive interactions introduce size bias, which may significantly impact the quantitative and qualitative conclusions drawn from studies. Size bias generally arises when estimates of competitive ability are erroneously influenced by the initial size of competing individuals. We employ a series of quantitative thought experiments to demonstrate the potential for size bias in analysis of four traditional experimental designs (pairwise, replacement series, additive series, and response surfaces) either when only final measurements are available or when both initial and final measurements are collected. We distinguish three questions relevant to describing competitive interactions: Which species dominates? Which species gains? and How do species affect each other? The choice of experimental design and measurements greatly influences the scope of inference permitted. Conditions under which the latter two questions can give biased information are tabulated. We outline a new approach to characterizing competition that avoids size bias and that improves the concordance between research question and experimental design. The implications of the choice of size metrics used to quantify both the initial state and the responses of elements in interspecific mixtures are discussed. The relevance of size bias in competition studies with organisms other than plants is also discussed.

  6. Spatial heterogeneity of plant-soil feedback affects root interactions and interspecific competition.

    Science.gov (United States)

    Hendriks, Marloes; Ravenek, Janneke M; Smit-Tiekstra, Annemiek E; van der Paauw, Jan Willem; de Caluwe, Hannie; van der Putten, Wim H; de Kroon, Hans; Mommer, Liesje

    2015-08-01

    Plant-soil feedback is receiving increasing interest as a factor influencing plant competition and species coexistence in grasslands. However, we do not know how spatial distribution of plant-soil feedback affects plant below-ground interactions. We investigated the way in which spatial heterogeneity of soil biota affects competitive interactions in grassland plant species. We performed a pairwise competition experiment combined with heterogeneous distribution of soil biota using four grassland plant species and their soil biota. Patches were applied as quadrants of 'own' and 'foreign' soils from all plant species in all pairwise combinations. To evaluate interspecific root responses, species-specific root biomass was quantified using real-time PCR. All plant species suffered negative soil feedback, but strength was species-specific, reflected by a decrease in root growth in own compared with foreign soil. Reduction in root growth in own patches by the superior plant competitor provided opportunities for inferior competitors to increase root biomass in these patches. These patterns did not cascade into above-ground effects during our experiment. We show that root distributions can be determined by spatial heterogeneity of soil biota, affecting plant below-ground competitive interactions. Thus, spatial heterogeneity of soil biota may contribute to plant species coexistence in species-rich grasslands. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  7. INTERSPECIFIC COMPETITION BETWEEN NATIVE AND EXOTIC FRUIT FLY PARASITOIDSIN MIXED ORCHARDS IN MACEIO, ALAGOAS, BRAZIL

    Directory of Open Access Journals (Sweden)

    JAKELINE MARIA DOS SANTOS

    2016-01-01

    Full Text Available The objective of this work was to assess the effects of the release and establishment of the exotic parasitoid Diachasmimorpha longicaudata (Ashmead, 1905 (Hymenoptera: Braconidae and its interspecific competitive relationship with native fruit fly parasitoids in organic and conventional orchards in Maceio, State of Alagoas, Brazil. The exotic parasitoids were reared in the Radio - Entomology Laboratory of the Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, São Paulo, and released (112,350 individuals between five and eight days old in orchards from June 8 to July12, 2013.Fruit samples were collected randomly every week during one year to assess the D. longicaudata recaptured from plants and fallen fruits on the ground, which were taken to the Entomology Laboratory of the CECA - UFAL, classified and individually placed in plastic containers, containing a layer of 1 cm of sand for pupation of the host larvae. The pupae, obtained after 10 days, were placed in Petri dishes with a layer of sand until the emergence of adults, which were then kept in plastic microtubes, containing ethanol 70%. The release of exotic parasitoids did not displace native species. The same species were found before and after the release in both cultures: Doryctobracon areolatus , Asobara anastrephae , Utetes anastrephae and Opius bellus (Braconidae, Aganaspis pelleranoi (Figitidae and individuals of the Pteromalidae family. One year after the last release, 44 individuals of the exotic parasitoid were found, showing its establishment in the studied areas.

  8. Behavioral and life-history evidence for interspecific competition in the larvae of two heliconian butterflies

    Science.gov (United States)

    Millan, Carolina; Borges, Simone Silva; Rodrigues, Daniela; Moreira, Gilson Rudinei Pires

    2013-10-01

    Interspecific competition in herbivorous insects remains a controversial issue. To date, many studied systems have not met assumptions of the traditional competition theory, and a new paradigm has been emerging. We examined the behavioral and life-history consequences of common host plant use of Heliconius erato and Dryas iulia (Nymphalidae) in relation to Passiflora suberosa (Passifloraceae). Larvae of the former use the apical portion of this host; the latter is presumably able to explore all plant parts. We assessed host use pattern in relation to leaf age, when reared either alone ( D. iulia) or together ( D. iulia and H. erato). Larval feeding choice tests with respect to leaf age were performed, and performance was recorded. Observations were made to assess antagonistic behavior of H. erato and D. iulia towards each other, if any. Similarly to H. erato, D. iulia fed on the young leaves significantly more than the mature ones; larvae were not induced to prefer mature leaves. First instars of H. erato used only the apical parts of P. suberosa and displayed aggressive behavior towards D. iulia, which moved to the lower shoot portions. Larval mortality and development time of both species significantly increased when reared together; such performance costs were more pronounced in D. iulia than H. erato. Our study gathers evidences that use of P. suberosa by these heliconian butterflies represent a case of competitive exclusion resulting in niche differentiation, where costs are higher for D. iulia than H. erato.

  9. Interspecific hybridization in the genus Hieracium (s. str.) – evidence for bidirectional gene flow and spontaneous allopolyploidization

    Czech Academy of Sciences Publication Activity Database

    Mráz, P.; Chrtek, Jindřich; Fehrer, Judith

    2011-01-01

    Roč. 293, 1-4 (2011), s. 237-245 ISSN 0378-2697 R&D Projects: GA ČR GAP506/10/1363 Institutional research plan: CEZ:AV0Z60050516 Keywords : additive polymorphism * hybridization * polyploidization Subject RIV: EF - Botanics Impact factor: 1.335, year: 2011

  10. Microdiversification of a Pelagic Polynucleobacter Species Is Mainly Driven by Acquisition of Genomic Islands from a Partially Interspecific Gene Pool

    Czech Academy of Sciences Publication Activity Database

    Hoetzinger, M.; Schmidt, J.; Jezberová, Jitka; Koll, U.; Hahn, M.W.

    2017-01-01

    Roč. 83, č. 3 (2017), č. článku e02266-16. ISSN 0099-2240 Institutional support: RVO:60077344 Keywords : Polynucleobacter * ecophysiology * environmental genomics * functional diversity Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 3.807, year: 2016

  11. A Drosophila melanogaster hobo-white + vector mediates low frequency gene transfer in D. vlrllls with full Interspecific white + complementation

    Science.gov (United States)

    Transformation of a Drosophila virilis white mutant host strain was attempted by using a hobo vector containing the D. melanogaster mini-white+ cassette (H[w+, hawN]) and an unmodified or heat shock regulated hobo transposase helper. Two transformant lines were recovered with the unmodified helper (...

  12. Disentangling the effects of species diversity, and intraspecific and interspecific tree size variation on aboveground biomass in dry zone homegarden agroforestry systems.

    Science.gov (United States)

    Ali, Arshad; Mattsson, Eskil

    2017-11-15

    The biodiversity - aboveground biomass relationship has been intensively studied in recent decades. However, no consensus has been arrived to consider the interplay of species diversity, and intraspecific and interspecific tree size variation in driving aboveground biomass, after accounting for the effects of plot size heterogeneity, soil fertility and stand quality in natural forest including agroforests. We tested the full, partial and no mediations effects of species diversity, and intraspecific and interspecific tree size variation on aboveground biomass by employing structural equation models (SEMs) using data from 45 homegarden agroforestry systems in Sri Lanka. The full mediation effect of either species diversity or intraspecific and interspecific tree size variation was rejected, while the partial and no mediation effects were accepted. In the no mediation SEM, homegarden size had the strongest negative direct effect (β=-0.49) on aboveground biomass (R 2 =0.65), followed by strong positive direct effect of intraspecific tree size variation (β=0.32), species diversity (β=0.29) and interspecific tree size variation (β=0.28). Soil fertility had a negative direct effect on interspecific tree size variation (β=-0.31). Stand quality had a significant positive total effect on aboveground biomass (β=0.28), but homegarden size had a significant negative total effect (β=-0.62), while soil fertility had a non-significant total effect on aboveground biomass. Similar to the no mediation SEM, the partial mediation SEMs had explained almost similar variation in aboveground biomass because species diversity, and intraspecific and interspecific tree size variation had non-significant indirect effects on aboveground biomass via each other. Our results strongly suggest that a multilayered tree canopy structure, due to high intraspecific and interspecific tree size variation, increases light capture and efficient utilization of resources among component species, and

  13. Tiger, Bengal and Domestic Cat Embryos Produced by Homospecific and Interspecific Zona-Free Nuclear Transfer.

    Science.gov (United States)

    Moro, L N; Jarazo, J; Buemo, C; Hiriart, M I; Sestelo, A; Salamone, D F

    2015-10-01

    The aim of this study was to evaluate three different cloning strategies in the domestic cat (Felis silvestris) and to use the most efficient to generate wild felid embryos by interspecific cloning (iSCNT) using Bengal (a hybrid formed by the cross of Felis silvestris and Prionailurus bengalensis) and tiger (Panthera tigris) donor cells. In experiment 1, zona-free (ZP-free) cloning resulted in higher fusion and expanded blastocyst rates with respect to zona included cloning techniques that involved fusion or injection of the donor cell. In experiment 2, ZP-free iSCNT and embryo aggregation (2X) were assessed. Division velocity and blastocyst rates were increased by embryo aggregation in the three species. Despite fewer tiger embryos than Bengal and cat embryos reached the blastocyst stage, Tiger 2X group increased the percentage of blastocysts with respect to Tiger 1X group (3.2% vs 12.1%, respectively). Moreover, blastocyst cell number was almost duplicated in aggregated embryos with respect to non-aggregated ones within Bengal and tiger groups (278.3 ± 61.9 vs 516.8 ± 103.6 for Bengal 1X and Bengal 2X groups, respectively; 41 vs 220 ± 60 for Tiger 1X and Tiger 2X groups, respectively). OCT4 analysis also revealed that tiger blastocysts had higher proportion of OCT4-positive cells with respect to Bengal blastocysts and cat intracytoplasmic sperm injection blastocysts. In conclusion, ZP-free cloning has improved the quality of cat embryos with respect to the other cloning techniques evaluated and was successfully applied in iSCNT complemented with embryo aggregation. © 2015 Blackwell Verlag GmbH.

  14. Relationships between Nutrient Heterogeneity, Root Growth, and Hormones: Evidence for Interspecific Variation.

    Science.gov (United States)

    Dong, Jia; Jones, Robert H; Mou, Pu

    2018-02-28

    (1) Background: Plant roots respond to nutrients through root architecture that is regulated by hormones. Strong inter-specific variation in root architecture has been well documented, but physiological mechanisms that may control the variation have not. (2) Methods: We examined correlations between root architecture and hormones to seek clues on mechanisms behind root foraging behavior. In the green house at Beijing Normal University, hydroponic culture experiments were used to examine the root responses of four species- Callistephus chinensis , Solidago canadensis , Ailanthus altissima , Oryza sativa- to two nitrogen types (NO₃ - or NH₄⁺), three nitrogen concentrations (low, medium, and high concentrations of 0.2, 1, and 18 mM, respectively) and two ways of nitrogen application (stable vs. variable). The plants were harvested after 36 days to measure root mass, 1st order root length, seminal root length for O. sativa , density of the 1st order laterals, seminal root number for O. sativa , the inter-node length of the 1st order laterals, and root hormone contents of indole-3-acetic acid, abscisic acid, and cytokinins (zeatin + zeatinriboside). (3) Results: Species differed significantly in their root architecture responses to nitrogen treatments. They also differed significantly in hormone responses to the nitrogen treatments. Additionally, the correlations between root architecture and hormone responses were quite variable across the species. Each hormone had highly species-specific relationships with root responses. (4) Conclusions: Our finding implies that a particular root foraging behavior is probably not controlled by the same biochemical pathway in all species.

  15. Relationships between Nutrient Heterogeneity, Root Growth, and Hormones: Evidence for Interspecific Variation

    Directory of Open Access Journals (Sweden)

    Jia Dong

    2018-02-01

    Full Text Available (1 Background: Plant roots respond to nutrients through root architecture that is regulated by hormones. Strong inter-specific variation in root architecture has been well documented, but physiological mechanisms that may control the variation have not. (2 Methods: We examined correlations between root architecture and hormones to seek clues on mechanisms behind root foraging behavior. In the green house at Beijing Normal University, hydroponic culture experiments were used to examine the root responses of four species—Callistephus chinensis, Solidago canadensis, Ailanthus altissima, Oryza sativa—to two nitrogen types (NO3− or NH4+, three nitrogen concentrations (low, medium, and high concentrations of 0.2, 1, and 18 mM, respectively and two ways of nitrogen application (stable vs. variable. The plants were harvested after 36 days to measure root mass, 1st order root length, seminal root length for O. sativa, density of the 1st order laterals, seminal root number for O. sativa, the inter-node length of the 1st order laterals, and root hormone contents of indole-3-acetic acid, abscisic acid, and cytokinins (zeatin + zeatinriboside. (3 Results: Species differed significantly in their root architecture responses to nitrogen treatments. They also differed significantly in hormone responses to the nitrogen treatments. Additionally, the correlations between root architecture and hormone responses were quite variable across the species. Each hormone had highly species-specific relationships with root responses. (4 Conclusions: Our finding implies that a particular root foraging behavior is probably not controlled by the same biochemical pathway in all species.

  16. Intra- and interspecific differences in diet quality and composition in a large herbivore community.

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    Claire Redjadj

    Full Text Available Species diversity in large herbivore communities is often explained by niche segregation allowed by differences in body mass and digestive morphophysiological features. Based on large number of gut samples in fall and winter, we analysed the temporal dynamics of diet composition, quality and interspecific overlap of 4 coexisting mountain herbivores. We tested whether the relative consumption of grass and browse differed among species of different rumen types (moose-type and intermediate-type, whether diet was of lower quality for the largest species, whether we could identify plant species which determined diet quality, and whether these plants, which could be "key-food-resources" were similar for all herbivores. Our analyses revealed that (1 body mass and rumen types were overall poor predictors of diet composition and quality, although the roe deer, a species with a moose-type rumen was confirmed as an "obligatory non grazer", while red deer, the largest species, had the most lignified diet; (2 diet overlap among herbivores was well predicted by rumen type (high among species of intermediate types only, when measured over broad plant groups, (3 the relationship between diet composition and quality differed among herbivore species, and the actual plant species used during winter which determined the diet quality, was herbivore species-specific. Even if diets overlapped to a great extent, the species-specific relationships between diet composition and quality suggest that herbivores may select different plant species within similar plant group types, or different plant parts and that this, along with other behavioural mechanisms of ecological niche segregation, may contribute to the coexistence of large herbivores of relatively similar body mass, as observed in mountain ecosystems.

  17. Receding Water Line and Interspecific Competition Determines Plant Community Composition and Diversity in Wetlands in Beijing

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    Wang, Zhengjun; Gong, Huili; Zhang, Jing

    2015-01-01

    Climate and human-induced wetland degradation has accelerated in recent years, not only resulting in reduced ecosystem services but also greatly affecting the composition and diversity of wetland plant communities. To date, the knowledge of the differences in community parameters and their successional trends in degraded wetlands remains scarce. Here based on remote sensing images, geographic information system technology, and statistical methods, we produced a successional gradient map of the Yeyahu Wetland Nature Reserve in Beijing, which has experienced a steady decline in water level in recent decades. In addition, we analyzed community composition and diversity along with each identified gradient. The results showed that community diversity decreases while dominance increases with the progress of succession, with the highest diversity occurring during the early stage of succession. Moreover, the community demonstrates greater similarity among subareas during later successional stages, and the similarity coefficients calculated from the important value (IV) of each species are more accurate. Correlation analysis showed that the impact of soil factors on diversity was not significant at a subarea scale, although these nutrients showed an increasing trend with the community succession. Furthermore, the IVs of the dominant species had a particularly significant impact on diversity, showing a significantly negative correlation with diversity indices and a significantly positive correlation with dominance indices. Further analysis showed that the retreat of water level resulted from sustained drought and local human activities was a major extrinsic driving force resulting in observed differences in the community successional stages, which resulted in differences in community composition and diversity. On the other hand, interspecific competition was the main intrinsic mechanism, which significantly influenced the IVs of the dominant species and community diversity

  18. Interspecific variation in life history relates to antipredator decisions by marine mesopredators on temperate reefs.

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    Alejandro Frid

    Full Text Available As upper-level predatory fishes become overfished, mesopredators rise to become the new 'top' predators of over-exploited marine communities. To gain insight into ensuing mechanisms that might alter indirect species interactions, we examined how behavioural responses to an upper-level predatory fish might differ between mesopredator species with different life histories. In rocky reefs of the northeast Pacific Ocean, adult lingcod (Ophiodon elongatus are upper-level predators that use a sit-and-wait hunting mode. Reef mesopredators that are prey to adult lingcod include kelp greenling (Hexagrammos decagrammus, younger lingcod, copper rockfish (Sebastes caurinus and quillback rockfish (S. maliger. Across these mesopredators species, longevity and age at maturity increases and, consequently, the annual proportion of lifetime reproductive output decreases in the order just listed. Therefore, we hypothesized that the level of risk taken to acquire resources would vary interspecifically in that same order. During field experiments we manipulated predation risk with a model adult lingcod and used fixed video cameras to quantify interactions between mesopredators and tethered prey (Pandalus shrimps. We predicted that the probabilities of inspecting and attacking tethered prey would rank from highest to lowest and the timing of these behaviours would rank from earliest to latest as follows: kelp greenling, lingcod, copper rockfish, and quillback rockfish. We also predicted that responses to the model lingcod, such as avoidance of interactions with tethered prey, would rank from weakest to strongest in the same order. Results were consistent with our predictions suggesting that, despite occupying similar trophic levels, longer-lived mesopredators with late maturity have stronger antipredator responses and therefore experience lower foraging rates in the presence of predators than mesopredators with faster life histories. The corollary is that the fishery

  19. Local climate determines intra- and interspecific variation in sexual size dimorphism in mountain grasshopper communities.

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    Laiolo, P; Illera, J C; Obeso, J R

    2013-10-01

    The climate is often evoked to explain broad-scale clines of body size, yet its involvement in the processes that generate size inequality in the two sexes (sexual size dimorphism) remains elusive. Here, we analyse climatic clines of sexual size dimorphism along a wide elevation gradient (i) among grasshopper species in a phylogenetically controlled scenario and (ii) within species differing in distribution and cold tolerance, to highlight patterns generated at different time scales, mainly evolutionary (among species or higher taxa) and ontogenetic or microevolutionary (within species). At the interspecific level, grasshoppers were slightly smaller and less dimorphic at high elevations. These clines were associated with gradients of precipitation and sun exposure, which are likely indicators of other factors that directly exert selective pressures, such as resource availability and conditions for effective thermoregulation. Within species, we found a positive effect of temperature and a negative effect of elevation on body size, especially on condition-dependent measures of body size (total body length rather than hind femur length) and in species inhabiting the highest elevations. In spite of a certain degree of species-specific variation, females tended to adjust their body size more often than males, suggesting that body size in females can evolve faster among species and can be more plastic or dependent on nutritional conditions within species living in adverse climates. Natural selection on female body size may therefore prevail over sexual selection on male body size in alpine environments, and abiotic factors may trigger consistent phenotypic patterns across taxonomic scales. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  20. Influence of Interspecific Competition and Landscape Structure on Spatial Homogenization of Avian Assemblages

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    Robertson, Oliver J.; McAlpine, Clive; House, Alan; Maron, Martine

    2013-01-01

    Human-induced biotic homogenization resulting from landscape change and increased competition from widespread generalists or ‘winners’, is widely recognized as a global threat to biodiversity. However, it remains unclear what aspects of landscape structure influence homogenization. This paper tests the importance of interspecific competition and landscape structure, for the spatial homogeneity of avian assemblages within a fragmented agricultural landscape of eastern Australia. We used field observations of the density of 128 diurnal bird species to calculate taxonomic and functional similarity among assemblages. We then examined whether taxonomic and functional similarity varied with patch type, the extent of woodland habitat, land-use intensity, habitat subdivision, and the presence of Manorina colonies (a competitive genus of honeyeaters). We found the presence of a Manorina colony was the most significant factor positively influencing both taxonomic and functional similarity of bird assemblages. Competition from members of this widespread genus of native honeyeater, rather than landscape structure, was the main cause of both taxonomic and functional homogenization. These species have not recently expanded their range, but rather have increased in density in response to agricultural landscape change. The negative impacts of Manorina honeyeaters on assemblage similarity were most pronounced in landscapes of moderate land-use intensity. We conclude that in these human-modified landscapes, increased competition from dominant native species, or ‘winners’, can result in homogeneous avian assemblages and the loss of specialist species. These interacting processes make biotic homogenization resulting from land-use change a global threat to biodiversity in modified agro-ecosystems. PMID:23724136

  1. Interspecific competition for shelters in territorial and gregarious intertidal grazers: consequences for individual behaviour.

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    Moisés A Aguilera

    Full Text Available Experiments have shown that interspecific interactions within consumer guilds can alter patterns of distribution, abundance and size of species. Plastic behavioural responses can be modulated by agonistic interactions. In many cases, consumers compete for space and shelters, and these interactions change the manner in which they exploit food. This study investigates the consequences of competition in the spatial and temporal organization of behaviour of intertidal grazers, which share algal resources and the use of rock crevices while resting, but exhibit different body sizes, spatial behaviour and foraging modes. We evaluate interaction strength between small gregarious Siphonaria lessoni and the larger territorial keyhole limpet Fissurella crassa and between S. lessoni and the medium-size gregarious chiton Chiton granosus. Using field manipulations and artificial arenas in the laboratory, we tested whether the use of crevices, micro-spatial distribution and activity are modified by the density of conspecifics and the presence of heterospecifics. Our results show that small-scale spatial segregation observed in the field between S. lessoni and C. granosus result from species-specific differences in habitat use. In turn, we found evidence that spatial segregation between F. crassa and S. lessoni results from highly asymmetric interference competition in the use of shelters. The presence of F. crassa reduced the use of crevices and growth rates of S. lessoni. Effects on growth rates are assumed to result from exposure to harsh environmental conditions rather than food limitation. Thus, neither gregarious behaviour nor differences in activity were sufficient to prevent competition with the larger grazer. Our study illustrates the importance of competition for shelters, which results in behavioural changes of the smaller-sized species, and how these plastic responses can translate into differences in growth rates. Use of shelters can thus be

  2. Different intra- and interspecific facilitation mechanisms between two Mediterranean trees under a climate change scenario.

    Science.gov (United States)

    Gimeno, Teresa E; Escudero, Adrián; Valladares, Fernando

    2015-01-01

    In harsh environments facilitation alleviates biotic and abiotic constraints on tree recruitment. Under ongoing drier climate change, we expect facilitation to increase as a driver of coexistence. However, this might not hold under extreme abiotic stress and when the outcome depends on the interaction with other drivers such as altered herbivore pressure due to land use change. We performed a field water-manipulation experiment to quantify the importance of facilitation in two coexisting Mediterranean trees (dominant Juniperus thurifera and coexisting Quercus ilex subsp. ballota) under a climate change scenario. Shifts in canopy dominance favouring Q. ilex could be based on the extension of heterospecific facilitation to the detriment of conspecific alleviation. We found that saplings of both species transplanted under the canopy of nurse trees had greater survival probability, growth and photochemical efficiency. Intra- and interspecific facilitation mechanisms differed: alleviation of abiotic stress benefited both species during summer and J. thurifera during winter, whereas browsing protection was relevant only for Q. ilex. Facilitation was greater under the dry treatment only for Q. ilex, which partially agreed with the predictions of the stress gradient hypothesis. We conclude that present rainfall availability limits neither J. thurifera nor Q. ilex establishment. Nevertheless, under current global change scenarios, imposing increasing abiotic stress together with altered herbivore browsing, nurse trees could differentially facilitate the establishment of Q. ilex due to species-specific traits, i.e. palatability; drought, heat and cold tolerance, underlying species differences in the facilitation mechanisms and eventually triggering a change from pure juniper woodlands to mixed formations.

  3. In situ cardiac perfusion reveals interspecific variation of intraventricular flow separation in reptiles.

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    Joyce, William; Axelsson, Michael; Altimiras, Jordi; Wang, Tobias

    2016-07-15

    The ventricles of non-crocodilian reptiles are incompletely divided and provide an opportunity for mixing of oxygen-poor blood and oxygen-rich blood (intracardiac shunting). However, both cardiac morphology and in vivo shunting patterns exhibit considerable interspecific variation within reptiles. In the present study, we develop an in situ double-perfused heart approach to characterise the propensity and capacity for shunting in five reptile species: the turtle Trachemys scripta, the rock python Python sebae, the yellow anaconda Eunectes notaeus, the varanid lizard Varanus exanthematicus and the bearded dragon Pogona vitticeps To simulate changes in vascular bed resistance, pulmonary and systemic afterloads were independently manipulated and changes in blood flow distribution amongst the central outflow tracts were monitored. As previously demonstrated in Burmese pythons, rock pythons and varanid lizards exhibited pronounced intraventricular flow separation. As pulmonary or systemic afterload was raised, flow in the respective circulation decreased. However, flow in the other circulation, where afterload was constant, remained stable. This correlates with the convergent evolution of intraventricular pressure separation and the large intraventricular muscular ridge, which compartmentalises the ventricle, in these species. Conversely, in the three other species, the pulmonary and systemic flows were strongly mutually dependent, such that the decrease in pulmonary flow in response to elevated pulmonary afterload resulted in redistribution of perfusate to the systemic circuit (and vice versa). Thus, in these species, the muscular ridge appeared labile and blood could readily transverse the intraventricular cava. We conclude that relatively minor structural differences between non-crocodilian reptiles result in the fundamental changes in cardiac function. Further, our study emphasises that functionally similar intracardiac flow separation evolved independently in

  4. Interspecific variation in life history relates to antipredator decisions by marine mesopredators on temperate reefs.

    Science.gov (United States)

    Frid, Alejandro; Marliave, Jeff; Heithaus, Michael R

    2012-01-01

    As upper-level predatory fishes become overfished, mesopredators rise to become the new 'top' predators of over-exploited marine communities. To gain insight into ensuing mechanisms that might alter indirect species interactions, we examined how behavioural responses to an upper-level predatory fish might differ between mesopredator species with different life histories. In rocky reefs of the northeast Pacific Ocean, adult lingcod (Ophiodon elongatus) are upper-level predators that use a sit-and-wait hunting mode. Reef mesopredators that are prey to adult lingcod include kelp greenling (Hexagrammos decagrammus), younger lingcod, copper rockfish (Sebastes caurinus) and quillback rockfish (S. maliger). Across these mesopredators species, longevity and age at maturity increases and, consequently, the annual proportion of lifetime reproductive output decreases in the order just listed. Therefore, we hypothesized that the level of risk taken to acquire resources would vary interspecifically in that same order. During field experiments we manipulated predation risk with a model adult lingcod and used fixed video cameras to quantify interactions between mesopredators and tethered prey (Pandalus shrimps). We predicted that the probabilities of inspecting and attacking tethered prey would rank from highest to lowest and the timing of these behaviours would rank from earliest to latest as follows: kelp greenling, lingcod, copper rockfish, and quillback rockfish. We also predicted that responses to the model lingcod, such as avoidance of interactions with tethered prey, would rank from weakest to strongest in the same order. Results were consistent with our predictions suggesting that, despite occupying similar trophic levels, longer-lived mesopredators with late maturity have stronger antipredator responses and therefore experience lower foraging rates in the presence of predators than mesopredators with faster life histories. The corollary is that the fishery removal of top

  5. Bathymetric and interspecific variability in maternal reproductive investment and diet of eurybathic echinoderms

    Science.gov (United States)

    Ross, David A. N.; Hamel, Jean-François; Mercier, Annie

    2013-10-01

    While conditions in shallow-water and deep-sea environments differ markedly, it remains unclear how eurybathic species adapt their life histories to cope with these changes. The present study compared indicators of maternal reproductive investment of three common echinoderms collected shallower than 20 m and deeper than 850 m: Cucumaria frondosa (Holothuroidea), Solaster endeca and Henricia sanguinolenta (Asteroidea). Depth-specific and species-specific differences were found in gonad indices (GI), potential fecundity, oocyte size frequency, as well as lipid classes and fatty acids measured in gonad tissue and oocytes. The asteroids, S. endeca and H. sanguinolenta, exemplified the interspecific trade-off between size and number of oocytes: the former had fewer larger oocytes than the latter, with higher total lipid proportions in them. However, intraspecifically, larger oocytes found in deep specimens of S. endeca did not translate into lower fecundity but rather into a seemingly higher GI, indicating greater investment per oocyte without reducing fecundity. Oocytes were absent in specimens of C. frondosa sampled in deep water, suggesting delayed or impaired maturation at the limit of their depth tolerance. Analysis of S. endeca sterol proportions in gonads and oocytes across depths showed higher sterol input into oocytes in females from the deep. Gonads of S. endeca and H. sanguinolenta contained similar essential fatty acids, but showed significant differences in major fatty acids and some of the less dominant ones, indicating diet specificities. Analyses within S. endeca showed evidence of similar feeding mode (carnivory) at both depths, but suggested shifts in the diet or synthesis of fatty acids, presumably reflecting differences in available food sources and/or adaptations to their respective environments.

  6. Interspecific correlates of plasticity in relative growth rate following a decrease in nitrogen availability.

    Science.gov (United States)

    Useche, Antonio; Shipley, Bill

    2010-02-01

    Nitrogen availability varies greatly over short time scales. This requires that a well-adapted plant modify its phenotype by an appropriate amount and at a certain speed in order to maximize growth and fitness. To determine how plastic ontogenetic changes in each trait interact and whether or not these changes are likely to maximize growth, ontogenetic changes in relative growth rate (RGR), net assimilation rate (NAR), specific leaf area (SLA) and root weight ratio (RWR), before and after a decrease in nitrogen supply, were studied in 14 herbaceous species. Forty-four plants of each species were grown in hydroponic culture under controlled conditions in a control treatment where the supply of nitrogen remained constant at 1 mm, and in a stress treatment where the nitrogen supply was abruptly decreased from 1 to 0.01 mm during the growth period. In the treatment series, and in comparison with the control, NAR and RGR decreased, RWR increased, and SLA did not change except for the timing of ontogenetic change. Species having greater increases in the maximum rate of change in RWR also had smaller reductions in RGR; plasticity in RWR is therefore adaptive. In contrast, species which showed a greater decrease in NAR showed stronger reductions in RGR; plasticity in NAR is therefore not adaptive. Plasticity in RGR was not related to plasticity in SLA. There were no significant relationships among the plasticities in NAR, RWR or SLA. Potentially fast-growing species experienced larger reductions in RGR following the nitrogen reduction. These results suggest that competitive responses to interspecific competition for nitrogen might be positively correlated with the plasticity in the maximum rate of change in RWR in response to a reduction in nitrogen supply.

  7. Interspecific variation in prey capture behavior by co-occurring Nepenthes pitcher plants

    Science.gov (United States)

    Chin, Lijin; Chung, Arthur YC; Clarke, Charles

    2014-01-01

    Pitcher plants of the genus Nepenthes capture a wide range of arthropod prey for nutritional benefit, using complex combinations of visual and olfactory signals and gravity-driven pitfall trapping mechanisms. In many localities throughout Southeast Asia, several Nepenthes different species occur in mixed populations. Often, the species present at any given location have strongly divergent trap structures and preliminary surveys indicate that different species trap different combinations of arthropod prey, even when growing at the same locality. On this basis, it has been proposed that co-existing Nepenthes species may be engaged in niche segregation with regards to arthropod prey, avoiding direct competition with congeners by deploying traps that have modifications that enable them to target specific prey types. We examined prey capture among 3 multi-species Nepenthes populations in Borneo, finding that co-existing Nepenthes species do capture different combinations of prey, but that significant interspecific variations in arthropod prey combinations can often be detected only at sub-ordinal taxonomic ranks. In all lowland Nepenthes species examined, the dominant prey taxon is Formicidae, but montane Nepenthes trap few (or no) ants and 2 of the 3 species studied have evolved to target alternative sources of nutrition, such as tree shrew feces. Using similarity and null model analyses, we detected evidence for niche segregation with regards to formicid prey among 5 lowland, sympatric Nepenthes species in Sarawak. However, we were unable to determine whether these results provide support for the niche segregation hypothesis, or whether they simply reflect unquantified variation in heterogeneous habitats and/or ant communities in the study sites. These findings are used to propose improvements to the design of field experiments that seek to test hypotheses about targeted prey capture patterns in Nepenthes. PMID:24481246

  8. Seasonal Occurrence and Interspecific Interactions of Egg Parasitoids of Megacopta cribraria (Heteroptera: Plataspidae) in Japan.

    Science.gov (United States)

    Hoshino, Keisuke; Adati, Tarô; Olson, Dawn M; Takasu, Keiji

    2017-06-01

    We conducted a field study to determine seasonal egg parasitism rates of the kudzu bug Megacopta cribraria (F.) on the kudzu plant, Pueraria montana (Lour.) Merr. var. lobata (Willd.) Maesen et Almeida ex Sanjappa and Pradeep, in Tokyo, Japan, during the period from May 2014 to September 2014. The eggs of M. cribraria per 1 m2 of kudzu at four locations in Tokyo were collected weekly and parasitism rates were assessed. Eggs of M. cribraria were laid on the kudzu plant from May to September. Megacopta cribraria eggs were parasitized by two parasitoid species, Paratelenomus saccharalis (Dodd) and Ooencyrtus nezarae Ishii. Paratelenomus saccharalis first appeared in May, and its parasitism rates peaked in July and September. Ooencyrtus nezarae first appeared in June and its parasitism rates peaked in July. Except for one location which could not be statistically analyzed because of the small sample size, occurrence of parasitism by P. saccharalis and O. nezarae in M. cribraria egg masses was independent at one location and positively associated at two locations, suggesting that the use of host egg masses by P. saccharalis and O. nezarae is not mutually exclusive. Parasitism rates by P. saccharalis and O. nezarae were significantly lower for egg masses parasitized by both species than for those parasitized by a single species. The proportion of males among O. nezarae progeny was significantly higher for egg masses parasitized by O. nezarae together with P. saccharalis than for those parasitized by O. nezarae alone. These results suggest that parasitism of host egg masses by the two species is influenced by their interspecific interactions. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Mechanosensing of stem bending and its interspecific variability in five neotropical rainforest species.

    Science.gov (United States)

    Coutand, Catherine; Chevolot, Malia; Lacointe, André; Rowe, Nick; Scotti, Ivan

    2010-02-01

    In rain forests, sapling survival is highly dependent on the regulation of trunk slenderness (height/diameter ratio): shade-intolerant species have to grow in height as fast as possible to reach the canopy but also have to withstand mechanical loadings (wind and their own weight) to avoid buckling. Recent studies suggest that mechanosensing is essential to control tree dimensions and stability-related morphogenesis. Differences in species slenderness have been observed among rainforest trees; the present study thus investigates whether species with different slenderness and growth habits exhibit differences in mechanosensitivity. Recent studies have led to a model of mechanosensing (sum-of-strains model) that predicts a quantitative relationship between the applied sum of longitudinal strains and the plant's responses in the case of a single bending. Saplings of five different neotropical species (Eperua falcata, E. grandiflora, Tachigali melinonii, Symphonia globulifera and Bauhinia guianensis) were subjected to a regimen of controlled mechanical loading phases (bending) alternating with still phases over a period of 2 months. Mechanical loading was controlled in terms of strains and the five species were subjected to the same range of sum of strains. The application of the sum-of-strain model led to a dose-response curve for each species. Dose-response curves were then compared between tested species. The model of mechanosensing (sum-of-strain model) applied in the case of multiple bending as long as the bending frequency was low. A comparison of dose-response curves for each species demonstrated differences in the stimulus threshold, suggesting two groups of responses among the species. Interestingly, the liana species B. guianensis exhibited a higher threshold than other Leguminosae species tested. This study provides a conceptual framework to study variability in plant mechanosensing and demonstrated interspecific variability in mechanosensing.

  10. Designing and creating Saccharomyces interspecific hybrids for improved, industry relevant, phenotypes.

    Science.gov (United States)

    Bellon, Jennifer R; Yang, Fei; Day, Martin P; Inglis, Debra L; Chambers, Paul J

    2015-10-01

    To remain competitive in increasingly overcrowded markets, yeast strain development programmes are crucial for fermentation-based food and beverage industries. In a winemaking context, there are many yeast phenotypes that stand to be improved. For example, winemakers endeavouring to produce sweet dessert wines wrestle with fermentation challenges particular to fermenting high-sugar juices, which can lead to elevated volatile acidity levels and extended fermentation times. In the current study, we used natural yeast breeding techniques to generate Saccharomyces spp. interspecific hybrids as a non-genetically modified (GM) strategy to introduce targeted improvements in important, wine-relevant traits. The hybrids were generated by mating a robust wine strain of Saccharomyces cerevisiae with a wine isolate of Saccharomyces bayanus, a species previously reported to produce wines with low concentrations of acetic acid. Two hybrids generated from the cross showed robust fermentation properties in high-sugar grape juice and produced botrytised Riesling wines with much lower concentrations of acetic acid relative to the industrial wine yeast parent. The hybrids also displayed suitability for icewine production when bench-marked against an industry standard icewine yeast, by delivering icewines with lower levels of acetic acid. Additionally, the hybrid yeast produced wines with novel aroma and flavour profiles and established that choice of yeast strain impacts on wine colour. These new hybrid yeasts display the desired targeted fermentation phenotypes from both parents, robust fermentation in high-sugar juice and the production of wines with low volatile acidity, thus establishing their suitability for wine styles that are traditionally troubled by excessive volatile acidity levels.

  11. Genes and Gene Therapy

    Science.gov (United States)

    ... correctly, a child can have a genetic disorder. Gene therapy is an experimental technique that uses genes to ... or prevent disease. The most common form of gene therapy involves inserting a normal gene to replace an ...

  12. Limitations of mitochondrial gene barcoding in Octocorallia.

    Science.gov (United States)

    McFadden, Catherine S; Benayahu, Yehuda; Pante, Eric; Thoma, Jana N; Nevarez, P Andrew; France, Scott C

    2011-01-01

    The widespread assumption that COI and other mitochondrial genes will be ineffective DNA barcodes for anthozoan cnidarians has not been well tested for most anthozoans other than scleractinian corals. Here we examine the limitations of mitochondrial gene barcoding in the sub-class Octocorallia, a large, diverse, and ecologically important group of anthozoans. Pairwise genetic distance values (uncorrected p) were compared for three candidate barcoding regions: the Folmer region of COI; a fragment of the octocoral-specific mitochondrial protein-coding gene, msh1; and an extended barcode of msh1 plus COI with a short, adjacent intergenic region (igr1). Intraspecific variation was barcodes, and there was no discernible barcoding gap between intra- and interspecific p values. In a case study to assess regional octocoral biodiversity, COI and msh1 barcodes each identified 70% of morphospecies. In a second case study, a nucleotide character-based analysis correctly identified 70% of species in the temperate genus Alcyonium. Although interspecific genetic distances were 2× greater for msh1 than COI, each marker identified similar numbers of species in the two case studies, and the extended COI + igr1 + msh1 barcode more effectively discriminated sister taxa in Alcyonium. Although far from perfect for species identification, a COI + igr1 + msh1 barcode nonetheless represents a valuable addition to the depauperate set of characters available for octocoral taxonomy. © 2010 Blackwell Publishing Ltd.

  13. Interactive effects of juvenile defoliation, light conditions, and interspecific competition on growth and ectomycorrhizal colonization of Fagus sylvatica and Pinus sylvestris seedlings.

    Science.gov (United States)

    Trocha, Lidia K; Weiser, Ewa; Robakowski, Piotr

    2016-01-01

    Seedlings of forest tree species are exposed to a number of abiotic (organ loss or damage, light shortage) and biotic (interspecific competition) stress factors, which may lead to an inhibition of growth and reproduction and, eventually, to plant death. Growth of the host and its mycorrhizal symbiont is often closely linked, and hence, host damage may negatively affect the symbiont. We designed a pot experiment to study the response of light-demanding Pinus sylvestris and shade-tolerant Fagus sylvatica seedlings to a set of abiotic and biotic stresses and subsequent effects on ectomycorrhizal (ECM) root tip colonization, seedling biomass, and leaf nitrogen content. The light regime had a more pronounced effect on ECM colonization than did juvenile damage. The interspecific competition resulted in higher ECM root tip abundance for Pinus, but this effect was insignificant in Fagus. Low light and interspecific competition resulted in lower seedling biomass compared to high light, and the effect of the latter was partially masked by high light. Leaf nitrogen responded differently in Fagus and Pinus when they grew in interspecific competition. Our results indicated that for both light-demanding (Pinus) and shade-tolerant (Fagus) species, the light environment was a major factor affecting seedling growth and ECM root tip abundance. The light conditions favorable for the growth of seedlings may to some extent compensate for the harmful effects of juvenile organ loss or damage and interspecific competition.

  14. Spatial patterns, ecological niches, and interspecific competition of avian brood parasites: inferring from a case study of Korea.

    Science.gov (United States)

    Lee, Jin-Won; Noh, Hee-Jin; Lee, Yunkyoung; Kwon, Young-Soo; Kim, Chang-Hoe; Yoo, Jeong-Chil

    2014-09-01

    Since obligate avian brood parasites depend completely on the effort of other host species for rearing their progeny, the availability of hosts will be a critical resource for their life history. Circumstantial evidence suggests that intense competition for host species may exist not only within but also between species. So far, however, few studies have demonstrated whether the interspecific competition really occurs in the system of avian brood parasitism and how the nature of brood parasitism is related to their niche evolution. Using the occurrence data of five avian brood parasites from two sources of nationwide bird surveys in South Korea and publically available environmental/climatic data, we identified their distribution patterns and ecological niches, and applied species distribution modeling to infer the effect of interspecific competition on their spatial distribution. We found that the distribution patterns of five avian brood parasites could be characterized by altitude and climatic conditions, but overall their spatial ranges and ecological niches extensively overlapped with each other. We also found that the predicted distribution areas of each species were generally comparable to the realized distribution areas, and the numbers of individuals in areas where multiple species were predicted to coexist showed positive relationships among species. In conclusion, despite following different coevolutionary trajectories to adapt to their respect host species, five species of avian brood parasites breeding in South Korea occupied broadly similar ecological niches, implying that they tend to conserve ancestral preferences for ecological conditions. Furthermore, our results indicated that contrary to expectation interspecific competition for host availability between avian brood parasites seemed to be trivial, and thus, play little role in shaping their spatial distributions and ecological niches. Future studies, including the complete ranges of avian brood

  15. Alternative stable states and alternative endstates of community assembly through intra- and interspecific positive and negative interactions.

    Science.gov (United States)

    Gerla, Daan J; Mooij, Wolf M

    2014-09-01

    Positive and negative interactions within and between species may occur simultaneously, with the net effect depending on population densities. For instance, at low densities plants may ameliorate stress, while competition for resources dominates at higher densities. Here, we propose a simple two-species model in which con- and heterospecifics have a positive effect on per capita growth rate at low densities, while negative interactions dominate at high densities. The model thus includes both Allee effects (intraspecific positive effects) and mutualism (interspecific positive effects), as well as intra- and interspecific competition. Using graphical methods we derive conditions for alternative stable states and species coexistence. We show that mutual non-invasibility (i.e. the inability of each species to invade a population of the other) is more likely when species have a strong positive effect on the own species or a strong negative effect on the other species. Mutual non-invasibility implies alternative stable states, however, there may also be alternative stable states at which species coexist. In the case of species symmetry (i.e. when species are indistinguishable), such alternative coexistence states require that if the positive effect exerted at low densities at the own species is stronger than on the other species, the negative effect at higher densities is also stronger on the own species than on the other species, or, vice versa, if the interspecific positive effects at low densities are stronger than the intraspecific effects, the negative effects at higher densities are also stronger between species than within species. However, the reachability of alternative stable states is restricted by the frequency and density at which species are introduced during community assembly, so that alternative stable states do not always represent alternative endstates of community assembly. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Observation by flow 1H NMR and dimerization kinetics and products of reactive ortho-quinodimethanes and benzocyclobutadiene

    International Nuclear Information System (INIS)

    Fischer, D.

    1990-01-01

    The reactive o-quinodimethanes, 1,2-dimethylene-1,2-dihydronaphthalene (9) and o-xylylene (1) were observed by flow 1 H NMR spectroscopy at room temperature. The 1 H NMR spectrum of 9 was obtained in the absence of precursor and dimers. However, the 1 H NMR spectrum of the more reactive 1, generated in a similar manner from [o-((trimethylsilyl)methyl)benzyl]trimethylammonium iodide (5.) could be obtained only in the presence of its stable [4 + 2] and [4 + 4] dimers. The dimerization kinetics of 3-methyl- (5'), 3,6-dimethyl- (11), 3-isopropyl- (12), and 3,6-diisoproply-1,2-xylylene (13) in acetonitrile (CH 3 CN) were studied by stopped-flow UV-visible spectroscopy. Fluoride ion induced 1,2-elimination from 2-elimination from 2-trimethylsilylbenzocyclobutenyl-1 mesylate (26) was used to generate the reactive molecule benzocyclobutadiene (1') in CD 3 CN, which was observed by flow 1 H NMR spectroscopy at room temperature. The 1 H NMR spectrum (in CD 3 CN) of 1,2-dimethylene-1,2-dihydrothiophene (1 double-prime), obtained by fluoride ion induced 1,4-elimination from 3-(trimethylammoniummethyl)-2-(trimethylsilylmethyl)thiophene iodine was observed by flow 1 H NMR spectroscopy at room temperature. The dimerization rate of 1 double-prime in CH 3 CN, generated in the same manner, was measured by UV-visible spectroscopy. 166 refs., 7 figs., 7 tabs

  17. Dissecting genomic hotspots underlying seed protein, oil, and sucrose content in an interspecific mapping population of soybean using high-density linkage mapping.

    Science.gov (United States)

    Patil, Gunvant; Vuong, Tri D; Kale, Sandip; Valliyodan, Babu; Deshmukh, Rupesh; Zhu, Chengsong; Wu, Xiaolei; Bai, Yonghe; Yungbluth, Dennis; Lu, Fang; Kumpatla, Siva; Grover Shannon, J; Varshney, Rajeev K; Nguyen, Henry T

    2018-04-04

    The cultivated [Glycine max (L) Merr.] and wild [Glycine soja Siebold & Zucc.] soybean species comprise wide variation in seed composition traits. Compared to wild soybean, cultivated soybean contains low protein, high oil and high sucrose. In this study, an inter-specific population was derived from a cross between G. max (Williams 82) and G. soja (PI 483460B). This recombinant inbred line (RIL) population of 188 lines was sequenced at 0.3x depth. Based on 91,342 single nucleotide polymorphisms (SNPs), recombination events in RILs were defined, and a high-resolution bin map was developed (4,070 bins). In addition to bin mapping, QTL analysis for protein, oil and sucrose was performed using 3,343 polymorphic SNPs (3K-SNP), derived from Illumina Infinium BeadChip sequencing platform. The QTL regions from both platforms were compared and a significant concordance was observed between bin and 3K-SNP markers. Importantly, the bin map derived from next generation sequencing technology enhanced mapping resolution (from 1325 Kb to 50 Kb). A total of 5, 9 and 4 QTLs were identified for protein, oil and sucrose content, respectively and some of the QTLs coincided with soybean domestication related genomic loci. The major QTL for protein and oil was mapped on Chr. 20 (qPro_20) and suggested negative correlation between oil and protein. In terms of sucrose content, a novel and major QTL was identified on Chr. 8 (qSuc_08) and harbors putative genes involved in sugar transport. In addition, genome-wide association (GWAS) using 91,342 SNPs confirmed the genomic loci derived from QTL mapping. A QTL based haplotype using whole genome resequencing of 106 diverse soybean lines identified unique allelic variation in wild soybean that could be utilized to widen the genetic base in cultivated soybean. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  18. Production of viable male unreduced gametes in Brassica interspecific hybrids is genotype specific and stimulated by cold temperatures

    Directory of Open Access Journals (Sweden)

    Cowling Wallace A

    2011-06-01

    Full Text Available Abstract Background Unreduced gametes (gametes with the somatic chromosome number may provide a pathway for evolutionary speciation via allopolyploid formation. We evaluated the effect of genotype and temperature on male unreduced gamete formation in Brassica allotetraploids and their interspecific hybrids. The frequency of unreduced gametes post-meiosis was estimated in sporads from the frequency of dyads or giant tetrads, and in pollen from the frequency of viable giant pollen compared with viable normal pollen. Giant tetrads were twice the volume of normal tetrads, and presumably resulted from pre-meiotic doubling of chromosome number. Giant pollen was defined as pollen with more than 1.5 × normal diameter, under the assumption that the doubling of DNA content in unreduced gametes would approximately double the pollen cell volume. The effect of genotype was assessed in five B. napus, two B. carinata and one B. juncea parents and in 13 interspecific hybrid combinations. The effect of temperature was assessed in a subset of genotypes in hot (day/night 30°C/20°C, warm (25°C/15°C, cool (18°C/13°C and cold (10°C/5°C treatments. Results Based on estimates at the sporad stage, some interspecific hybrid genotypes produced unreduced gametes (range 0.06 to 3.29% at more than an order of magnitude higher frequency than in the parents (range 0.00% to 0.11%. In nine hybrids that produced viable mature pollen, the frequency of viable giant pollen (range 0.2% to 33.5% was much greater than in the parents (range 0.0% to 0.4%. Giant pollen, most likely formed from unreduced gametes, was more viable than normal pollen in hybrids. Two B. napus × B. carinata hybrids produced 9% and 23% unreduced gametes based on post-meiotic sporad observations in the cold temperature treatment, which was more than two orders of magnitude higher than in the parents. Conclusions These results demonstrate that sources of unreduced gametes, required for the triploid

  19. Impact of Quaternary climatic changes and interspecific competition on the demographic history of a highly mobile generalist carnivore, the coyote.

    Science.gov (United States)

    Koblmüller, Stephan; Wayne, Robert K; Leonard, Jennifer A

    2012-08-23

    Recurrent cycles of climatic change during the Quaternary period have dramatically affected the population genetic structure of many species. We reconstruct the recent demographic history of the coyote (Canis latrans) through the use of Bayesian techniques to examine the effects of Late Quaternary climatic perturbations on the genetic structure of a highly mobile generalist species. Our analysis reveals a lack of phylogeographic structure throughout the range but past population size changes correlated with climatic changes. We conclude that even generalist carnivorous species are very susceptible to environmental changes associated with climatic perturbations. This effect may be enhanced in coyotes by interspecific competition with larger carnivores.

  20. Identification of single nucleotide polymorphisms (SNPs) at candidate genes involved in abiotic stress in two Prosopis species of hybrids

    OpenAIRE

    Maria F. Pomponio; Susana Marcucci Poltri; Diego Lopez Lauenstein; Susana Torales

    2014-01-01

    Aim of the study: Identify and compare SNPs on candidate genes related to abiotic stress in Prosopis chilensis, Prosopis flexuosa and interspecific hybridsArea of the study: Chaco árido, Argentina. Material and Methods: Fragments from 6 candidate genes were sequenced in 60 genotypes. DNA polymorphisms were analyzed.Main Results: The analysis revealed that the hybrids had the highest rate of polymorphism, followed by P. flexuosa and P. chilensis, the values found are comparable to other forest...

  1. Mapping quantitative trait loci (QTLs for fatty acid composition in an interspecific cross of oil palm

    Directory of Open Access Journals (Sweden)

    Sharma Mukesh

    2009-08-01

    Full Text Available Abstract Background Marker Assisted Selection (MAS is well suited to a perennial crop like oil palm, in which the economic products are not produced until several years after planting. The use of DNA markers for selection in such crops can greatly reduce the number of breeding cycles needed. With the use of DNA markers, informed decisions can be made at the nursery stage, regarding which individuals should be retained as breeding stock, which are satisfactory for agricultural production, and which should be culled. The trait associated with oil quality, measured in terms of its fatty acid composition, is an important agronomic trait that can eventually be tracked using molecular markers. This will speed up the production of new and improved oil palm planting materials. Results A map was constructed using AFLP, RFLP and SSR markers for an interspecific cross involving a Colombian Elaeis oleifera (UP1026 and a Nigerian E. guinneensis (T128. A framework map was generated for the male parent, T128, using Joinmap ver. 4.0. In the paternal (E. guineensis map, 252 markers (199 AFLP, 38 RFLP and 15 SSR could be ordered in 21 linkage groups (1815 cM. Interval mapping and multiple-QTL model (MQM mapping (also known as composite interval mapping, CIM were used to detect quantitative trait loci (QTLs controlling oil quality (measured in terms of iodine value and fatty acid composition. At a 5% genome-wide significance threshold level, QTLs associated with iodine value (IV, myristic acid (C14:0, palmitic acid (C16:0, palmitoleic acid (C16:1, stearic acid (C18:0, oleic acid (C18:1 and linoleic acid (C18:2 content were detected. One genomic region on Group 1 appears to be influencing IV, C14:0, C16:0, C18:0 and C18:1 content. Significant QTL for C14:0, C16:1, C18:0 and C18:1 content was detected around the same locus on Group 15, thus revealing another major locus influencing fatty acid composition in oil palm. Additional QTL for C18:0 was detected on Group 3

  2. Microenxertia interespecífica ex vitro em maracujazeiros Ex vitro interspecific micrografting in passionflower

    Directory of Open Access Journals (Sweden)

    Wilson Vicente Souza Pereira

    2009-05-01

    Full Text Available Este trabalho teve como objetivo avaliar o efeito da espécie de Passiflora usada como porta-enxerto no pegamento e desenvolvimento da microenxertia interespecífica ex vitro e caracterizar anatomicamente a região em que ela é realizada. Ápices caulinares de Passiflora edulis f. flavicarpa foram enxertados em hipocótilo de porta-enxertos de P. alata, P. cincinnata, P. edulis e P. setacea. Foram avaliados o desenvolvimento da microenxertia, a ocorrência de brotações adventícias do porta-enxerto e o percentual de microenxertos com folhas expandidas. Os porta-enxertos foram submetidos à avaliação anatômica e histoquímica. O desenvolvimento dos microenxertos e o número de brotações adventícias foram maiores quando se utilizou porta-enxertos de P. edulis e menores com porta-enxertos de P. setacea e P. alata. Porta-enxertos de P. edulis, P. cincinnata, P. alata e P. setacea proporcionaram, respectivamente, 30,3, 10, 1,6 e 0% de microenxertos com folhas expandidas. As avaliações histológicas evidenciaram maior espessura da região cortical em porta-enxertos de P. edulis, enquanto em P. setacea foi observado menor número de camadas corticais, maior quantidade de fibras floemáticas e de alcaloides, características que influenciaram negativamente o resultado da microenxertia.This study aimed at evaluating the effect of Passiflora species used as rootstocks on the success and development of ex vitro interspecific micrografting, and at anatomically characterizing the region where it is done. Stem apices of Passiflora edulis f. flavicarpa were grafted onto the hypocotyl of P. alata, P. cincinnata, P. edulis, and P. setacea seedlings. The micrografting development, the occurrence of adventitious shoots in rootstocks and the percentage of micrografts with expanded leaves were evaluated. The rootstocks were subjected to anatomical and histochemical evaluation. Micrograft development and adventitious shoot number were higher when P. edulis

  3. Rooting depth and root depth distribution of Trifolium repens × T. uniflorum interspecific hybrids.

    Science.gov (United States)

    Nichols, S N; Hofmann, R W; Williams, W M; van Koten, C

    2016-05-20

    Traits related to root depth distribution were examined in Trifolium repens × T. uniflorum backcross 1 (BC 1 ) hybrids to determine whether root characteristics of white clover could be improved by interspecific hybridization. Two white clover cultivars, two T. uniflorum accessions and two BC 1 populations were grown in 1 -m deep tubes of sand culture. Maximum rooting depth and root mass distribution were measured at four harvests over time, and root distribution data were fitted with a regression model to provide measures of root system shape. Morphological traits were measured at two depths at harvest 3. Root system shape of the hybrids was more similar to T. uniflorum than to white clover. The hybrids and T. uniflorum had a higher rate of decrease in root mass with depth than white clover, which would result in higher proportions of root mass in the upper profile. Percentage total root mass at 100-200 mm depth was higher for T. uniflorum than white clover, and for Crusader BC 1 than 'Crusader'. Roots of the hybrids and T. uniflorum also penetrated deeper than those of white clover. T. uniflorum had thicker roots at 50-100 mm deep than the other entries, and more of its fine root mass at 400-500 mm. The hybrids and white clover had more of their fine root mass higher in the profile. Consequently, T. uniflorum had a higher root length density at 400-500 mm than most entries, and a smaller decrease in root length density with depth. These results demonstrate that rooting characteristics of white clover can be altered by hybridization with T. uniflorum, potentially improving water and nutrient acquisition and drought resistance. Root traits of T. uniflorum are likely to be adaptations to soil moisture and fertility in its natural environment. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Interspecific comparison of the effects of continuous ionizing radiation on the primitive mammalian stem germ cell

    International Nuclear Information System (INIS)

    Erickson, B.H.

    1978-01-01

    The response of the mammalian oocyte to radiation is characterized by wide interspecific differences, and results of preliminary assays suggest that this may be the case with the primitive stem germ cell. To test the validity of this observation and to define probable causes for the differences, prenatal mice, rats, and guinea pigs were irradiated continuously throughout gestation at rates of 1 and 3 rads per 23-hr day. Prenatal pigs were irradiated continuously for 108 days at a dose rate of 0.25 rad per 23-hr day. In all cases germ cells were enumerated in gonads excised either at birth or 6 days after birth. A dose rate of 0.25 rad/day reduced the germ-cell number in the male and female pig to 38 and 60% of control, respectively, and only 1 and 5% of the germ cells in the respective sexes survived a dose rate of 1 rad/day. Application of the single-hit multitarget model to all pig data yielded values for D 0 and n of 28 and 0.8, respectively, for the male and 27 and 3.2, respectively, for the female. Corresponding values for the male and female rat were 275 (D 0 ) and 0.3 (n) and 159 (D 0 ) and 0.8 (n), respectively. Both sexes of the pig were either sterilized or brought near sterility by a dose rate of 1 rad/day. In the case of the male rodent, however, this dose rate reduced germ-cell number to only 71% of control in the mouse, 50% of control in the rat, and 41% of control in the guinea pig. Ninety percent of the germ cells in the female rat survived a dose rate of 1 rad/day, as did 87% in the mouse and 71% in the guinea pig. When total dose was used as the basis of comparison, the pig remained the most sensitive species. Thus the differences among rodent species are not great when compared to the tremendous difference between the rodent and pig. When rodents are compared with pigs, the difference in the magnitude of the effect of continuous irradiation on the primitive stem cells of both sexes appears to be dependent on length of time at risk

  5. Effects of interspecific competition on the growth of macrophytes and nutrient removal in constructed wetlands: A comparative assessment of free water surface and horizontal subsurface flow systems.

    Science.gov (United States)

    Zheng, Yucong; Wang, Xiaochang; Dzakpasu, Mawuli; Zhao, Yaqian; Ngo, Huu Hao; Guo, Wenshan; Ge, Yuan; Xiong, Jiaqing

    2016-05-01

    The outcome of competition between adjoining interspecific colonies of Phragmites and Typha in two large field pilot-scale free water surface (FWS) and subsurface flow (SSF) CWs is evaluated. According to findings, the effect of interspecific competition was notable for Phragmites australis, whereby it showed the highest growth performance in both FWS and SSF wetland. In a mixed-culture, P. australis demonstrates superiority in terms of competitive interactions for space between plants. Furthermore, the interspecific competition among planted species seemed to cause different ecological responses of plant species in the two CWs. For example, while relatively high density and shoot height determined the high aboveground dry weight of P. australis in the FWS wetland, this association was not evident in the SSF. Additionally, while plants nutrients uptake accounts for a higher proportion of the nitrogen removal in FWS, that in the SSF accounts for a higher proportion of the phosphorous removal. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Parrotfish grazing ability: interspecific differences in relation to jaw-lever mechanics and relative weight of adductor mandibulae on an Okinawan coral reef.

    Science.gov (United States)

    Nanami, Atsushi

    2016-01-01

    Parrotfishes (family Labridae: Scarini) are regarded to have important roles for maintaining the ecosystem balance in coral reefs due to their removal of organic matter and calcic substrates by grazing. The purpose of the present study was to clarify the interspecific differences in grazing ability of five parrotfish species (Chlorurus sordidus, C. bowersi, Scarus rivulatus, S. niger and S. forsteni) in relation to interspecific differences in jaw-lever mechanics and the relative weight of the adductor mandibulae (muscles operating jaw closing). The grazing ability was calculated by using stomach contents (CaCO3 weight/organic matter weight) defined as the grazing ability index (GAI). There were significant interspecific differences in GAI (C. sordidus = C. bowersi > S. rivulatus > S. niger = S. forsteni). Teeth of C. sordidus and C. bowersi were protrusive-shape whereas teeth of S. rivulatus, S. niger and S. forsteni were flat-shape. C. sordidus and C. bowersihave jaw-lever mechanics producing a greater biting force and have a larger weight of adductor mandibulae. S. rivulatus has jaw-lever mechanics producing a greater biting force but a smaller weight of adductor mandibulae that produce an intermediate biting force. In contrast, S. niger and S. forsteni have jaw-lever mechanics producing a lesser biting force and have a smaller weight of adductor mandibulae. Feeding rates and foray size of S. rivulatus, S. niger and S. forsteni were greater than C. sordidus and C. bowersi. The degree in bioerosion (GAI × feeding rate) was the largest for S. rivulatusand the smallest for S. forsteni. The degree in bioerosion for C. sordidus was larger than S. niger whereas relatively equal between C. bowersi and S. niger. These results suggest that interspecific difference in GAI was explained by interspecific differences in teeth shape, jaw-lever mechanics and relative weight of adductor mandibulae. The interspecific difference in the degree of bioerosion suggests the

  7. Evidence for the emergence of new rice types of interspecific hybrid origin in West African farmers' fields.

    Directory of Open Access Journals (Sweden)

    Edwin Nuijten

    2009-10-01

    Full Text Available In West Africa two rice species (Oryza glaberrima Steud. and Oryza sativa L. co-exist. Although originally it was thought that interspecific hybridization is impossible without biotechnological methods, progenies of hybridization appear to occur in farmer fields. AFLP analysis was used to assess genetic diversity in West Africa (including the countries The Gambia, Senegal, Guinea Bissau, Guinea Conakry, Sierra Leone, Ghana and Togo using 315 rice samples morphologically classified prior to analysis. We show evidence for farmer interspecific hybrids of African and Asian rice, resulting in a group of novel genotypes, and identify possible mechanisms for in-field hybridization. Spontaneous back-crossing events play a crucial role, resulting in different groups of genetic diversity in different regions developed by natural and cultural selection, often under adverse conditions. These new groups of genotypes may have potential relevance for exploitation by plant breeders. Future advances in crop development could be achieved through co-operation between scientists and marginalized farmer groups in order to address challenges of rapid adaptation in a world of increasing socio-political and climatic uncertainty.

  8. Fungal Volatiles Can Act as Carbon Sources and Semiochemicals to Mediate Interspecific Interactions Among Bark Beetle-Associated Fungal Symbionts.

    Directory of Open Access Journals (Sweden)

    Jonathan A Cale

    Full Text Available Mountain pine beetle (Dendroctonus ponderosae has killed millions of hectares of pine forests in western North America. Beetle success is dependent upon a community of symbiotic fungi comprised of Grosmannia clavigera, Ophiostoma montium, and Leptographium longiclavatum. Factors regulating the dynamics of this community during pine infection are largely unknown. However, fungal volatile organic compounds (FVOCs help shape fungal interactions in model and agricultural systems and thus may be important drivers of interactions among bark beetle-associated fungi. We investigated whether FVOCs can mediate interspecific interactions among mountain pine beetle's fungal symbionts by affecting fungal growth and reproduction. Headspace volatiles were collected and identified to determine species-specific volatile profiles. Interspecific effects of volatiles on fungal growth and conidia production were assessed by pairing physically-separated fungal cultures grown either on a carbon-poor or -rich substrate, inside a shared-headspace environment. Fungal VOC profiles differed by species and influenced the growth and/or conidia production of the other species. Further, our results showed that FVOCs can be used as carbon sources for fungi developing on carbon-poor substrates. This is the first report demonstrating that FVOCs can drive interactions among bark beetle fungal symbionts, and thus are important factors in beetle attack success.

  9. Elevated CO2 changes interspecific competition among three species of wheat aphids: Sitobion avenae, Rhopalosiphum padi, and Schizaphis graminum.

    Science.gov (United States)

    Sun, Yu Cheng; Chen, Fa Jun; Ge, Feng

    2009-02-01

    Effects of elevated CO2 (twice ambient) on the interspecific competition among three species of wheat aphids (Sitobion avenae, Rhopalosiphum padi, and Schizaphis graminum) and on wheat-aphid interactions were studied. Wheat plants had higher biomass and yield and lower water and nitrogen content of grain when grown under elevated CO2 than under ambient CO2; levels of condensed tannins, total phenols, and total nonstructural carbohydrates were also higher in wheat ears under elevated CO2. Compared with ambient CO2, elevated CO2 increased the abundance of R. padi when introduced solely but reduced its abundance when S. avenae was also present. The spatial distribution of wheat aphids was apparently influenced by CO2 levels, with significantly more S. avenae on ears and a more even distribution of R. padi on wheat plants under elevated CO2 versus ambient CO2. Elevated CO2 did not affect the abundance and spatial distribution of S. graminus when inoculated solely. Moreover, when S. avenae was present with either R. padi or S. graminum, spatial niche overlap was significantly decreased with elevated CO2. When three species co-occurred, elevated CO2 reduced spatial niche overlap between S. avenae and S. graminum and between R. padi and S. graminum. Our results suggest that increases in atmospheric CO2 would alleviate interspecific competition for these cases, which would accentuate the abundance of and the damage caused by these wheat aphids.

  10. Occupancy of yellow-billed and Pacific loons: evidence for interspecific competition and habitat mediated co-occurrence

    Science.gov (United States)

    Haynes, Trevor B.; Schmutz, Joel A.; Lindberg, Mark S.; Wright, Kenneth G.; Uher-Koch, Brian D.; Rosenberger, Amanda E.

    2014-01-01

    Interspecific competition is an important process structuring ecological communities, however, it is difficult to observe in nature. We used an occupancy modelling approach to evaluate evidence of competition between yellow-billed (Gavia adamsii) and Pacific (G. pacifica) loons for nesting lakes on the Arctic Coastal Plain of Alaska. With multiple years of data and survey platforms, we estimated dynamic occupancy states (e.g. rates of colonization or extinction from individual lakes) and controlled for detection differences among aircraft platforms and ground survey crews. Results indicated that yellow-billed loons were strong competitors and negatively influenced the occupancy of Pacific loons by excluding them from potential breeding lakes. Pacific loon occupancy was conditional on the presence of yellow-billed loons, with Pacific loons having almost a tenfold decrease in occupancy probability when yellow-billed loons were present and a threefold decrease in colonization probability when yellow-billed loons were present in the current or previous year. Yellow-billed and Pacific loons co-occurred less than expected by chance except on very large lakes or lakes with convoluted shorelines; variables which may decrease the cost of maintaining a territory in the presence of the other species. These results imply the existence of interspecific competition between yellow-billed and Pacific loons for nesting lakes; however, habitat characteristics which facilitate visual and spatial separation of territories can reduce competitive interactions and promote species co-occurrence.

  11. INTERSPECIFIC AGGRESSIVE BEHAVIOR OF THE CORALLIMORPHARIAN CORYNACTIS CALIFORNICA (CNIDARIA: ANTHOZOA): EFFECTS ON SYMPATRIC CORALS AND SEA ANEMONES.

    Science.gov (United States)

    Chadwick, Nanette E

    1987-08-01

    Corallimorpharians are sessile cnidarians that are morphologically similar to the actiniarian sea anemones and scleractinian corals. This study describes for the first time the behavioral mechanism and effects of aggression by a corallimorpharian. Polyps of the temperate clonal corallimorpharian Corynactis californica extruded their mesenteries and associated filaments onto members of certain species of sea anemones and corals. They did not exhibit this behavior intraspecifically, and members of different clones of C. californica remained expanded upon contact. In contrast, members of four species of corals and zoanthids responded to contact with C. californica by contracting their tentacles, and members of three sea anemone species bent or moved away, detached from the substrate, or attacked using their aggressive structures. When interspecific contact was prolonged, individuals of C. californica extruded filaments onto, and killed polyps of, the sea anemones Anthopleura elegantissima and Metridium senile within 3 weeks, and the corals Astrangia lajollaensis and Balanophyllia elegans within 4-10 months under laboratory conditions. The use of extruded mesenterial filaments by C. californica to attack members of other anthozoan species is similar to the aggressive behavior exhibited by many scleractinian reef corals. Field observations suggest that C. californica may use this agonistic behavior during interspecific competition for space on hard marine substrate.

  12. Intra- and interspecific trait variations reveal functional relationships between specific leaf area and soil niche within a subtropical forest.

    Science.gov (United States)

    He, Dong; Chen, Yongfa; Zhao, Kangning; Cornelissen, J H C; Chu, Chengjin

    2018-02-03

    How functional traits vary with environmental conditions is of fundamental importance in trait-based community ecology. However, how intraspecific variability in functional traits is connected to species distribution is not well understood. This study investigated inter- and intraspecific variation of a key functional trait, i.e. specific leaf area (leaf area per unit dry mass; SLA), in relation to soil factors and tested if trait variation is more closely associated with specific environmental regimes for low-variability species than for high-variability species. In a subtropical evergreen forest plot (50 ha, southern China), 106 700 leaves from 5335 individuals of 207 woody species were intensively collected, with 30 individuals sampled for most species to ensure a sufficient sample size representative of intraspecific variability. Soil conditions for each plant were estimated by kriging from more than 1700 observational soil locations across the plot. Intra- and interspecific variation in SLA were separately related to environmental factors. Based on the species-specific variation of SLA, species were categorized into three groups: low-, intermediate- and high-intraspecific variability. Intraspecific habitat ranges and the strength of SLA-habitat relationships were compared among these three groups. Interspecific variation in SLA overrides the intraspecific variation (77 % vs. 8 %). Total soil nitrogen (TN, positively) and total organic carbon (TOC, negatively) are the most important explanatory factors for SLA variation at both intra- and interspecific levels. SLA, both within and between species, decreases with decreasing soil nitrogen availability. As predicted, species with low intraspecific variability in SLA have narrower habitat ranges with respect to soil TOC and TN and show a stronger SLA-habitat association than high-variability species. For woody plants low SLA is a phenotypic and probably adaptive response to nitrogen stress, which drives the

  13. A shift in nuclear state as the result of natural interspecific hybridization between two North American taxa of the basidiomycete complex Heterobasidion

    Science.gov (United States)

    Matteo Garbelotto; Paolo Gonthier; Rachel Linzer; Giovanni Nicolotti; William Otrosina

    2004-01-01

    A natural first generation hybrid fungus shows interspecific heterozygosity. The nuclear condition of a rare natural hybrid between two taxa of the Heterobasidion complex is investigated. Heterobasidion species are known to be either homokaryotic (haploid) or heterokaryotic (n + n), but heterokaryons are made up of both...

  14. Repeated observations of interspecific „mating“ between males of the arctiid moth Amata phegea and females of the burnet moth Zygaena filipendulae (Lepidoptera: Zyganeidae and Arctiidae)

    Czech Academy of Sciences Publication Activity Database

    Novotný, David; Beneš, Jiří; Konvička, M.

    2009-01-01

    Roč. 30, 1/2 (2009), s. 81-82 ISSN 0723-9912 R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z50070508 Keywords : visual discrimination * interspecific copulation * mate locating behaviour Subject RIV: EB - Genetics ; Molecular Biology

  15. Wintercuring of Prunus dulcis cv ‘Butte,’ P. webbii and their interspecific hybrid in response to Xylella fastidiosa infections

    Science.gov (United States)

    Clonal replicates of Prunus dulcis cv ‘Butte,’ P. webbii and their interspecific hybrid P 63-61 were inoculated with Xylella fastidiosa strain M23 and evaluated for Almond Leaf Scorch Disease and subsequent wintercuring of infections during three growing seasons. Initial inoculations established gr...

  16. Does interspecific competition alter effects of early season ozone exposure on plants from wet grasslands? Results of a three-year experiment in open-top chambers

    NARCIS (Netherlands)

    Tonneijck, A.E.G.; Franzaring, J.; Brouwer, G.; Metselaar, K.; Dueck, T.A.

    2004-01-01

    Chronic effects of ozone on wet grassland species early in the growing season might be altered by interspecific competition. Individual plants of Holcus lanatus, Lychnis flos-cuculi, Molinia caerulea and Plantago lanceolata were grown in monocultures and in mixed cultures with Agrostis capillaris.

  17. Draft Genome Sequence of Acinetobacter johnsonii C6, an Environmental Isolate Engaging in Interspecific Metabolic Interactions

    DEFF Research Database (Denmark)

    Kaas, Rolf Sommer; Mordhorst, Hanne; Leekitcharoenphon, Pimlapas

    2017-01-01

    Acinetobacter johnsonii C6 originates from creosote-polluted groundwater and performs ecological and evolutionary interactions with Pseudomonas putida in biofilms. The draft genome of A. johnsonii C6 is 3.7 Mbp and was shaped by mobile genetic elements. It reveals genes facilitating the biodegrad......Acinetobacter johnsonii C6 originates from creosote-polluted groundwater and performs ecological and evolutionary interactions with Pseudomonas putida in biofilms. The draft genome of A. johnsonii C6 is 3.7 Mbp and was shaped by mobile genetic elements. It reveals genes facilitating...

  18. Interspecific variation in anthocyanins, phenolics, and antioxidant capacity among genotypes of highbush and lowbush blueberries (Vaccinium section cyanococcus spp.).

    Science.gov (United States)

    Kalt, W; Ryan, D A; Duy, J C; Prior, R L; Ehlenfeldt, M K; Vander Kloet, S P

    2001-10-01

    Recent interest in the possible protective effects of dietary antioxidant compounds against human degenerative disease has prompted investigation of foods such as blueberries (Vaccinium sp.), which have a high antioxidant capacity. Fruit obtained from genotypes of highbush blueberries (Vaccinium corymbosum L.) and lowbush blueberries (Vaccinium angustifolium Aiton) were analyzed for their antioxidant capacity, their content of anthocyanins, and total phenolic compounds, to evaluate the intraspecific and interspecific variation in these parameters. The method of extraction influenced the composition of fruit extracts; the highest anthocyanin and total phenolic contents and antioxidant capacity were found in extracts obtained using a solvent of acidified aqueous methanol. Regardless of the method, lowbush blueberries were consistently higher in anthocyanins, total phenolics, and antioxidant capacity, compared with highbush blueberries. There was no relationship between fruit size and anthocyanin content in either species.

  19. Interspecific variation and plasticity in hemoglobin nitrite reductase activity and its correlation with oxygen affinity in vertebrates

    DEFF Research Database (Denmark)

    Jensen, Frank B.; Kolind, Rasmus A. H.; Jensen, Natashia S.

    2017-01-01

    -dependent manner. The initial second order rate constant of the deoxyHb-mediated nitrite reduction showed a strong curvilinear correlation with oxygen affinity among all ectothermic vertebrates, and the relationship also applied to plastic variations of Hb properties via organic phosphates. The relationship...... determines oxygen affinity. In the present study we investigated nitrite reductase activity and O2 affinity in Hbs from ten different vertebrate species under identical conditions to disclose interspecific variations and allow an extended test for a correlation between the rate constant for nitrite reduction...... and O2 affinity. We also tested plastic changes in Hb properties via addition of T-structure-stabilizing organic phosphates (ATP and GTP). The decay in deoxyHb during its reaction with nitrite was exponential-like in ectotherms (Atlantic hagfish, carp, crucian carp, brown trout, rainbow trout, cane toad...

  20. Cytogenetic evidence for genome elimination during microsporogenesis in interspecific hybrid between Brachiaria ruziziensis and B. brizantha (Poaceae

    Directory of Open Access Journals (Sweden)

    Andréa Beatriz Mendes-Bonato

    2006-01-01

    Full Text Available Microsporogenesis was analyzed in an interspecific hybrid between an artificially tetraploidized sexual accession of Brachiaria ruziziensis (R genome and a natural apomictic tetraploid accession of B. brizantha (B genome. Chromosomes associated predominantly as bivalents. From this phase to the end of meiosis, chromosomes presented irregular segregation and abnormal arrangement in the metaphase plate. During metaphase I, in 27.8% of meiocytes, bivalents were distributed in two metaphase plates. In anaphase I, two distinct and typical bipolar spindles were formed. In 29.7% of pollen mother cells, one genome did not divide synchronically, with chromosomes lagging behind or not segregating at all. The second division was very irregular, resulting in polyads. Based on previous results from analysis of a triploid hybrid between these species, where the R genome was eliminated by asynchrony during meiosis, it is suggested that the laggard genome in this hybrid also belongs to B. ruziziensis.

  1. Plant breeding by using radiation mutation - Development of disease tolerant lines of hotpepper by using radiation and interspecific hybridization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Su; Song, Hi Sup; Kim, Jin Kyu; Shin, In Chul [Nongwoo Seed Co., Suwon (Korea)

    2000-04-01

    To obtain disease resistant mutant lines, 6 inbred lines were hotppepers were irradiated with 250Gy of gamma ray and crossed between cultivar and wild species. 1) 4500 M{sub 1} plants were cultivated for obtaining M{sub 2} seed in 6 inbred lines of hotpeppers irradiated with 250 Gy of gamma ray. 2) Crossability was not generally existed among interspecific crosses, crossability between C. annum and C. chacoense was successful except crosses between C. annum, C. pubescens and C. eximium. 3) The embryo disected 45 days after pollination was suitable for embryo culture. 4) Hybrid plants were obtained from the embryo culture of the combination between C. annum and C. chacoense, while abnormal hybrid plants occurred from the combination between C. annum and C. baccatum. 15 refs., 4 figs., 4 tabs. (Author)

  2. Welcome to the neighbourhood: interspecific genotype by genotype interactions in Solidago influence above- and belowground biomass and associated communities.

    Science.gov (United States)

    Genung, Mark A; Bailey, Joseph K; Schweitzer, Jennifer A

    2012-01-01

    Intra- and interspecific plant-plant interactions are fundamental to patterns of community assembly and to the mixture effects observed in biodiversity studies. Although much research has been conducted at the species level, very little is understood about how genetic variation within and among interacting species may drive these processes. Using clones of both Solidago altissima and Solidago gigantea, we found that genotypic variation in a plant's neighbours affected both above- and belowground plant traits, and that genotype by genotype interactions between neighbouring plants impacted associated pollinator communities. The traits for which focal plant genotypic variation explained the most variation varied by plant species, whereas neighbour genotypic variation explained the most variation in coarse root biomass. Our results provide new insight into genotypic and species diversity effects in plant-neighbour interactions, the extended consequences of diversity effects, and the potential for evolution in response to competitive or to facilitative plant-neighbour interactions. © 2011 Blackwell Publishing Ltd/CNRS.

  3. A Bayesian analysis of gene flow from crops to their wild relatives: cultivated (Lactuca sativa L.) and prickly lettuce (L. serriola L.) and the recent expansion of L. serriola in Europe

    NARCIS (Netherlands)

    Uwimana, B; D'andrea, L.; Felber, F.; Hooftman, D.A.P.; den Nijs, H.C.M.; Smulders, M.J.M.; Visser, R.G.F.; van de Wiel, C.C.M.

    2012-01-01

    Interspecific gene flow can lead to the formation of hybrid populations that have a competitive advantage over the parental populations, even for hybrids from a cross between crops and wild relatives. Wild prickly lettuce (Lactuca serriola) has recently expanded in Europe and hybridization with the

  4. Genome wide SSR high density genetic map construction from an interspecific cross of Gossypium hirsutum × Gossypium tomentosum

    Directory of Open Access Journals (Sweden)

    Muhammad Kashif Riaz eKhan

    2016-04-01

    Full Text Available A high density genetic map was constructed using F2 population derived from an interspecific cross of G. hirsutum x G. tomentosum. The map consisted of 3,093 marker loci distributed across all the 26 chromosomes and covered 4,365.3 cM of cotton genome with an average inter-marker distance of 1.48 cM. The maximum length of chromosome was 218.38 cM and the minimum was 122.09 cM with an average length of 167.90 cM. A sub-genome covers more genetic distance (2,189.01 cM with an average inter loci distance of 1.53 cM than D sub-genome which covers a length of 2,176.29 cM with an average distance of 1.43 cM. There were 716 distorted loci in the map accounting for 23.14% and most distorted loci were distributed on D sub-genome (25.06%, which were more than on A sub-genome (21.23%. In our map 49 segregation hotspots (SDR were distributed across the genome with more on D sub-genome as compared to A genome. Two post-polyploidization reciprocal translocations of A2/A3 and A4/A5 were suggested by 7 pairs of duplicate loci. The map constructed through these studies is one of the three densest genetic maps in cotton however; this is the first dense genome wide SSR interspecific genetic map between G. hirsutum and G. tomentosum.

  5. Interspecific variation in persistence of buried weed seeds follows trade-offs among physiological, chemical, and physical seed defenses.

    Science.gov (United States)

    Davis, Adam S; Fu, Xianhui; Schutte, Brian J; Berhow, Mark A; Dalling, James W

    2016-10-01

    Soil seedbanks drive infestations of annual weeds, yet weed management focuses largely on seedling mortality. As weed seedbanks increasingly become reservoirs of herbicide resistance, species-specific seedbank management approaches will be essential to weed control. However, the development of seedbank management strategies can only develop from an understanding of how seed traits affect persistence.We quantified interspecific trade-offs among physiological, chemical, and physical traits of weed seeds and their persistence in the soil seedbank in a common garden study. Seeds of 11 annual weed species were buried in Savoy, IL, from 2007 through 2012. Seedling recruitment was measured weekly and seed viability measured annually. Seed physiological (dormancy), chemical (phenolic compound diversity and concentration; invertebrate toxicity), and physical traits (seed coat mass, thickness, and rupture resistance) were measured.Seed half-life in the soil ( t 0.5 ) showed strong interspecific variation ( F 10,30  = 15, p  central role of seed dormancy in controlling seed persistence.A quantitative comparison between our results and other published work indicated that weed seed dormancy and seedbank persistence are linked across diverse environments and agroecosystems. Moreover, among seedbank-forming early successional plant species, relative investment in chemical and physical seed defense varies with seedbank persistence. Synthesis and applications . Strong covariance among weed seed traits and persistence in the soil seedbank indicates potential for seedbank management practices tailored to specific weed species. In particular, species with high t 0.5 values tend to invest less in chemical defenses. This makes them highly vulnerable to physical harvest weed seed control strategies, with small amounts of damage resulting in their full decay.

  6. Interspecific Differences in Metabolic Rate and Metabolic Temperature Sensitivity Create Distinct Thermal Ecological Niches in Lizards (Plestiodon).

    Science.gov (United States)

    Watson, Charles M; Burggren, Warren W

    2016-01-01

    Three congeneric lizards from the southeastern United States (Plestiodon fasciatus, P. inexpectatus, and P. laticeps) exhibit a unique nested distribution. All three skink species inhabit the US Southeast, but two extend northward to central Ohio (P. fasciatus and P. laticeps) and P. fasciatus extends well into Canada. Distinct interspecific differences in microhabitat selection and behavior are associated with the cooler temperatures of the more Northern ranges. We hypothesized that interspecific differences in metabolic temperature sensitivity locally segregates them across their total range. Resting oxygen consumption was measured at 20°, 25° and 30°C. Plestiodon fasciatus, from the coolest habitats, exhibited greatly elevated oxygen consumption compared to the other species at high ecologically-relevant temperatures (0.10, 0.17 and 0.83 ml O2. g-1. h-1 at 20°, 25° and 30°C, respectively). Yet, P. inexpectatus, from the warmest habitats, exhibited sharply decreased oxygen consumption compared to the other species at lower ecologically-relevant temperatures (0.09, 0.27 and 0.42 ml O2. g-1. h-1 at 20°, 25° and 30°C, respectively). Plestiodon laticeps, from both open and closed microhabitats and intermediate latitudinal range, exhibited oxygen consumptions significantly lower than the other two species (0.057, 0.104 and 0.172 ml O2. g-1. h-1 at 20°, 25° and 30°C, respectively). Overall, Plestiodon showed metabolic temperature sensitivities (Q10s) in the range of 2-3 over the middle of each species' normal temperature range. However, especially P. fasciatus and P. inexpectatus showed highly elevated Q10s (9 to 25) at the extreme ends of their temperature range. While morphologically similar, these skinks are metabolically distinct across the genus' habitat, likely having contributed to their current distribution.

  7. Interspecific interference competition at the resource patch scale: do large herbivores spatially avoid elephants while accessing water?

    Science.gov (United States)

    Ferry, Nicolas; Dray, Stéphane; Fritz, Hervé; Valeix, Marion

    2016-11-01

    Animals may anticipate and try to avoid, at some costs, physical encounters with other competitors. This may ultimately impact their foraging distribution and intake rates. Such cryptic interference competition is difficult to measure in the field, and extremely little is known at the interspecific level. We tested the hypothesis that smaller species avoid larger ones because of potential costs of interference competition and hence expected them to segregate from larger competitors at the scale of a resource patch. We assessed fine-scale spatial segregation patterns between three African herbivore species (zebra Equus quagga, kudu Tragelaphus strepsiceros and giraffe Giraffa camelopardalis) and a megaherbivore, the African elephant Loxodonta africana, at the scale of water resource patches in the semi-arid ecosystem of Hwange National Park, Zimbabwe. Nine waterholes were monitored every two weeks during the dry season of a drought year, and observational scans of the spatial distribution of all herbivores were performed every 15 min. We developed a methodological approach to analyse such fine-scale spatial data. Elephants increasingly used waterholes as the dry season progressed, as did the probability of co-occurrence and agonistic interaction with elephants for the three study species. All three species segregated from elephants at the beginning of the dry season, suggesting a spatial avoidance of elephants and the existence of costs of being close to them. However, contrarily to our expectations, herbivores did not segregate from elephants the rest of the dry season but tended to increasingly aggregate with elephants as the dry season progressed. We discuss these surprising results and the existence of a trade-off between avoidance of interspecific interference competition and other potential factors such as access to quality water, which may have relative associated costs that change with the time of the year. © 2016 The Authors. Journal of Animal Ecology

  8. Spatial Patterns and Interspecific Associations of Three Canopy Species at Different Life Stages in a Subtropical Forest,China

    Institute of Scientific and Technical Information of China (English)

    Lin Li; Shi-Guang Wei; Zhong-Liang Huang; Wan-Hui Ye; Hong-Lin Cao

    2008-01-01

    Spatial patterns of species at different life stages are an important aspect for understanding causal mechanisms that facilitate species co-existence.Using Ripley's univariate L(t) and bivariate L12(t) functions,we analyzed the spatial patterns and interspecific associations of three canopy species at different life history stages in a 20-ha subtropical forest plot in Dinghushan Nature Reserve.Based on diameter at breast height (DBH),four life stages were distinguished.Castanopsis chinensis and Schima superba showed a unimodal DBH distribution.Engelhardtia roxburghiana showed a bimodal curve.L(t) function analysis showed significantly aggregated distributions of all three species at later life stages and random distribution at early life stages at some scales.From the analysis of L12(t) function,the results showed the positive association was a dominant pattern for most species pairs at most scales but the intensity of association decreases with the increase of life stages.Juveniles of the three species had no negative intra- and interspecific associations with the older life stages.Only premature trees were suppressed by overmature trees at some scales.Considering these results,we found three canopy-dominant species that lacked regeneration.There was no direct competition occurring between understorey individuals.Young trees can grow well under conspecific species with two other species.Longevity and lack of regeneration led to a large number of trees stored in mature and overmature stages,therefore,intra-and inter-competition can be strong at later life stages.

  9. Incorporating interspecific competition into species-distribution mapping by upward scaling of small-scale model projections to the landscape.

    Directory of Open Access Journals (Sweden)

    Mark Baah-Acheamfour

    Full Text Available There are a number of overarching questions and debate in the scientific community concerning the importance of biotic interactions in species distribution models at large spatial scales. In this paper, we present a framework for revising the potential distribution of tree species native to the Western Ecoregion of Nova Scotia, Canada, by integrating the long-term effects of interspecific competition into an existing abiotic-factor-based definition of potential species distribution (PSD. The PSD model is developed by combining spatially explicit data of individualistic species' response to normalized incident photosynthetically active radiation, soil water content, and growing degree days. A revised PSD model adds biomass output simulated over a 100-year timeframe with a robust forest gap model and scaled up to the landscape using a forestland classification technique. To demonstrate the method, we applied the calculation to the natural range of 16 target tree species as found in 1,240 provincial forest-inventory plots. The revised PSD model, with the long-term effects of interspecific competition accounted for, predicted that eastern hemlock (Tsuga canadensis, American beech (Fagus grandifolia, white birch (Betula papyrifera, red oak (Quercus rubra, sugar maple (Acer saccharum, and trembling aspen (Populus tremuloides would experience a significant decline in their original distribution compared with balsam fir (Abies balsamea, black spruce (Picea mariana, red spruce (Picea rubens, red maple (Acer rubrum L., and yellow birch (Betula alleghaniensis. True model accuracy improved from 64.2% with original PSD evaluations to 81.7% with revised PSD. Kappa statistics slightly increased from 0.26 (fair to 0.41 (moderate for original and revised PSDs, respectively.

  10. Interspecific variability of class II hydrophobin GEO1 in the genus Geosmithia10

    Czech Academy of Sciences Publication Activity Database

    Frascella, A.; Bettini, P.P.; Kolařík, Miroslav; Comparini, C.; Pazzagli, L.; Lutti, S.; Scala, F.; Scala, A.

    2014-01-01

    Roč. 118, č. 11 (2014), s. 862-871 ISSN 1878-6146 R&D Projects: GA ČR(CZ) GAP506/11/2302 Institutional support: RVO:61388971 Keywords : Ascomycetes * Entomochoric fungi * Gene expression Subject RIV: EE - Microbiology, Virology Impact factor: 2.342, year: 2014

  11. Genetic Diversity and Phenotypic Variation in an Introgression Line Population Derived from an Interspecific Cross between Oryza glaberrima and Oryza sativa.

    Directory of Open Access Journals (Sweden)

    Caijin Chen

    Full Text Available The introduction of closely related species genomic fragments is an effective way to enrich genetic diversity and creates new germplasms in crops. Here, we studied the genetic diversity of an introgression line (IL population composed of 106 ILs derived from an interspecific tetra cross between O. glaberrima and O. sativa (RAM3/Jin23B//Jin23B///YuetaiB. The proportion of O. glaberrima genome (PGG in the ILs ranged from 0.3% to 36.7%, with an average value of 12.32% which is close to the theoretically expected proportion. A total of 250 polymorphic alleles were amplified by 21 AFLP primer combinations with an average of 12 alleles per primer. Population structure analysis revealed that the IL population can be divided into four genetically distinct subpopulations. Both principal component analysis and neighbor-joining tree analysis showed that ILs with a higher PGG displayed greater genetic diversity. Canonical discriminant analysis identified six phenotypic traits (plant height, yield per plant, filled grain percentage, panicle length, panicle number and days to flowering as the main discriminatory traits among the ILs and between the subpopulations and showed significant phenotypic distances between subpopulations. The effects of PGG on phenotypic traits in the ILs were estimated using a linear admixed model, which showed a significant positive effect on grain yield per plant (0.286±0.117, plant height (0.418 ± 0.132, panicle length (0.663 ± 0.107, and spikelet number per panicle (0.339 ± 0.128, and a significant negative effect on filled grain percentage (-0.267 ± 0.123 and days to flowering (-0.324 ± 0.075. We found that an intermediate range (10% - 20% of PGG was more effective for producing ILs with favorable integrated agronomic traits. Our results confirm that construction of IL population carrying O. glaberrima genomic fragments could be an effective approach to increase the genetic diversity of O. sativa genome and an appropriate

  12. Parrotfish grazing ability: interspecific differences in relation to jaw-lever mechanics and relative weight of adductor mandibulae on an Okinawan coral reef

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    Atsushi Nanami

    2016-09-01

    Full Text Available Parrotfishes (family Labridae: Scarini are regarded to have important roles for maintaining the ecosystem balance in coral reefs due to their removal of organic matter and calcic substrates by grazing. The purpose of the present study was to clarify the interspecific differences in grazing ability of five parrotfish species (Chlorurus sordidus, C. bowersi, Scarus rivulatus, S. niger and S. forsteni in relation to interspecific differences in jaw-lever mechanics and the relative weight of the adductor mandibulae (muscles operating jaw closing. The grazing ability was calculated by using stomach contents (CaCO3 weight/organic matter weight defined as the grazing ability index (GAI. There were significant interspecific differences in GAI (C. sordidus = C. bowersi > S. rivulatus > S. niger = S. forsteni. Teeth of C. sordidus and C. bowersi were protrusive-shape whereas teeth of S. rivulatus, S. niger and S. forsteni were flat-shape. C. sordidus and C. bowersihave jaw-lever mechanics producing a greater biting force and have a larger weight of adductor mandibulae. S. rivulatus has jaw-lever mechanics producing a greater biting force but a smaller weight of adductor mandibulae that produce an intermediate biting force. In contrast, S. niger and S. forsteni have jaw-lever mechanics producing a lesser biting force and have a smaller weight of adductor mandibulae. Feeding rates and foray size of S. rivulatus, S. niger and S. forsteni were greater than C. sordidus and C. bowersi. The degree in bioerosion (GAI × feeding rate was the largest for S. rivulatusand the smallest for S. forsteni. The degree in bioerosion for C. sordidus was larger than S. niger whereas relatively equal between C. bowersi and S. niger. These results suggest that interspecific difference in GAI was explained by interspecific differences in teeth shape, jaw-lever mechanics and relative weight of adductor mandibulae. The interspecific difference in the degree of bioerosion suggests

  13. Identification of single nucleotide polymorphisms (SNPs at candidate genes involved in abiotic stress in two Prosopis species of hybrids

    Directory of Open Access Journals (Sweden)

    Maria F. Pomponio

    2014-12-01

    Full Text Available Aim of the study: Identify and compare SNPs on candidate genes related to abiotic stress in Prosopis chilensis, Prosopis flexuosa and interspecific hybridsArea of the study: Chaco árido, Argentina. Material and Methods: Fragments from 6 candidate genes were sequenced in 60 genotypes. DNA polymorphisms were analyzed.Main Results: The analysis revealed that the hybrids had the highest rate of polymorphism, followed by P. flexuosa and P. chilensis, the values found are comparable to other forest tree species.Research highlights: This approach will help to study genetic diversity variation on natural populations for assessing the effects of environmental changes.Keywords: SNPs; abiotic stress; interspecific variation; molecular markers. 

  14. Ecological and spatial factors drive intra- and interspecific variation in exposure of subarctic predatory bird nestlings to persistent organic pollutants.

    Science.gov (United States)

    Eulaers, Igor; Jaspers, Veerle L B; Bustnes, Jan O; Covaci, Adrian; Johnsen, Trond V; Halley, Duncan J; Moum, Truls; Ims, Rolf A; Hanssen, Sveinn A; Erikstad, Kjell E; Herzke, Dorte; Sonne, Christian; Ballesteros, Manuel; Pinxten, Rianne; Eens, Marcel

    2013-07-01

    Top predators in northern ecosystems may suffer from exposure to persistent organic pollutants (POPs) as this exposure may synergistically interact with already elevated natural stress in these ecosystems. In the present study, we aimed at identifying biological (sex, body condition), ecological (dietary carbon source, trophic level) and spatial factors (local habitat, regional nest location) that may influence intra- and interspecific variation in exposure of subarctic predatory bird nestlings to polychlorinated biphenyl 153 (CB 153), polybrominated diphenyl ether 47 (BDE 47), dichlorodiphenyldichloroethylene (p,p'-DDE) and hexachlorobenzene (HCB). During three breeding seasons (2008-2010), we sampled body feathers from fully-grown nestlings of three ecologically distinct predatory bird species in subarctic Norway: Northern Goshawk (Accipiter gentilis), White-tailed Eagle (Haliaeetus albicilla) and Golden Eagle (Aquila chrysaetos). The present study analysed, for the first time, body feathers for both POPs and carbon (δ(13)C) and nitrogen (δ(15)N) stable isotopes, thus integrating the dietary carbon source, trophic level and POP exposure for the larger part of the nestling stage. Intraspecific variation in exposure was driven by a combination of ecological and spatial factors, often different for individual compounds. In addition, combinations for individual compounds differed among species. Trophic level and local habitat were the predominant predictors for CB 153, p,p'-DDE and BDE 47, indicating their biomagnification and decreasing levels according to coast>fjord>inland. Variation in exposure may also have been driven by inter-annual variation arisen from primary sources (e.g. p,p'-DDE) and/or possible revolatilisation from secondary sources (e.g. HCB). Interspecific differences in POP exposure were best explained by a combination of trophic level (biomagnification), dietary carbon source (food chain discrimination) and regional nest location (historical POP

  15. Chromosomal rearrangements in interspecific hybrids between Nicotiana gossei Domin and N. tabacum L., obtained by crossing with pollen exposed to helium ion beams or gamma-rays

    International Nuclear Information System (INIS)

    Kitamura, S.; Inoue, M.; Ohmido, N.; Fukui, K.; Tanaka, A.

    2003-01-01

    It is very difficult to obtain interspecific hybrids between Nicotiana tabacum L. (2n=48) and N. gossei Domin (2n=36), because of strong cross incompatibility. We had already obtained interspecific hybrids between these two species, crossing N. gossei flower with N. tabacum pollen exposed to He ions or gamma-rays. Here, we analyze chromosome constitution of these hybrids by genomic in situ hybridization. In root tip cells of the two hybrids obtained with He ion exposure, most mitotic cells contained 18 chromosomes of N. gossei and 24 chromosomes of N. tabacum. However, in some cells, translocations and insertions between parental genomes were observed. On the other hand, in a hybrid obtained by gamma-ray irradiation, intergenomic rearrangements were not observed, although mitotic cells showed 19 hybridization signals with N. gossei DNA in 41 chromosomes. Such chromosomal changes in structure or constitution may be related to overcoming cross incompatibility between these two species

  16. Nitrogen-controlled intra- and interspecific competition between Populus purdomii and Salix rehderiana drive primary succession in the Gongga Mountain glacier retreat area.

    Science.gov (United States)

    Song, Mengya; Yu, Lei; Jiang, Yonglei; Lei, Yanbao; Korpelainen, Helena; Niinemets, Ülo; Li, Chunyang

    2017-06-01

    In this study, intra- and interspecific competition were investigated in early successional Salix rehderiana Schneider and later-appearing Populus purdomii Rehder under non-fertilized (control) and nitrogen (N)-fertilized conditions in the Hailuogou glacier retreat area. Our aim was to discover whether N is a key factor in plant-plant competition and whether N drives the primary succession process in a glacier retreat area. We analyzed differences in responses to intra- and interspecific competition and N fertilization between P. purdomii and S. rehderiana, including parameters such as biomass accumulation, nutrient absorption, non-structural carbohydrates, photosynthetic capacity, hydrolysable amino acids and leaf ultrastructure. In the control treatments, S. rehderiana individuals subjected to interspecific competition benefited from the presence of P. purdomii plants, as indicated by higher levels of biomass accumulation, photosynthetic capacity, N absorption, amino acid contents and photosynthetic N-use efficiency. However, in the N-fertilized treatments, P. purdomii individuals exposed to interspecific competition benefited from the presence of S. rehderiana plants, as shown by a higher growth rate, enhanced carbon gain capacity, greater amino acid contents, and elevated water-use efficiency, whereas the growth of S. rehderiana was significantly reduced. Our results demonstrate that N plays a pivotal role in determining the asymmetric competition pattern among Salicaceae species during primary succession. We argue that the interactive effects of plant-plant competition and N availability are key mechanisms that drive primary succession in the Gongga Mountain glacier retreat area. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. DNA barcoding for molecular identification of Demodex based on mitochondrial genes.

    Science.gov (United States)

    Hu, Li; Yang, YuanJun; Zhao, YaE; Niu, DongLing; Yang, Rui; Wang, RuiLing; Lu, Zhaohui; Li, XiaoQi

    2017-12-01

    There has been no widely accepted DNA barcode for species identification of Demodex. In this study, we attempted to solve this issue. First, mitochondrial cox1-5' and 12S gene fragments of Demodex folloculorum, D. brevis, D. canis, and D. caprae were amplified, cloned, and sequenced for the first time; intra/interspecific divergences were computed and phylogenetic trees were reconstructed. Then, divergence frequency distribution plots of those two gene fragments were drawn together with mtDNA cox1-middle region and 16S obtained in previous studies. Finally, their identification efficiency was evaluated by comparing barcoding gap. Results indicated that 12S had the higher identification efficiency. Specifically, for cox1-5' region of the four Demodex species, intraspecific divergences were less than 2.0%, and interspecific divergences were 21.1-31.0%; for 12S, intraspecific divergences were less than 1.4%, and interspecific divergences were 20.8-26.9%. The phylogenetic trees demonstrated that the four Demodex species clustered separately, and divergence frequency distribution plot showed that the largest intraspecific divergence of 12S (1.4%) was less than cox1-5' region (2.0%), cox1-middle region (3.1%), and 16S (2.8%). The barcoding gap of 12S was 19.4%, larger than cox1-5' region (19.1%), cox1-middle region (11.3%), and 16S (13.0%); the interspecific divergence span of 12S was 6.2%, smaller than cox1-5' region (10.0%), cox1-middle region (14.1%), and 16S (11.4%). Moreover, 12S has a moderate length (517 bp) for sequencing at once. Therefore, we proposed mtDNA 12S was more suitable than cox1 and 16S to be a DNA barcode for classification and identification of Demodex at lower category level.

  18. Interspecific somatic hybrid plants between eggplant (Solanum melongena) and Solanum torvum.

    Science.gov (United States)

    Guri, A; Sink, K C

    1988-10-01

    Mesophyll protoplasts of eggplant (cv Black Beauty) and of Solanum torvum (both 2n=2x=24) were fused using a modification of the Menczel and Wolfe PEG/DMSO procedure. Protoplasts post-fusion were plated at 1 × 10(5)/ml in modified KM medium, which inhibited division of S. torvum protoplasts. One week prior to shoot regeneration, ten individual calluses had a unique light-green background and were verified as cell hybrids by the presence of the dimer isozyme patterns for phosphoglucoisomerase (PGI) and glutamate oxaloacetate transaminase (GOT). Hybridity was also confirmed at the plant stage by DNA-DNA hybridization to a pea 45S ribosomal RNA gene probe. The ten somatic hybrid plants were established in the greenhouse and exhibited intermediate morphological characteristics such as leaf size and shape, flower size, shape, color and plant stature. Their chromosome number ranged from 46-48 (expected 2n=4x=48) and pollen viability was 5%-70%. In vitro shoots taken from the ten hybrid plants exhibited resistance to a verticillium wilt extract. Total DNA from the ten hybrids was restricted and hybridized with a 5.9 kb Oenothera chloroplast cytochrome f gene probe, a 2.4 kb EcoRI clone encoding mitochondrial cytochrome oxidase subunit II from maize and a 22.1 kb Sal I mitochondrial clone from Nicotiana sylvestris. Southern blot hybridization patterns showed that eight of ten somatic hybrids contained the eggplant cpDNA, while two plants contained the cpDNA hybridization patterns of both parents. The mtDNA analysis revealed the presence of novel bands, loss of some specific parental bands and mixture of specific bands from both parents in the restriction hybridization profiles of the hybrids.

  19. Interspecific hybridization, polyploidization, and backcross of Brassica oleracea var. alboglabra with B. rapa var. purpurea morphologically recapitulate the evolution of Brassica vegetables.

    Science.gov (United States)

    Zhang, Xiaohui; Liu, Tongjin; Li, Xixiang; Duan, Mengmeng; Wang, Jinglei; Qiu, Yang; Wang, Haiping; Song, Jiangping; Shen, Di

    2016-01-04

    Brassica oleracea and B. rapa are two important vegetable crops. Both are composed of dozens of subspecies encompassing hundreds of varieties and cultivars. Synthetic B. napus with these two plants has been used extensively as a research model for the investigation of allopolyploid evolution. However, the mechanism underlying the explosive evolution of hundreds of varieties of B. oleracea and B. rapa within a short period is poorly understood. In the present study, interspecific hybridization between B. oleracea var. alboglabra and B. rapa var. purpurea was performed. The backcross progeny displayed extensive morphological variation, including some individuals that phenocopied subspecies other than their progenitors. Numerous interesting novel phenotypes and mutants were identified among the backcross progeny. The chromosomal recombination between the A and C genomes and the chromosomal asymmetric segregation were revealed using Simple Sequence Repeats (SSR) markers. These findings provide direct evidence in support of the hypothesis that interspecific hybridization and backcrossing have played roles in the evolution of the vast variety of vegetables among these species and suggest that combination of interspecific hybridization and backcrossing may facilitate the development of new mutants and novel phenotypes for both basic research and the breeding of new vegetable crops.

  20. Identification of a novel interspecific hybrid yeast from a metagenomic spontaneously inoculated beer sample using Hi-C.

    Science.gov (United States)

    Smukowski Heil, Caiti; Burton, Joshua N; Liachko, Ivan; Friedrich, Anne; Hanson, Noah A; Morris, Cody L; Schacherer, Joseph; Shendure, Jay; Thomas, James H; Dunham, Maitreya J

    2018-01-01

    Interspecific hybridization is a common mechanism enabling genetic diversification and adaptation; however, the detection of hybrid species has been quite difficult. The identification of microbial hybrids is made even more complicated, as most environmental microbes are resistant to culturing and must be studied in their native mixed communities. We have previously adapted the chromosome conformation capture method Hi-C to the assembly of genomes from mixed populations. Here, we show the method's application in assembling genomes directly from an uncultured, mixed population from a spontaneously inoculated beer sample. Our assembly method has enabled us to de-convolute four bacterial and four yeast genomes from this sample, including a putative yeast hybrid. Downstream isolation and analysis of this hybrid confirmed its genome to consist of Pichia membranifaciens and that of another related, but undescribed, yeast. Our work shows that Hi-C-based metagenomic methods can overcome the limitation of traditional sequencing methods in studying complex mixtures of genomes. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  1. Biochemical and physiological characterization of oil palm interspecific hybrids (elaeis oleifera x elaeis guineensis) grown in hydroponics

    International Nuclear Information System (INIS)

    Rivera Mendez, Yurany Dayanna; Moreno Chacon, Andres Leonardo; Romero, Hernan Mauricio

    2013-01-01

    The interspecific hybrid, Elaeis oleifera x Elaeis guineensis (OxG) is an alternative for improving the competitiveness and sustainability of the Latin American oil palm agro-industry, because of its partial resistance to some lethal diseases and also because of the high quality of its oil. A comparative characterization was conducted of the physiological and biochemical performance of seedlings of six OxG hybrids grown in hydroponics. Gas exchange, vegetative growth, protein, sugar and photosynthetic pigment content, and antioxidant system activity were determined. With the exception of gas exchange, the other variables showed significant differences between materials. The U1273 and U1737 materials showed greater vegetative growth with no expression of biochemical traits, while the U1914 and U1990 materials showed high levels of reducing and total sugars, photosynthetic pigments, and antioxidant system activities, characteristics that could confer them adaptation to stress conditions. With the standardized hydroponics technique, the optimal conditions for the growth of seedlings were ensured, the differences between materials were established, and so those with promising features from the physiological and biochemical standpoint were identified. Finally, it could be used to study in a simple, fast, clean and inexpensive way, the effect of levels and sources of mineral nutrients on the growth and development of oil palm.

  2. Interspecific interaction between Telenomus remus (Hymenoptera: Platygastridae) and Trichogramma pretiosum (Hymenoptera: Trichogrammatidae) on Spodoptera frugiperda (Lepidoptera: Noctuidae) eggs.

    Science.gov (United States)

    Carneiro, Tatiana R; Fernandes, Odair A

    2012-12-01

    This work aims to evaluate the interspecific interaction between Trichogramma pretiosum and Telenomus remus, two biological control agents of fall armyworm (Spodoptera frugiperda) eggs. Eggs of Spodoptera frugiperda previously parasitized by Telenomus remus were offered to Trichogramma pretiosum, and those parasitized by Trichogramma pretiosum were offered to Telenomus remus. The previously parasitized eggs were tested at different embryonic development stages for each parasitoid. In addition, to evaluate the competition between species, Spodoptera frugiperda eggs were offered to the parasitoids simultaneously. The behavior of the insects was recorded under a stereomicroscope. When Spodoptera frugiperda eggs were previously exposed to either parasitoid, there was no emergence of the other parasitoid. When the Telenomus remus and Trichogramma pretiosum females were placed together with Spodoptera frugiperda eggs, Telenomus remus had a greater parasitism rate. Except searching time, all Trichogramma pretiosum behaviors took a longer time than Telenomus remus behaviors. Thus, despite belonging to different families, each of these parasitoids is able to recognize host eggs previously parasitized by the other. So, this suggests that the recognition mechanism involved is not exclusively specific.

  3. Food choice effects on herbivory: Intra-specific seagrass palatability and inter-specific macrophyte palatability in seagrass communities

    Science.gov (United States)

    Jiménez-Ramos, Rocío; Brun, Fernando G.; Egea, Luis G.; Vergara, Juan J.

    2018-05-01

    Interactions between the palatability and abundance of different food sources may influence herbivory patterns in seagrass-dominated communities. In addition, intra-specific differences in nutrient and structural quality of leaves may also alter seagrass palatability and generate different rates of consumption within these communities. We offered two temperate seagrasses species, (Cymodocea nodosa and Zostera noltei) from two different locations to look at intraspecific differences, and two other macrophytes, both of which occur at the same location as seagrasses but represent the extremes of palatability, to a generalist herbivore Paracentrotus lividus (purple sea urchin). Using feeding assays, we compared the consumption rates in individual (single plant species) and combined diets at different food availabilities. Intra-specific differences between seagrass species growing at different locations (inner and outer bay) were indeed found to significantly modify the consumption rate for one species. Structural traits such as carbon content were linked to the low consumption found in Cymodocea nodosa from the inner bay location. In addition, we found that the co-occurrence of different macrophyte species can result in preferential consumption of the more palatable macrophyte with high nutritional content and low structural defence over seagrasses, especially when P. lividus has an abundant food supply. Overall, our findings suggest that intra- and inter-specific differences in seagrass traits and the relative abundance of other macrophytes may explain the variability in patterns of herbivory found within seagrass communities.

  4. Unilateral compatibility and genotypic difference in crossability in interspecific hybridization between Dianthus caryophyllus L. and Dianthus japonicus Thunb.

    Science.gov (United States)

    Nimura, M; Kato, J; Mii, M; Morioka, K

    2003-05-01

    Reciprocal interspecific crosses were carried out between six lines of Dianthus caryophyllus L. and one line of Dianthus japonicus Thunb. Although no seed was set when D. japonicus was used as the seed parent, six seedlings were successfully obtained from 2,380 immature ovules by applying the embryo-rescue technique. However, they showed seed parent-like morphology and no evidence for the hybridity by flow cytometry and RAPD analyses. When six lines of D. caryophyllus were used as seed parents, a total of 192 seedlings were successfully obtained without using the embryo-rescue technique. Among these seedlings, 12 out of 25 progenies obtained from the carnation line '98sp1651' were confirmed to be the hybrids. The remaining 13 progenies of this line, and the total 167 progenies obtained from the other carnation lines, had carnation-like morphology without any evidence of hybridity by flow cytometry and RAPD analyses. The progenies confirmed as hybrids had intermediate characters of the parents with respect to leaf width and flower size, but they had a uniform flower color, reddish purple, which was different from that of either parent. Since the hybrids obtained in the present study have some profitable characters such as vigorous growth in summer time, upright robust stem, broad leaves and early flowering, they are expected to be used for the breeding of carnation which is suitable for growing under the Japanese climate.

  5. Nature and Age of Neighbours Matter: Interspecific Associations among Tree Species Exist and Vary across Life Stages in Tropical Forests.

    Directory of Open Access Journals (Sweden)

    Alicia Ledo

    Full Text Available Detailed information about interspecific spatial associations among tropical tree species is scarce, and hence the ecological importance of those associations may have been underestimated. However, they can play a role in community assembly and species diversity maintenance. This study investigated the spatial dependence between pairs of species. First, the spatial associations (spatial attraction and spatial repulsion that arose between species were examined. Second, different sizes of trees were considered in order to evaluate whether the spatial relationships between species are constant or vary during the lifetime of individuals. Third, the consistency of those spatial associations with the species-habitat associations found in previous studies was assessed. Two different tropical ecosystems were investigated: a montane cloud forest and a lowland moist forest. The results showed that spatial associations among species exist, and these vary among life stages and species. The rarity of negative spatial interactions suggested that exclusive competition was not common in the studied forests. On the other hand, positive interactions were common, and the results of this study strongly suggested that habitat associations were not the only cause of spatial attraction among species. If this is true, habitat associations and density dependence are not the only mechanisms that explain species distribution and diversity; other ecological interactions, such as facilitation among species, may also play a role. These spatial associations could be important in the assembly of tropical tree communities and forest succession, and should be taken into account in future studies.

  6. Interspecific variation in leaf pigments and nutrients of five tree species from a subtropical forest in southern Brazil

    Directory of Open Access Journals (Sweden)

    MÁRCIA BÜNDCHEN

    2016-01-01

    Full Text Available ABSTRACT The purpose of this study was to analyze the seasonal variation in the nutrient and pigment content of leaves from five tree species - of which three are perennial (Cupania vernalis, Matayba elaeagnoides and Nectandra lanceolata and two are deciduous (Cedrela fissilis and Jacaranda micrantha - in an ecotone between a Deciduous Seasonal Forest and a Mixed Ombrophilous Forest in the state of Santa Catarina, Brazil. Leaf samples were collected in the four seasons of the year to determine the content of macronutrients (N, K, P, Mg, Ca, S and photosynthetic pigments (Chla, Chlb, Chltot, Cartot, Chla:Chlb and Cartot:Chltot. The principal component analysis showed that leaf pigments contributed to the formation of the first axis, which explains most of the data variance for all species, while leaf nutrient contribution showed strong interspecific variation. These results demonstrate that the studied species have different strategies for acquisition and use of mineral resources and acclimation to light, which are determinant for them to coexist in the forest environment.

  7. Experimental study on the interspecific interactions between the two bloom-forming algal species and the rotifer Brachionus plicatilis

    Science.gov (United States)

    Xie, Zhihao; Xiao, Hui; Tang, Xuexi; Cai, Hengjiang

    2009-06-01

    The interspecific interactions between the rotifer Brachionus plicatilis and two harmful algal blooms (HAB) species were investigated experimentally by single culture method. B. plicatilis population and the growth of the two algae were compared at different algal cell densities. The results demonstrated that the B. plicatilis obtained sufficient nutrition from Prorocentrum donghaiense to support net population increase. With exposure to 2.5×104 cells mL-1 of P. donghaiense, the number of B. plicatilis increased faster than it did when exposed to other four algal densities (5, 10, 15 and 20 ×104 cells mL-1), and the increase rate of B. plicatilis population ( r) at this algal density was 0.104 ± 0.015 rd-1. Cell densities of P. donghaiense decreased due to the grazing of B. plicatilis. In contrast, Heterosigma akashiwo had an adverse effect on B. plicatilis population and its growth was largely unaffected by rotifer grazing. In this case, B. plicatilis population decreased and H. akashiwo grew at a rate similar to that of the control.

  8. Physiological and biochemical stress responses in grassland species are influenced by both early-season ozone exposure and interspecific competition

    Energy Technology Data Exchange (ETDEWEB)

    Scebba, Francesca [Department of Agricultural Chemistry and Biotechnology, University of Pisa, Via del Borghetto 80, 56124 Pisa (Italy); Canaccini, Francesca [Department of Agricultural Chemistry and Biotechnology, University of Pisa, Via del Borghetto 80, 56124 Pisa (Italy); Castagna, Antonella [Department of Agricultural Chemistry and Biotechnology, University of Pisa, Via del Borghetto 80, 56124 Pisa (Italy); Bender, Juergen [Institute of Agroecology, FAL, Bundesallee 50, 38116 Braunschweig (Germany); Weigel, Hans-Joachim [Institute of Agroecology, FAL, Bundesallee 50, 38116 Braunschweig (Germany); Ranieri, Annamaria [Department of Agricultural Chemistry and Biotechnology, University of Pisa, Via del Borghetto 80, 56124 Pisa (Italy)]. E-mail: aranieri@agr.unipi.it

    2006-08-15

    The effects of two-year early season ozone exposure on physiological and biochemical stress response were investigated in model plant communities. Achillea millefolium and Veronica chamaedrys target plants were grown in monocultures and in mixed cultures with Poa pratensis (phytometer) and exposed in open-top chambers over two years for five weeks to charcoal-filtered (CF) air plus 25 nl l{sup -1} O{sub 3} (control) and non-filtered (NF) air plus 50 nl l{sup -1} O{sub 3}. Significant O{sub 3} effects were detected in different physiological and biochemical parameters, evidencing interspecific differences in metabolic stress responses and a strong influence of the competition factor. O{sub 3} induced strong oxidative effects in Achillea irrespective to the different growth modality. Veronica showed less O{sub 3}-induced effects in monoculture than when grown in competition with the phytometer. Poa exhibited a different behaviour against O{sub 3} depending on the species in competition, showing an overall higher sensitivity to O{sub 3} when in mixture with Achillea. - The competition between species modulates the ozone effect in a short-term.

  9. Comparison of species ordinations resulting from alternative indices of interspecific association and different numbers of included species

    Energy Technology Data Exchange (ETDEWEB)

    Goff, F G

    1975-12-19

    Several measures of interspecific association are compared. Dispersion and covariance are limited in value because they respond to the commonness of the species compared. Correlation is not so limited but it responds to discrepancies in commonness among the species. The practical result of these relationships between commonness and association is that only the most common species can occupy peripheral positions in a species ordination. Rare species are relegated to positions near the center not on the basis of their phytosociological pattern but simply because of their rarity. Both Cole's index of association and the tetrachoric correlation overcome the problem imposed by the relationship between ordination position and species commonness and they both produce very similar results. The effect of differing numbers of species on the ordination configuration is examined using both Pearson's correlation and Cole's index. The basic pattern of the ordination is set with the first few species when Cole's index is used, however, since rare species are given more weight in the analysis with this index, the addition of several very rare species can change the configuration of the ordination. (auth)

  10. Physiological and biochemical stress responses in grassland species are influenced by both early-season ozone exposure and interspecific competition

    International Nuclear Information System (INIS)

    Scebba, Francesca; Canaccini, Francesca; Castagna, Antonella; Bender, Juergen; Weigel, Hans-Joachim; Ranieri, Annamaria

    2006-01-01

    The effects of two-year early season ozone exposure on physiological and biochemical stress response were investigated in model plant communities. Achillea millefolium and Veronica chamaedrys target plants were grown in monocultures and in mixed cultures with Poa pratensis (phytometer) and exposed in open-top chambers over two years for five weeks to charcoal-filtered (CF) air plus 25 nl l -1 O 3 (control) and non-filtered (NF) air plus 50 nl l -1 O 3 . Significant O 3 effects were detected in different physiological and biochemical parameters, evidencing interspecific differences in metabolic stress responses and a strong influence of the competition factor. O 3 induced strong oxidative effects in Achillea irrespective to the different growth modality. Veronica showed less O 3 -induced effects in monoculture than when grown in competition with the phytometer. Poa exhibited a different behaviour against O 3 depending on the species in competition, showing an overall higher sensitivity to O 3 when in mixture with Achillea. - The competition between species modulates the ozone effect in a short-term

  11. Interspecific comparison of the performance of soaring migrants in relation to morphology, meteorological conditions and migration strategies.

    Directory of Open Access Journals (Sweden)

    Ugo Mellone

    Full Text Available BACKGROUND: Performance of migrating birds can be affected by a number of intrinsic and extrinsic factors like morphology, meteorological conditions and migration strategies. We compared travel speeds of four raptor species during their crossing of the Sahara desert. Focusing the analyses on this region allows us to compare different species under equivalent conditions in order to disentangle which factors affect migratory performance. METHODOLOGY/PRINCIPAL FINDING: We tracked raptors using GPS satellite transmitters from Sweden, Spain and Italy, and evaluated their migratory performance at both an hourly and a daily scale. Hourly data (flight speed and altitude for intervals of two hours were analyzed in relation to time of day, species and season, and daily data (distance between roosting sites in relation to species, season, day length and tailwind support. CONCLUSIONS/SIGNIFICANCE: Despite a clear variation in morphology, interspecific differences were generally very small, and did only arise in spring, with long-distance migrants (>5000 km: osprey and Western marsh-harrier being faster than species that migrate shorter distances (Egyptian vulture and short-toed eagle. Our results suggest that the most important factor explaining hourly variation in flight speed is time of day, while at a daily scale, tailwind support is the most important factor explaining variation in daily distance, raising new questions about the consequences of possible future changes in worldwide wind patterns.

  12. Quantitative inheritance of crop timing traits in interspecific hybrid Petunia populations and interactions with crop quality parameters.

    Science.gov (United States)

    Warner, Ryan M; Walworth, Aaron E

    2010-01-01

    The leaf unfolding rate (i.e., development rate) and the number of nodes forming prior to floral initiation are 2 factors determining production times for floriculture crops. Wild relative species of the cultivated petunia (Petunia x hybrida Vilm.) that exhibited faster development rates than modern cultivars and may therefore be useful genetic sources to develop cultivars with decreased production time were identified. Three interspecific F(2) families, Petunia exserta Stehmann x P. axillaris (Lam.) Britton et al., P. x hybrida 'Mitchell' x P. axillaris, and P. axillaris x P. integrifolia (Hook.) Schinz & Thell. all exhibited transgressive segregation for development rate and node number below the first flower. Development rate and time to flower segregated independently in all families. Leaf number below the first flower was positively correlated with leaf unfolding rate in all families except P. axillaris x P. integrifolia. Time to flower was positively correlated with flower bud number in the P. x hybrida 'Mitchell' x P. axillaris and P. axillaris x P. integrifolia families only. Based on these results, wild Petunia germplasm should be useful for developing petunia cultivars with reduced crop production times, but some negative effects on crop quality parameters may need to be overcome.

  13. Plant distribution and stand characteristics in brackish marshes: Unravelling the roles of abiotic factors and interspecific competition

    Science.gov (United States)

    Carus, Jana; Heuner, Maike; Paul, Maike; Schröder, Boris

    2017-09-01

    Due to increasing pressure on estuarine marshes from sea level rise and river training, there is a growing need to understand how species-environment relationships influence the zonation and growth of tidal marsh vegetation. In the present study, we investigated the distribution and stand characteristics of the two key brackish marsh species Bolboschoenus maritimus and Phragmites australis in the Elbe estuary together with several abiotic habitat factors. We then tested the effect of these habitat factors on plant growth and zonation with generalised linear models (GLMs). Our study provides detailed information on the importance of single habitat factors and their interactions for controlling the distribution patterns and stand characteristics of two key marsh species. Our results suggest that flow velocity is the main factor influencing species distribution and stand characteristics and together with soil-water salinity even affects the inundation tolerance of the two specie investigated here. Additionally, inundation height and duration as well as interspecific competition helped explain the distribution patterns and stand characteristics. By identifying the drivers of marsh zonation and stand characteristics and quantifying their effects, this study provides useful information for evaluating a future contribution of tidal marsh vegetation to ecosystem-based shore protection.

  14. Physiological and biochemical stress responses in grassland species are influenced by both early-season ozone exposure and interspecific competition.

    Science.gov (United States)

    Scebba, Francesca; Canaccini, Francesca; Castagna, Antonella; Bender, Jürgen; Weigel, Hans-Joachim; Ranieri, Annamaria

    2006-08-01

    The effects of two-year early season ozone exposure on physiological and biochemical stress response were investigated in model plant communities. Achillea millefolium and Veronica chamaedrys target plants were grown in monocultures and in mixed cultures with Poa pratensis (phytometer) and exposed in open-top chambers over two years for five weeks to charcoal-filtered (CF) air plus 25 nl l(-1) O3 (control) and non-filtered (NF) air plus 50 nl l(-1) O3. Significant O3 effects were detected in different physiological and biochemical parameters, evidencing interspecific differences in metabolic stress responses and a strong influence of the competition factor. O3 induced strong oxidative effects in Achillea irrespective to the different growth modality. Veronica showed less O3-induced effects in monoculture than when grown in competition with the phytometer. Poa exhibited a different behaviour against O3 depending on the species in competition, showing an overall higher sensitivity to O3 when in mixture with Achillea.

  15. Changes in abundance and spatial distribution of geese molting near Teshekpuk Lake, Alaska: Interspecific competition or ecological change?

    Science.gov (United States)

    Flint, P.L.; Mallek, E.J.; King, R.J.; Schmutz, J.A.; Bollinger, K.S.; Derksen, D.V.

    2008-01-01

    Goose populations molting in the Teshekpuk Lake Special Area of the National Petroleum Reserve-Alaska have changed in size and distribution over the past 30 years. Black brant (Branta bernicla nigricans) are relatively stable in numbers but are shifting from large, inland lakes to salt marshes. Concurrently, populations of greater white-fronted geese (Anser albifrons frontalis) have increased seven fold. Populations of Canada geese (Branta canadensis and/or B. hutchinsii) are stable with little indication of distributional shifts. The lesser snow goose (Anser caerulescens caerulescens) population is proportionally small, but increasing rapidly. Coastline erosion of the Beaufort Sea has altered tundra habitats by allowing saltwater intrusion, which has resulted in shifts in composition of forage plant species. We propose two alternative hypotheses for the observed shift in black brant distribution. Ecological change may have altered optimal foraging habitats for molting birds, or alternatively, interspecific competition between black brant and greater white-fronted geese may be excluding black brant from preferred habitats. Regardless of the causative mechanism, the observed shifts in species distributions are an important consideration for future resource planning. ?? 2007 Springer-Verlag.

  16. Characteristics of the mouse genomic histamine H1 receptor gene

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Isao; Taniuchi, Ichiro; Kitamura, Daisuke [Kyushu Univ., Fukuoka (Japan)] [and others

    1996-08-15

    We report here the molecular cloning of a mouse histamine H1 receptor gene. The protein deduced from the nucleotide sequence is composed of 488 amino acid residues with characteristic properties of GTP binding protein-coupled receptors. Our results suggest that the mouse histamine H1 receptor gene is a single locus, and no related sequences were detected. Interspecific backcross analysis indicated that the mouse histamine H1 receptor gene (Hrh1) is located in the central region of mouse Chromosome 6 linked to microphthalmia (Mitfmi), ras-related fibrosarcoma oncogene 1 (Raf1), and ret proto-oncogene (Ret) in a region of homology with human chromosome 3p. 12 refs., 3 figs.

  17. Gene Therapy

    Science.gov (United States)

    Gene therapy Overview Gene therapy involves altering the genes inside your body's cells in an effort to treat or stop disease. Genes contain your ... that don't work properly can cause disease. Gene therapy replaces a faulty gene or adds a new ...

  18. Interspecific somatic hybrids between Cyclamen persicum and C. coum, two sexually incompatible species.

    Science.gov (United States)

    Prange, Anika Nadja Sabine; Bartsch, Melanie; Meiners, Julia; Serek, Margrethe; Winkelmann, Traud

    2012-04-01

    By applying polyethylene glycol (PEG)-mediated protoplast fusion, the first somatic hybrids were obtained between Cyclamen persicum (2n = 2x = 48) and C. coum (2n = 2x = 30)-two species that cannot be combined by cross breeding. Heterofusion was detected by double fluorescent staining with fluorescein diacetate and scopoletin. The highest heterofusion frequencies (of about 5%) resulted from a protocol using a protoplast density of 1 × 10(6)/mL and 40% PEG. The DNA content of C. coum was estimated for the first time by propidium iodide staining to be 14.7 pg/2C and was 4.6 times higher than that of C. persicum. Among 200 in vitro plantlets regenerated from fusion experiments, most resembled the C. coum parent, whereas only 5 plants showed typical C. persicum phenotypes and 46 had a deviating morphology. By flow cytometry, six putative somatic hybrids were identified. A species-specific DNA marker was developed based on the sequence of the 5.8S gene in the ribosomal nuclear DNA and its flanking internal transcribed spacers ITS1 and ITS2. The hybrid status of only one plant could be verified by the species-specific DNA marker as well as sequencing of the amplification product. RAPD markers turned out to be less informative and applicable for hybrid identification, as no clear additivity of the parental marker bands was observed. Chromosome counting in root tips of four hybrids revealed the presence of the 30 C. coum chromosomes and 2-41 additional ones indicating elimination of C. persicum chromosomes. © Springer-Verlag 2011

  19. Protoplasting impact on polyketide activity and characterization of the interspecific fusants from Streptomyces spp

    International Nuclear Information System (INIS)

    Slama, N.; Lazim, H.; Barkallah, Insaf; Abbassi, M.; Ben Hassen, A.; Limam, F.

    2009-01-01

    Streptomycetes are gram-positive, soil-inhabiting bacteria of the order Actinomycetales. These organisms exhibit an unusual, developmentally complex life cycle and produce many economically important secondary metabolites, such as antibiotics, immunosuppressants, insecticides, and antitumor agents. Streptomyces species have been the subject of genetic investigation for over 50 years, with many studies focusing on the production of bioactives compounds. The protoplast formation and regeneration are important processes, and they are a major step following genetic manipulations such as fusion and DNA-mediated transformation, which can improve antibiotic production. The protoplast fusion, transformation and improved fermentation features can be used to regenerate strains with increased antibiotic activity. Local Streptomyces spp. CN207 produce a broad range of secondary metabolites which is active against bacteria and fungi. This strain was used as a donor and S. coelicolor strain M145 was used as a recipient host for protoplast fusion. The protoplast fusion resulted in increased isolation of variants with higher antibiotic activity. Recombinant Streptomyces coelicolor PF04 was increased 10 times more than the wild strain. The antimicrobial activity from PF04 strain was studied using the disc method agar. TLC analysis confirmed that the Rf of cell extract for PF04 strain is identical to antimicrobial compound of Streptomyces CN207. Our results confirm the possibility of transferring antibiotics cluster genes by fusion. In fact, many of the selective markers such as Ticarcillin, Cefalotin, Oxacillin and Cefotaxim were transferred during the protoplast fusion. PFGE analysis and DNA-hybridization confirmed the presence of homologous fragments between a wild-type Streptomyces CN207 and a recombinant S. coelicolor PF04

  20. Ecological character displacement in the face of gene flow: Evidence from two species of nightingales

    Science.gov (United States)

    2011-01-01

    Background Ecological character displacement is a process of phenotypic differentiation of sympatric populations caused by interspecific competition. Such differentiation could facilitate speciation by enhancing reproductive isolation between incipient species, although empirical evidence for it at early stages of divergence when gene flow still occurs between the species is relatively scarce. Here we studied patterns of morphological variation in sympatric and allopatric populations of two hybridizing species of birds, the Common Nightingale (Luscinia megarhynchos) and the Thrush Nightingale (L. luscinia). Results We conducted principal component (PC) analysis of morphological traits and found that nightingale species converged in overall body size (PC1) and diverged in relative bill size (PC3) in sympatry. Closer analysis of morphological variation along geographical gradients revealed that the convergence in body size can be attributed largely to increasing body size with increasing latitude, a phenomenon known as Bergmann's rule. In contrast, interspecific interactions contributed significantly to the observed divergence in relative bill size, even after controlling for the effects of geographical gradients. We suggest that the divergence in bill size most likely reflects segregation of feeding niches between the species in sympatry. Conclusions Our results suggest that interspecific competition for food resources can drive species divergence even in the face of ongoing hybridization. Such divergence may enhance reproductive isolation between the species and thus contribute to speciation. PMID:21609448

  1. Ecological character displacement in the face of gene flow: Evidence from two species of nightingales

    Directory of Open Access Journals (Sweden)

    Reif Jiří

    2011-05-01

    Full Text Available Abstract Background Ecological character displacement is a process of phenotypic differentiation of sympatric populations caused by interspecific competition. Such differentiation could facilitate speciation by enhancing reproductive isolation between incipient species, although empirical evidence for it at early stages of divergence when gene flow still occurs between the species is relatively scarce. Here we studied patterns of morphological variation in sympatric and allopatric populations of two hybridizing species of birds, the Common Nightingale (Luscinia megarhynchos and the Thrush Nightingale (L. luscinia. Results We conducted principal component (PC analysis of morphological traits and found that nightingale species converged in overall body size (PC1 and diverged in relative bill size (PC3 in sympatry. Closer analysis of morphological variation along geographical gradients revealed that the convergence in body size can be attributed largely to increasing body size with increasing latitude, a phenomenon known as Bergmann's rule. In contrast, interspecific interactions contributed significantly to the observed divergence in relative bill size, even after controlling for the effects of geographical gradients. We suggest that the divergence in bill size most likely reflects segregation of feeding niches between the species in sympatry. Conclusions Our results suggest that interspecific competition for food resources can drive species divergence even in the face of ongoing hybridization. Such divergence may enhance reproductive isolation between the species and thus contribute to speciation.

  2. Evaluation of relationships between growth rate, tree size, lignocellulose composition and enzymatic saccharification in interspecific Corymbia hybrids and parental taxa.

    Directory of Open Access Journals (Sweden)

    Adam L Healey

    2016-11-01

    Full Text Available In order for a lignocellulosic bioenergy feedstock to be considered sustainable, it must possess a high rate of growth to supply biomass for conversion. Despite the desirability of a fast growth rate for industrial application, it is unclear what effect growth rate has on biomass composition or saccharification. We characterized Klason lignin, glucan, and xylan content with response to growth in Corymbia interspecific F1 hybrid families (HF and parental species C. torelliana (CT and C. citriodora subspecies variegata (CCV and measured the effects on enzymatic hydrolysis from hydrothermally pretreated biomass. Analysis of biomass composition within Corymbia populations found similar amounts of Klason lignin content (19.7-21.3% among parental and hybrid populations, whereas glucan content was clearly distinguished within CCV (52% and HF148 (60% as compared to other populations (28-38%. Multiple linear regression indicates that biomass composition is significantly impacted by tree size measured at the same age, with Klason lignin content increasing with diameter breast height (DBH (+0.12% per cm DBH increase, and glucan and xylan typically decreasing per DBH cm increase (-0.7% and -0.3%, respectively. Polysaccharide content within CCV and HF-148 were not significantly affected by tree size. High-throughput enzymatic saccharification of hydrothermally pretreated biomass found significant differences among Corymbia populations for total glucose production from biomass, with parental CT and hybrids HF-148 and HF-51 generating the highest amounts of glucose (~180 mg/g biomass, respectively, with HF-51 undergoing the most efficient glucan-to-glucose conversion (74%. Based on growth rate, biomass composition, and further optimization of enzymatic saccharification yield, high production Corymbia hybrid trees are potentially suitable for fast-rotation bioenergy or biomaterial production.

  3. GWAS analysis using interspecific backcross progenies reveals superior blue catfish alleles responsible for strong resistance against enteric septicemia of catfish.

    Science.gov (United States)

    Tan, Suxu; Zhou, Tao; Wang, Wenwen; Jin, Yulin; Wang, Xiaozhu; Geng, Xin; Luo, Jian; Yuan, Zihao; Yang, Yujia; Shi, Huitong; Gao, Dongya; Dunham, Rex; Liu, Zhanjiang

    2018-05-08

    Infectious diseases pose significant threats to the catfish industry. Enteric septicemia of catfish (ESC) caused by Edwardsiella ictaluri is the most devastating disease for catfish aquaculture, causing huge economic losses annually. Channel catfish and blue catfish exhibit great contrast in resistance against ESC, with channel catfish being highly susceptible and blue catfish being highly resistant. As such, the interspecific backcross progenies provide an ideal system for the identification of quantitative trait locus (QTL). We previously reported one significant QTL on linkage group (LG) 1 using the third-generation backcrosses, but the number of founders used to make the second- and third-generation backcross progenies was very small. Although the third-generation backcross progenies provided a greater power for fine mapping than the first-generation backcrosses, some major QTL for disease resistance may have been missing due to the small numbers of founders used to produce the higher generation backcrosses. In this study, we performed a genome-wide association study using first-generation backcrosses with the catfish 690 K SNP arrays to identify additional ESC disease resistance QTL, especially those at the species level. Two genomic regions on LG1 and LG23 were determined to be significantly associated with ESC resistance as revealed by a mixed linear model and family-based association test. Examination of the resistance alleles indicated their origin from blue catfish, indicating that at least two major disease resistance loci exist among blue catfish populations. Upon further validation, markers linked with major ESC disease resistance QTL should be useful for marker-assisted introgression, allowing development of highly ESC resistant breeds of catfish.

  4. Evaluation of Relationships between Growth Rate, Tree Size, Lignocellulose Composition, and Enzymatic Saccharification in Interspecific Corymbia Hybrids and Parental Taxa.

    Science.gov (United States)

    Healey, Adam L; Lee, David J; Lupoi, Jason S; Papa, Gabriella; Guenther, Joel M; Corno, Luca; Adani, Fabrizio; Singh, Seema; Simmons, Blake A; Henry, Robert J

    2016-01-01

    In order for a lignocellulosic bioenergy feedstock to be considered sustainable, it must possess a high rate of growth to supply biomass for conversion. Despite the desirability of a fast growth rate for industrial application, it is unclear what effect growth rate has on biomass composition or saccharification. We characterized Klason lignin, glucan, and xylan content with response to growth in Corymbia interspecific F1 hybrid families (HF) and parental species Corymbia torelliana and C. citriodora subspecies variegata and measured the effects on enzymatic hydrolysis from hydrothermally pretreated biomass. Analysis of biomass composition within Corymbia populations found similar amounts of Klason lignin content (19.7-21.3%) among parental and hybrid populations, whereas glucan content was clearly distinguished within C. citriodora subspecies variegata (52%) and HF148 (60%) as compared to other populations (28-38%). Multiple linear regression indicates that biomass composition is significantly impacted by tree size measured at the same age, with Klason lignin content increasing with diameter breast height (DBH) (+0.12% per cm DBH increase), and glucan and xylan typically decreasing per DBH cm increase (-0.7 and -0.3%, respectively). Polysaccharide content within C. citriodora subspecies variegata and HF-148 were not significantly affected by tree size. High-throughput enzymatic saccharification of hydrothermally pretreated biomass found significant differences among Corymbia populations for total glucose production from biomass, with parental Corymbia torelliana and hybrids HF-148 and HF-51 generating the highest amounts of glucose (~180 mg/g biomass, respectively), with HF-51 undergoing the most efficient glucan-to-glucose conversion (74%). Based on growth rate, biomass composition, and further optimization of enzymatic saccharification yield, high production Corymbia hybrid trees are potentially suitable for fast-rotation bioenergy or biomaterial production.

  5. Species distribution models contribute to determine the effect of climate and interspecific interactions in moving hybrid zones.

    Science.gov (United States)

    Engler, J O; Rödder, D; Elle, O; Hochkirch, A; Secondi, J

    2013-11-01

    Climate is a major factor delimiting species' distributions. However, biotic interactions may also be prominent in shaping geographical ranges, especially for parapatric species forming hybrid zones. Determining the relative effect of each factor and their interaction of the contact zone location has been difficult due to the lack of broad scale environmental data. Recent developments in species distribution modelling (SDM) now allow disentangling the relative contributions of climate and species' interactions in hybrid zones and their responses to future climate change. We investigated the moving hybrid zone between the breeding ranges of two parapatric passerines in Europe. We conducted SDMs representing the climatic conditions during the breeding season. Our results show a large mismatch between the realized and potential distributions of the two species, suggesting that interspecific interactions, not climate, account for the present location of the contact zone. The SDM scenarios show that the southerly distributed species, Hippolais polyglotta, might lose large parts of its southern distribution under climate change, but a similar gain of novel habitat along the hybrid zone seems unlikely, because interactions with the other species (H. icterina) constrain its range expansion. Thus, whenever biotic interactions limit range expansion, species may become 'trapped' if range loss due to climate change is faster than the movement of the contact zone. An increasing number of moving hybrid zones are being reported, but the proximate causes of movement often remain unclear. In a global context of climate change, we call for more interest in their interactions with climate change. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  6. Neural activity patterns in response to interspecific and intraspecific variation in mating calls in the túngara frog.

    Directory of Open Access Journals (Sweden)

    Mukta Chakraborty

    2010-09-01

    Full Text Available During mate choice, individuals must classify potential mates according to species identity and relative attractiveness. In many species, females do so by evaluating variation in the signals produced by males. Male túngara frogs (Physalaemus pustulosus can produce single note calls (whines and multi-note calls (whine-chucks. While the whine alone is sufficient for species recognition, females greatly prefer the whine-chuck when given a choice.To better understand how the brain responds to variation in male mating signals, we mapped neural activity patterns evoked by interspecific and intraspecific variation in mating calls in túngara frogs by measuring expression of egr-1. We predicted that egr-1 responses to conspecific calls would identify brain regions that are potentially important for species recognition and that at least some of those brain regions would vary in their egr-1 responses to mating calls that vary in attractiveness. We measured egr-1 in the auditory brainstem and its forebrain targets and found that conspecific whine-chucks elicited greater egr-1 expression than heterospecific whines in all but three regions. We found no evidence that preferred whine-chuck calls elicited greater egr-1 expression than conspecific whines in any of eleven brain regions examined, in contrast to predictions that mating preferences in túngara frogs emerge from greater responses in the auditory system.Although selectivity for species-specific signals is apparent throughout the túngara frog brain, further studies are necessary to elucidate how neural activity patterns vary with the attractiveness of conspecific mating calls.

  7. When David beats Goliath: the advantage of large size in interspecific aggressive contests declines over evolutionary time.

    Directory of Open Access Journals (Sweden)

    Paul R Martin

    Full Text Available Body size has long been recognized to play a key role in shaping species interactions. For example, while small species thrive in a diversity of environments, they typically lose aggressive contests for resources with larger species. However, numerous examples exist of smaller species dominating larger species during aggressive interactions, suggesting that the evolution of traits can allow species to overcome the competitive disadvantage of small size. If these traits accumulate as lineages diverge, then the advantage of large size in interspecific aggressive interactions should decline with increased evolutionary distance. We tested this hypothesis using data on the outcomes of 23,362 aggressive interactions among 246 bird species pairs involving vultures at carcasses, hummingbirds at nectar sources, and antbirds and woodcreepers at army ant swarms. We found the advantage of large size declined as species became more evolutionarily divergent, and smaller species were more likely to dominate aggressive contests when interacting with more distantly-related species. These results appear to be caused by both the evolution of traits in smaller species that enhanced their abilities in aggressive contests, and the evolution of traits in larger species that were adaptive for other functions, but compromised their abilities to compete aggressively. Specific traits that may provide advantages to small species in aggressive interactions included well-developed leg musculature and talons, enhanced flight acceleration and maneuverability, novel fighting behaviors, and traits associated with aggression, such as testosterone and muscle development. Traits that may have hindered larger species in aggressive interactions included the evolution of morphologies for tree trunk foraging that compromised performance in aggressive contests away from trunks, and the evolution of migration. Overall, our results suggest that fundamental trade-offs, such as those

  8. The genetic and phenotypic variability of interspecific hybrid bermudagrasses (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy) used on golf course putting greens.

    Science.gov (United States)

    Reasor, Eric H; Brosnan, James T; Trigiano, Robert N; Elsner, J Earl; Henry, Gerald M; Schwartz, Brian M

    2016-10-01

    Some interspecific hybrid bermudagrass cultivars used on golf course putting greens are genetically unstable, which has caused phenotypically different off-type grasses to occur in production nurseries and putting surfaces. Management practices to reduce the occurrence of off-type grasses in putting green surfaces and the effect they can have on putting quality and performance need to be researched until genetically stable cultivars are developed. Golf course putting green surfaces in subtropical and tropical climates are typically planted with an interspecific hybrid bermudagrass (Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy), because of the superior putting quality and performance of these cultivars. 'Tifgreen' was one of the first interspecific hybrids developed for putting green use in lieu of common bermudagrass. However, off-type grasses began appearing in established Tifgreen stands soon after commercial release. Off-type grasses are those with different morphology and performance when compared to the surrounding, desirable cultivar. Off-types have the potential to decrease surface uniformity, which negatively affects putting surface quality. However, several unique off-types from Tifgreen have been selected as commercial cultivars, the first being 'Tifdwarf'; then 'Floradwarf', 'MS-Supreme', 'Pee Dee-102', and 'TL-2', identified later. The cultivars 'Champion Dwarf', 'P-18', 'RJT', and 'Emerald Dwarf' were subsequently selected as off-types in Tifdwarf. The naturally occurring off-types and cultivars that have been identified within the Tifgreen family have widely differing phenotypes; however, they are reported to be genetically similar, supporting the hypothesis that their occurrence is a result of somatic mutations. Genetic instability in currently available commercial cultivars is likely to lead to the continued presence of off-types in production nurseries and putting greens. Additional research is needed to understand the nature of

  9. Head color and caruncles of sympatric Cathartes vultures (Aves Cathartidae) in Guyana and their possible function in intra- and interspecific signaling

    DEFF Research Database (Denmark)

    Graves, Gary R.

    2016-01-01

    The naked heads of Cathartes vultures are widely believed to be adaptations for temperature regulation and to reduce plumage fouling during carrion feeding. Bright head color and the elaborate pattern of caruncles on the head and neck skin have a likely function in intra- and interspecific...... signaling. These integumentary characters have been difficult to study because of extensive postmortem color fading and shrinkage in museum specimens. Here I provide the first detailed description of head color and caruncles of the Greater Yellow-headed Vulture (C. melambrotus) from freshly collected...

  10. A Study of Selected Isozymes in Capsicum baccatum, Capsicum eximium, Capsicum cardenasii and Two Interspecific F1 Hybrids in Capsicum Species

    OpenAIRE

    ONUS, Ahmet Naci

    2014-01-01

    Selected isozymes were investigated in plants of Capsicum baccatum L. ( Solanaceae) accessions SA219 (P.G.Smith), Hawkes 6489 (P.G.Smith), Capsicum cardenasii Heiser and Smith accession SA268 (P.G.Smith), Capsicum eximium A.T.Hunz accession Hawkes 3860 (J.G.Hawkes) and two interspecific F1 hybrids, C. baccatum SA219 x C. eximium Hawkes 3860 and C. baccatum Hawkes 6489 x C. cardenasii SA 268. The standard technique of horizontal gel electrophoresis was employed. The gel was cut into severa...

  11. Do Interspecific Differences in Sapling Growth Traits Contribute to the Co-dominance of Acer saccharum and Fagus grandifolia?

    Science.gov (United States)

    Takahashi, Koichi; Lechowicz, Martin J.

    2008-01-01

    Background and Aims Acer saccharum and Fagus grandifolia are among the most dominant late-successional tree species in North America. The influence of sapling growth responses to canopy gaps on the co-dominance of the two species in an old-growth forest in southern Quebec, Canada was examined. Two predictions were evaluated: (a) F. grandifolia is more shade tolerant than A. saccharum due to greater sapling leaf area and net production per sapling in closed-canopy conditions; and (b) the height growth rate of A. saccharum in canopy gaps is greater than that of F. grandifolia due to increased net production per sapling. Methods Sapling crown allometry, net production and height growth rates were compared between and within the two species in closed canopy vs. canopy gaps. Standardized major axis regression was used to analyse differences in crown allometry. Key Results F. grandifolia had greater crown projection, sapling leaf area and net production rate per sapling than A. saccharum in closed-canopy conditions. In response to canopy gaps, net production per sapling increased to the same degree in both species. The net production per sapling of F. grandifolia thus was much greater than that of A. saccharum in both canopy gap and closed-canopy conditions. The height growth rate of both species increased in canopy gaps, but the degree of increase was greater in F. grandifolia than in A. saccharum. Conclusions F. grandifolia regenerated more successfully than A. saccharum in both closed-canopy conditions and canopy gaps, which indicates that the co-dominance of the two species cannot be maintained simply by interspecific differences in shade tolerance and growth in gaps. Previous research showed that although Fagus and Acer shared dominance at this site, their relative dominance shifted with edaphic conditions. This suggests that the widespread co-dominance of the two species in eastern North American forests is maintained by the joint influence of canopy disturbance

  12. Impact of interspecific interactions on the soil water uptake depth in a young temperate mixed species plantation

    Science.gov (United States)

    Grossiord, Charlotte; Gessler, Arthur; Granier, André; Berger, Sigrid; Bréchet, Claude; Hentschel, Rainer; Hommel, Robert; Scherer-Lorenzen, Michael; Bonal, Damien

    2014-11-01

    and broadleaves). Furthermore, water uptake depth of beech was already influenced at this young development stage by interspecific interactions whereas no clear niche differentiation occurred for the other species. This finding does not preclude that plasticity-mediated responses to species interactions could increase as the plantation ages, leading to the coexistence of these species in adult forest stands.

  13. Distribution of 45S rDNA in Modern Rose Cultivars (Rosa hybrida), Rosa rugosa, and Their Interspecific Hybrids Revealed by Fluorescence in situ Hybridization.

    Science.gov (United States)

    Ding, Xiao-Liu; Xu, Ting-Liang; Wang, Jing; Luo, Le; Yu, Chao; Dong, Gui-Min; Pan, Hui-Tang; Zhang, Qi-Xiang

    2016-01-01

    To elucidate the evolutionary dynamics of the location and number of rDNA loci in the process of polyploidization in the genus Rosa, we examined 45S rDNA sites in the chromosomes of 6 modern rose cultivars (R. hybrida), 5 R. rugosa cultivars, and 20 hybrid progenies by fluorescence in situ hybridization. Variation in the number of rDNA sites in parents and their interspecific hybrids was detected. As expected, 4 rDNA sites were observed in the genomes of 4 modern rose cultivars, while 3 hybridization sites were observed in the 2 others. Two expected rDNA sites were found in 2 R. rugosa cultivars, while in the other 3 R. rugosa cultivars 4 sites were present. Among the 20 R. hybrida × R. rugosa offspring, 13 carried the expected number of rDNA sites, and 1 had 6 hybridization sites, which exceeded the expected number by far. The other 6 offspring had either 2 or 3 hybridization sites, which was less than expected. Differences in the number of rDNA loci were observed in interspecific offspring, indicating that rDNA loci exhibit instability after distant hybridization events. Abnormal chromosome pairing may be the main factor explaining the variation in rDNA sites during polyploidization. © 2016 S. Karger AG, Basel.

  14. Detailed ordering of markers localizing to the Xq26-Xqter region of the human X chromosome by the use of an interspecific Mus spretus mouse cross

    International Nuclear Information System (INIS)

    Avner, P.; Amar, L.; Arnaud, D.; Hanauer, A.; Cambrou, J.

    1987-01-01

    Five probes localizing to the Xq26-Xqter region of the human X chromosome have been genetically mapped on the mouse X chromosome using an interspecific cross involving Mus spretus to a contiguous region lying proximally to the Tabby (Ta) locus. Pedigree and recombinational analysis establish the marker order as being Hprt-FIX-c11-G6PD-St14-1. The size of this contiguous region is such that the X-linked muscular dystrophy (mdx) mouse mutation probably maps within this segment. This in turn suggests that it is highly improbable that the mouse mdx locus represents a model for Duchenne muscular dystrophy (DMD). It is, however, compatible with the idea that this mutation may correspond in man to Emery Dreifuss muscular dystrophy. The high frequency of restriction fragment length polymorphisms found in this interspecific system for all the human cross-reacting probes examined up until now, using only a limited number of restriction enzymes, suggests that the Mus spretus mapping system may be of great potential value for establishing the linkage relationships existing in man when conserved chromosomal regions are concerned and human/mouse cross-reacting probes are available or can be obtained

  15. Centromere separation and association in the nuclei of an interspecific hybrid between Torenia fournieri and T. baillonii (Scrophulariaceae) during mitosis and meiosis.

    Science.gov (United States)

    Kikuchi, Shinji; Tanaka, Hiroyuki; Wako, Toshiyuki; Tsujimoto, Hisashi

    2007-10-01

    In the nuclei of some interspecific hybrid and allopolyploid plant species, each genome occupies a separate spatial domain. To analyze this phenomenon, we studied localization of the centromeres in the nuclei of a hybrid between Torenia fournieri and T. baillonii during mitosis and meiosis using three-dimensional fluorescence in situ hybridization (3D-FISH) probed with species-specific centromere repeats. Centromeres of each genome were located separately in undifferentiated cells but not differentiated cells, suggesting that cell division might be the possible force causing centromere separation. However, no remarkable difference of dividing distance was detected between chromatids with different centromeres in anaphase and telophase, indicating that tension of the spindle fiber attached to each chromatid is not the cause of centromere separation in Torenia. In differentiated cells, centromeres in both genomes were not often observed for the expected chromosome number, indicating centromere association. In addition, association of centromeres from the same genome was observed at a higher frequency than between different genomes. This finding suggests that centromeres within one genome are spatially separated from those within the other. This close position may increase possibility of association between centromeres of the same genome. In meiotic prophase, all centromeres irrespective of the genome were associated in a certain portion of the nucleus. Since centromere association in the interspecific hybrid and amphiploid was tighter than that in the diploid parents, it is possible that this phenomenon may be involved in sorting and pairing of homologous chromosomes.

  16. Effects of Temporal and Interspecific Variation of Specific Leaf Area on Leaf Area Index Estimation of Temperate Broadleaved Forests in Korea

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    Boram Kwon

    2016-09-01

    Full Text Available This study investigated the effects of interspecific and temporal variation of specific leaf area (SLA, cm2·g−1 on leaf area index (LAI estimation for three deciduous broadleaved forests (Gwangneung (GN, Taehwa (TH, and Gariwang (GRW in Korea with varying ages and composition of tree species. In fall of 2014, fallen leaves were periodically collected using litter traps and classified by species. LAI was estimated by obtaining SLAs using four calculation methods (A: including both interspecific and temporal variation in SLA; B: species specific mean SLA; C: period-specific mean SLA; and D: overall mean, then multiplying the SLAs by the amount of leaves. SLA varied across different species in all plots, and SLAs of upper canopy species were less than those of lower canopy species. The LAIs calculated using method A, the reference method, were GN 6.09, TH 5.42, and GRW 4.33. LAIs calculated using method B showed a difference of up to 3% from the LAI of method A, but LAIs calculated using methods C and D were overestimated. Therefore, species specific SLA must be considered for precise LAI estimation for broadleaved forests that include multiple species.

  17. Evaluation of inter-specific hybrid of P. atlantica and P. vera L. cv. ‘Badami Riz-e-Zarand’ as pistachio rootstock to salinity stress according to some growth indices and eco-physiological and biochemical parameters

    OpenAIRE

    Karimi, Hamid; MALEKI-KUHBANANI; Roosta, H.

    2014-01-01

    In order to evaluate the inter-specific hybrid of P. atlantica Desf. and P. vera L. cv. ‘Badami- Riz-e- Zarand’ to salinity stress, a factorial experiment was conducted based on completely randomized design with 0, 60 and 120 mM of salinity levels of sodium chloride, calcium chloride and magnesium chloride (3:2:1) with four replications on ‘Qazvini’, ‘Badami-Riz-e-Zarand’ and inter-specific of P. atlantica Ч P. vera cv. ‘Badami-Rize-Zarand’ rootstocks of pistachio. The results showed that sa...

  18. Potential efficacy of mitochondrial genes for animal DNA barcoding: a case study using eutherian mammals.

    Science.gov (United States)

    Luo, Arong; Zhang, Aibing; Ho, Simon Yw; Xu, Weijun; Zhang, Yanzhou; Shi, Weifeng; Cameron, Stephen L; Zhu, Chaodong

    2011-01-28

    A well-informed choice of genetic locus is central to the efficacy of DNA barcoding. Current DNA barcoding in animals involves the use of the 5' half of the mitochondrial cytochrome oxidase 1 gene (CO1) to diagnose and delimit species. However, there is no compelling a priori reason for the exclusive focus on this region, and it has been shown that it performs poorly for certain animal groups. To explore alternative mitochondrial barcoding regions, we compared the efficacy of the universal CO1 barcoding region with the other mitochondrial protein-coding genes in eutherian mammals. Four criteria were used for this comparison: the number of recovered species, sequence variability within and between species, resolution to taxonomic levels above that of species, and the degree of mutational saturation. Based on 1,179 mitochondrial genomes of eutherians, we found that the universal CO1 barcoding region is a good representative of mitochondrial genes as a whole because the high species-recovery rate (> 90%) was similar to that of other mitochondrial genes, and there were no significant differences in intra- or interspecific variability among genes. However, an overlap between intra- and interspecific variability was still problematic for all mitochondrial genes. Our results also demonstrated that any choice of mitochondrial gene for DNA barcoding failed to offer significant resolution at higher taxonomic levels. We suggest that the CO1 barcoding region, the universal DNA barcode, is preferred among the mitochondrial protein-coding genes as a molecular diagnostic at least for eutherian species identification. Nevertheless, DNA barcoding with this marker may still be problematic for certain eutherian taxa and our approach can be used to test potential barcoding loci for such groups.

  19. Hybrid Weakness Found in the Backcross Progeny of an Inter-Specific Cross of Oryza Sativa / O. Glumaepatula

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    Sobrizal

    2009-01-01

    Full Text Available Hybrid breakdown expressed as sterility or weakness or both in F2 or later generations is considered to be a reproductive barrier between two distantly related taxa. Hybrid breakdown that showed poor growth habit with fertile seeds was found in the backcross progenies (BC4F2 which were derived from a cross between a cultivated rice Oryza sativa L. cv. Taichung 65 and a wild rice Oryza glumaepatula Steud (Acc. IRGC 105668 where Taichung 65 was used as a recurrent parent. Through segregation analysis of BC4F2 population, a novel gene for weakness was identified, and this gene was designated as hwf1 (hybrid weakness f-1. RFLP (Restriction Fragment Length Polymorphism analysis was employed to determine the chromosomal location of hwf1 gene. The result revealed that hwf1 was located between G3006 and C933 RFLP markers, with map distances of 0.5 cM and 1.9 cM, respectively, and co-segregated with C708, C820, and R288 on the short arm of chromosome 4. Since both O. glumaepatula (Acc. IRGC 105668 and Taichung 65 that was used as parents showed normal growth habit, the weakness in this study was assumed to be controlled by a set of complementary recessive genes. One of the complementary genes is hwf1 from O. glumaepatula, and another gene should be from Taichung 65, because the genetic background of the BC4F2 populations that were used for analysis is Taichung 65. The gene from Taichung 65 has not been identified yet, therefore, it is necessary to conduct the experiment for finding out the complement of hwf1 gene in near future.

  20. Hybrid Weakness Found In the Backcross Progeny of an Inter-Specific Cross of Oryza Sativa / O. Glumaepatula

    International Nuclear Information System (INIS)

    Sobrizal; Yoshimura, A

    2009-01-01

    Hybrid breakdown expressed as sterility or weakness or both in F 2 or later generations is considered to be a reproductive barrier between two distantly related taxa. Hybrid breakdown that showed poor growth habit with fertile seeds was found in the backcross progenies (BC 4 F 2 ) which were derived from a cross between a cultivated rice Oryza sativa L. cv. Taichung 65 and a wild rice Oryza glumaepatula Steud (Acc. IRGC 105668) where Taichung 65 was used as a recurrent parent. Through segregation analysis of BC 4 F 2 population, a novel gene for weakness was identified, and this gene was designated as hwf1 (hybrid weakness f-1). RFLP (Restriction Fragment Length Polymorphism) analysis was employed to determine the chromosomal location of hwf1 gene. The result revealed that hwf1 was located between G3006 and C933 RFLP markers, with map distances of 0.5 cM and 1.9 cM, respectively, and co-segregated with C708, C820, and R288 on the short arm of chromosome 4. Since both O. glumaepatula (Acc. IRGC 105668) and Taichung 65 that was used as parents showed normal growth habit, the weakness in this study was assumed to be controlled by a set of complementary recessive genes. One of the complementary genes is hwf1 from O. glumaepatula, and another gene should be from Taichung 65, because the genetic background of the BC 4 F 2 populations that were used for analysis is Taichung 65. The gene from Taichung 65 has not been identified yet, therefore, it is necessary to conduct the experiment for finding out the complement of hwf1 gene in near future. (author)

  1. Evaluation of interspecific hybrids and cultivars of Brachiaria spp. submitted to sourcers and levels of nitrogen fertilization

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    Márcia Atauri Cardelli Lucena

    2012-12-01

    Full Text Available The management of nitrogen supply (N is a very important issue concerned to plant growth and the environment healthy. For farmers, to know how much N the plant requires enables the application of appropriate amounts of nitrogen fertilizer, maximizing the use of this material. The availability of N has been identified as one of the main limiting factors, but also a management tool in the production of grasses. The nitrogen in the soil either, as a constituent of organic matter or in the mineral form (ammonium and nitrate, has a limited supply and can be depleted rapidly in a few crops. The aim of this study was to evaluate the effects of sources and nitrogen levels in four genotypes of Brachiaria (Brachiaria brizantha cv. Marandu, Brachiaria brizantha cv. Piata and two interspecific hybrids of Brachiaria spp on the total and the leaf dry matter production, leaf percentage and leaf: stem ratio. The soil was an Psament-Entisol, coming from a pasture of Brachiaria decumbens with low organic matter content. The experiment was conducted in greenhouse, in Nova Odessa, Sao Paulo, from October 2009 to April 2010. The experimental design was in randomized complete blocks and the treatments were arranged in a factorial 4 x 2 x 4, four genotypes of Brachiaria , two N sources (urea and ammonium nitrate and four nitrogen rates (0, 75, 150 or 225 mg dm-3 with five replicates, totaling 160 pots with a capacity of 3.34 dm3 of soil. Two cuts were performed in the plants. After the second cut a soil sample was collected from each experimental unit. Two evaluations were performed on plants. The first one 52 days after sowing, and the second 56 days after the first cut. Data were analyzed by the mixed procedure of SAS V. 9.2; average qualitative factors were compared by Tukey test at 5% probability. The degrees of freedom related to N rates (quantitative factor were decomposed into orthogonal polynomials; to obtain the best equation fits the data. The variables

  2. Landscape-level movement patterns by lions in western Serengeti: comparing the influence of inter-specific competitors, habitat attributes and prey availability.

    Science.gov (United States)

    Kittle, Andrew M; Bukombe, John K; Sinclair, Anthony R E; Mduma, Simon A R; Fryxell, John M

    2016-01-01

    Where apex predators move on the landscape influences ecosystem structure and function and is therefore key to effective landscape-level management and species-specific conservation. However the factors underlying predator distribution patterns within functional ecosystems are poorly understood. Predator movement should be sensitive to the spatial patterns of inter-specific competitors, spatial variation in prey density, and landscape attributes that increase individual prey vulnerability. We investigated the relative role of these fundamental factors on seasonal resource utilization by a globally endangered apex carnivore, the African lion (Panthera leo) in Tanzania's Serengeti National Park. Lion space use was represented by novel landscape-level, modified utilization distributions (termed "localized density distributions") created from telemetry relocations of individual lions from multiple neighbouring prides. Spatial patterns of inter-specific competitors were similarly determined from telemetry re-locations of spotted hyenas (Crocuta crocuta), this system's primary competitor for lions; prey distribution was derived from 18 months of detailed census data; and remote sensing data was used to represent relevant habitat attributes. Lion space use was consistently influenced by landscape attributes that increase individual prey vulnerability to predation. Wet season activity, when available prey were scarce, was concentrated near embankments, which provide ambush opportunities, and dry season activity, when available prey were abundant, near remaining water sources where prey occurrence is predictable. Lion space use patterns were positively associated with areas of high prey biomass, but only in the prey abundant dry season. Finally, at the broad scale of this analysis, lion and hyena space use was positively correlated in the comparatively prey-rich dry season and unrelated in the wet season, suggesting lion movement was unconstrained by the spatial patterns

  3. Early interspecific interference in the wheat/faba bean (Triticum aestivum/ Vicia faba ssp. minor and rapeseed/squarrosum clover (Brassica napus var. oleifera/Trifolium squarrosum intercrops

    Directory of Open Access Journals (Sweden)

    Paolo Benincasa

    2012-04-01

    Full Text Available Most of research on intercrops evaluate performances and interference between species on the basis of final yield, while little knowledge is available on the interference in early stages and at the root level, at least for cultivated intercrops. In fact, in the few studies on this subject species are often combined minding at experimental needs (e.g. common substrate, temperature and water requirements, easy root separation more than at their actual use in the farm. The present work evaluates interspecific interference during early developmental stages for two intercrops of agricultural interest: soft wheat-faba bean and rapeseed-squarrosum clover. Improving this knowledge would help intercrop growth modelling and rational cultivation. The experiments were carried out on soft wheat (Triticum aestivum, faba bean (Vicia faba var. minor, rapeseed (Brassica napus var. oleifera and squarrosum clover (Trifolium squarrosum, germinated and grown until 32 days after sowing (DAS as one-species stands or as wheat/faba bean and rapeseed/squarrosum clover intercrops, with different densities and proportions for the two species in each couple. Germination was studied in controlled-temperature chamber, plantlet growth was studied on pots in the greenhouse. During germination no interspecific interference was observed for both wheat/faba bean and rapeseed/squarrosum clover intercrops. During plantlet growth, interspecific interference occurred in both intercrops causing variations in whole plant and root dry matter accumulation. In the wheat/faba bean intercrop each species suffered from the competitive effect of the companion species and faba bean was the dominant species when present in lower proportion than wheat. The unexpectedly high aggressivity of faba bean may be explained either with the greater seed size that could have represented an initial advantage within the short duration of the experiment or with the competition towards wheat for substrate N

  4. Interspecific Comparison and annotation of two complete mitochondrial genome sequences from the plant pathogenic fungus Mycosphaerella graminicola

    Energy Technology Data Exchange (ETDEWEB)

    Millenbaugh, Bonnie A; Pangilinan, Jasmyn L.; Torriani, Stefano F.F.; Goodwin, Stephen B.; Kema, Gert H.J.; McDonald, Bruce A.

    2007-12-07

    The mitochondrial genomes of two isolates of the wheat pathogen Mycosphaerella graminicola were sequenced completely and compared to identify polymorphic regions. This organism is of interest because it is phylogenetically distant from other fungi with sequenced mitochondrial genomes and it has shown discordant patterns of nuclear and mitochondrial diversity. The mitochondrial genome of M. graminicola is a circular molecule of approximately 43,960 bp containing the typical genes coding for 14 proteins related to oxidative phosphorylation, one RNA polymerase, two rRNA genes and a set of 27 tRNAs. The mitochondrial DNA of M. graminicola lacks the gene encoding the putative ribosomal protein (rps5-like), commonly found in fungal mitochondrial genomes. Most of the tRNA genes were clustered with a gene order conserved with many other ascomycetes. A sample of thirty-five additional strains representing the known global mt diversity was partially sequenced to measure overall mitochondrial variability within the species. Little variation was found, confirming previous RFLP-based findings of low mitochondrial diversity. The mitochondrial sequence of M. graminicola is the first reported from the family Mycosphaerellaceae or the order Capnodiales. The sequence also provides a tool to better understand the development of fungicide resistance and the conflicting pattern of high nuclear and low mitochondrial diversity in global populations of this fungus.

  5. DDC and COBL, flanking the imprinted GRB10 gene on 7p12, are biallelically expressed.

    Science.gov (United States)

    Hitchins, Megan P; Bentley, Louise; Monk, David; Beechey, Colin; Peters, Jo; Kelsey, Gavin; Ishino, Fumitoshi; Preece, Michael A; Stanier, Philip; Moore, Gudrun E

    2002-12-01

    Maternal duplication of human 7p11.2-p13 has been associated with Silver-Russell syndrome (SRS) in two familial cases. GRB10 is the only imprinted gene identified within this region to date. GRB10 demonstrates an intricate tissue- and isoform-specific imprinting profile in humans, with paternal expression in fetal brain and maternal expression of one isoform in skeletal muscle. The mouse homolog is maternally transcribed. The GRB10 protein is a potent growth inhibitor and represents a candidate for SRS, which is characterized by pre- and postnatal growth retardation and a spectrum of additional dysmorphic features. Since imprinted genes tend to be grouped in clusters, we investigated the imprinting status of the dopa-decarboxylase gene (DDC) and the Cordon-bleu gene (COBL) which flank GRB10 within the 7p11.2-p13 SRS duplicated region. Although both genes were found to replicate asynchronously, suggestive of imprinting, SNP expression analyses showed that neither gene was imprinted in multiple human fetal tissues. The mouse homologues, Ddc and Cobl, which map to the homologous imprinted region on proximal Chr 11, were also biallelically expressed in mice with uniparental maternal or paternal inheritance of this region. With the intent of using mouse Grb10 as an imprinted control, biallelic expression was consistently observed in fetal, postnatal, and adult brain of these mice, in contrast to the maternal-specific transcription previously demonstrated in brain in inter-specific F1 progeny. This may be a further example of over-expression of maternally derived transcripts in inter-specific mouse crosses. GRB10 remains the only imprinted gene identified within 7p11.2-p13.

  6. Geographic Variation in Advertisement Calls in a Tree Frog Species: Gene Flow and Selection Hypotheses

    Science.gov (United States)

    Jang, Yikweon; Hahm, Eun Hye; Lee, Hyun-Jung; Park, Soyeon; Won, Yong-Jin; Choe, Jae C.

    2011-01-01

    Background In a species with a large distribution relative to its dispersal capacity, geographic variation in traits may be explained by gene flow, selection, or the combined effects of both. Studies of genetic diversity using neutral molecular markers show that patterns of isolation by distance (IBD) or barrier effect may be evident for geographic variation at the molecular level in amphibian species. However, selective factors such as habitat, predator, or interspecific interactions may be critical for geographic variation in sexual traits. We studied geographic variation in advertisement calls in the tree frog Hyla japonica to understand patterns of variation in these traits across Korea and provide clues about the underlying forces for variation. Methodology We recorded calls of H. japonica in three breeding seasons from 17 localities including localities in remote Jeju Island. Call characters analyzed were note repetition rate (NRR), note duration (ND), and dominant frequency (DF), along with snout-to-vent length. Results The findings of a barrier effect on DF and a longitudinal variation in NRR seemed to suggest that an open sea between the mainland and Jeju Island and mountain ranges dominated by the north-south Taebaek Mountains were related to geographic variation in call characters. Furthermore, there was a pattern of IBD in mitochondrial DNA sequences. However, no comparable pattern of IBD was found between geographic distance and call characters. We also failed to detect any effects of habitat or interspecific interaction on call characters. Conclusions Geographic variations in call characters as well as mitochondrial DNA sequences were largely stratified by geographic factors such as distance and barriers in Korean populations of H. japoinca. Although we did not detect effects of habitat or interspecific interaction, some other selective factors such as sexual selection might still be operating on call characters in conjunction with restricted gene

  7. Analysis of genomic instability in primary spermatocytes of interspecific hybrids of the red fox (Vulpes vulpes) and the Arctic fox (Alopex lagopus).

    Science.gov (United States)

    Bugno-Poniewierska, Monika; Pawlina, Klaudia; Jakubczak, Andrzej; Jeżewska-Witkowska, Grażyna

    2014-01-01

    The aim of this study was to analyse meiotic cells of male interspecific hybrids of the red fox (Vulpes vulpes) and the arctic fox (Alopex lagopus). To this end we determined stages of meiotic cells as well as carried out FISH analyses with probes specific to heterosomes and a TUNEL assay on synaptonemal complex preparations. The meiotic cell analysis revealed only the presence of stages of the first meiotic division from leptotene to pachytene. Moreover, we observed an increased level of early dissociation of the X-Y bivalent as well as a high percentage of apoptotic cells. These results indicate the disruption of meiotic division in male hybrids manifested through meiotic arrest of the cells. Faulty pairing of the heterosomes can be considered as one of the causes leading to the initiation of the apoptotic process.

  8. Resource quantity and quality determine the inter-specific associations between ecosystem engineers and resource users in a cavity-nest web.

    Science.gov (United States)

    Robles, Hugo; Martin, Kathy

    2013-01-01

    While ecosystem engineering is a widespread structural force of ecological communities, the mechanisms underlying the inter-specific associations between ecosystem engineers and resource users are poorly understood. A proper knowledge of these mechanisms is, however, essential to understand how communities are structured. Previous studies suggest that increasing the quantity of resources provided by ecosystem engineers enhances populations of resource users. In a long-term study (1995-2011), we show that the quality of the resources (i.e. tree cavities) provided by ecosystem engineers is also a key feature that explains the inter-specific associations in a tree cavity-nest web. Red-naped sapsuckers (Sphyrapicusnuchalis) provided the most abundant cavities (52% of cavities, 0.49 cavities/ha). These cavities were less likely to be used than other cavity types by mountain bluebirds (Sialiacurrucoides), but provided numerous nest-sites (41% of nesting cavities) to tree swallows (Tachycinetabicolour). Swallows experienced low reproductive outputs in northern flicker (Colaptesauratus) cavities compared to those in sapsucker cavities (1.1 vs. 2.1 fledglings/nest), but the highly abundant flickers (33% of cavities, 0.25 cavities/ha) provided numerous suitable nest-sites for bluebirds (58%). The relative shortage of cavities supplied by hairy woodpeckers (Picoidesvillosus) and fungal/insect decay (high quality nest-sites for both bluebirds and swallows. Because both the quantity and quality of resources supplied by different ecosystem engineers may explain the amount of resources used by each resource user, conservation strategies may require different management actions to be implemented for the key ecosystem engineer of each resource user. We, therefore, urge the incorporation of both resource quantity and quality into models that assess community dynamics to improve conservation actions and our understanding of ecological communities based on ecosystem engineering.

  9. Relationships between morphology, diet and spatial distribution: testing the effects of intra and interspecific morphological variations on the patterns of resource use in two Neotropical Cichlids

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    Ana Lúcia A. Sampaio

    Full Text Available Considering th e morphology, diet and spatial distribution of Satanoperca pappaterraand Crenicichla britskii (Perciformes: Cichlidae in the Upper Paraná River floodplain (Brazil, the following questions were investigated: (1 Could the body shape predict the use of trophic resources and habitat by C. britskiiand S. pappaterra? (2 Could the relationship between morphology and use of trophic resources and habitat be also extended to the intraspecific scale? (3 What are the most important morphological traits used to predict the variation on diet and habitat occupation within and between species? We hypothesized that intra and interspecific differences in morphological patterns imply in different forms of resource exploitation and that the ecomorphological analysis enables the identification of trophic and spatial niche segregation. Fish samplings were performed in different types of habitats (rivers, secondary channels, connected and disconnected lagoons in the Upper Paraná River floodplain. Analyses of the stomach content was conducted to characterize the feeding patterns and twenty-two ecomorphological indices were calculated from linear morphological measurements and areas. A principal component analysis (PCA run with these indices evidenced the formation of two significant axes, revealing in the axis 1 an ecomorphological ordination according to the type of habitat, regardless the species. The individuals of both species exploiting lotic habitats tended to have morphological traits that enable rapid progressive and retrograde movements, braking and continuous swimming, whereas individuals found in lentic and semi-lotic habitats presented morphology adapted to a greater maneuverability and stabilization in deflections. On the other hand the axis 2 evidenced a segregation related to the feeding ecology, between S. pappaterra and C. britskii. The relationship between morphology and use of spatial and feeding resource was corroborated by the

  10. Intra- and Interspecific Interactions as Proximate Determinants of Sexual Dimorphism and Allometric Trajectories in the Bottlenose Dolphin Tursiops truncatus (Cetacea, Odontoceti, Delphinidae.

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    Maria Carla de Francesco

    Full Text Available Feeding adaptation, social behaviour, and interspecific interactions related to sexual dimorphism and allometric growth are particularly challenging to be investigated in the high sexual monomorphic Delphinidae. We used geometric morphometrics to extensively explore sexual dimorphism and ontogenetic allometry of different projections of the skull and the mandible of the bottlenose dolphin Tursiops truncatus. Two-dimensional landmarks were recorded on the dorsal, ventral, lateral, and occipital views of the skull, and on the lateral view of the left and the right mandible of 104 specimens from the Mediterranean and the North Seas, differing environmental condition and degree of interspecific associations. Landmark configurations were transformed, standardized and superimposed through a Generalized Procrustes Analysis. Size and shape differences between adult males and females were respectively evaluated through ANOVA on centroid size, Procrustes ANOVA on Procrustes distances, and MANOVA on Procrustes coordinates. Ontogenetic allometry was investigated by multivariate regression of shape coordinates on centroid size in the largest homogenous sample from the North Sea. Results evidenced sexual dimorphic asymmetric traits only detected in the adults of the North Sea bottlenose dolphins living in monospecific associations, with females bearing a marked incision of the cavity hosting the left tympanic bulla. These differences were related to a more refined echolocalization system that likely enhances the exploitation of local resources by philopatric females. Distinct shape in immature versus mature stages and asymmetric changes in postnatal allometry of dorsal and occipital traits, suggest that differences between males and females are established early during growth. Allometric growth trajectories differed between males and females for the ventral view of the skull. Allometric trajectories differed among projections of skull and mandible, and were

  11. Interspecific competition between Diadegma semiclausum Hellen and Diadegma mollipla (Holmgren), parasitoids of the diamondback moth, Plutella xylostella (L), feeding on a new host plant.

    Science.gov (United States)

    Rossbach, A; Löhr, B; Vidal, S

    2008-04-01

    Interspecific competition between an introduced parasitoid species aimed at controlling a herbivorous pest species and a native parasitoid parasitising the same host may influence the success of classical biological control programmes. In Kenya, interspecific competition between an introduced and a local parasitoid on two diamondback moth populations (DBM, Plutella xylostella) was investigated on two different host plants. We tested simultaneous and delayed competition of the local parasitoid Diadegma mollipla Holmgren and its exotic congenus D. semiclausum Hellen on a newly aquired DBM host plant (snowpea) in the laboratory. Under simultaneous competition, D. mollipla produced more progeny than D. semiclausum on snowpea. A head start of D. Mollipla, of four and eight hours before its congenus was introduced, resulted in a similar number of progeny of both species. In delayed competition (time intervals of 24 h, 48 h and 72 h), progeny production was similar for both parasitoids when the time interval was 24 h, irrespective of which species parasitized first. More progeny was produced by the species which attacked first, when the time interval was greater than 24 h, although it was only significant at 72 h. Competitive abilites of both parasitoids on the new host plant differed largely between laboratory and semi-field conditions. The influence of two host plants (snowpea and cabbage) on competition was studied in the greenhouse with different host and parasitoid densities. Parasitism levels of D. semiclausum were significantly higher than those of D. mollipla, regardless of host plant, host and parasitoid densities, but progeny production of D. mollipla on snowpea was still slightly higher than on cabbage. As compared to the confinement of parasitoids and larvae to small containers, D. mollipla parasitized very few larvae in the cages. Competitive ability of the two parasitoid species tested was influenced both by the density of the searching females and by

  12. Triticale powdery mildew: population characterization and wheat gene efficiency.

    Science.gov (United States)

    Bouguennec, Annaig; Trottet, Maxime; du Cheyron, Philippe; Lonnet, Philippe

    2014-01-01

    Powdery mildew has emerged on triticale in the early 2000s in many locations, probably due to a host range expansion of the wheat formae speciales, Blumeria graminis f.sp. tritici. Many triticale cultivars are highly susceptible to powdery mildew, mainly in seedling stage, revealing a probably narrow genetic basis for powdery mildew resistance genes (Pm). Moreover, as Blumeria graminis is an obligate biotrophic fungus, it is very time consuming and difficult to maintain powdery mildew isolates for a non-specialized laboratory and populations can evolve. In order to identify wheat Pm genes efficient against natural populations of powdery mildew, wheat differential hosts and triticale seedlings were inoculated below susceptible triticale crop naturally contaminated by mildew, in several locations and several years. Symptoms on seedlings were measured after approximately two weeks of incubation in favorable fungus growth conditions. According to these data, we classified the Pm genes presents in our wheat differential hosts set in 3 classes: Pm already overcame by triticale powdery mildew, Pm having variable effects and Pm still efficient against triticale mildew. Data on triticale seedlings allowed us to identify some few triticale cultivars resistant to Blumeria graminis in seedling stage. We will try to identify Pm genes present in those cultivars next year by testing them with the characterized isolates of powdery mildew from Gent University. Nevertheless, interspecific crossing of wheat, resistant to powdery mildew in seedling stage, and rye have been initiated to introduce potentially interesting genes for resistance in triticale.

  13. Introgression study reveals two quantitative trait loci involved in interspecific variation in memory retention among Nasonia wasp species

    NARCIS (Netherlands)

    Hoedjes, K.M.; Smid, H.M.; Vet, L.E.M.; Werren, J.H.

    2014-01-01

    Genes involved in the process of memory formation have been studied intensively in model organisms; however, little is known about the mechanisms that are responsible for natural variation in memory dynamics. There is substantial variation in memory retention among closely related species in the

  14. Gene expression

    International Nuclear Information System (INIS)

    Hildebrand, C.E.; Crawford, B.D.; Walters, R.A.; Enger, M.D.

    1983-01-01

    We prepared probes for isolating functional pieces of the metallothionein locus. The probes enabled a variety of experiments, eventually revealing two mechanisms for metallothionein gene expression, the order of the DNA coding units at the locus, and the location of the gene site in its chromosome. Once the switch regulating metallothionein synthesis was located, it could be joined by recombinant DNA methods to other, unrelated genes, then reintroduced into cells by gene-transfer techniques. The expression of these recombinant genes could then be induced by exposing the cells to Zn 2+ or Cd 2+ . We would thus take advantage of the clearly defined switching properties of the metallothionein gene to manipulate the expression of other, perhaps normally constitutive, genes. Already, despite an incomplete understanding of how the regulatory switch of the metallothionein locus operates, such experiments have been performed successfully

  15. Polyphyly and gene flow between non-sibling Heliconius species

    Directory of Open Access Journals (Sweden)

    Jiggins Chris D

    2006-04-01

    Full Text Available Abstract Background The view that gene flow between related animal species is rare and evolutionarily unimportant largely antedates sensitive molecular techniques. Here we use DNA sequencing to investigate a pair of morphologically and ecologically divergent, non-sibling butterfly species, Heliconius cydno and H. melpomene (Lepidoptera: Nymphalidae, whose distributions overlap in Central and Northwestern South America. Results In these taxa, we sequenced 30–45 haplotypes per locus of a mitochondrial region containing the genes for cytochrome oxidase subunits I and II (CoI/CoII, and intron-spanning fragments of three unlinked nuclear loci: triose-phosphate isomerase (Tpi, mannose-6-phosphate isomerase (Mpi and cubitus interruptus (Ci genes. A fifth gene, dopa decarboxylase (Ddc produced sequence data likely to be from different duplicate loci in some of the taxa, and so was excluded. Mitochondrial and Tpi genealogies are consistent with reciprocal monophyly, whereas sympatric populations of the species in Panama share identical or similar Mpi and Ci haplotypes, giving rise to genealogical polyphyly at the species level despite evidence for rapid sequence divergence at these genes between geographic races of H. melpomene. Conclusion Recent transfer of Mpi haplotypes between species is strongly supported, but there is no evidence for introgression at the other three loci. Our results demonstrate that the boundaries between animal species can remain selectively porous to gene flow long after speciation, and that introgression, even between non-sibling species, can be an important factor in animal evolution. Interspecific gene flow is demonstrated here for the first time in Heliconius and may provide a route for the transfer of switch-gene adaptations for Müllerian mimicry. The results also forcefully demonstrate how reliance on a single locus may give an erroneous picture of the overall genealogical history of speciation and gene flow.

  16. Controle genético da concentração de 2-Tridecanona e de 2-Undecanona em cruzamentos interespecíficos de tomateiro Genetic control of 2-Tridecanone and 2-Undecanone concentration in tomato interspecific cross

    Directory of Open Access Journals (Sweden)

    NORMA ELIANE PEREIRA

    2000-01-01

    Full Text Available Estudou-se o controle genético da concentração das metil-cetonas 2-tridecanona (2-TD e 2-undecanona (2-UN no cruzamento de Lycopersicon esculentum cv IPA-6 x L. hirsutum f. glabratum PI 134418. Para tal, as gerações parentais F1 e F2 foram avaliadas em experimento de casa de vegetação, sendo a quantificação das metil-cetonas foliares realizada por cromatografia gasosa com coluna capilar. Os resultados revelaram alta correlação (0,97; P > 0,001 entre as concentrações de 2-TD e 2-UN, possivelmente devido à ocorrência de efeitos pleiotrópicos ou de ligação gênica. O grau médio de dominância revelou a ocorrência de dominância parcial para as menores concentrações de 2-TD e 2-UN, cujas herdabilidades foram 0,75 e 0,78 respectivamente. A análise de média de gerações mostrou não haver adequação dos dados de concentração de 2-TD e 2-UN ao modelo aditivo-dominante, devido, possivelmente, a problemas de incongruidade ou a efeitos epistáticos.Genetic control of methyl-ketones 2-tridecanone (2-TD and 2-undecanone (2-UN concentration was studied in a cross of Lycopersicon esculentum cv IPA-6 x L. hirsutum f. glabratum PI 134418. The progenitors F1 and F2 generations were evalueted in a green house experiment, and the level of methyl-ketones in the leaves were determined by capilar gas chromatography. The results indicate that there is high correlations between 2-TD and 2-UN concentrations (0.97; P > 0.001, indicating that pleiotropic or genic linkage effects may be occurring. The 2-TD and 2-UN showed complete dominance for low concentration and high heritability, 0.75 and 0.78, respectively. The generation means analysis showed that the results of 2-TD and 2-UN concentration can not be explained by the simple additive-dominant model, suggesting that the segregation distortion could be due to incongruity problems of interspecific crosses or epistatic gene action.

  17. Accelerated Senescence and Enhanced Disease Resistance in Hybrid Chlorosis Lines Derived from Interspecific Crosses between Tetraploid Wheat and Aegilops tauschii

    Science.gov (United States)

    Tosa, Yukio; Yoshida, Kentaro; Park, Pyoyun; Takumi, Shigeo

    2015-01-01

    Hybrid chlorosis, a type of hybrid incompatibility, has frequently been reported in inter- and intraspecific crosses of allopolyploid wheat. In a previous study, we reported some types of growth abnormalities such as hybrid necrosis and observed hybrid chlorosis with mild or severe abnormalities in wheat triploids obtained in crosses between tetraploid wheat cultivar Langdon and four Ae. tauschii accessions and in their derived synthetic hexaploids. However, the molecular mechanisms underlying hybrid chlorosis are not well understood. Here, we compared cytology and gene expression in leaves to characterize the abnormal growth in wheat synthetics showing mild and severe chlorosis. In addition, we compared disease resistance to wheat blast fungus. In total 55 and 105 genes related to carbohydrate metabolism and 53 and 89 genes for defense responses were markedly up-regulated in the mild and severe chlorosis lines, respectively. Abnormal chloroplasts formed in the mesophyll cells before the leaves yellowed in the hybrid chlorosis lines. The plants with mild chlorosis showed increased resistance to wheat blast and powdery mildew fungi, although significant differences only in two, third internode length and maturation time, out of the examined agricultural traits were found between the wild type and plants showing mild chlorosis. These observations suggest that senescence might be accelerated in hybrid chlorosis lines of wheat synthetics. Moreover, in wheat synthetics showing mild chlorosis, the negative effects on biomass can be minimized, and they may show substantial fitness under pathogen-polluted conditions. PMID:25806790

  18. Accelerated senescence and enhanced disease resistance in hybrid chlorosis lines derived from interspecific crosses between tetraploid wheat and Aegilops tauschii.

    Directory of Open Access Journals (Sweden)

    Hiroki Nakano

    Full Text Available Hybrid chlorosis, a type of hybrid incompatibility, has frequently been reported in inter- and intraspecific crosses of allopolyploid wheat. In a previous study, we reported some types of growth abnormalities such as hybrid necrosis and observed hybrid chlorosis with mild or severe abnormalities in wheat triploids obtained in crosses between tetraploid wheat cultivar Langdon and four Ae. tauschii accessions and in their derived synthetic hexaploids. However, the molecular mechanisms underlying hybrid chlorosis are not well understood. Here, we compared cytology and gene expression in leaves to characterize the abnormal growth in wheat synthetics showing mild and severe chlorosis. In addition, we compared disease resistance to wheat blast fungus. In total 55 and 105 genes related to carbohydrate metabolism and 53 and 89 genes for defense responses were markedly up-regulated in the mild and severe chlorosis lines, respectively. Abnormal chloroplasts formed in the mesophyll cells before the leaves yellowed in the hybrid chlorosis lines. The plants with mild chlorosis showed increased resistance to wheat blast and powdery mildew fungi, although significant differences only in two, third internode length and maturation time, out of the examined agricultural traits were found between the wild type and plants showing mild chlorosis. These observations suggest that senescence might be accelerated in hybrid chlorosis lines of wheat synthetics. Moreover, in wheat synthetics showing mild chlorosis, the negative effects on biomass can be minimized, and they may show substantial fitness under pathogen-polluted conditions.

  19. Trichoderma genes

    Science.gov (United States)

    Foreman, Pamela [Los Altos, CA; Goedegebuur, Frits [Vlaardingen, NL; Van Solingen, Pieter [Naaldwijk, NL; Ward, Michael [San Francisco, CA

    2012-06-19

    Described herein are novel gene sequences isolated from Trichoderma reesei. Two genes encoding proteins comprising a cellulose binding domain, one encoding an arabionfuranosidase and one encoding an acetylxylanesterase are described. The sequences, CIP1 and CIP2, contain a cellulose binding domain. These proteins are especially useful in the textile and detergent industry and in pulp and paper industry.

  20. Neuropeptide Y receptor genes on human chromosome 4q31-q32 map to conserved linkage groups on mouse chromosomes 3 and 8

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, C.M.; Frankel, W.N. [Jackson Lab., Bar Harbor, ME (United States); Richards, J.E. [Univ. of Michigan Medical School, Ann Arbor, MI (United States)] [and others

    1997-05-01

    Npy1r and Npy2r, the genes encoding mouse type 1 and type 2 neuropeptide Y receptors, have been mapped by interspecific backcross analysis. Previous studies have localized the human genes encoding these receptors to chromosome 4q31-q32. We have now assigned Npy1r and Npy2r to conserved linkage groups on mouse Chr 8 and Chr 3, respectively, which correspond to the distal region of human chromosome 4q. Using yeast artificial chromosomes, we have estimated the distance between the human genes to be approximately 6 cM. Although ancient tandem duplication events may account for some closely spaced G-protein-coupled receptor genes, the large genetic distance between the human type 1 and type 2 neuropeptide Y receptor genes raises questions about whether this mechanism accounts for their proximity. 20 refs., 1 fig.

  1. Sibling competition arena: selfing and a competition arena can combine to constitute a barrier to gene flow in sympatry.

    Science.gov (United States)

    Gibson, A K; Hood, M E; Giraud, T

    2012-06-01

    Closely related species coexisting in sympatry provide critical insight into the mechanisms underlying speciation and the maintenance of genetic divergence. Selfing may promote reproductive isolation by facilitating local adaptation, causing reduced hybrid fitness in parental environments. Here, we propose a novel mechanism by which selfing can further impair interspecific gene flow: selfing may act to ensure that nonhybrid progeny systematically co-occur whenever hybrid genotypes are produced. Under a competition arena, the fitness differentials between nonhybrid and hybrid progeny are then magnified, preventing development of interspecific hybrids. We investigate whether this "sibling competition arena" can explain the coexistence in sympatry of closely related species of the plant fungal pathogens (Microbotryum) causing anther-smut disease. The probabilities of intrapromycelial mating (automixis), outcrossing, and sibling competition were manipulated in artificial inoculations to evaluate their contribution to reproductive isolation. We report that both intrapromycelial selfing and sibling competition significantly reduced rates of hybrid infection beyond that expected based solely upon selfing rates and noncompetitive fitness differentials between hybrid and nonhybrid progeny. Our results thus suggest that selfing and a sibling competition arena can combine to constitute a barrier to gene flow and diminish selection for additional barriers to gene flow in sympatry. © 2012 The Author(s). Evolution © 2012 The Society for the Study of Evolution.

  2. Differential SPL gene expression patterns reveal candidate genes underlying flowering time and architectural differences in Mimulus and Arabidopsis.

    Science.gov (United States)

    Jorgensen, Stacy A; Preston, Jill C

    2014-04-01

    Evolutionary transitions in growth habit and flowering time responses to variable environmental signals have occurred multiple times independently across angiosperms and have major impacts on plant fitness. Proteins in the SPL family of transcription factors collectively regulate flowering time genes that have been implicated in interspecific shifts in annuality/perenniality. However, their potential importance in the evolution of angiosperm growth habit has not been extensively investigated. Here we identify orthologs representative of the major SPL gene clades in annual Arabidopsis thaliana and Mimulus guttatus IM767, and perennial A. lyrata and M. guttatus PR, and characterize their expression. Spatio-temporal expression patterns are complex across both diverse tissues of the same taxa and comparable tissues of different taxa, consistent with genic sub- or neo-functionalization. However, our data are consistent with a general role for several SPL genes in the promotion of juvenile to adult phase change and/or flowering time in Mimulus and Arabidopsis. Furthermore, several candidate genes were identified for future study whose differential expression correlates with growth habit and architectural variation in annual versus perennial taxa. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. The evolutionary history of bears is characterized by gene flow across species

    Science.gov (United States)

    Kumar, Vikas; Lammers, Fritjof; Bidon, Tobias; Pfenninger, Markus; Kolter, Lydia; Nilsson, Maria A.; Janke, Axel

    2017-01-01

    Bears are iconic mammals with a complex evolutionary history. Natural bear hybrids and studies of few nuclear genes indicate that gene flow among bears may be more common than expected and not limited to polar and brown bears. Here we present a genome analysis of the bear family with representatives of all living species. Phylogenomic analyses of 869 mega base pairs divided into 18,621 genome fragments yielded a well-resolved coalescent species tree despite signals for extensive gene flow across species. However, genome analyses using different statistical methods show that gene flow is not limited to closely related species pairs. Strong ancestral gene flow between the Asiatic black bear and the ancestor to polar, brown and American black bear explains uncertainties in reconstructing the bear phylogeny. Gene flow across the bear clade may be mediated by intermediate species such as the geographically wide-spread brown bears leading to large amounts of phylogenetic conflict. Genome-scale analyses lead to a more complete understanding of complex evolutionary processes. Evidence for extensive inter-specific gene flow, found also in other animal species, necessitates shifting the attention from speciation processes achieving genome-wide reproductive isolation to the selective processes that maintain species divergence in the face of gene flow. PMID:28422140

  4. The evolutionary history of bears is characterized by gene flow across species.

    Science.gov (United States)

    Kumar, Vikas; Lammers, Fritjof; Bidon, Tobias; Pfenninger, Markus; Kolter, Lydia; Nilsson, Maria A; Janke, Axel

    2017-04-19

    Bears are iconic mammals with a complex evolutionary history. Natural bear hybrids and studies of few nuclear genes indicate that gene flow among bears may be more common than expected and not limited to polar and brown bears. Here we present a genome analysis of the bear family with representatives of all living species. Phylogenomic analyses of 869 mega base pairs divided into 18,621 genome fragments yielded a well-resolved coalescent species tree despite signals for extensive gene flow across species. However, genome analyses using different statistical methods show that gene flow is not limited to closely related species pairs. Strong ancestral gene flow between the Asiatic black bear and the ancestor to polar, brown and American black bear explains uncertainties in reconstructing the bear phylogeny. Gene flow across the bear clade may be mediated by intermediate species such as the geographically wide-spread brown bears leading to large amounts of phylogenetic conflict. Genome-scale analyses lead to a more complete understanding of complex evolutionary processes. Evidence for extensive inter-specific gene flow, found also in other animal species, necessitates shifting the attention from speciation processes achieving genome-wide reproductive isolation to the selective processes that maintain species divergence in the face of gene flow.

  5. Gametocidal genes of Aegilops: segregation distorters in wheat-Aegilops wide hybridization.

    Science.gov (United States)

    Niranjana, M

    2017-08-01

    Aegilops is a genus belonging to the family Poaceace, which have played an indispensible role in the evolution of bread wheat and continues to do so by transferring genes by wide hybridization. Being the secondary gene pool of wheat, gene transfer from Aegilops poses difficulties and segregation distortion is common. Gametocidal genes are the most well characterized class of segregation distorters reported in interspecific crosses of wheat with Aegilops. These "selfish" genetic elements ensure their preferential transmission to progeny at the cost of gametes lacking them without providing any phenotypic benefits to the plant, thereby causing a proportional reduction in fertility. Gametocidal genes (Gc) have been reported in different species of Aegilops belonging to the sections Aegilops (Ae. geniculata and Ae. triuncialis), Cylindropyrum (Ae. caudata and Ae. cylindrica), and Sitopsis (Ae. longissima, Ae. sharonensis, and Ae. speltoides). Gametocidal activity is mostly confined to 2, 3, and 4 homeologous groups of C, S, S 1 , S sh , and M g genomes. Removal of such genes is necessary for successful alien gene introgression and can be achieved by mutagenesis or allosyndetic pairing. However, there are some instances where Gc genes are constructively utilized for development of deletion stocks in wheat, improving genetic variability and chromosome engineering.

  6. Risk and efficacy of human-enabled interspecific hybridization for climate-change adaptation: Response to Hamilton and Miller (2016)

    Science.gov (United States)

    Kovach, Ryan P.; Luikart, Gordon; Lowe, Winsor H.; Boyer, Matthew C.; Muhlfeld, Clint C.

    2016-01-01

    Hamilton and Miller (2016) provide an interesting and provocative discussion of how hybridization and introgression can promote evolutionary potential in the face of climate change. They argue that hybridization—mating between individuals from genetically distinct populations—can alleviate inbreeding depression and promote adaptive introgression and evolutionary rescue. We agree that deliberate intraspecific hybridization (mating between individuals of the same species) is an underused management tool for increasing fitness in inbred populations (i.e., genetic rescue; Frankham 2015; Whiteley et al. 2015). The potential risks and benefits of assisted gene flow have been discussed in the literature, and an emerging consensus suggests that mating between populations isolated for approximately 50–100 generations can benefit fitness, often with a minor risk of outbreeding depression (Frankham et al. 2011; Aitken & Whitlock 2013; Allendorf et al. 2013).

  7. Interspecific geographic distribution and variation of the pathogens Nosema bombi and Crithidia species in United States bumble bee populations.

    Science.gov (United States)

    Cordes, Nils; Huang, Wei-Fone; Strange, James P; Cameron, Sydney A; Griswold, Terry L; Lozier, Jeffrey D; Solter, Leellen F

    2012-02-01

    Several bumble bee (Bombus) species in North America have undergone range reductions and rapid declines in relative abundance. Pathogens have been suggested as causal factors, however, baseline data on pathogen distributions in a large number of bumble bee species have not been available to test this hypothesis. In a nationwide survey of the US, nearly 10,000 specimens of 36 bumble bee species collected at 284 sites were evaluated for the presence and prevalence of two known Bombus pathogens, the microsporidium Nosema bombi and trypanosomes in the genus Crithidia. Prevalence of Crithidia was ≤10% for all host species examined but was recorded from 21% of surveyed sites. Crithidia was isolated from 15 of the 36 Bombus species screened, and were most commonly recovered from Bombus bifarius, Bombus bimaculatus, Bombus impatiens and Bombus mixtus. Nosema bombi was isolated from 22 of the 36 US Bombus species collected. Only one species with more than 50 sampled bees, Bombus appositus, was free of the pathogen; whereas, prevalence was highest in Bombus occidentalis and Bombus pensylvanicus, two species that are reportedly undergoing population declines in North America. A variant of a tetranucleotide repeat in the internal transcribed spacer (ITS) of the N. bombi rRNA gene, thus far not reported from European isolates, was isolated from ten US Bombus hosts, appearing in varying ratios in different host species. Given the genetic similarity of the rRNA gene of N. bombi sampled in Europe and North America to date, the presence of a unique isolate in US bumble could reveal one or more native North American strains and indicate that N. bombi is enzootic across the Holarctic Region, exhibiting some genetic isolation. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Characterization of courtship sounds of species of the subgroup fasciola (Diptera, Drosophilidae, Drosophila repleta group: interspecific and interpopulational analyses

    Directory of Open Access Journals (Sweden)

    C. T. A. COSTA

    Full Text Available The aim of this work was to characterize the male courtship song pattern of various species of the fasciola subgroup and to determine the level of variation both within and among species. The parameters analyzed were intrapulse interval (PI, interpulse interval (IPI, and intrapulse frequency (IF. Six different species were analyzed: D. coroica (three populations, D. ellisoni, D. fascioloides, D. moju, D. onca, and D. rosinae (one population each. There were significant differences among the six species for these three courtship song parameters. The IPI was the most variable parameter among these species, suggesting that this parameter is important for female discrimination. Four different hypotheses could explain this variation: 1. different selection pressures with absence of flow gene; 2. intraspecific sexual selection; 3. sympatric effects on song evolution; and 4. genetic drift. The PI was the only parameter that was significantly different among the three population of D. coroica. Low variability among populations within the same species was already observed for other subgroups and could be explained by the following hypotheses: strong selection acting on the song parameters, gene flow, or recent colonization from a common source. Additional studies of the courtship song of other species of the fasciola subgroup, as well as for other subgroups of the repleta group, and studies, using molecular makers, that focus on the genetic basis of the differences among these species in courtship song would allow us to evaluate the association of courtship song and sexual isolation in these species, and would also help us to understand the evolution of these behavioural differences.

  9. Ageing genes

    DEFF Research Database (Denmark)

    Rattan, Suresh

    2018-01-01

    The idea of gerontogenes is in line with the evolutionary explanation of ageing as being an emergent phenomenon as a result of the imperfect maintenance and repair systems. Although evolutionary processes did not select for any specific ageing genes that restrict and determine the lifespan...... of an individual, the term ‘gerontogenes’ primarily refers to any genes that may seem to influence ageing and longevity, without being specifically selected for that role. Such genes can also be called ‘virtual gerontogenes’ by virtue of their indirect influence on the rate and process of ageing. More than 1000...... virtual gerontogenes have been associated with ageing and longevity in model organisms and humans. The ‘real’ genes, which do influence the essential lifespan of a species, and have been selected for in accordance with the evolutionary life history of the species, are known as the longevity assurance...

  10. Effects of gamma-ray irradiation on interspecific hybridization between Chamaecyparis obtusa S. et Z. and Chamaecyparis pisifera S. et Z

    Energy Technology Data Exchange (ETDEWEB)

    Maeta, Takehiko (Institute of Radiation Breeding, Omiya, Ibaraki (Japan))

    1982-03-01

    C. obtusa S. et Z. is one of the most important forest trees in Japan, and possesses high wood quality. It adapts to dry or semi-dry planting sites, but when it is planted in humid and productive soil, physiological damage is often seen, and its woods are not resistant against termite harm. On the contrary, C. pisifera S. et Z. has high adaptability to humid and productive soil, and is resistant against termite harm. In order to improve the resistance of C. obtusa against diseases and insects, an attempt to obtain a hybrid between C. obtusa and C. pisifera has been made. However, it was found to be very difficult to obtain the hybrid because of low cross compatibility. Therefore, the radiosensitivity of reproductive organs and the induction of mutation in C. obtusa and C. pisifera, the cause of interspecific incompatibility between both species, and the possibility of breaking down the incompatibility were investigated. Also, the cytological screening of the hybrids between C. obtusa and C. pisifera was made. It was considered that the acute gamma-ray irradiation from 500 to 600 R on male flowers was optimum for the hybridization of the present purpose. All of the hybrids produced in this study were triploid.

  11. Assessing genetic divergence in interspecific hybrids of Aechmea gomosepala and A. recurvata var. recurvata using inflorescence characteristics and sequence-related amplified polymorphism markers.

    Science.gov (United States)

    Zhang, F; Ge, Y Y; Wang, W Y; Shen, X L; Yu, X Y

    2012-12-03

    Conventional hybridization and selection techniques have aided the development of new ornamental crop cultivars. However, little information is available on the genetic divergence of bromeliad hybrids. In the present study, we investigated the genetic variability in interspecific hybrids of Aechmea gomosepala and A. recurvata var. recurvata using inflorescence characteristics and sequence-related amplified polymorphism (SRAP) markers. The morphological analysis showed that the putative hybrids were intermediate between both parental species with respect to inflorescence characteristics. The 16 SRAP primer combinations yield 265 bands, among which 154 (57.72%) were polymorphic. The genetic similarity was an average of 0.59 and ranged from 0.21 to 0.87, indicating moderate genetic divergence among the hybrids. The unweighted pair group method with arithmetic average (UPGMA)-based cluster analysis distinguished the hybrids from their parents with a genetic distance coefficient of 0.54. The cophenetic correlation was 0.93, indicating a good fit between the dendrogram and the original distance matrix. The two-dimensional plot from the principal coordinate analysis showed that the hybrids were intermediately dispersed between both parents, corresponding to the results of the UPGMA cluster and the morphological analysis. These results suggest that SRAP markers could help to identify breeders, characterize F(1) hybrids of bromeliads at an early stage, and expedite genetic improvement of bromeliad cultivars.

  12. [Intra- and interspecific polymorphism of (AAT)n in microsatellite locus du47D in parthenogenetic species of the genus Darevskia].

    Science.gov (United States)

    Korchagin, V I; Vergun, A A; Godakova, S A; Tokarskaia, O N

    2013-03-01

    The molecular structure of the allelic variants of (AAT)n of the Du47D microsatellite locus was determined in parthenogenetic lizards Darevskia dahli, D. armeniaca, and D. rostombekovi. Comparative analysis of these alleles showed that they were characterized by perfect structure of microsatellite cluster, and were different in the number of (AAT) monomeric units, as well as in the combinations of species-specific substitutions and deletions in the microsatellite flanking regions. Molecular structure of microsatellite cluster, species-specific single nucleotide polymorphism (SNP), and different representation of alleles Du47 in the samples of parthenogenetic species examined point to the origin of the alleles from different bisexual species, which is consistent with the hybrid nature of unisexual species of the genus Darevskia. In addition, these data reflect different combination patterns of interspecific hybridization events with the participation of the same bisexual species upon the formation of hybrid genomes of parthenogenetic species. Possible application of the allelic variants of microsatellite loci of parthenogenetic lizards as the genetic markers for the analysis of the genomes of parthenogenetic species in the light of evolution, ecology, and parthenogenetic type of reproduction in vertebrates is discussed.

  13. Interspecific cooperation: enhanced growth, attachment and strain-specific distribution in biofilms through Azospirillum brasilense-Pseudomonas protegens co-cultivation.

    Science.gov (United States)

    Pagnussat, Luciana A; Salcedo, Florencia; Maroniche, Guillermo; Keel, Christoph; Valverde, Claudio; Creus, Cecilia M

    2016-10-01

    Plant-growth-promoting bacteria belonging to Azospirillum and Pseudomonas genera are major inhabitants of the rhizosphere. Both are increasingly commercialized as crops inoculants. Interspecific interaction in the rhizosphere is critical for inoculants aptness. The objective of this work was to evaluate Azospirillum and Pseudomonas interaction in mixed biofilms by co-cultivation of the model strains Azospirillum brasilense Sp245 and Pseudomonas protegens CHA0. The results revealed enhanced growth of both strains when co-cultured in static conditions. Moreover, Sp245 biofilm formed in plastic surfaces was increased 2-fold in the presence of CHA0. Confocal microscopy revealed highly structured mixed biofilms showing Sp245 mainly on the bottom and CHA0 towards the biofilm surface. In addition, A. brasilense biofilm was thicker and denser when co-cultured with P. protegens. In a colony-colony interaction assay, Sp245 changed nearby CHA0 producing small colony phenotype, which accounts for a diffusible metabolite mediator; though CHA0 spent medium did not affect Sp245 colony phenotype. Altogether, these results point to a cooperative interaction between A. brasilense Sp245 and P. protegens CHA0 in which both strains increase their static growth and produce structured mixed biofilms with a strain-specific distribution. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Does interspecific competition alter effects of early season ozone exposure on plants from wet grasslands? Results of a three-year experiment in open-top chambers.

    Science.gov (United States)

    Tonneijck, A E G; Franzaring, J; Brouwer, G; Metselaar, K; Dueck, Th A

    2004-09-01

    Chronic effects of ozone on wet grassland species early in the growing season might be altered by interspecific competition. Individual plants of Holcus lanatus, Lychnis flos-cuculi, Molinia caerulea and Plantago lanceolata were grown in monocultures and in mixed cultures with Agrostis capillaris. Mesocosms were exposed to charcoal-filtered air plus 25 nl l(-1) ozone (CF+25), non-filtered air (NF), non-filtered air plus 25 nl l(-1) ozone (NF+25) and non-filtered air plus 50 nl l(-1) ozone (NF+50) early in the growing seasons of 2000 through 2002. Ozone-enhanced senescence and visible foliar injury were recorded on some of the target plants in the first year only. Ozone effects on biomass production were minimal and plant response to ozone did not differ between monocultures and mixed cultures. After three years, above-ground biomass of the plants in mixed culture compared to monocultures was three times greater for H. lanatus and two to four times smaller for the other species.

  15. Does interspecific competition alter effects of early season ozone exposure on plants from wet grasslands? Results of a three-year experiment in open-top chambers

    Energy Technology Data Exchange (ETDEWEB)

    Tonneijck, A.E.G.; Franzaring, J.; Brouwer, G.; Metselaar, K.; Dueck, Th.A

    2004-09-01

    Chronic effects of ozone on wet grassland species early in the growing season might be altered by interspecific competition. Individual plants of Holcus lanatus, Lychnis flos-cuculi, Molinia caerulea and Plantago lanceolata were grown in monocultures and in mixed cultures with Agrostis capillaris. Mesocosms were exposed to charcoal-filtered air plus 25 nl l{sup -1} ozone (CF + 25), non-filtered air (NF), non-filtered air plus 25 nl l{sup -1} ozone (NF + 25) and non-filtered air plus 50 nl l{sup -1} ozone (NF + 50) early in the growing seasons of 2000 through 2002. Ozone-enhanced senescence and visible foliar injury were recorded on some of the target plants in the first year only. Ozone effects on biomass production were minimal and plant response to ozone did not differ between monocultures and mixed cultures. After three years, above-ground biomass of the plants in mixed culture compared to monocultures was three times greater for H. lanatus and two to four times smaller for the other species.

  16. Does interspecific competition alter effects of early season ozone exposure on plants from wet grasslands? Results of a three-year experiment in open-top chambers

    International Nuclear Information System (INIS)

    Tonneijck, A.E.G.; Franzaring, J.; Brouwer, G.; Metselaar, K.; Dueck, Th.A.

    2004-01-01

    Chronic effects of ozone on wet grassland species early in the growing season might be altered by interspecific competition. Individual plants of Holcus lanatus, Lychnis flos-cuculi, Molinia caerulea and Plantago lanceolata were grown in monocultures and in mixed cultures with Agrostis capillaris. Mesocosms were exposed to charcoal-filtered air plus 25 nl l -1 ozone (CF + 25), non-filtered air (NF), non-filtered air plus 25 nl l -1 ozone (NF + 25) and non-filtered air plus 50 nl l -1 ozone (NF + 50) early in the growing seasons of 2000 through 2002. Ozone-enhanced senescence and visible foliar injury were recorded on some of the target plants in the first year only. Ozone effects on biomass production were minimal and plant response to ozone did not differ between monocultures and mixed cultures. After three years, above-ground biomass of the plants in mixed culture compared to monocultures was three times greater for H. lanatus and two to four times smaller for the other species

  17. Duration of plant damage by host larvae affects attraction of two parasitoid species (Microplitis croceipes and Cotesia marginiventris) to cotton: implications for interspecific competition.

    Science.gov (United States)

    Morawo, Tolulope; Fadamiro, Henry

    2014-12-01

    Volatile organic compounds (VOCs) released by herbivore-damaged plants can guide parasitoids to their hosts. The quantity and quality of VOC blends emitted by plants may be affected by the duration of plant damage by herbivores, which could have potential ramifications on the recruitment of competing parasitoids. We used two parasitoid species, Microplitis croceipes and Cotesia marginiventris (Hymenoptera: Braconidae), to address the question of whether duration of plant damage affects parasitoid use of plant VOCs for host location. Both wasp species are larval endoparasitoids of Heliothis virescens (Lepidoptera: Noctuidae), an important pest of cotton. Attraction of the two parasitoid species to odors emitted by undamaged (UD), fresh (6 h infestation) damage (FD), and old (24 h infestation) damage (OD) cotton plants infested by H. virescens larvae was investigated using a headspace volatile collection system coupled with four-choice olfactometer bioassay. Both sexes of M. croceipes showed a preference for FD- and OD-plant odors over UD-plants. On the other hand, more C. marginiventris females were attracted to UD- and FD-plants than to OD-plants. GC/MS analyses showed qualitative and quantitative differences in the VOC profiles of UD, FD, and OD-plants, which may explain the observed preferences of the parasitoids. These results suggest a temporal partitioning in the recruitment of M. croceipes and C. marginiventris to H. virescens-damaged cotton, and may have potential implications for interspecific competition between the two parasitoid species.

  18. The dynamic process of interspecific interactions of competitive nitrogen capture between intercropped wheat (Triticum aestivum L. and Faba Bean (Vicia faba L..

    Directory of Open Access Journals (Sweden)

    Chunjie Li

    Full Text Available Wheat (Triticum aestivum L./faba bean (Vicia faba L. intercropping shows significant overyielding and high nitrogen (N-use efficiency, but the dynamics of plant interactions have rarely been estimated. The objective of the present study was to investigate the temporal dynamics of competitive N acquisition between intercropped wheat and faba bean with the logistic model. Wheat and faba bean were grown together or alone with limited N supply in pots. Data of shoot and root biomass and N content measured from 14 samplings were fitted to logistic models to determine instantaneous rates of growth and N uptake. The superiority of instantaneous biomass production and N uptake shifted from faba bean to wheat with their growth. Moreover, the shift of superiority on N uptake occurred 7-12 days earlier than that of biomass production. Interspecific competition stimulated intercropped wheat to have a much earlier and stronger superiority on instantaneous N uptake compared with isolated wheat. The modeling methodology characterized the temporal dynamics of biomass production and N uptake of intercropped wheat and faba bean in different planting systems, which helps to understand the underlying process of plant interaction for intercropping plants.

  19. The dynamic process of interspecific interactions of competitive nitrogen capture between intercropped wheat (Triticum aestivum L.) and Faba Bean (Vicia faba L.).

    Science.gov (United States)

    Li, Chunjie; Dong, Yan; Li, Haigang; Shen, Jianbo; Zhang, Fusuo

    2014-01-01

    Wheat (Triticum aestivum L.)/faba bean (Vicia faba L.) intercropping shows significant overyielding and high nitrogen (N)-use efficiency, but the dynamics of plant interactions have rarely been estimated. The objective of the present study was to investigate the temporal dynamics of competitive N acquisition between intercropped wheat and faba bean with the logistic model. Wheat and faba bean were grown together or alone with limited N supply in pots. Data of shoot and root biomass and N content measured from 14 samplings were fitted to logistic models to determine instantaneous rates of growth and N uptake. The superiority of instantaneous biomass production and N uptake shifted from faba bean to wheat with their growth. Moreover, the shift of superiority on N uptake occurred 7-12 days earlier than that of biomass production. Interspecific competition stimulated intercropped wheat to have a much earlier and stronger superiority on instantaneous N uptake compared with isolated wheat. The modeling methodology characterized the temporal dynamics of biomass production and N uptake of intercropped wheat and faba bean in different planting systems, which helps to understand the underlying process of plant interaction for intercropping plants.

  20. Effects of gamma-ray irradiation on interspecific hybridization between Chamaecyparis obtusa S. et Z. and Chamaecyparis pisifera S. et Z

    International Nuclear Information System (INIS)

    Maeta, Takehiko

    1982-01-01

    C. obtusa S. et Z. is one of the most important forest trees in Japan, and possesses high wood quality. It adapts to dry or semi-dry planting sites, but when it is planted in humid and productive soil, physiological damage is often seen, and its woods are not resistant against termite harm. On the contrary, C. pisifera S. et Z. has high adaptability to humid and productive soil, and is resistant against termite harm. In order to improve the resistance of C. obtusa against diseases and insects, an attempt to obtain a hybrid between C. obtusa and C. pisifera has been made. However, it was found to be very difficult to obtain the hybrid because of low cross compatibility. Therefore, the radiosensitivity of reproductive organs and the induction of mutation in C. obtusa and C. pisifera, the cause of interspecific incompatibility between both species, and the possibility of breaking down the incompatibility were investigated. Also, the cytological screening of the hybrids between C. obtusa and C. pisifera was made. It was considered that the acute gamma-ray irradiation from 500 to 600 R on male flowers was optimum for the hybridization of the present purpose. All of the hybrids produced in this study were triploid. (Kako, I.)

  1. Nuclear introns outperform mitochondrial DNA in inter-specific phylogenetic reconstruction: Lessons from horseshoe bats (Rhinolophidae: Chiroptera).

    Science.gov (United States)

    Dool, Serena E; Puechmaille, Sebastien J; Foley, Nicole M; Allegrini, Benjamin; Bastian, Anna; Mutumi, Gregory L; Maluleke, Tinyiko G; Odendaal, Lizelle J; Teeling, Emma C; Jacobs, David S

    2016-04-01

    Despite many studies illustrating the perils of utilising mitochondrial DNA in phylogenetic studies, it remains one of the most widely used genetic markers for this purpose. Over the last decade, nuclear introns have been proposed as alternative markers for phylogenetic reconstruction. However, the resolution capabilities of mtDNA and nuclear introns have rarely been quantified and compared. In the current study we generated a novel ∼5kb dataset comprising six nuclear introns and a mtDNA fragment. We assessed the relative resolution capabilities of the six intronic fragments with respect to each other, when used in various combinations together, and when compared to the traditionally used mtDNA. We focused on a major clade in the horseshoe bat family (Afro-Palaearctic clade; Rhinolophidae) as our case study. This old, widely distributed and speciose group contains a high level of conserved morphology. This morphological stasis renders the reconstruction of the phylogeny of this group with traditional morphological characters complex. We sampled multiple individuals per species to represent their geographic distributions as best as possible (122 individuals, 24 species, 68 localities). We reconstructed the species phylogeny using several complementary methods (partitioned Maximum Likelihood and Bayesian and Bayesian multispecies-coalescent) and made inferences based on consensus across these methods. We computed pairwise comparisons based on Robinson-Foulds tree distance metric between all Bayesian topologies generated (27,000) for every gene(s) and visualised the tree space using multidimensional scaling (MDS) plots. Using our supported species phylogeny we estimated the ancestral state of key traits of interest within this group, e.g. echolocation peak frequency which has been implicated in speciation. Our results revealed many potential cryptic species within this group, even in taxa where this was not suspected a priori and also found evidence for mt

  2. Positive selection in the SLC11A1 gene in the family Equidae.

    Science.gov (United States)

    Bayerova, Zuzana; Janova, Eva; Matiasovic, Jan; Orlando, Ludovic; Horin, Petr

    2016-05-01

    Immunity-related genes are a suitable model for studying effects of selection at the genomic level. Some of them are highly conserved due to functional constraints and purifying selection, while others are variable and change quickly to cope with the variation of pathogens. The SLC11A1 gene encodes a transporter protein mediating antimicrobial activity of macrophages. Little is known about the patterns of selection shaping this gene during evolution. Although it is a typical evolutionarily conserved gene, functionally important polymorphisms associated with various diseases were identified in humans and other species. We analyzed the genomic organization, genetic variation, and evolution of the SLC11A1 gene in the family Equidae to identify patterns of selection within this important gene. Nucleotide SLC11A1 sequences were shown to be highly conserved in ten equid species, with more than 97 % sequence identity across the family. Single nucleotide polymorphisms (SNPs) were found in the coding and noncoding regions of the gene. Seven codon sites were identified to be under strong purifying selection. Codons located in three regions, including the glycosylated extracellular loop, were shown to be under diversifying selection. A 3-bp indel resulting in a deletion of the amino acid 321 in the predicted protein was observed in all horses, while it has been maintained in all other equid species. This codon comprised in an N-glycosylation site was found to be under positive selection. Interspecific variation in the presence of predicted N-glycosylation sites was observed.

  3. Patterns of evolution of MHC class II genes of crows (Corvus suggest trans-species polymorphism

    Directory of Open Access Journals (Sweden)

    John A. Eimes

    2015-03-01

    Full Text Available A distinguishing characteristic of genes that code for the major histocompatibility complex (MHC is that alleles often share more similarity between, rather than within species. There are two likely mechanisms that can explain this pattern: convergent evolution and trans-species polymorphism (TSP, in which ancient allelic lineages are maintained by balancing selection and retained by descendant species. Distinguishing between these two mechanisms has major implications in how we view adaptation of immune genes. In this study we analyzed exon 2 of the MHC class IIB in three passerine bird species in the genus Corvus: jungle crows (Corvus macrorhynchos japonensis American crows (C. brachyrhynchos and carrion crows (C. corone orientalis. Carrion crows and American crows are recently diverged, but allopatric, sister species, whereas carrion crows and jungle crows are more distantly related but sympatric species, and possibly share pathogens linked to MHC IIB polymorphisms. These patterns of evolutionary divergence and current geographic ranges enabled us to test for trans-species polymorphism and convergent evolution of the MHC IIB in crows. Phylogenetic reconstructions of MHC IIB sequences revealed several well supported interspecific clusters containing all three species, and there was no biased clustering of variants among the sympatric carrion crows and jungle crows. The topologies of phylogenetic trees constructed from putatively selected sites were remarkably different than those constructed from putatively neutral sites. In addition, trees constructed using non-synonymous substitutions from a continuous fragment of exon 2 had more, and generally more inclusive, supported interspecific MHC IIB variant clusters than those constructed from the same fragment using synonymous substitutions. These phylogenetic patterns suggest that recombination, especially gene conversion, has partially erased the signal of allelic ancestry in these species. While

  4. Multiyear evaluation of the durability of the resistance conferred by Ma and RMia genes to Meloidogyne incognita in Prunus under controlled conditions.

    Science.gov (United States)

    Khallouk, Samira; Voisin, Roger; Portier, Ulysse; Polidori, Joël; Van Ghelder, Cyril; Esmenjaud, Daniel

    2013-08-01

    Root-knot nematodes (RKNs) (Meloidogyne spp.) are highly polyphagous pests that parasitize Prunus crops in Mediterranean climates. Breeding for RKN-resistant Prunus cultivars, as an alternative to the now-banned use of nematicides, is a real challenge, because the perennial nature of these trees increases the risk of resistance breakdown. The Ma plum resistance (R) gene, with a complete spectrum, and the RMia peach R gene, with a more restricted spectrum, both provide total control of Meloidogyne incognita, the model parthenogenetic species of the genus and the most important RKN in terms of economic losses. We investigated the durability of the resistance to this nematode conferred by these genes, comparing the results obtained with those for the tomato Mi-1 reference gene. In multiyear experiments, we applied a high and continuous nematode inoculum pressure by cultivating nematode-infested susceptible tomato plants with either Prunus accessions carrying Ma or RMia R genes, or with resistant tomato plants carrying the Mi-1 gene. Suitable conditions for Prunus development were achieved by carrying out the studies in a glasshouse, in controlled conditions allowing a short winter leaf fall and dormancy. We first assessed the plum accession 'P.2175', which is heterozygous for the Ma gene, in two successive 2-year evaluations, for resistance to two M. incognita isolates. Whatever the isolate used, no nematodes reproducing on P.2175 were detected, whereas galls and nematodes reproducing on tomato plants carrying Mi-1 were observed. In a second experiment with the most aggressive isolate, interspecific full-sib material (P.2175 × ['Garfi' almond × 'Nemared' peach]), carrying either Ma or RMia (from Nemared) or both (in the heterozygous state) or neither of these genes, was evaluated for 4 years. No virulent nematodes developed on Prunus spp. carrying R genes, whereas galling and virulent individuals were observed on Mi-1-resistant tomato plants. Thus, the resistance to

  5. Gene doping.

    Science.gov (United States)

    Haisma, H J; de Hon, O

    2006-04-01

    Together with the rapidly increasing knowledge on genetic therapies as a promising new branch of regular medicine, the issue has arisen whether these techniques might be abused in the field of sports. Previous experiences have shown that drugs that are still in the experimental phases of research may find their way into the athletic world. Both the World Anti-Doping Agency (WADA) and the International Olympic Committee (IOC) have expressed concerns about this possibility. As a result, the method of gene doping has been included in the list of prohibited classes of substances and prohibited methods. This review addresses the possible ways in which knowledge gained in the field of genetic therapies may be misused in elite sports. Many genes are readily available which may potentially have an effect on athletic performance. The sporting world will eventually be faced with the phenomena of gene doping to improve athletic performance. A combination of developing detection methods based on gene arrays or proteomics and a clear education program on the associated risks seems to be the most promising preventive method to counteract the possible application of gene doping.

  6. Genetics of hybrid male sterility between drosophila sibling species: a complex web of epistasis is revealed in interspecific studies.

    Science.gov (United States)

    Palopoli, M F; Wu, C I

    1994-10-01

    To study the genetic differences responsible for the sterility of their male hybrids, we introgressed small segments of an X chromosome from Drosophila simulans into a pure Drosophila mauritiana genetic background, then assessed the fertility of males carrying heterospecific introgressions of varying size. Although this analysis examined less than 20% of the X chromosome (roughly 5% of the euchromatic portion of the D. simulans genome), and the segments were introgressed in only one direction, a minimum of four factors that contribute to hybrid male sterility were revealed. At least two of the factors exhibited strong epistasis: males carrying either factor alone were consistently fertile, whereas males carrying both factors together were always sterile. Distinct spermatogenic phenotypes were observed for sterile introgressions of different lengths, and it appeared that an interaction between introgressed segments also influenced the stage of spermatogenic defect. Males with one category of introgression often produced large quantities of motile sperm and were observed copulating, but never inseminated females. Evidently these two species have diverged at a large number of loci which have varied effects on hybrid male fertility. By extrapolation, we estimate that there are at least 40 such loci on the X chromosome alone. Because these species exhibit little DNA-sequence divergence at arbitrarily chosen loci, it seems unlikely that the extensive functional divergence observed could be due mainly to random genetic drift. Significant epistasis between conspecific genes appears to be a common component of hybrid sterility between recently diverged species of Drosophila. The linkage relationships of interacting factors could shed light on the role played by epistatic selection in the dynamics of the allele substitutions responsible for reproductive barriers between species.

  7. Gene Locater

    DEFF Research Database (Denmark)

    Anwar, Muhammad Zohaib; Sehar, Anoosha; Rehman, Inayat-Ur

    2012-01-01

    software's for calculating recombination frequency is mostly limited to the range and flexibility of this type of analysis. GENE LOCATER is a fully customizable program for calculating recombination frequency, written in JAVA. Through an easy-to-use interface, GENE LOCATOR allows users a high degree...... of flexibility in calculating genetic linkage and displaying linkage group. Among other features, this software enables user to identify linkage groups with output visualized graphically. The program calculates interference and coefficient of coincidence with elevated accuracy in sample datasets. AVAILABILITY...

  8. Gene expression analysis of the ovary of hybrid females of Xenopus laevis and X. muelleri

    Directory of Open Access Journals (Sweden)

    Malone John H

    2008-03-01

    Full Text Available Abstract Background Interspecific hybrids of frogs of the genus Xenopus result in sterile hybrid males and fertile hybrid females. Previous work has demonstrated a dramatic asymmetrical pattern of misexpression in hybrid males compared to the two parental species with relatively few genes misexpressed in comparisons of hybrids and the maternal species (X. laevis and dramatically more genes misexpressed in hybrids compared to the paternal species (X. muelleri. In this work, we examine the gene expression pattern in hybrid females of X. laevis × X. muelleri to determine if this asymmetrical pattern of expression also occurs in hybrid females. Results We find a similar pattern of asymmetry in expression compared to males in that there were more genes differentially expressed between hybrids and X. muelleri compared to hybrids and X. laevis. We also found a dramatic increase in the number of misexpressed genes with hybrid females having about 20 times more genes misexpressed in ovaries compared to testes of hybrid males and therefore the match between phenotype and expression pattern is not supported. Conclusion We discuss these intriguing findings in the context of reproductive isolation and suggest that divergence in female expression may be involved in sterility of hybrid males due to the inherent sensitivity of spermatogenesis as defined by the faster male evolution hypothesis for Haldane's rule.

  9. Interspecific differences and commonalities in maternity roosting by tree cavity-roosting bats over a maternity season in a timber production landscape

    Science.gov (United States)

    Law, Brad; Goldingay, Ross

    2018-01-01

    Understanding maternity roost requirements is fundamental to guide timber production forest management given such roosts are vital to sustain bat populations. We tracked lactating females of three tree cavity-roosting species: Gould's long-eared bat (Nyctophilus gouldi) (n = 7), eastern broad-nosed bat (Scotorepens orion) (n = 6) and little forest bat (Vespadelus vulturnus) (n = 25), over five weeks in young (predominately trees were located. Bats displayed a degree of maternity roost selection plasticity, however, interspecific differences were found. Nyctophilus gouldi roosted selectively in retained riparian buffers, in trees of high senescence and switched roosts every day. Vespadelus vulturnus roosted in logged areas and displayed high roost site fidelity, with one roost used for 33 consecutive days. Scotorepens orion selected large live trees of low senescence. The preliminary data for this species suggests that females roost most days in ‘primary’ roosts but display a roost switching behaviour conforming to the fission-fusion model. Dead trees were identified to be important for both N. gouldi and V. vulturnus. Historical and recent logging at our study area drastically reduced cavity-bearing tree density to 1.4 trees per hectare in the logging zones (outside of exclusion areas), potentially limiting local populations of tree cavity-roosting bats and other cavity-dependent wildlife. Our data demonstrate that forest management must consider a range of maternity roost requirements to accommodate differences among species and highlight the importance of exclusion areas for roost habitat. We propose that an expanded ‘retention forestry’ approach should be implemented in logged areas that includes in-perpetuity forest patch retention to increase habitat complexity and continuity. PMID:29543883

  10. Interspecific and geographic variation in the diets of sympatric carnivores: dingoes/wild dogs and red foxes in south-eastern Australia.

    Directory of Open Access Journals (Sweden)

    Naomi E Davis

    Full Text Available Dingoes/wild dogs (Canis dingo/familiaris and red foxes (Vulpes vulpes are widespread carnivores in southern Australia and are controlled to reduce predation on domestic livestock and native fauna. We used the occurrence of food items in 5875 dingo/wild dog scats and 11,569 fox scats to evaluate interspecific and geographic differences in the diets of these species within nine regions of Victoria, south-eastern Australia. The nine regions encompass a wide variety of ecosystems. Diet overlap between dingoes/wild dogs and foxes varied among regions, from low to near complete overlap. The diet of foxes was broader than dingoes/wild dogs in all but three regions, with the former usually containing more insects, reptiles and plant material. By contrast, dingoes/wild dogs more regularly consumed larger mammals, supporting the hypothesis that niche partitioning occurs on the basis of mammalian prey size. The key mammalian food items for dingoes/wild dogs across all regions were black wallaby (Wallabia bicolor, brushtail possum species (Trichosurus spp., common wombat (Vombatus ursinus, sambar deer (Rusa unicolor, cattle (Bos taurus and European rabbit (Oryctolagus cuniculus. The key mammalian food items for foxes across all regions were European rabbit, sheep (Ovis aries and house mouse (Mus musculus. Foxes consumed 6.1 times the number of individuals of threatened Critical Weight Range native mammal species than did dingoes/wild dogs. The occurrence of intraguild predation was asymmetrical; dingoes/wild dogs consumed greater biomass of the smaller fox. The substantial geographic variation in diet indicates that dingoes/wild dogs and foxes alter their diet in accordance with changing food availability. We provide checklists of taxa recorded in the diets of dingoes/wild dogs and foxes as a resource for managers and researchers wishing to understand the potential impacts of policy and management decisions on dingoes/wild dogs, foxes and the food

  11. Interspecific differences and commonalities in maternity roosting by tree cavity-roosting bats over a maternity season in a timber production landscape.

    Science.gov (United States)

    Rueegger, Niels; Law, Brad; Goldingay, Ross

    2018-01-01

    Understanding maternity roost requirements is fundamental to guide timber production forest management given such roosts are vital to sustain bat populations. We tracked lactating females of three tree cavity-roosting species: Gould's long-eared bat (Nyctophilus gouldi) (n = 7), eastern broad-nosed bat (Scotorepens orion) (n = 6) and little forest bat (Vespadelus vulturnus) (n = 25), over five weeks in young (predominately maternity roost selection in a regenerating landscape and by doing so, increase our understanding of the three species' roost ecology. Sixteen V. vulturnus, 15 N. gouldi and six S. orion unique maternity roost trees were located. Bats displayed a degree of maternity roost selection plasticity, however, interspecific differences were found. Nyctophilus gouldi roosted selectively in retained riparian buffers, in trees of high senescence and switched roosts every day. Vespadelus vulturnus roosted in logged areas and displayed high roost site fidelity, with one roost used for 33 consecutive days. Scotorepens orion selected large live trees of low senescence. The preliminary data for this species suggests that females roost most days in 'primary' roosts but display a roost switching behaviour conforming to the fission-fusion model. Dead trees were identified to be important for both N. gouldi and V. vulturnus. Historical and recent logging at our study area drastically reduced cavity-bearing tree density to 1.4 trees per hectare in the logging zones (outside of exclusion areas), potentially limiting local populations of tree cavity-roosting bats and other cavity-dependent wildlife. Our data demonstrate that forest management must consider a range of maternity roost requirements to accommodate differences among species and highlight the importance of exclusion areas for roost habitat. We propose that an expanded 'retention forestry' approach should be implemented in logged areas that includes in-perpetuity forest patch retention to increase habitat

  12. Representation of pheromones, interspecific signals, and plant odors in higher olfactory centers; mapping physiologically identified antennal-lobe projection neurons in the male heliothine moth

    Directory of Open Access Journals (Sweden)

    Xin-Cheng eZhao

    2014-10-01

    Full Text Available In the primary olfactory centre of the moth brain, for example, a few enlarged glomeruli situated dorsally, at the entrance of the antennal nerve, are devoted to information about female-produced substances whereas a set of more numerous ordinary glomeruli receives input about general odorants. Heliothine moths are particularly suitable for studying central chemosensory mechanisms not only because of their anatomically separated systems for plant odours and pheromones but also due to their use of female-produced substances in communication across the species. Thus, the male-specific system of heliothine moths includes two sub arrangements, one ensuring attraction and mating behavior by carrying information about pheromones released by conspecifics, and the other reproductive isolation via signal information emitted from heterospecifics. Based on previous tracing experiments, a general chemotopic organization of the male-specific glomeruli has been demonstrated in a number of heliothine species. As compared to the well explored organization of the moth antennal lobe, demonstrating a non-overlapping representation of the biologically relevant stimuli, less is known about the neural arrangement residing at the following synaptic level, i.e. the mushroom body calyces and the lateral horn. In the study presented here, we have labelled physiologically characterized antennal-lobe projection neurons in males of the two heliothine species, Heliothis virescens and Helicoverpa assulta, for the purpose of mapping their target regions in the protocerebrum. In order to compare the representation of plant odours, pheromones, and interspecific signals in the higher brain regions of each species, we have created standard brain atlases and registered three-dimensional models of distinct uniglomerular projection neuron types into the relevant atlas.

  13. Interspecific and intraspecific variation in selenium:mercury molar ratios in saltwater fish from the Aleutians: Potential protection on mercury toxicity by selenium

    Science.gov (United States)

    Burger, Joanna; Gochfeld, Michael; Jeitner, Christian; Donio, Mark; Pittfield, Taryn

    2014-01-01

    A number of factors affect the consumption risk from mercury in fish, including mercury levels, seasonal patterns of mercury concentrations, human consumption patterns, and sensitive populations (e.g. pregnant women, fetuses, young children, and yet unknown genetic factors). Recently the protective effects of selenium on methylmercury toxicity have been publicized, particularly for saltwater fish. We examine levels of mercury and selenium in several species of fish and seabirds from the Aleutians (Alaska), determine selenium:mercury molar ratios, and examine species-specific and individual variation in the ratios as a means of exploring the use of the ratio in risk assessment and risk management. Variation among species was similar for mercury and selenium. There was significant inter-specific and intraspecific variation in selenium:mercury molar ratios for fish, and for birds. The mean selenium:mercury molar ratios for all fish and bird species were above 1, meaning there was an excess of selenium relative to mercury. It has been suggested that an excess of selenium confers some protective advantage for salt water fish, although the degree of excess necessary is unclear. The selenium:mercury molar ratio was significantly correlated negatively with total length for most fish species, but not for dolly varden. Some individuals of Pacific cod, yellow irish lord, rock greenling, Pacific halibut, dolly varden, and to a lesser extent, flathead sole, had selenium:mercury ratios below 1. No bird muscle had an excess of mercury (ratio below 1), and only glaucous-winged gull and pigeon guillemot had ratios between 1 and 5. There was a great deal of variation in selenium:mercury molar ratios within fish species, and within bird species, making it difficult and impractical to use these ratios in risk assessment or management, for fish advisories, or for consumers, particularly given the difficulty of interpreting the ratios. PMID:22664537

  14. Effect of intra- and interspecific competition on the performance of native and invasive species of Impatiens under varying levels of shade and moisture.

    Science.gov (United States)

    Skálová, Hana; Jarošík, Vojtěch; Dvořáčková, Śárka; Pyšek, Petr

    2013-01-01

    Many alien plants are thought to be invasive because of unique traits and greater phenotypic plasticity relative to resident species. However, many studies of invasive species are unable to quantify the importance of particular traits and phenotypic plasticity in conferring invasive behavior because traits used in comparative studies are often measured in a single environment and by using plants from a single population. To obtain a deeper insight into the role of environmental factors, local differences and competition in plant invasions, we compared species of Impatiens (Balsaminaceae) of different origin and invasion status that occur in central Europe: native I. noli-tangere and three alien species (highly invasive I. glandulifera, less invasive I. parviflora and potentially invasive I. capensis). In two experiments we harvested late-stage reproductive plants to estimate performance. The first experiment quantified how populations differed in performance under varying light and moisture levels in the absence of competition. The second experiment quantified performance across these environments in the presence of intra- and inter-specific competition. The highly invasive I. glandulifera was the strongest competitor, was the tallest and produced the greatest biomass. Small size and high plasticity were characteristic for I. parviflora. This species appeared to be the second strongest competitor, especially under low soil moisture. The performance of I. capensis was within the range of the other Impatiens species studied, but sometimes limited by alien competitors. Our results suggest that invasion success within the genus Impatiens depends on the ability to grow large under a range of environmental conditions, including competition. The invasive species also exhibited greater phenotypic plasticity across environmental conditions than the native species. Finally, the decreased performance of the native I. noli-tangere in competition with other species studied

  15. Interspecific variation in prey capture behavior by co-occurring Nepenthes pitcher plants: evidence for resource partitioning or sampling-scheme artifacts?

    Science.gov (United States)

    Chin, Lijin; Chung, Arthur Y C; Clarke, Charles

    2014-01-01

    Pitcher plants of the genus Nepenthes capture a wide range of arthropod prey for nutritional benefit, using complex combinations of visual and olfactory signals and gravity-driven pitfall trapping mechanisms. In many localities throughout Southeast Asia, several Nepenthes different species occur in mixed populations. Often, the species present at any given location have strongly divergent trap structures and preliminary surveys indicate that different species trap different combinations of arthropod prey, even when growing at the same locality. On this basis, it has been proposed that co-existing Nepenthes species may be engaged in niche segregation with regards to arthropod prey, avoiding direct competition with congeners by deploying traps that have modifications that enable them to target specific prey types. We examined prey capture among 3 multi-species Nepenthes populations in Borneo, finding that co-existing Nepenthes species do capture different combinations of prey, but that significant interspecific variations in arthropod prey combinations can often be detected only at sub-ordinal taxonomic ranks. In all lowland Nepenthes species examined, the dominant prey taxon is Formicidae, but montane Nepenthes trap few (or no) ants and 2 of the 3 species studied have evolved to target alternative sources of nutrition, such as tree shrew feces. Using similarity and null model analyses, we detected evidence for niche segregation with regards to formicid prey among 5 lowland, sympatric Nepenthes species in Sarawak. However, we were unable to determine whether these results provide support for the niche segregation hypothesis, or whether they simply reflect unquantified variation in heterogeneous habitats and/or ant communities in the study sites. These findings are used to propose improvements to the design of field experiments that seek to test hypotheses about targeted prey capture patterns in Nepenthes.

  16. Effect of intra- and interspecific competition on the performance of native and invasive species of Impatiens under varying levels of shade and moisture.

    Directory of Open Access Journals (Sweden)

    Hana Skálová

    Full Text Available Many alien plants are thought to be invasive because of unique traits and greater phenotypic plasticity relative to resident species. However, many studies of invasive species are unable to quantify the importance of particular traits and phenotypic plasticity in conferring invasive behavior because traits used in comparative studies are often measured in a single environment and by using plants from a single population. To obtain a deeper insight into the role of environmental factors, local differences and competition in plant invasions, we compared species of Impatiens (Balsaminaceae of different origin and invasion status that occur in central Europe: native I. noli-tangere and three alien species (highly invasive I. glandulifera, less invasive I. parviflora and potentially invasive I. capensis. In two experiments we harvested late-stage reproductive plants to estimate performance. The first experiment quantified how populations differed in performance under varying light and moisture levels in the absence of competition. The second experiment quantified performance across these environments in the presence of intra- and inter-specific competition. The highly invasive I. glandulifera was the strongest competitor, was the tallest and produced the greatest biomass. Small size and high plasticity were characteristic for I. parviflora. This species appeared to be the second strongest competitor, especially under low soil moisture. The performance of I. capensis was within the range of the other Impatiens species studied, but sometimes limited by alien competitors. Our results suggest that invasion success within the genus Impatiens depends on the ability to grow large under a range of environmental conditions, including competition. The invasive species also exhibited greater phenotypic plasticity across environmental conditions than the native species. Finally, the decreased performance of the native I. noli-tangere in competition with other

  17. Incongruence between morphotypes and genetically delimited species in the coral genus Stylophora: phenotypic plasticity, morphological convergence, morphological stasis or interspecific hybridization?

    Directory of Open Access Journals (Sweden)

    Flot Jean-François

    2011-10-01

    Full Text Available Abstract Background Morphological data suggest that, unlike most other groups of marine organisms, scleractinian corals of the genus Stylophora are more diverse in the western Indian Ocean and in the Red Sea than in the central Indo-Pacific. However, the morphology of corals is often a poor predictor of their actual biodiversity: hence, we conducted a genetic survey of Stylophora corals collected in Madagascar, Okinawa, the Philippines and New Caledonia in an attempt to find out the true number of species in these various locations. Results A molecular phylogenetic analysis of the mitochondrial ORF and putative control region concurs with a haploweb analysis of nuclear ITS2 sequences in delimiting three species among our dataset: species A and B are found in Madagascar whereas species C occurs in Okinawa, the Philippines and New Caledonia. Comparison of ITS1 sequences from these three species with data available online suggests that species C is also found on the Great Barrier Reef, in Malaysia, in the South China Sea and in Taiwan, and that a distinct species D occurs in the Red Sea. Shallow-water morphs of species A correspond to the morphological description of Stylophora madagascarensis, species B presents the morphology of Stylophora mordax, whereas species C comprises various morphotypes including Stylophora pistillata and Stylophora mordax. Conclusions Genetic analysis of the coral genus Stylophora reveals species boundaries that are not congruent with morphological traits. Of the four hypotheses that may explain such discrepancy (phenotypic plasticity, morphological stasis, morphological convergence, and interspecific hybridization, the first two appear likely to play a role but the fourth one is rejected since mitochondrial and nuclear markers yield congruent species delimitations. The position of the root in our molecular phylogenies suggests that the center of origin of Stylophora is located in the western Indian Ocean, which probably

  18. The effects of recombination, mutation and selection on the evolution of the Rp1 resistance genes in grasses.

    Science.gov (United States)

    Jouet, Agathe; McMullan, Mark; van Oosterhout, Cock

    2015-06-01

    Plant immune genes, or resistance genes, are involved in a co-evolutionary arms race with a diverse range of pathogens. In agronomically important grasses, such R genes have been extensively studied because of their role in pathogen resistance and in the breeding of resistant cultivars. In this study, we evaluate the importance of recombination, mutation and selection on the evolution of the R gene complex Rp1 of Sorghum, Triticum, Brachypodium, Oryza and Zea. Analyses show that recombination is widespread, and we detected 73 independent instances of sequence exchange, involving on average 1567 of 4692 nucleotides analysed (33.4%). We were able to date 24 interspecific recombination events and found that four occurred postspeciation, which suggests that genetic introgression took place between different grass species. Other interspecific events seemed to have been maintained over long evolutionary time, suggesting the presence of balancing selection. Significant positive selection (i.e. a relative excess of nonsynonymous substitutions (dN /dS >1)) was detected in 17-95 codons (0.42-2.02%). Recombination was significantly associated with areas with high levels of polymorphism but not with an elevated dN /dS ratio. Finally, phylogenetic analyses show that recombination results in a general overestimation of the divergence time (mean = 14.3%) and an alteration of the gene tree topology if the tree is not calibrated. Given that the statistical power to detect recombination is determined by the level of polymorphism of the amplicon as well as the number of sequences analysed, it is likely that many studies have underestimated the importance of recombination relative to the mutation rate. © 2015 John Wiley & Sons Ltd.

  19. Gene Ontology

    Directory of Open Access Journals (Sweden)

    Gaston K. Mazandu

    2012-01-01

    Full Text Available The wide coverage and biological relevance of the Gene Ontology (GO, confirmed through its successful use in protein function prediction, have led to the growth in its popularity. In order to exploit the extent of biological knowledge that GO offers in describing genes or groups of genes, there is a need for an efficient, scalable similarity measure for GO terms and GO-annotated proteins. While several GO similarity measures exist, none adequately addresses all issues surrounding the design and usage of the ontology. We introduce a new metric for measuring the distance between two GO terms using the intrinsic topology of the GO-DAG, thus enabling the measurement of functional similarities between proteins based on their GO annotations. We assess the performance of this metric using a ROC analysis on human protein-protein interaction datasets and correlation coefficient analysis on the selected set of protein pairs from the CESSM online tool. This metric achieves good performance compared to the existing annotation-based GO measures. We used this new metric to assess functional similarity between orthologues, and show that it is effective at determining whether orthologues are annotated with similar functions and identifying cases where annotation is inconsistent between orthologues.

  20. Environmental factors influencing gene transfer agent (GTA mediated transduction in the subtropical ocean.

    Directory of Open Access Journals (Sweden)

    Lauren D McDaniel

    Full Text Available Microbial genomic sequence analyses have indicated widespread horizontal gene transfer (HGT. However, an adequate mechanism accounting for the ubiquity of HGT has been lacking. Recently, high frequencies of interspecific gene transfer have been documented, catalyzed by Gene Transfer Agents (GTAs of marine α-Proteobacteria. It has been proposed that the presence of bacterial genes in highly purified viral metagenomes may be due to GTAs. However, factors influencing GTA-mediated gene transfer in the environment have not yet been determined. Several genomically sequenced strains containing complete GTA sequences similar to Rhodobacter capsulatus (RcGTA, type strain were screened to ascertain if they produced putative GTAs, and at what abundance. Five of nine marine strains screened to date spontaneously produced virus-like particles (VLP's in stationary phase. Three of these strains have demonstrated gene transfer activity, two of which were documented by this lab. These two strains Roseovarius nubinhibens ISM and Nitratireductor 44B9s, were utilized to produce GTAs designated RnGTA and NrGTA and gene transfer activity was verified in culture. Cell-free preparations of purified RnGTA and NrGTA particles from marked donor strains were incubated with natural microbial assemblages to determine the level of GTA-mediated gene transfer. In conjunction, several ambient environmental parameters were measured including lysogeny indicated by prophage induction. GTA production in culture systems indicated that approximately half of the strains produced GTA-like particles and maximal GTA counts ranged from 10-30% of host abundance. Modeling of GTA-mediated gene transfer frequencies in natural samples, along with other measured environmental variables, indicated a strong relationship between GTA mediated gene transfer and the combined factors of salinity, multiplicity of infection (MOI and ambient bacterial abundance. These results indicate that GTA

  1. Clock gene evolution: seasonal timing, phylogenetic signal, or functional constraint?

    Science.gov (United States)

    Krabbenhoft, Trevor J; Turner, Thomas F

    2014-01-01

    Genetic determinants of seasonal reproduction are not fully understood but may be important predictors of organism responses to climate change. We used a comparative approach to study the evolution of seasonal timing within a fish community in a natural common garden setting. We tested the hypothesis that allelic length variation in the PolyQ domain of a circadian rhythm gene, Clock1a, corresponded to interspecific differences in seasonal reproductive timing across 5 native and 1 introduced cyprinid fishes (n = 425 individuals) that co-occur in the Rio Grande, NM, USA. Most common allele lengths were longer in native species that initiated reproduction earlier (Spearman's r = -0.70, P = 0.23). Clock1a allele length exhibited strong phylogenetic signal and earlier spawners were evolutionarily derived. Aside from length variation in Clock1a, all other amino acids were identical across native species, suggesting functional constraint over evolutionary time. Interestingly, the endangered Rio Grande silvery minnow (Hybognathus amarus) exhibited less allelic variation in Clock1a and observed heterozygosity was 2- to 6-fold lower than the 5 other (nonimperiled) species. Reduced genetic variation in this functionally important gene may impede this species' capacity to respond to ongoing environmental change.

  2. Molecular genetic analysis of cereal β-amylase genes using exon-primed intron-crossing (EPIC PCR

    Directory of Open Access Journals (Sweden)

    Stratula Olga

    2014-01-01

    Full Text Available The proteins encoded by cereal β-amylase genes Bamy1 and Bamy2 genes play an important role in seedling germination and in the brewing process. Here, we use exon-primed intron-crossing (EPIC to analyse Bamy1 and Bamy2 genetic diversity among 38 accessions belonging to six Poaceae tribes. DNA sequence alignment of multiple Poaceae species β-amylase sequences allowed design of EPIC primers that simultaneously amplify Bamy1 and Bamy2 in all the cereal species investigated. The genetic variation observed in the samples investigated is analysed and discussed, and illustrates the effectiveness of this approach for intra- and interspecific analysis in plant species.

  3. Gene doping: gene delivery for olympic victory

    OpenAIRE

    Gould, David

    2012-01-01

    With one recently recommended gene therapy in Europe and a number of other gene therapy treatments now proving effective in clinical trials it is feasible that the same technologies will soon be adopted in the world of sport by unscrupulous athletes and their trainers in so called ‘gene doping’. In this article an overview of the successful gene therapy clinical trials is provided and the potential targets for gene doping are highlighted. Depending on whether a doping gene product is secreted...

  4. The effect of interspecific variation in photosynthetic plasticity on 4-year growth rate and 8-year survival of understorey tree seedlings in response to gap formations in a cool-temperate deciduous forest.

    Science.gov (United States)

    Oguchi, Riichi; Hiura, Tsutom; Hikosaka, Kouki

    2017-08-01

    Gap formation increases the light intensity in the forest understorey. The growth responses of seedlings to the increase in light availability show interspecific variation, which is considered to promote biodiversity in forests. At the leaf level, some species increase their photosynthetic capacity in response to gap formation, whereas others do not. Here we address the question of whether the interspecific difference in the photosynthetic response results in the interspecific variation in the growth response. If so, the interspecific difference in photosynthetic response would also contribute to species coexistence in forests. We also address the further relevant question of why some species do not increase their photosynthetic capacity. We assumed that some cost of photosynthetic plasticity may constrain acquisition of the plasticity in some species, and hypothesized that species with larger photosynthetic plasticity exhibit better growth after gap formation and lower survivorship in the shade understorey of a cool-temperate deciduous forest. We created gaps by felling canopy trees and studied the relationship between the photosynthetic response and the subsequent growth rate of seedlings. Naturally growing seedlings of six deciduous woody species were used and their mortality was examined for 8 years. The light-saturated rate of photosynthesis (Pmax) and the relative growth rate (RGR) of the seedlings of all study species increased at gap plots. The extent of these increases varied among the species. The stimulation of RGR over 4 years after gap formation was strongly correlated with change in photosynthetic capacity of newly expanded leaves. The increase in RGR and Pmax correlated with the 8-year mortality at control plots. These results suggest a trade-off between photosynthetic plasticity and the understorey shade tolerance. Gap-demanding species may acquire photosynthetic plasticity, sacrificing shade tolerances, whereas gap-independent species may acquire

  5. Phylogenetic Relationships of Pseudorasbora, Pseudopungtungia, and Pungtungia (Teleostei; Cypriniformes; Gobioninae Inferred from Multiple Nuclear Gene Sequences

    Directory of Open Access Journals (Sweden)

    Keun-Yong Kim

    2013-01-01

    Full Text Available Gobionine species belonging to the genera Pseudorasbora, Pseudopungtungia, and Pungtungia (Teleostei; Cypriniformes; Cyprinidae have been heavily studied because of problems on taxonomy, threats of extinction, invasion, and human health. Nucleotide sequences of three nuclear genes, that is, recombination activating protein gene 1 (rag1, recombination activating gene 2 (rag2, and early growth response 1 gene (egr1, from Pseudorasbora, Pseudopungtungia, and Pungtungia species residing in China, Japan, and Korea, were analyzed to elucidate their intergeneric and interspecific phylogenetic relationships. In the phylogenetic tree inferred from their multiple gene sequences, Pseudorasbora, Pseudopungtungia and Pungtungia species ramified into three phylogenetically distinct clades; the “tenuicorpa” clade composed of Pseudopungtungia tenuicorpa, the “parva” clade composed of all Pseudorasbora species/subspecies, and the “herzi” clade composed of Pseudopungtungia nigra, and Pungtungia herzi. The genus Pseudorasbora was recovered as monophyletic, while the genus Pseudopungtungia was recovered as polyphyletic. Our phylogenetic result implies the unstable taxonomic status of the genus Pseudopungtungia.

  6. Assessment of the potential for gene flow from transgenic maize (Zea mays L.) to eastern gamagrass (Tripsacum dactyloides L.).

    Science.gov (United States)

    Lee, Moon-Sub; Anderson, Eric K; Stojšin, Duška; McPherson, Marc A; Baltazar, Baltazar; Horak, Michael J; de la Fuente, Juan Manuel; Wu, Kunsheng; Crowley, James H; Rayburn, A Lane; Lee, D K

    2017-08-01

    Eastern gamagrass (Tripsacum dactyloides L.) belongs to the same tribe of the Poaceae family as maize (Zea mays L.) and grows naturally in the same region where maize is commercially produced in the USA. Although no evidence exists of gene flow from maize to eastern gamagrass in nature, experimental crosses between the two species were produced using specific techniques. As part of environmental risk assessment, the possibility of transgene flow from maize to eastern gamagrass populations in nature was evaluated with the objectives: (1) to assess the seeds of eastern gamagrass populations naturally growing near commercial maize fields for the presence of a transgenic glyphosate-tolerance gene (cp4 epsps) that would indicate cross-pollination between the two species, and (2) to evaluate the possibility of interspecific hybridization between transgenic maize used as male parent and eastern gamagrass used as female parent. A total of 46,643 seeds from 54 eastern gamagrass populations collected in proximity of maize fields in Illinois, USA were planted in a field in 2014 and 2015. Emerged seedlings were treated with glyphosate herbicide and assessed for survival. An additional 48,000 seeds from the same 54 eastern gamagrass populations were tested for the presence of the cp4 epsps transgene markers using TaqMan ® PCR method. The results from these trials showed that no seedlings survived the herbicide treatment and no seed indicated presence of the herbicide tolerant cp4 epsps transgene, even though these eastern gamagrass populations were exposed to glyphosate-tolerant maize pollen for years. Furthermore, no interspecific hybrid seeds were produced from 135 hand-pollination attempts involving 1529 eastern gamagrass spikelets exposed to maize pollen. Together, these results indicate that there is no evidence of gene flow from maize to eastern gamagrass in natural habitats. The outcome of this study should be taken in consideration when assessing for environmental

  7. Assignment of adenosine deaminase complexing protein (ADCP) gene(s) to human chromosome 2 in rodent-human somatic cell hybrids.

    Science.gov (United States)

    Herbschleb-Voogt, E; Grzeschik, K H; Pearson, P L; Meera Khan, P

    1981-01-01

    The experiments reported in this paper indicate that the expression of human adenosine deaminase complexing protein (ADCP) in the human-rodent somatic cell hybrids is influenced by the state of confluency of the cells and the background rodent genome. Thus, the complement of the L-cell derived A9 or B82 mouse parent apparently prevents the expression of human ADCP in the interspecific somatic cell hybrids. In the a3, E36, or RAG hybrids the human ADCP expression was not prevented by the rodent genome and was found to be proportional to the degree of confluency of the cell in the culture as in the case of primary human fibroblasts. An analysis of human chromosomes, chromosome specific enzyme markers, and ADCP in a panel of rodent-human somatic cell hybrids optimally maintained and harvested at full confluency has shown that the expression of human ADCP in the mouse (RAG)-human as well as in the hamster (E36 or a3)-human hybrids is determined by a gene(s) in human chromosome 2 and that neither chromosome 6 nor any other of the chromosomes of man carry any gene(s) involved in the formation of human ADCP at least in the Chinese hamster-human hybrids. A series of rodent-human hybrid clones exhibiting a mitotic separation of IDH1 and MDH1 indicated that ADCP is most probably situated between corresponding loci in human chromosome 2.

  8. Genes and Hearing Loss

    Science.gov (United States)

    ... ENTCareers Marketplace Find an ENT Doctor Near You Genes and Hearing Loss Genes and Hearing Loss Patient ... mutation may only have dystopia canthorum. How Do Genes Work? Genes are a road map for the ...

  9. Modalities of gene action predicted by the classical evolutionary biological theory of aging.

    Science.gov (United States)

    Martin, George M

    2007-04-01

    What might now be referred to as the "classical" evolutionary biological theory of why we age has had a number of serious challenges in recent years. While the theory might therefore have to be modified under certain circumstances, in the author's opinion, it still provides the soundest theoretical basis for thinking about how we age. Nine modalities of gene action that have the potential to modulate processes of aging are reviewed, including the two most widely reviewed and accepted concepts ("antagonistic pleiotropy" and "mutation accumulation"). While several of these nine mechanisms can be regarded as derivatives of the antagonistic pleiotropic concept, they frame more specific questions for future research. Such research should pursue what appears to be the dominant factor in the determination of intraspecific variations in longevity-stochastic mechanisms, most likely based upon epigenetics. This contrasts with the dominant factor in the determination of interspecific variations in longevity-the constitutional genome, most likely based upon variations in regulatory loci.

  10. Plant response to lead in the presence or absence EDTA in two sunflower genotypes (cultivated H. annuus cv. 1114 and interspecific line H. annuus × H. argophyllus).

    Science.gov (United States)

    Doncheva, Snezhana; Moustakas, Michael; Ananieva, Kalina; Chavdarova, Martina; Gesheva, Emiliya; Vassilevska, Rumyana; Mateev, Plamen

    2013-02-01

    interspecific hybridization. The ability of EDTA to prevent Pb absorption by the plants could underly the mechanism of limiting of the negative impact of Pb ions. Hence, EDTA cannot be used to enhance Pb absorption from nutrient solution by sunflower plants for phytoremediation purposes.

  11. Interspecific Mating between Wild and Sterile Fruit Flies of Oriental Fruit Fly, Bactrocera dorsalis (Hendel) with Guava Fruit Fly, Bactrocera correcta (Bezzi) in Cages

    International Nuclear Information System (INIS)

    Pransopon, Prapon; Sutantawong, Manon

    2003-06-01

    Copulation and sperm transfer were observed between wild flies and sterile flies of Bactrocera dorsalis (Hendel) and Bactrocera correcta (Bezzi) in cages. 8-day old pupae of B. dorsalis and B. correcta were irradiated with gamma rays at 90 and 80 gray respectively. Wild flies from infested fruits and sterile flies from artificial diet in the labolatory were used for testing. The experiments were conducted 3 treatments and 3 replications. The ratio of sterile male : wild male: wild female were 3:1:1 by using sterile male of B. dorsalis: wild male of B. correcta : wild female of B. correcta and sterile male of B. correcta: wild male of B. dorsalis: wild female of B. dorsalis as 60:20:20 flies respectively. The experiment found 69 pairs of copulation consisting of 3 mating pairs(4.3%) of wild male with wild female of B. dorsalis, 22 mating pairs (31.9%) of wild male with wild female of B. correcta, 2 mating pairs(2.9%) of sterile male of B dorsalis with wild female of B. correcta, 42 mating pairs(60.9%) of sterile male of B. correcta with wild female of B. dorsalis. The cages which ratio 1:1 consisted of wild B. dorsalis and wild B. correcta (male and female = 50:50 flies) were observed and found that 43 pairs of copulation such as 2 mating pairs (4.6%) of wild male with wild female of B. dorsalis, 26 mating pairs (60.5%) of wild male with wild female of B. correcta, 2 mating pairs(2.9%) of sterile male of B. dorsalis with wild female of B. correcta and 15 mating pairs(34.9%) of wild male of B. correcta with wild female of B. dorsalis. Mated female flies were separated from male flies. Egg hatch and sperm were checked. The hatchability of normal copulation of B. dorsalis and B. correcta were 81 and 90%. The average sperm level in spermathecae of normal copulation of B. dorsalis and B. correcta were 2.2 and 2.3 respectively but had no sperm in their spemathecae of females of interspecific copulations Mating behavior of both species began in the evening before sunset at

  12. Gene expression and gene therapy imaging

    International Nuclear Information System (INIS)

    Rome, Claire; Couillaud, Franck; Moonen, Chrit T.W.

    2007-01-01

    The fast growing field of molecular imaging has achieved major advances in imaging gene expression, an important element of gene therapy. Gene expression imaging is based on specific probes or contrast agents that allow either direct or indirect spatio-temporal evaluation of gene expression. Direct evaluation is possible with, for example, contrast agents that bind directly to a specific target (e.g., receptor). Indirect evaluation may be achieved by using specific substrate probes for a target enzyme. The use of marker genes, also called reporter genes, is an essential element of MI approaches for gene expression in gene therapy. The marker gene may not have a therapeutic role itself, but by coupling the marker gene to a therapeutic gene, expression of the marker gene reports on the expression of the therapeutic gene. Nuclear medicine and optical approaches are highly sensitive (detection of probes in the picomolar range), whereas MRI and ultrasound imaging are less sensitive and require amplification techniques and/or accumulation of contrast agents in enlarged contrast particles. Recently developed MI techniques are particularly relevant for gene therapy. Amongst these are the possibility to track gene therapy vectors such as stem cells, and the techniques that allow spatiotemporal control of gene expression by non-invasive heating (with MRI guided focused ultrasound) and the use of temperature sensitive promoters. (orig.)

  13. [Polymorphism of KPI-A genes from plants of the subgenus Potatoe (sect. Petota, Estolonifera and Lycopersicum) and subgenus Solanum].

    Science.gov (United States)

    Krinitsyna, A A; Mel'nikova, N V; Belenikin, M S; Poltronieri, P; Santino, A; Kudriavtseva, A V; Savilova, A M; Speranskaia, A S

    2013-01-01

    Kunitz-type proteinase inhibitor proteins of group A (KPI-A) are involved in the protection of potato plants from pathogens and pests. Although sequences of large number of the KPI-A genes from different species of cultivated potato (Solanum tuberosum subsp. tuberosum) and a few genes from tomato (Solanum lycopersicum) are known to date, information about the allelic diversity of these genes in other species of the genus Solanum is lacking. In our work, the consensus sequences of the KPI-A genes were established in two species of subgenus Potatoe sect. Petota (Solanum tuberosum subsp. andigenum--5 genes and Solanum stoloniferum--2 genes) and in the subgenus Solanum (Solanum nigrum--5 genes) by amplification, cloning, sequencing and subsequent analysis. The determined sequences of KPI-A genes were 97-100% identical to known sequences of the cultivated potato of sect. Petota (cultivated potato Solanum tuberosum subsp. tuberosum) and sect. Etuberosum (S. palustre). The interspecific variability of these genes did not exceed the intraspecific variability for all studied species except Solanum lycopersicum. The distribution of highly variable and conserved sequences in the mature protein-encoding regions was uniform for all investigated KPI-A genes. However, our attempts to amplify the homologous genes using the same primers and the genomes of Solanum dulcamarum, Solanum lycopersicum and Mandragora officinarum resulted in no product formation. Phylogenetic analysis of KPI-A diversity showed that the sequences of the S. lycopersicum form independent cluster, whereas KPI-A of S. nigrum and species of sect. Etuberosum and sect. Petota are closely related and do not form species-specific subclasters. Although Solanum nigrum is resistant to all known races of economically one of the most important diseases of solanaceous plants oomycete Phytophthora infestans aminoacid sequences encoding by KPI-A genes from its genome have nearly or absolutely no differences to the same from

  14. Larrea interspecific hybrids revisited (Zygophyllaceae

    Directory of Open Access Journals (Sweden)

    Juan H. Hunziker

    2002-01-01

    Full Text Available Estudios moleculares recientes nos han inducido a realizar una reinterpretación de las relaciones genómicas entre Larrea ameghinoi y las otras especies sudamericanas del género. Se hicieron nuevos intentos para estudiar el apareamiento de los cromosomas del híbrido L. ameghinoi x L. cuneifolia (2n = 3x = 39. El promedio de bivalentes y univalentes fue de 9.8 y 19.4, respectivamente. Dado que el número básico x es 13 la interpretación más razonable es que L. ameghinoi (2n = 2x = 26 (AA y L. cuneifolia (2n = 4x = 52 (DDCC comparten genomas parcialmente homeólogos (A y C que forman la mayoría de los bivalentes y eso explicaría la producción de semillas (15-19.4 % de estos híbridos triploides. El genoma de L. ameghinoi (A podría haber retenido varias partes de un genoma ancestral que hace posible algún apareamiento con aquellos de las otras especies y que lo capacitaría para funcionar como un genoma pivote que permite alguna fertilidad (desde parcial a completa en todas las posibles combinaciones híbridas con sus tres congéneres sudamericanos. Se incluye un apéndice con las leyendas completas del capítulo 2 del libro de Mabry et al. (1977 que fueran omitidas por error en el proceso editorial y de impresión

  15. CHARACTERISATION OF Phaseolus coccineus INTERSPECIFIC ...

    African Journals Online (AJOL)

    ACSS

    2018-02-20

    Feb 20, 2018 ... genetic base of this crop, especially for adaptation to extreme environments. The runner bean (Phaseolus coccineus) in particular, has been shown to contribute to disease ...... Emerging disease problems: The case of.

  16. Interploidy interspecific hybridization in Fuchsia

    Indian Academy of Sciences (India)

    number (EBN) at 2 : 1 ratio is often essential for postfertiliza- ... maternal or paternal genomes. Under the EBN .... germination and high seedling mortality, a postfertilization ... the maternal tissue or both might lead to seed abortion (Bohs. 1991 ...

  17. Mining into interspecific bacterial interactions

    NARCIS (Netherlands)

    Tyc, Olaf

    2016-01-01

    In terrestrial ecosystems bacteria live in close proximity with many different microbial species and form complex multi-species networks. Within those networks bacteria are constantly interacting with each other and produce a plethora of secondary metabolites like antibiotics, enzymes, volatiles

  18. CHARACTERISATION OF Phaseolus coccineus INTERSPECIFIC ...

    African Journals Online (AJOL)

    ACSS

    2018-02-20

    Feb 20, 2018 ... habit) and agronomic attributes (plant vigour, days to physiological maturity; DPM and days to 50% flowering; ... Days to flowering and to DPM ranged from 31-39 and 81-86, ...... evolution, and classification in Phaseolus. pp.

  19. Relationships between morphology, diet and spatial distribution: testing the effects of intra and interspecific morphological variations on the patterns of resource use in two Neotropical Cichlids

    Directory of Open Access Journals (Sweden)

    Ana Lúcia A. Sampaio

    Full Text Available Considering th e morphology, diet and spatial distribution of Satanoperca pappaterra and Crenicichla britskii (Perciformes: Cichlidae in the Upper Paraná River floodplain (Brazil, the following questions were investigated: (1 Could the body shape predict the use of trophic resources and habitat by C. britskii and S. pappaterra? (2 Could the relationship between morphology and use of trophic resources and habitat be also extended to the intraspecific scale? (3 What are the most important morphological traits used to predict the variation on diet and habitat occupation within and between species? We hypothesized that intra and interspecific differences in morphological patterns imply in different forms of resource exploitation and that the ecomorphological analysis enables the identification of trophic and spatial niche segregation. Fish samplings were performed in different types of habitats (rivers, secondary channels, connected and disconnected lagoons in the Upper Paraná River floodplain. Analyses of the stomach content was conducted to characterize the feeding patterns and twenty-two ecomorphological indices were calculated from linear morphological measurements and areas. A principal component analysis (PCA run with these indices evidenced the formation of two significant axes, revealing in the axis 1 an ecomorphological ordination according to the type of habitat, regardless the species. The individuals of both species exploiting lotic habitats tended to have morphological traits that enable rapid progressive and retrograde movements, braking and continuous swimming, whereas individuals found in lentic and semi-lotic habitats presented morphology adapted to a greater maneuverability and stabilization in deflections. On the other hand the axis 2 evidenced a segregation related to the feeding ecology, between S. pappaterra and C. britskii. The relationship between morphology and use of spatial and feeding resource was corroborated by the

  20. Evaluation of Inter-Specific Hybrid of P. atlantica and P. vera L. cv. ‘Badami - Riz-e-Zarand’ as Pistachio rootstock to Salinity Stress According to Some Growth Indices and Eco-physiological and Biochemical Parameters

    Directory of Open Access Journals (Sweden)

    Hamid Reza Karimi

    2014-08-01

    Full Text Available In order to evaluate the inter-specific hybrid of P. atlantica Desf. and P. vera L. cv. ‘Badami- Riz-e- Zarand’ to salinity stress, a factorial experiment was conducted based on completely randomized design with 0, 60 and 120 mM of salinity levels of sodium chloride, calcium chloride and magnesium chloride (3:2:1 with four replications on ‘Qazvini’, ‘Badami-Riz-e-Zarand’ and inter-specific of P. atlantica Ч P. vera cv. ‘Badami-Rize-Zarand’ rootstocks of pistachio. The results showed that salinity has increased proline content of leaves. Chlorophyll index, relative water content of leaf, leaf area, shoot and root fresh and dry weight, stem diameter and number of leaves were decreased by increasing salinity. Rootstocks responded differently to salinity, so that the most reduction in chlorophyll index, leaf area and leaf number were observed in ‘Badami-Riz-e-Zarand’ rootstock and the least reduction was observed in the hybrid.

  1. Imaging reporter gene for monitoring gene therapy

    International Nuclear Information System (INIS)

    Beco, V. de; Baillet, G.; Tamgac, F.; Tofighi, M.; Weinmann, P.; Vergote, J.; Moretti, J.L.; Tamgac, G.

    2002-01-01

    Scintigraphic images can be obtained to document gene function at cellular level. This approach is presented here and the use of a reporter gene to monitor gene therapy is described. Two main ways are presented: either the use of a reporter gene coding for an enzyme the action of which will be monitored by radiolabeled pro-drug, or a cellular receptor gene, the action of which is documented by a radio labeled cognate receptor ligand. (author)

  2. Evaluation of the efficacy of twelve mitochondrial protein-coding genes as barcodes for mollusk DNA barcoding.

    Science.gov (United States)

    Yu, Hong; Kong, Lingfeng; Li, Qi

    2016-01-01

    In this study, we evaluated the efficacy of 12 mitochondrial protein-coding genes from 238 mitochondrial genomes of 140 molluscan species as potential DNA barcodes for mollusks. Three barcoding methods (distance, monophyly and character-based methods) were used in species identification. The species recovery rates based on genetic distances for the 12 genes ranged from 70.83 to 83.33%. There were no significant differences in intra- or interspecific variability among the 12 genes. The monophyly and character-based methods provided higher resolution than the distance-based method in species delimitation. Especially in closely related taxa, the character-based method showed some advantages. The results suggested that besides the standard COI barcode, other 11 mitochondrial protein-coding genes could also be potentially used as a molecular diagnostic for molluscan species discrimination. Our results also showed that the combination of mitochondrial genes did not enhance the efficacy for species identification and a single mitochondrial gene would be fully competent.

  3. Currencies of Mutualisms: Sources of Alkaloid Genes in Vertically Transmitted Epichloae

    Directory of Open Access Journals (Sweden)

    Christopher L. Schardl

    2013-06-01

    Full Text Available The epichloae (Epichloë and Neotyphodium species, a monophyletic group of fungi in the family Clavicipitaceae, are systemic symbionts of cool-season grasses (Poaceae subfamily Poöideae. Most epichloae are vertically transmitted in seeds (endophytes, and most produce alkaloids that attack nervous systems of potential herbivores. These protective metabolites include ergot alkaloids and indole-diterpenes (tremorgens, which are active in vertebrate systems, and lolines and peramine, which are more specific against invertebrates. Several Epichloë species have been described which are sexual and capable of horizontal transmission, and most are vertically transmissible also. Asexual epichloae are mainly or exclusively vertically transmitted, and many are interspecific hybrids with genomic contributions from two or three ancestral Epichloë species. Here we employ genome-scale analyses to investigate the origins of biosynthesis gene clusters for ergot alkaloids (EAS, indole-diterpenes (IDT, and lolines (LOL in 12 hybrid species. In each hybrid, the alkaloid-gene and housekeeping-gene relationships were congruent. Interestingly, hybrids frequently had alkaloid clusters that were rare in their sexual ancestors. Also, in those hybrids that had multiple EAS, IDT or LOL clusters, one cluster lacked some genes, usually for late pathway steps. Possible implications of these findings for the alkaloid profiles and endophyte ecology are discussed.

  4. Currencies of Mutualisms: Sources of Alkaloid Genes in Vertically Transmitted Epichloae

    Science.gov (United States)

    Schardl, Christopher L.; Young, Carolyn A.; Pan, Juan; Florea, Simona; Takach, Johanna E.; Panaccione, Daniel G.; Farman, Mark L.; Webb, Jennifer S.; Jaromczyk, Jolanta; Charlton, Nikki D.; Nagabhyru, Padmaja; Chen, Li; Shi, Chong; Leuchtmann, Adrian

    2013-01-01

    The epichloae (Epichloë and Neotyphodium species), a monophyletic group of fungi in the family Clavicipitaceae, are systemic symbionts of cool-season grasses (Poaceae subfamily Poöideae). Most epichloae are vertically transmitted in seeds (endophytes), and most produce alkaloids that attack nervous systems of potential herbivores. These protective metabolites include ergot alkaloids and indole-diterpenes (tremorgens), which are active in vertebrate systems, and lolines and peramine, which are more specific against invertebrates. Several Epichloë species have been described which are sexual and capable of horizontal transmission, and most are vertically transmissible also. Asexual epichloae are mainly or exclusively vertically transmitted, and many are interspecific hybrids with genomic contributions from two or three ancestral Epichloë species. Here we employ genome-scale analyses to investigate the origins of biosynthesis gene clusters for ergot alkaloids (EAS), indole-diterpenes (IDT), and lolines (LOL) in 12 hybrid species. In each hybrid, the alkaloid-gene and housekeeping-gene relationships were congruent. Interestingly, hybrids frequently had alkaloid clusters that were rare in their sexual ancestors. Also, in those hybrids that had multiple EAS, IDT or LOL clusters, one cluster lacked some genes, usually for late pathway steps. Possible implications of these findings for the alkaloid profiles and endophyte ecology are discussed. PMID:23744053

  5. Currencies of mutualisms: sources of alkaloid genes in vertically transmitted epichloae.

    Science.gov (United States)

    Schardl, Christopher L; Young, Carolyn A; Pan, Juan; Florea, Simona; Takach, Johanna E; Panaccione, Daniel G; Farman, Mark L; Webb, Jennifer S; Jaromczyk, Jolanta; Charlton, Nikki D; Nagabhyru, Padmaja; Chen, Li; Shi, Chong; Leuchtmann, Adrian

    2013-06-06

    The epichloae (Epichloë and Neotyphodium species), a monophyletic group of fungi in the family Clavicipitaceae, are systemic symbionts of cool-season grasses (Poaceae subfamily Poöideae). Most epichloae are vertically transmitted in seeds (endophytes), and most produce alkaloids that attack nervous systems of potential herbivores. These protective metabolites include ergot alkaloids and indole-diterpenes (tremorgens), which are active in vertebrate systems, and lolines and peramine, which are more specific against invertebrates. Several Epichloë species have been described which are sexual and capable of horizontal transmission, and most are vertically transmissible also. Asexual epichloae are mainly or exclusively vertically transmitted, and many are interspecific hybrids with genomic contributions from two or three ancestral Epichloë species. Here we employ genome-scale analyses to investigate the origins of biosynthesis gene clusters for ergot alkaloids (EAS), indole-diterpenes (IDT), and lolines (LOL) in 12 hybrid species. In each hybrid, the alkaloid-gene and housekeeping-gene relationships were congruent. Interestingly, hybrids frequently had alkaloid clusters that were rare in their sexual ancestors. Also, in those hybrids that had multiple EAS, IDT or LOL clusters, one cluster lacked some genes, usually for late pathway steps. Possible implications of these findings for the alkaloid profiles and endophyte ecology are discussed.

  6. Cytoskeletal actin genes function downstream of HNF-3beta in ascidian notochord development.

    Science.gov (United States)

    Jeffery, W R; Ewing, N; Machula, J; Olsen, C L; Swalla, B J

    1998-11-01

    We have examined the expression and regulation of cytoskeletal actin genes in ascidians with tailed (Molgula oculata) and tailless larvae (Molgula occulta). Four cDNA clones were isolated representing two pairs of orthologous cytoskeletal actin genes (CA1 and CA2), which encode proteins differing by five amino acids in the tailed and tailless species. The CA1 and CA2 genes are present in one or two copies, although several related genes may also be present in both species. Maternal CA1 and CA2 mRNA is present in small oocytes but transcript levels later decline, suggesting a role in early oogenesis. In the tailed species, embryonic CA1 and CA2 mRNAs first appear in the presumptive mesenchyme and muscle cells during gastrulation, subsequently accumulate in the presumptive notochord cells, and can be detected in these tissues through the tadpole stage. CA1 mRNAs accumulate initially in the same tissues in the tailless species but subsequently disappear, in concert with the arrest of notochord and tail development. In contrast, CA2 mRNAs were not detected in embryos of the tailless species. Fertilization of eggs of the tailless species with sperm of the tailed species, which restores the notochord and the tail, also results in the upregulation of CA1 and CA2 gene expression in hybrid embryos. Antisense oligodeoxynucleotide experiments suggest that CA1 and CA2 expression in the notochord, but not in the muscle cells, is dependent on prior expression of Mocc FHI, an ascidian HNF-3beta-like gene. The expression of the CA1 and CA2 genes in the notochord in the tailed species, downregulation in the tailless species, upregulation in interspecific hybrids, and dependence on HNF-3beta activity is consistent with a role of these genes in development of the ascidian notochord.

  7. The phylogenetic position of Lygodactylus angularis and the utility of using the 16S rDNA gene for delimiting species in Lygodactylus (Squamata, Gekkonidae

    Directory of Open Access Journals (Sweden)

    Riccardo Castiglia

    2011-06-01

    Full Text Available The African genus Lygodactylus Gray, is composed of roughly 60 species of diurnal geckos that inhabit tropical and temperate Africa, Madagascar, and South America. In this study, we assessed the phylogenetic position of L. angularis, for which molecular data were so far lacking, by means of sequence analysis of the mitochondrial 16S rDNA gene. We also compared intraspecific vs. interspecific genetic divergences using an extended data set (34 species, 153 sequences, to determine whether a fragment of this gene can be useful for species identification and to reveal the possible existence of new cryptic species in the genus. The analysis placed L. angularis in a monophyletic group together with members of “fischeri” and “picturatus” groups. Nevertheless, the independence of the “angularis” lineage is supported by the high genetic divergence. Comparison of intraspecific vs. interspecific genetic distances highlights that, assuming an equal molecular rate of evolution among the studied species for the used gene, the threshold value useful for recognising a candidate new species can be tentatively placed at 7%. We identified four species that showed an intraspecific divergence higher than, or close to, the 7% threshold: L. capensis (8.7%, L. gutturalis (9.3%, L. madagascariensis (6.5% and L. picturatus (8.1%. Moreover, two species, L. mombasicus and L. verticillatus, are paraphyletic in terms of gene genealogy. Thus, the study shows that a short fragment of the 16S rDNA gene can be an informative tool for species-level taxonomy in the genus Lygodactylus.

  8. Phylogenetic relationships and the occurrence of interspecific recombination between beet chlorosis virus (BChV) and Beet mild yellowing virus (BMYV).

    Science.gov (United States)

    Kozlowska-Makulska, Anna; Hasiow-Jaroszewska, Beata; Szyndel, Marek S; Herrbach, Etienne; Bouzoubaa, Salah; Lemaire, Olivier; Beuve, Monique

    2015-02-01

    Samples containing two viruses belonging to the genus Polerovirus, beet chlorosis virus (BChV) and beet mild yellowing virus (BMYV), were collected from French and Polish sugar beet fields. The molecular properties of 24 isolates of BChV and BMYV were investigated, and their genetic diversity was examined in the coat protein (CP)- and P0-encoding genes. For the first time, we have demonstrated that beet polerovirus populations include recombinants between BChV and BMYV containing breakpoints within the CP gene. Moreover, a partial correlation between geographic origin and phylogenetic clustering was observed for BMYV isolates.

  9. Imaging gene expression in gene therapy

    International Nuclear Information System (INIS)

    Wiebe, Leonard I.

    1997-01-01

    Full text. Gene therapy can be used to introduce new genes, or to supplement the function of indigenous genes. At the present time, however, there is non-invasive test to demonstrate efficacy of the gene transfer and expression processes. It has been postulated that scintigraphic imaging can offer unique information on both the site at which the transferred gene is expressed, and the degree of expression, both of which are critical issue for safety and clinical efficacy. Many current studies are based on 'suicide gene therapy' of cancer. Cells modified to express these genes commit metabolic suicide in the presence of an enzyme encoded by the transferred gene and a specifically-convertible pro drug. Pro drug metabolism can lead to selective metabolic trapping, required for scintigraphy. Herpes simplex virus type-1 thymidine kinase (H S V-1 t k + ) has been use for 'suicide' in vivo tumor gene therapy. It has been proposed that radiolabelled nucleosides can be used as radiopharmaceuticals to detect H S V-1 t k + gene expression where the H S V-1 t k + gene serves a reporter or therapeutic function. Animal gene therapy models have been studied using purine-([ 18 F]F H P G; [ 18 F]-A C V), and pyrimidine- ([ 123 / 131 I]I V R F U; [ 124 / 131I ]) antiviral nucleosides. Principles of gene therapy and gene therapy imaging will be reviewed and experimental data for [ 123 / 131I ]I V R F U imaging with the H S V-1 t k + reporter gene will be presented

  10. Imaging gene expression in gene therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wiebe, Leonard I. [Alberta Univ., Edmonton (Canada). Noujaim Institute for Pharmaceutical Oncology Research

    1997-12-31

    Full text. Gene therapy can be used to introduce new genes, or to supplement the function of indigenous genes. At the present time, however, there is non-invasive test to demonstrate efficacy of the gene transfer and expression processes. It has been postulated that scintigraphic imaging can offer unique information on both the site at which the transferred gene is expressed, and the degree of expression, both of which are critical issue for safety and clinical efficacy. Many current studies are based on `suicide gene therapy` of cancer. Cells modified to express these genes commit metabolic suicide in the presence of an enzyme encoded by the transferred gene and a specifically-convertible pro drug. Pro drug metabolism can lead to selective metabolic trapping, required for scintigraphy. Herpes simplex virus type-1 thymidine kinase (H S V-1 t k{sup +}) has been use for `suicide` in vivo tumor gene therapy. It has been proposed that radiolabelled nucleosides can be used as radiopharmaceuticals to detect H S V-1 t k{sup +} gene expression where the H S V-1 t k{sup +} gene serves a reporter or therapeutic function. Animal gene therapy models have been studied using purine-([{sup 18} F]F H P G; [{sup 18} F]-A C V), and pyrimidine- ([{sup 123}/{sup 131} I]I V R F U; [{sup 124}/{sup 131I}]) antiviral nucleosides. Principles of gene therapy and gene therapy imaging will be reviewed and experimental data for [{sup 123}/{sup 131I}]I V R F U imaging with the H S V-1 t k{sup +} reporter gene will be presented

  11. Comparison of loline alkaloid gene clusters across fungal endophytes: predicting the co-regulatory sequence motifs and the evolutionary history.

    Science.gov (United States)

    Kutil, Brandi L; Greenwald, Charles; Liu, Gang; Spiering, Martin J; Schardl, Christopher L; Wilkinson, Heather H

    2007-10-01

    LOL, a fungal secondary metabolite gene cluster found in Epichloë and Neotyphodium species, is responsible for production of insecticidal loline alkaloids. To analyze the genetic architecture and to predict the evolutionary history of LOL, we compared five clusters from four fungal species (single clusters from Epichloë festucae, Neotyphodium sp. PauTG-1, Neotyphodium coenophialum, and two clusters we previously characterized in Neotyphodium uncinatum). Using PhyloCon to compare putative lol gene promoter regions, we have identified four motifs conserved across the lol genes in all five clusters. Each motif has significant similarity to known fungal transcription factor binding sites in the TRANSFAC database. Conservation of these motifs is further support for the hypothesis that the lol genes are co-regulated. Interestingly, the history of asexual Neotyphodium spp. includes multiple interspecific hybridization events. Comparing clusters from three Neotyphodium species and E. festucae allowed us to determine which Epichloë ancestors are the most likely contributors of LOL in these asexual species. For example, while no present day Epichloë typhina isolates are known to produce lolines, our data support the hypothesis that the E. typhina ancestor(s) of three asexual endophyte species contained a LOL gene cluster. Thus, these data support a model of evolution in which the polymorphism in loline alkaloid production phenotypes among endophyte species is likely due to the loss of the trait over time.

  12. Gene doping: gene delivery for olympic victory.

    Science.gov (United States)

    Gould, David

    2013-08-01

    With one recently recommended gene therapy in Europe and a number of other gene therapy treatments now proving effective in clinical trials it is feasible that the same technologies will soon be adopted in the world of sport by unscrupulous athletes and their trainers in so called 'gene doping'. In this article an overview of the successful gene therapy clinical trials is provided and the potential targets for gene doping are highlighted. Depending on whether a doping gene product is secreted from the engineered cells or is retained locally to, or inside engineered cells will, to some extent, determine the likelihood of detection. It is clear that effective gene delivery technologies now exist and it is important that detection and prevention plans are in place. © 2012 The Author. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.

  13. Genetic analysis of a hybrid sterility gene that causes both pollen and embryo sac sterility in hybrids between Oryza sativa L. and Oryza longistaminata.

    Science.gov (United States)

    Chen, H; Zhao, Z; Liu, L; Kong, W; Lin, Y; You, S; Bai, W; Xiao, Y; Zheng, H; Jiang, L; Li, J; Zhou, J; Tao, D; Wan, J

    2017-09-01

    Oryza longistaminata originates from African wild rice and contains valuable traits conferring tolerance to biotic and abiotic stress. However, interspecific crosses between O. longistaminata and Oryza sativa cultivars are hindered by reproductive barriers. To dissect the mechanism of interspecific hybrid sterility, we developed a near-isogenic line (NIL) using indica variety RD23 as the recipient parent and O. longistaminata as the donor parent. Both pollen and embryo sac semi-sterility were observed in F 1 hybrids between RD23 and NIL. Cytological analysis demonstrated that pollen abortion in F 1 hybrids occurred at the early bi-nucleate stage due to a failure of the first mitosis in microspores. Partial embryo sacs in the F 1 hybrids were defective during the functional megaspore formation stage. Most notably, nearly half of the male or female gametes were aborted in heterozygotes S40 i S40 l , regardless of their genotypes. Thus, S40 was indicated as a one-locus sporophytic sterility gene controlling both male and female fertility in hybrids between RD23 and O. longistaminata. A population of 16 802 plants derived from the hybrid RD23/NIL-S40 was developed to fine-map S40. Finally, the S40 locus was delimited to an 80-kb region on the short arm of chromosome 1 in terms with reference sequences of cv. 93-11. Eight open reading frames (ORFs) were localized in this region. On the basis of gene expression and genomic sequence analysis, ORF5 and ORF8 were identified as candidate genes for the S40 locus. These results are helpful in cloning the S40 gene and marker-assisted transferring of the corresponding neutral allele in rice breeding programs.

  14. Interspecific Interactions and the Scope for Parent-Offspring Conflict: High Mite Density Temporarily Changes the Trade-Off between Offspring Size and Number in the Burying Beetle, Nicrophorus vespilloides.

    Directory of Open Access Journals (Sweden)

    Ornela De Gasperin

    Full Text Available Parents have a limited amount of resources to invest in reproduction and commonly trade-off how much they invest in offspring size (or quality versus brood size. A negative relationship between offspring size and number has been shown in numerous taxa and it underpins evolutionary conflicts of interest between parents and their young. For example, previous work on vertebrates shows that selection favours mothers that produce more offspring, at the expense of individual offspring size, yet favours offspring that have relatively few siblings and therefore attain a greater size at independence. Here we analyse how this trade-off is temporarily affected by stochastic variation in the intensity of interspecific interactions. We examined the effect of the mite Poecilochirus carabi on the relationship between offspring size and number in the burying beetle, Nicrophorus vespilloides. We manipulated the initial number of mites in the reproductive event (by introducing either no mites, 4 mites, 10 mites, or 16 mites, and assessed the effect on the brood. We found a similar trade-off between offspring size and number in all treatments, except in the '16 mite' treatment where the correlation between offspring number and size flattened considerably. This effect arose because larvae in small broods failed to attain a high mass by dispersal. Our results show that variation in the intensity of interspecific interactions can temporarily change the strength of the trade-off between offspring size and number. In this study, high densities of mites prevented individual offspring from attaining their optimal weight, thus potentially temporarily biasing the outcome of parent-offspring conflict in favour of parents.

  15. Interspecific Interactions and the Scope for Parent-Offspring Conflict: High Mite Density Temporarily Changes the Trade-Off between Offspring Size and Number in the Burying Beetle, Nicrophorus vespilloides.

    Science.gov (United States)

    De Gasperin, Ornela; Kilner, Rebecca M

    2016-01-01

    Parents have a limited amount of resources to invest in reproduction and commonly trade-off how much they invest in offspring size (or quality) versus brood size. A negative relationship between offspring size and number has been shown in numerous taxa and it underpins evolutionary conflicts of interest between parents and their young. For example, previous work on vertebrates shows that selection favours mothers that produce more offspring, at the expense of individual offspring size, yet favours offspring that have relatively few siblings and therefore attain a greater size at independence. Here we analyse how this trade-off is temporarily affected by stochastic variation in the intensity of interspecific interactions. We examined the effect of the mite Poecilochirus carabi on the relationship between offspring size and number in the burying beetle, Nicrophorus vespilloides. We manipulated the initial number of mites in the reproductive event (by introducing either no mites, 4 mites, 10 mites, or 16 mites), and assessed the effect on the brood. We found a similar trade-off between offspring size and number in all treatments, except in the '16 mite' treatment where the correlation between offspring number and size flattened considerably. This effect arose because larvae in small broods failed to attain a high mass by dispersal. Our results show that variation in the intensity of interspecific interactions can temporarily change the strength of the trade-off between offspring size and number. In this study, high densities of mites prevented individual offspring from attaining their optimal weight, thus potentially temporarily biasing the outcome of parent-offspring conflict in favour of parents.

  16. Inheritance of resistance to sunflower broomrape (Orobanche cumana Wallr.) in an interspecific cross between Helianthus annuus and Helianthus debilis subsp. tardiflorus

    Science.gov (United States)

    Sunflower broomrape (Orobanche cumana Wallr.) constrains sunflower cultivation in increasing areas of Europe and Asia. Populations classified as race G that overcome all known resistance genes have recently appeared. The objective of this research was to study the inheritance of resistance to broomr...

  17. Complex genetics controls natural variation among seed quality phenotypes in a recombinant inbred population of an interspecific cross between Solanum lycopersicum × Solanum pimpinellifolium

    NARCIS (Netherlands)

    Kazmi, R.H.; Khan, N.; Willems, L.A.J.; Heusden, van A.W.; Ligterink, J.W.; Hilhorst, H.W.M.

    2012-01-01

    Seed quality in tomato is associated with many complex physiological and genetic traits. While plant processes are frequently controlled by the action of small- to large-effect genes that follow classic Mendelian inheritance, our study suggests that seed quality is primarily quantitative and

  18. Isolation, characterization and mapping of genes differentially ...

    Indian Academy of Sciences (India)

    Agricultural University, Wuhan 430070, Hubei, People's Republic of China. Abstract ... world. The two cultivated tetraploid species, upland cotton. (G. hirsutum) and extra-long staple cotton (G. bar- .... Polymorphic loci were integrated into our interspecific BC1 ..... that there are similar expression regulation mechanisms in.

  19. RUNX: a trilogy of cancer genes

    DEFF Research Database (Denmark)

    Lund, Anders H; van Lohuizen, Maarten

    2002-01-01

    The RUNX family of transcription factors plays pivotal roles during normal development and in neoplasias. Recent data involve RUNX3 as an important tumor suppressor in gastric cancers and pose interesting questions about how perturbed levels and interspecific competition among RUNX family members...

  20. A complex selection signature at the human AVPR1B gene

    Directory of Open Access Journals (Sweden)

    Cagliani Rachele

    2009-06-01

    Full Text Available Abstract Background The vasopressin receptor type 1b (AVPR1B is mainly expressed by pituitary corticotropes and it mediates the stimulatory effects of AVP on ACTH release; common AVPR1B haplotypes have been involved in mood and anxiety disorders in humans, while rodents lacking a functional receptor gene display behavioral defects and altered stress responses. Results Here we have analyzed the two exons of the gene and the data we present suggest that AVPR1B has been subjected to natural selection in humans. In particular, analysis of exon 2 strongly suggests the action of balancing selection in African populations and Europeans: the region displays high nucleotide diversity, an excess of intermediate-frequency alleles, a higher level of within-species diversity compared to interspecific divergence and a genealogy with common haplotypes separated by deep branches. This relatively unambiguous situation coexists with unusual features across exon 1, raising the possibility that a nonsynonymous variant (Gly191Arg in this region has been subjected to directional selection. Conclusion Although the underlying selective pressure(s remains to be identified, we consider this to be among the first documented examples of a gene involved in mood disorders and subjected to natural selection in humans; this observation might add support to the long-debated idea that depression/low mood might have played an adaptive role during human evolution.

  1. Widespread introgression of mountain hare genes into Fennoscandian brown hare populations.

    Directory of Open Access Journals (Sweden)

    Riikka Levänen

    Full Text Available In Fennoscandia, mountain hare (Lepus timidus and brown hare (Lepus europaeus hybridize and produce fertile offspring, resulting in gene flow across the species barrier. Analyses of maternally inherited mitochondrial DNA (mtDNA show that introgression occur frequently, but unavailability of appropriate nuclear DNA markers has made it difficult to evaluate the scale- and significance for the species. The extent of introgression has become important as the brown hare is continuously expanding its range northward, at the apparent expense of the mountain hare, raising concerns about possible competition. We report here, based on analysis of 6833 SNP markers, that the introgression is highly asymmetrical in the direction of gene flow from mountain hare to brown hare, and that the levels of nuclear gene introgression are independent of mtDNA introgression. While it is possible that brown hares obtain locally adapted alleles from the resident mountain hares, the low levels of mountain hare alleles among allopatric brown hares suggest that hybridization is driven by stochastic processes. Interspecific geneflow with the brown hare is unlikely to have major impacts on mountain hare in Fennoscandia, but direct competition may.

  2. A complex selection signature at the human AVPR1B gene.

    Science.gov (United States)

    Cagliani, Rachele; Fumagalli, Matteo; Pozzoli, Uberto; Riva, Stefania; Cereda, Matteo; Comi, Giacomo P; Pattini, Linda; Bresolin, Nereo; Sironi, Manuela

    2009-06-01

    The vasopressin receptor type 1b (AVPR1B) is mainly expressed by pituitary corticotropes and it mediates the stimulatory effects of AVP on ACTH release; common AVPR1B haplotypes have been involved in mood and anxiety disorders in humans, while rodents lacking a functional receptor gene display behavioral defects and altered stress responses. Here we have analyzed the two exons of the gene and the data we present suggest that AVPR1B has been subjected to natural selection in humans. In particular, analysis of exon 2 strongly suggests the action of balancing selection in African populations and Europeans: the region displays high nucleotide diversity, an excess of intermediate-frequency alleles, a higher level of within-species diversity compared to interspecific divergence and a genealogy with common haplotypes separated by deep branches. This relatively unambiguous situation coexists with unusual features across exon 1, raising the possibility that a nonsynonymous variant (Gly191Arg) in this region has been subjected to directional selection. Although the underlying selective pressure(s) remains to be identified, we consider this to be among the first documented examples of a gene involved in mood disorders and subjected to natural selection in humans; this observation might add support to the long-debated idea that depression/low mood might have played an adaptive role during human evolution.

  3. Evolution of homeobox genes.

    Science.gov (United States)

    Holland, Peter W H

    2013-01-01

    Many homeobox genes encode transcription factors with regulatory roles in animal and plant development. Homeobox genes are found in almost all eukaryotes, and have diversified into 11 gene classes and over 100 gene families in animal evolution, and 10 to 14 gene classes in plants. The largest group in animals is the ANTP class which includes the well-known Hox genes, plus other genes implicated in development including ParaHox (Cdx, Xlox, Gsx), Evx, Dlx, En, NK4, NK3, Msx, and Nanog. Genomic data suggest that the ANTP class diversified by extensive tandem duplication to generate a large array of genes, including an NK gene cluster and a hypothetical ProtoHox gene cluster that duplicated to generate Hox and ParaHox genes. Expression and functional data suggest that NK, Hox, and ParaHox gene clusters acquired distinct roles in patterning the mesoderm, nervous system, and gut. The PRD class is also diverse and includes Pax2/5/8, Pax3/7, Pax4/6, Gsc, Hesx, Otx, Otp, and Pitx genes. PRD genes are not generally arranged in ancient genomic clusters, although the Dux, Obox, and Rhox gene clusters arose in mammalian evolution as did several non-clustered PRD genes. Tandem duplication and genome duplication expanded the number of homeobox genes, possibly contributing to the evolution of developmental complexity, but homeobox gene loss must not be ignored. Evolutionary changes to homeobox gene expression have also been documented, including Hox gene expression patterns shifting in concert with segmental diversification in vertebrates and crustaceans, and deletion of a Pitx1 gene enhancer in pelvic-reduced sticklebacks. WIREs Dev Biol 2013, 2:31-45. doi: 10.1002/wdev.78 For further resources related to this article, please visit the WIREs website. The author declares that he has no conflicts of interest. Copyright © 2012 Wiley Periodicals, Inc.

  4. Gene cluster statistics with gene families.

    Science.gov (United States)

    Raghupathy, Narayanan; Durand, Dannie

    2009-05-01

    Identifying genomic regions that descended from a common ancestor is important for understanding the function and evolution of genomes. In distantly related genomes, clusters of homologous gene pairs are evidence of candidate homologous regions. Demonstrating the statistical significance of such "gene clusters" is an essential component of comparative genomic analyses. However, currently there are no practical statistical tests for gene clusters that model the influence of the number of homologs in each gene family on cluster significance. In this work, we demonstrate empirically that failure to incorporate gene family size in gene cluster statistics results in overestimation of significance, leading to incorrect conclusions. We further present novel analytical methods for estimating gene cluster significance that take gene family size into account. Our methods do not require complete genome data and are suitable for testing individual clusters found in local regions, such as contigs in an unfinished assembly. We consider pairs of regions drawn from the same genome (paralogous clusters), as well as regions drawn from two different genomes (orthologous clusters). Determining cluster significance under general models of gene family size is computationally intractable. By assuming that all gene families are of equal size, we obtain analytical expressions that allow fast approximation of cluster probabilities. We evaluate the accuracy of this approximation by comparing the resulting gene cluster probabilities with cluster probabilities obtained by simulating a realistic, power-law distributed model of gene family size, with parameters inferred from genomic data. Surprisingly, despite the simplicity of the underlying assumption, our method accurately approximates the true cluster probabilities. It slightly overestimates these probabilities, yielding a conservative test. We present additional simulation results indicating the best choice of parameter values for data

  5. Carboxylesterase 1 genes

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Berg; Madsen, Majbritt Busk

    2018-01-01

    The carboxylesterase 1 gene (CES1) encodes a hydrolase that metabolizes commonly used drugs. The CES1-related pseudogene, carboxylesterase 1 pseudogene 1 (CES1P1), has been implicated in gene exchange with CES1 and in the formation of hybrid genes including the carboxylesterase 1A2 gene (CES1A2...

  6. Why close a bacterial genome? The plasmid of Alteromonas macleodii HOT1A3 is a vector for inter-specific transfer of a flexible genomic island

    Directory of Open Access Journals (Sweden)

    Eduard eFadeev

    2016-03-01

    Full Text Available Genome sequencing is rapidly becoming a staple technique in environmental and clinical microbiology, yet computational challenges still remain, leading to many draft genomes which are typically fragmented into many contigs. We sequenced and completely assembled the genome of a marine heterotrophic bacterium, Alteromonas macleodii HOT1A3, and compared its full genome to several draft genomes obtained using different reference-based and de-novo methods. In general, the de-novo assemblies clearly outperformed the reference-based or hybrid ones, covering>99% of the genes and representing essentially all of the gene functions. However, only the fully closed genome (~4.5Mbp allowed us to identify the presence of a large, 148 kbp plasmid, pAM1A3. While HOT1A3 belongs to Alteromonas macleodii, typically found in surface waters (surface ecotype, this plasmid consists of an almost complete flexible genomic island, containing many genes involved in metal resistance previously identified in the genomes of Alteromonas mediterranea (deep ecotype. Indeed, similar to A. mediterranea, A. macleodii HOT1A3 grows at concentrations of zinc, mercury and copper that are inhibitory for other A. macleodii strains. The presence of a plasmid encoding almost an entire flexible genomic island suggests that wholesale genomic exchange between heterotrophic marine bacteria belonging to related but ecologically different populations is not uncommon.

  7. Fine-mapping and cross-validation of QTLs linked to fatty acid composition in multiple independent interspecific crosses of oil palm.

    Science.gov (United States)

    Ting, Ngoot-Chin; Yaakub, Zulkifli; Kamaruddin, Katialisa; Mayes, Sean; Massawe, Festo; Sambanthamurthi, Ravigadevi; Jansen, Johannes; Low, Leslie Eng Ti; Ithnin, Maizura; Kushairi, Ahmad; Arulandoo, Xaviar; Rosli, Rozana; Chan, Kuang-Lim; Amiruddin, Nadzirah; Sritharan, Kandha; Lim, Chin Ching; Nookiah, Rajanaidu; Amiruddin, Mohd Din; Singh, Rajinder

    2016-04-14

    The commercial oil palm (Elaeis guineensis Jacq.) produces a mesocarp oil (commonly called 'palm oil') with approximately equal proportions of saturated and unsaturated fatty acids (FAs). An increase in unsaturated FAs content or iodine value (IV) as a measure of the degree of unsaturation would help to open up new markets for the oil. One way to manipulate the fatty acid composition (FAC) in palm oil is through introgression of favourable alleles from the American oil palm, E. oleifera, which has a more unsaturated oil. In this study, a segregating E. oleifera x E. guineensis (OxG) hybrid population for FAC is used to identify quantitative trait loci (QTLs) linked to IV and various FAs. QTL analysis revealed 10 major and two putative QTLs for IV and six FAs, C14:0, C16:0, C16:1, C18:0, C18:1 and C18:2 distributed across six linkage groups (LGs), OT1, T2, T3, OT4, OT6 and T9. The major QTLs for IV and C16:0 on LGOT1 explained 60.0 - 69.0 % of the phenotypic trait variation and were validated in two independent BC2 populations. The genomic interval contains several key structural genes in the FA and oil biosynthesis pathways such as PATE/FATB, HIBCH, BASS2, LACS4 and DGAT1 and also a relevant transcription factor (TF), WRI1. The literature suggests that some of these genes can exhibit pleiotropic effects in the regulatory networks of these traits. Using the whole genome sequence data, markers tightly linked to the candidate genes were also developed. Clustering trait values according to the allelic forms of these candidate markers revealed significant differences in the IV and FAs of the palms in the mapping and validation crosses. The candidate gene approach described and exploited here is useful to identify the potential causal genes linked to FAC and can be adopted for marker-assisted selection (MAS) in oil palm.

  8. Gene doping in sports.

    Science.gov (United States)

    Unal, Mehmet; Ozer Unal, Durisehvar

    2004-01-01

    Gene or cell doping is defined by the World Anti-Doping Agency (WADA) as "the non-therapeutic use of genes, genetic elements and/or cells that have the capacity to enhance athletic performance". New research in genetics and genomics will be used not only to diagnose and treat disease, but also to attempt to enhance human performance. In recent years, gene therapy has shown progress and positive results that have highlighted the potential misuse of this technology and the debate of 'gene doping'. Gene therapies developed for the treatment of diseases such as anaemia (the gene for erythropoietin), muscular dystrophy (the gene for insulin-like growth factor-1) and peripheral vascular diseases (the gene for vascular endothelial growth factor) are potential doping methods. With progress in gene technology, many other genes with this potential will be discovered. For this reason, it is important to develop timely legal regulations and to research the field of gene doping in order to develop methods of detection. To protect the health of athletes and to ensure equal competitive conditions, the International Olympic Committee, WADA and International Sports Federations have accepted performance-enhancing substances and methods as being doping, and have forbidden them. Nevertheless, the desire to win causes athletes to misuse these drugs and methods. This paper reviews the current status of gene doping and candidate performance enhancement genes, and also the use of gene therapy in sports medicine and ethics of genetic enhancement. Copyright 2004 Adis Data Information BV

  9. mQTL-seq and classical mapping implicates the role of an AT-HOOK MOTIF CONTAINING NUCLEAR LOCALIZED (AHL) family gene in Ascochyta blight resistance of chickpea.

    Science.gov (United States)

    Kumar, Kamal; Purayannur, Savithri; Kaladhar, Vemula Chandra; Parida, Swarup Kumar; Verma, Praveen Kumar

    2018-03-01

    Ascochyta blight (AB) caused by the fungal pathogen Ascochyta rabiei is a serious foliar disease of chickpea (Cicer arietinum L.). Despite many genetic studies on chickpea-Ascochyta interaction, genome-wide scan of chickpea for the identification of AB-associated quantitative trait loci (QTLs) and their gene(s) has not been accomplished. To elucidate narrow QTLs for AB resistance, here, we report the use of multiple QTL-sequencing approach on 2 sets of extreme AB phenotype bulks derived from Cicer intraspecific and interspecific crosses. Two major QTLs, qABR4.1 and qABR4.2, and a minor QTL, qABR4.3, were identified on assembled chickpea pseudomolecule 4. We narrowed qABR4.1 to a "robust region" at 4.568-4.618 Mb through mapping on a larger intraspecific cross-derived population and comparative analysis. Among 4 genes, the CaAHL18 gene showed higher expression under Ascochyta stress in AB resistant parent suggesting that it is the candidate gene under "robust qABR4.1." Dual-luciferase assay with CaAHL18 polymorphic cis-regulatory sequences showed that allelic variation is associated with higher expression. Thus, our findings on chickpea-Ascochyta interaction have narrowed down AB resistance associated QTLs on chickpea physical map. The narrowed QTLs and gene-associated markers will help in biotechnological and breeding programs for chickpea improvement. © 2018 John Wiley & Sons Ltd.

  10. Hypoxia-activated genes from early placenta are elevated in Preeclampsia, but not in Intra-Uterine Growth Retardation

    Directory of Open Access Journals (Sweden)

    Danan Jean-Louis

    2005-08-01

    Full Text Available Abstract Background As a first step to explore the possible relationships existing between the effects of low oxygen pressure in the first trimester placenta and placental pathologies developing from mid-gestation, two subtracted libraries totaling 2304 cDNA clones were constructed. For achieving this, two reciprocal suppressive/subtractive hybridization procedures (SSH were applied to early (11 weeks human placental villi after incubation either in normoxic or in hypoxic conditions. The clones from both libraries (1440 hypoxia-specific and 864 normoxia-specific were spotted on nylon macroarrays. Complex cDNAs probes prepared from placental villi (either from early pregnancy, after hypoxic or normoxic culture conditions, or near term for controls or pathological placentas were hybridized to the membranes. Results Three hundred and fifty nine clones presenting a hybridization signal above the background were sequenced and shown to correspond to 276 different genes. Nine of these genes are mitochondrial, while 267 are nuclear. Specific expression profiles characteristic of preeclampsia (PE could be identified, as well as profiles specific of intra-uterine growth retardation (IUGR. Focusing on the chromosomal distribution of the fraction of genes that responded in at least one hybridization experiment, we could observe a highly significant chromosomal clustering of 54 genes into 8 chromosomal regions, four of which containing imprinted genes. Comparative mapping data indicate that these imprinted clusters are maintained in synteny in mice, and apparently in cattle and pigs, suggesting that the maintenance of such syntenies is requested for achieving a normal placental physiology in eutherian mammals. Conclusion We could demonstrate that genes induced in PE were also genes highly expressed under hypoxic conditions (P = 5.10-5, which was not the case for isolated IUGR. Highly expressed placental genes may be in syntenies conserved interspecifically

  11. Human Gene Therapy: Genes without Frontiers?

    Science.gov (United States)

    Simon, Eric J.

    2002-01-01

    Describes the latest advancements and setbacks in human gene therapy to provide reference material for biology teachers to use in their science classes. Focuses on basic concepts such as recombinant DNA technology, and provides examples of human gene therapy such as severe combined immunodeficiency syndrome, familial hypercholesterolemia, and…

  12. Tumor targeted gene therapy

    International Nuclear Information System (INIS)

    Kang, Joo Hyun

    2006-01-01

    Knowledge of molecular mechanisms governing malignant transformation brings new opportunities for therapeutic intervention against cancer using novel approaches. One of them is gene therapy based on the transfer of genetic material to an organism with the aim of correcting a disease. The application of gene therapy to the cancer treatment had led to the development of new experimental approaches such as suicidal gene therapy, inhibition of oncogenes and restoration of tumor-suppressor genes. Suicidal gene therapy is based on the expression in tumor cells of a gene encoding an enzyme that converts a prodrug into a toxic product. Representative suicidal genes are Herpes simplex virus type 1 thymidine kinase (HSV1-tk) and cytosine deaminase (CD). Especially, physicians and scientists of nuclear medicine field take an interest in suicidal gene therapy because they can monitor the location and magnitude, and duration of expression of HSV1-tk and CD by PET scanner

  13. Essential Bacillus subtilis genes

    DEFF Research Database (Denmark)

    Kobayashi, K.; Ehrlich, S.D.; Albertini, A.

    2003-01-01

    To estimate the minimal gene set required to sustain bacterial life in nutritious conditions, we carried out a systematic inactivation of Bacillus subtilis genes. Among approximate to4,100 genes of the organism, only 192 were shown to be indispensable by this or previous work. Another 79 genes were...... predicted to be essential. The vast majority of essential genes were categorized in relatively few domains of cell metabolism, with about half involved in information processing, one-fifth involved in the synthesis of cell envelope and the determination of cell shape and division, and one-tenth related...... to cell energetics. Only 4% of essential genes encode unknown functions. Most essential genes are present throughout a wide range of Bacteria, and almost 70% can also be found in Archaea and Eucarya. However, essential genes related to cell envelope, shape, division, and respiration tend to be lost from...

  14. Radiotechnologies and gene therapy

    International Nuclear Information System (INIS)

    Xia Jinsong

    2001-01-01

    Gene therapy is an exciting frontier in medicine today. Radiologist will make an uniquely contribution to these exciting new technologies at every level by choosing sites for targeting therapy, perfecting and establishing routes of delivery, developing imaging strategies to monitor therapy and assess gene expression, developing radiotherapeutic used of gene therapy

  15. Discovering genes underlying QTL

    Energy Technology Data Exchange (ETDEWEB)

    Vanavichit, Apichart [Kasetsart University, Kamphaengsaen, Nakorn Pathom (Thailand)

    2002-02-01

    A map-based approach has allowed scientists to discover few genes at a time. In addition, the reproductive barrier between cultivated rice and wild relatives has prevented us from utilizing the germ plasm by a map-based approach. Most genetic traits important to agriculture or human diseases are manifested as observable, quantitative phenotypes called Quantitative Trait Loci (QTL). In many instances, the complexity of the phenotype/genotype interaction and the general lack of clearly identifiable gene products render the direct molecular cloning approach ineffective, thus additional strategies like genome mapping are required to identify the QTL in question. Genome mapping requires no prior knowledge of the gene function, but utilizes statistical methods to identify the most likely gene location. To completely characterize genes of interest, the initially mapped region of a gene location will have to be narrowed down to a size that is suitable for cloning and sequencing. Strategies for gene identification within the critical region have to be applied after the sequencing of a potentially large clone or set of clones that contains this gene(s). Tremendous success of positional cloning has been shown for cloning many genes responsible for human diseases, including cystic fibrosis and muscular dystrophy as well as plant disease resistance genes. Genome and QTL mapping, positional cloning: the pre-genomics era, comparative approaches to gene identification, and positional cloning: the genomics era are discussed in the report. (M. Suetake)

  16. Studies on the widening of the variation of the fatty acid pattern in flax (Linum usitatissimum L. ) by means of interspecific hybridisation and in-vitro techniques. Untersuchungen zur Erweiterung der genetischen Variation des Fettsaeuremusters beim Lein (Linum usitatissimum L. ) mit Hilfe von Artkreuzungen und in vitro Techniken

    Energy Technology Data Exchange (ETDEWEB)

    Nickel, M.

    1993-01-01

    Oil flux genotypes with strongly divergent fatty acid compositions of the seed oil are vegetable raw materials of great interest to industrial users, notably to manufacturers of edible oils and dietetic products. Compared with the moderately variable fatty acid pattern of Linum usitatissimum that of wild forms shows a far greater scatter. The studies on the widening of the genetic variation of the fatty acid pattern in cultivated flax by means of interspecific hybridization and embryo cultures have revealed the possibilities offered by, and limits to, these methods. Optimisation of the embryo culture techniques have for the first time made it possible to regenerate plants from globular embryos obtained by interspecific hybridization between Linum usitatissimum and L. monogynum. (orig./EF)

  17. Relationship between Psidium species (Myrtaceae) by resistance gene analog markers: focus on nematode resistance.

    Science.gov (United States)

    Noia, L R; Tuler, A C; Ferreira, A; Ferreira, M F S

    2017-03-16

    Guava (Psidium guajava L.) crop is severely affected by the nematode Meloidogyne enterolobii. Native Psidium species have been reported as sources of resistance against this nematode. Knowledge on the molecular relationship between Psidium species based on plant resistance gene analogs (RGA) can be useful in the genetic breeding of guava for resistance to M. enterolobii. In this study, RGA markers from conserved domains, and structural features of plant R genes, were employed to characterize Psidium species and establish genetic proximity, with a focus on nematode resistance. SSR markers were also applied owing to their neutral nature, thus differing from RGA markers. For this, species reported as sources of resistance to M. enterolobii, such as P. cattleianum and P. friedrichsth