WorldWideScience

Sample records for interspecific hybrid origin

  1. Origin of a new Phytophthora pathogen through interspecific hybridization.

    Science.gov (United States)

    Brasier, C M; Cooke, D E; Duncan, J M

    1999-05-11

    Plant disease epidemics resulting from introductions of exotic fungal plant pathogens are a well known phenomenon. An associated risk-that accelerated pathogen evolution may be occurring as a consequence of genetic exchange between introduced, or introduced and resident, fungal pathogens-is largely unrecognized. This is, in part, because examples of natural, interspecific hybridization in fungi are very rare. Potential evolutionary developments range from the acquisition of new host specificities to emergence of entirely new pathogen taxa. We present evidence from cytological behavior, additive nucleotide bases in repetitive internal transcribed spacer regions of the rRNA-encoding DNA (rDNA), and amplified fragment length polymorphisms of total DNA that a new, aggressive Phytophthora pathogen of alder trees in Europe comprises a range of heteroploid-interspecific hybrids involving a Phytophthora cambivora-like species and an unknown taxon similar to Phytophthora fragariae. The hybrids' marked developmental instabilities, unusual morphological variability, and evidence for recombination in their internal transcribed spacer profiles indicates that they are of recent origin and that their evolution is continuing. The likelihood of such evolutionary events may be increasing as world trade in plants intensifies. However, routine diagnostic procedures currently in use are insufficiently sensitive to allow their detection.

  2. A new Epichloe species with interspecific hybrid origins from Poa pratensis ssp. pratensis in Liyang, China.

    Science.gov (United States)

    Yan, Kang; Yanling, Ji; Kunran, Zhu; Hui, Wang; Huimin, Miao; Zhiwei, Wang

    2011-01-01

    We describe a new Epichloë species found in symbiosis with Poa pratensis ssp. pratensis in Liyang, China. Stromata characteristic of Epichloë spp. were present on some of the reproductive tillers of individual host grasses. Only three of the 98 stromata observed on field plants became orange and produced perithecia. Phylogenetic analyses based on sequences of tubB and tefA indicated that this Epichloë sp. was an interspecific hybrid related to both E. yangzii and members in the E. typhina complex clade (ETC). Allele-1 of tefA and tubB grouped in the E. bromicola/E. yangzii clade; allele-2 of these two genes clustered in a distinct subclade in the ETC. This is the first report of an Epichloë species that has interspecific hybrid origins. We propose the name Epichloë liyangensis Z. Wang, Y. Kang et H. Miao, sp. nov. for this species.

  3. 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

  4. Interspecific Hybridization within Ornamental Plants

    DEFF Research Database (Denmark)

    Kuligowska, Katarzyna

    . Interspecific hybridization is one of the most important breeding strategies to increase the genetic variation. The main difficulty in obtaining interspecific hybrids is due to occurrence of reproductive barriers. In the study, the possibilities of developing novel interspecific hybrids were studied within two...... 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...

  5. Interploidy interspecific hybridization in Fuchsia

    Indian Academy of Sciences (India)

    School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland Mail Centre,. Auckland 1142, New Zealand. [Talluri R. S. 2012 Interploidy interspecific hybridization in Fuchsia. J. Genet. 91, 71–74]. Introduction. In the past, many hypotheses were put forward to explain the failure of the endosperm in ...

  6. Interspecific Hybridization within Ornamental Plants

    DEFF Research Database (Denmark)

    Kuligowska, Katarzyna

    The economic importance of the ornamental plant industry requires constant development of novel and high quality varieties. Traits attractive for production of new ornamental plants may not be available within the commercial cultivars, but broad genetic variation is present within the plant genera...... 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...

  7. Interspecific hybridization between Mauremys reevesii and ...

    African Journals Online (AJOL)

    Turtle hybrids have been found in some taxa, but so far, studies on interspecific hybridization between Mauremy reevesii and Mauremy sinensis have not been reported. Recently, we obtained three specimens (Hy1, Hy2, Hy3)with unusual morphological characteristics from pet trade Market, which are suspected to be ...

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

    African Journals Online (AJOL)

    Interspecific reciprocal crosses between three cultivated Brassica allotetraploids and one wild species Brassica fruticulosa (FF, 2n =16) were made and the trigenomic hybrids were produced only with embryo rescue. From the crosses with Brassica juncea (AABB, 2n = 36) and Brassica napus (AACC, 2n = 38), hybrids (F.AB ...

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

    African Journals Online (AJOL)

    Jane

    2011-09-28

    Sep 28, 2011 ... interspecific hybrid between Brassica fruticulosa and B. rapa. Plant. Breed. 123: 497-498. Chopra VL, Kirti PB, Prakash S (1996). Accessing and exploiting genes of breeding value of distant relatives of crop brassicas. Genetica 97: 305-312. Ellis PR, Kift NB, Pink DAC, Jukes PL, Lynn J, Tatchell GM (2000).

  10. 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%.

  11. 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

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

    Indian Academy of Sciences (India)

    Banerjee P. and Singh B. N. 2012 Interspecific sexual isolation and phylogeny among different members of the Drosophila bipectinata species complex. Genetica 140, 75–81. Banerjee P. and Singh B. N. 2014 Pattern of mating preference of interspecific hybrid females and phylogeny in the Drosophila bipectinata species ...

  13. 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)

  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. Production of interspecific Campanula hybrids by ovule culture

    DEFF Research Database (Denmark)

    Röper, Anna Catharina; Lütken, Henrik Vlk; 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...... the success rate of interspecific hybridisation between C. portenschlagiana × C. poscharskyana and C. medium × C. formanekiana. The effect of different ovule isolation times on ovule germination in vitro was examined. In general, the number of collectible ovules and ovule germination was low. Interspecific....... 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....

  16. Occurrence of numerically unreduced (2n) gametes in Alstroemeria interspecific hybrids and their significance for sexual polyploidization

    NARCIS (Netherlands)

    Ramanna, M.S.; Kuipers, G.; Jacobsen, E.

    2003-01-01

    The F1 hybrids of seven diploid Alstroemeria species (2n=2x=16) were investigated for the production of numerically unreduced (2n) gametes and their mode of origin. Based on a survey of 17 interspecific hybrid combinations, consisting of 119 genotypes, it was found that the F1 hybrids of

  17. 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 ...

  18. 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

  19. Evolution of invading forest pathogens via interspecific hybridization

    Science.gov (United States)

    Clive Brasier

    2003-01-01

    Traditional morphologically-based fungal species concepts have tended to go hand in-hand with a perception that fungal species are genetically 'firewalled' units between which almost no gene flow occurs. Also, prior to 1990, known examples of interspecific hybridization in fungi were very rare. However, observations on the internationally invading Dutch elm...

  20. Molecular genetic evidence for interspecific hybridization among endemic Hispaniolan Bursera (Burseraceae).

    Science.gov (United States)

    Weeks, Andrea; Simpson, Beryl B

    2004-06-01

    Historically, genetic introgression among species as well as hybrid origins for species of the diploid tree genus Bursera (Burseraceae) have been proposed based on the supposition that individuals morphologically intermediate between sympatric "parent" species must be derived from hybridization. This study reports the first molecular genetic evidence for both unidirectional and reciprocal interspecific hybridization within Bursera. Phylogenies of hybrids and other species in B. subgenus Bursera are reconstructed based on nuclear and chloroplast sequence data. Compelling evidence supports the hybrid origin of three endemic Hispaniolan species: B. brunea (B. nashii × B. simaruba), B. gracilipes (B. spinescens × B. simaruba), and B. ovata (B. simaruba × B. spinescens). Cloning studies of nuclear markers from B. ovata suggests that this species is an introgressed or later backcross generation hybrid and thus reproduces sexually.

  1. 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.

  2. 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.

  3. Molecular Cytogenetic Analysis of Spontaneous Interspecific Hybrid Between Oryza sativa and Oryza minuta

    Directory of Open Access Journals (Sweden)

    Chuan-deng YI

    2008-12-01

    Full Text Available Genomic in situ hybridization (GISH is a powerful tool to characterize parental chromosomes in interspecific hybrids, including the behaviour of autosynapsis and chromosome pairing. It was used to distinguish the chromosomes of Oryza sativa from wild species in a spontaneous interspecific hybrid and to investigate the chromosome pairing at metaphase I in meiosis of the hybrid in this study. The hybrid was a triploid with 36 chromosomes according to the chromosome number investigated in mitosis of root tips. During metaphase I of meiosis in the hybrid, less chromosome pairing was observed and most of the chromosomes existed as univalent. Based on GISH and FISH (Fluorescent in situ hybridization analyses, the chromosomes of the hybrid were composed of genomes A, B and C. Thus, it was believed that the hybrid was the result of natural hybridization between cultivated rice and wild species O. minuta which was planted in experimental fields.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. Interspecific hybridization among cultivars of hardy Hibiscus species section Muenchhusia

    DEFF Research Database (Denmark)

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

    2016-01-01

    Rose mallows belong to the Muenchhusia section of the Hibiscus genus. They represent a small group of cold tolerant North American plants and are popular ornamentals mainly because of their abundant, large and colorful flowers. Due to their geographical origin they are well suited for garden use...... in temperate regions worldwide. The aim of the study was to investigate hybridization barriers in crosses among cultivars of Hibiscus species from the Muenchhusia section: H. coccineus, H. laevis and H. moscheutos. Crossing barriers were identified as both pre- and post-zygotic. The analysis of pollen tube...

  9. Plant Regeneration and Somatic Embryogenesis from Immature Embryos Derived through Interspecific Hybridization among Different Carica Species

    OpenAIRE

    Azad, Md. Abul; Rabbani, Md. Golam; Amin, Latifah

    2012-01-01

    Plant regeneration and somatic embryogenesis through interspecific hybridization among different Carica species were studied for the development of a papaya ringspot virus-resistant variety. The maximum fruit sets were recorded from the cross of the native variety C. papaya cv. Shahi with the wild species C. cauliflora. The highest hybrid embryos were recorded at 90 days after pollination and the embryos were aborted at 150 days after pollination. The immature hybrid embryos were used for pla...

  10. Interspecific somatic hybrids between Solanum khasianum and S. aculeatissimum produced by electrofusion.

    Science.gov (United States)

    Stattmann, M; Gerick, E; Wenzel, G

    1994-01-01

    Mesophyll derived protoplasts of Solanum khasianum Clarke and S. aculeatissimum Jacq. were fused by electrofusion and resulted in interspecific hybrids. In total, 249 calluses were obtained from which more than 65% produced shoots. From the regenerated plantlets 45% could be identified as hybrids by chromosome counts (4x = 48) and esterase isozyme pattern. Most hybrids showing intermediate phenotypic characteristics, had a normal flower morphology with fertile pollen and produced fertile berries. More than 80% of the seeds germinated.

  11. Aroma chemistry of African Oryza glaberrima and Oryza sativa rice and their interspecific hybrids

    NARCIS (Netherlands)

    Cho, S.; Nuijten, H.A.C.P.; Shewfelt, R.L.; Kays, S.J.

    2014-01-01

    BackgroundTo increase rice production in Africa, considerable research has focused on creating interspecific hybrids between African (Oryza glaberrima Steud.) and Asian (O. sativa L.) rice in an attempt to obtain the positive attributes of each in new cultivars. Since flavor is a key criterion in

  12. Mapping three new interspecific hybrid sterile loci between Oryza sativa and O. glaberrima

    Science.gov (United States)

    Xu, Peng; Zhou, Jiawu; Li, Jing; Hu, Fengyi; Deng, Xianneng; Feng, Sufeng; Ren, Guangyun; Zhang, Zhi; Deng, Wei; Tao, Dayun

    2014-01-01

    Hybrid sterility hinders the transfer of useful traits between Oryza sativa and O. glaberrima. In order to further understand the nature of interspecific hybrid sterility between these two species, a strategy of multi-donors was used to elucidate the range of interspecific hybrid sterility in this study. Fifty-nine accessions of O. glaberrima were used as female parents for hybridization with japonica cultivar Dianjingyou 1, after several backcrossings using Dianjingyou 1 as the recurrent parent and 135 BC6F1 sterile plants were selected for genotyping and deducing hybrid sterility QTLs. BC6F1 plants containing heterozygous target markers were selected and used to raise BC7F1 mapping populations for QTL confirmation and as a result, one locus for gamete elimination on chromosome 1 and two loci for pollen sterility on chromosome 4 and 12, which were distinguished from previous reports, were confirmed and designated as S37(t), S38(t) and S39(t), respectively. These results will be valuable for understanding the range of interspecific hybrid sterility, cloning these genes and improving rice breeding through gene introgression. PMID:24757387

  13. 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.

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

    OpenAIRE

    V. S. Romanov; N. I. Timin

    2016-01-01

    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 st...

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

    Indian Academy of Sciences (India)

    7-day-aged flies, in food vials. Virgin hybrid daughters of reciprocal crosses were collected and aged for 7 days. Meanwhile parental males were also collected and aged for. 7 days. Mating preference of hybrid daughters was tested with parental males by following the male choice technique, in which a male of one of the ...

  16. Field reactions of interspecific hybrids of tomato ( Solanum ...

    African Journals Online (AJOL)

    Crosses were made on four selected parent plants in a diallel fashion in 2011. Seedlings of the parent plants and their resulting hybrids were ... The hybrids, W x P and wild x insulata could be selected as they had less leaf spot disease severity and high fruit yield. Keywords: disease incidence, disease severity, heterosis, ...

  17. 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

  18. 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.

  19. 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.

  20. Hypersensitive response-like reaction is associated with hybrid necrosis in interspecific crosses between tetraploid wheat and Aegilops tauschii coss.

    Directory of Open Access Journals (Sweden)

    Nobuyuki Mizuno

    Full Text Available BACKGROUND: Hybrid speciation is classified into homoploid and polyploid based on ploidy level. Common wheat is an allohexaploid species that originated from a naturally occurring interploidy cross between tetraploid wheat and diploid wild wheat Aegilops tauschii Coss. Aegilops tauschii provides wide naturally occurring genetic variation. Sometimes its triploid hybrids with tetraploid wheat show the following four types of hybrid growth abnormalities: types II and III hybrid necrosis, hybrid chlorosis, and severe growth abortion. The growth abnormalities in the triploid hybrids could act as postzygotic hybridization barriers to prevent formation of hexaploid wheat. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report on the geographical and phylogenetic distribution of Ae. tauschii accessions inducing the hybrid growth abnormalities and showed that they are widely distributed across growth habitats in Ae. tauschii. Molecular and cytological characterization of the type III necrosis phenotype was performed. The hybrid abnormality causing accessions were widely distributed across growth habitats in Ae. tauschii. Transcriptome analysis showed that a number of defense-related genes such as pathogenesis-related genes were highly up-regulated in the type III necrosis lines. Transmission electron microscope observation revealed that cell death occurred accompanied by generation of reactive oxygen species in leaves undergoing type III necrosis. The reduction of photosynthetic activity occurred prior to the appearance of necrotic symptoms on the leaves exhibiting hybrid necrosis. CONCLUSIONS/SIGNIFICANCE: Taking these results together strongly suggests that an autoimmune response might be triggered by intergenomic incompatibility between the tetraploid wheat and Ae. tauschii genomes in type III necrosis, and that genetically programmed cell death could be regarded as a hypersensitive response-like cell death similar to that observed in Arabidopsis

  1. Hypersensitive response-like reaction is associated with hybrid necrosis in interspecific crosses between tetraploid wheat and Aegilops tauschii coss.

    Science.gov (United States)

    Mizuno, Nobuyuki; Hosogi, Naoki; Park, Pyoyun; Takumi, Shigeo

    2010-06-25

    Hybrid speciation is classified into homoploid and polyploid based on ploidy level. Common wheat is an allohexaploid species that originated from a naturally occurring interploidy cross between tetraploid wheat and diploid wild wheat Aegilops tauschii Coss. Aegilops tauschii provides wide naturally occurring genetic variation. Sometimes its triploid hybrids with tetraploid wheat show the following four types of hybrid growth abnormalities: types II and III hybrid necrosis, hybrid chlorosis, and severe growth abortion. The growth abnormalities in the triploid hybrids could act as postzygotic hybridization barriers to prevent formation of hexaploid wheat. Here, we report on the geographical and phylogenetic distribution of Ae. tauschii accessions inducing the hybrid growth abnormalities and showed that they are widely distributed across growth habitats in Ae. tauschii. Molecular and cytological characterization of the type III necrosis phenotype was performed. The hybrid abnormality causing accessions were widely distributed across growth habitats in Ae. tauschii. Transcriptome analysis showed that a number of defense-related genes such as pathogenesis-related genes were highly up-regulated in the type III necrosis lines. Transmission electron microscope observation revealed that cell death occurred accompanied by generation of reactive oxygen species in leaves undergoing type III necrosis. The reduction of photosynthetic activity occurred prior to the appearance of necrotic symptoms on the leaves exhibiting hybrid necrosis. Taking these results together strongly suggests that an autoimmune response might be triggered by intergenomic incompatibility between the tetraploid wheat and Ae. tauschii genomes in type III necrosis, and that genetically programmed cell death could be regarded as a hypersensitive response-like cell death similar to that observed in Arabidopsis intraspecific and Nicotiana interspecific hybrids. Only Ae. tauschii accessions without such

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

    Indian Academy of Sciences (India)

    development and which can be successfully used in the breeding. Hybrids with high frequency of meiotic abnormalities can seriously compromise seed production, a key trait in assuring adoption of a new apomictic cultivar of Brachiaria for pasture formation. [Adamowski E. V., Pagliarini M. S. and Valle C. B. 2008 Meiotic ...

  3. An autosomal locus controls sex reversal in interspecific XY hybrids of the medaka fishes.

    Science.gov (United States)

    Kato, M; Takehana, Y; Fukuda, Y; Naruse, K; Sakaizumi, M; Hamaguchi, S

    2011-12-01

    Although the two medaka species Oryzias latipes and O. curvinotus share the sex-determining gene Dmy, XY sex reversal occurs in interspecific hybridization between O. latipes females of the Hd-rR inbred strain and O. curvinotus males. In this Hd-rR-curvinotus mating, all XX and XY hybrids developed as females. In this study, we used another O. latipes inbred strain (HNI) for the mating, and found that 23% of XY hybrids developed as males, although all XX and the remaining XY hybrids developed as females. Linkage analysis using 236 XY hybrid males obtained from (Hd-rR × HNI) F(1) females showed that a single major locus, Hybrid maleless (Hml), on autosomal linkage group 17, contributed to the strain difference in the XY sex reversal. Furthermore, we found that crossing females of a different O. latipes inbred strain, HO4C, did not cause XY sex reversal in the interspecific hybrids, and that the XY hybrids from (Hd-rR × HO4C) F(1) females showed a 1:1 sex ratio. XY hybrid males had the HO4C allele at sequence-tagged site loci around the Hml locus whereas XY females had the Hd-rR allele, confirming the strong contribution of this locus to XY sex reversal. Reverse transcriptase PCR analysis showed a reduced expression of Dmy(curvinotus) in XY fry of the Hd-rR-curvinotus hybrids at hatching. These results suggest that the Hd-rR allele at the Hml locus interfere with the function of Dmy(curvinotus) on a hybrid background, thus resulting in XY sex reversal.

  4. Aroma chemistry of African Oryza glaberrima and Oryza sativa rice and their interspecific hybrids.

    Science.gov (United States)

    Cho, Sungeun; Nuijten, Edwin; Shewfelt, Robert L; Kays, Stanley J

    2014-03-15

    To increase rice production in Africa, considerable research has focused on creating interspecific hybrids between African (Oryza glaberrima Steud.) and Asian (O. sativa L.) rice in an attempt to obtain the positive attributes of each in new cultivars. Since flavor is a key criterion in consumer acceptance of rice, as an initial inquiry we characterized and compared the aroma chemistry of selected cultivars of African O. sativa ssp. japonica, O. sativa ssp. indica, O. glaberrima, and their interspecific hybrids grown in West Africa, using gas chromatography-mass spectrometry, gas chromatography-olfactometry and descriptive sensory analysis. Of 41 volatiles identified across seven representative rice cultivars grown in West Africa, 3,5,5-trimethyl-2-cyclopenten-1-one, styrene, eucalyptol, linalool, myrtenal and L-α-terpineol had not been previously reported in rice. Thirty-three odor-active compounds were characterized. 4-Ethylphenol and (E,E)-2,4-heptadienal were unique to O. glaberrima, and pyridine, eucalyptol and myrtenal were described only in an interspecific hybrid. Descriptive sensory analysis indicated 'cooked grain', 'barny' and 'earthy' attributes were statistically different among the cultivars. The aroma chemistry data suggest that it should be possible to separate African cultivars into distinct flavor types thereby facilitating selection of new cultivars with superior flavor in African rice breeding programs. © 2013 Society of Chemical Industry.

  5. Hybrid incompatibilities in interspecific crosses between tetraploid wheat and its wild diploid relative Aegilops umbellulata.

    Science.gov (United States)

    Okada, Moeko; Yoshida, Kentaro; Takumi, Shigeo

    2017-12-01

    Hybrid abnormalities, severe growth abortion and grass-clump dwarfism, were found in the tetraploid wheat/Aegilops umbellulata hybrids, and the gene expression changes were conserved in the hybrids with those in other wheat synthetic hexaploids. Aegilops umbellulata Zhuk., a diploid goatgrass species with a UU genome, has been utilized as a genetic resource for wheat breeding. Here, we examine the reproductive barriers between tetraploid wheat cultivar Langdon (Ldn) and various Ae. umbellulata accessions by conducting interspecific crossings. Through systematic cross experiments, three types of hybrid incompatibilities were found: seed production failure in crosses, hybrid growth abnormalities and sterility in the ABU hybrids. Hybrid incompatibilities were widely distributed over the entire range of the natural species, and in about 50% of the cross combinations between tetraploid Ldn and Ae. umbellulata accessions, ABU F 1 hybrids showed one of two abnormal growth phenotypes: severe growth abortion (SGA) or grass-clump dwarfism. Expression of the shoot meristem maintenance-related and cell cycle-related genes was markedly repressed in crown tissues of hybrids showing SGA, suggesting dysfunction of mitotic cell division in the shoot apices. The grass-clump dwarf phenotype may be explained by down-regulation of wheat APETALA1-like MADS box genes, which act as flowering promoters, and altered expression in crown tissues of the miR156/SPLs module, which controls tiller number and branching. These gene expression changes in growth abnormalities were well conserved between the Ldn/Ae. umbellulata plants and interspecific hybrids from crosses of Ldn and wheat D-genome progenitor Ae. tauschii.

  6. 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.

  7. 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)

  8. IMPROVING WHEAT TRITICUM AESTIVUM L. BY INTERSPECIFIC AND INTERGENERIC HYBRIDIZATION WITH POACEAE FAMILY SPECIES

    Directory of Open Access Journals (Sweden)

    Czaplicki A.Z.

    2012-08-01

    Full Text Available The related species of the family Poaceae (Triticeae are the source of unprecedented new genes that allow the extension of genetic variation of common wheat Triticum aestivum L. These species have similar homoeologous chromosomes and rDNA sequences very similar to T. aestivum L. [1-3]. This allows the introgression of alien genes and their incorporation into the genomes A, B and D of wheat, where they can function permanently in the wheat genetic systems. Many of them have already been transferred to the varieties of T. aestivum L. [4].The experimental material consisted of 28 lines of winter wheat obtained using the interspecific and intergeneric hybridization of T. aestivum L. with alien species T. durum Desf., T. timopheevii Zhuk., Lolium perenne L. and Aegilops speltoides Taush. Among them, 15 lines were developed from the cross-combination with tetraploid species (AABB T. durum Desf., 4 lines from the combination with other tetraploid species of different genome composition (AAGG T. timopheevii Zhuk., 4 lines from cross with L. perenne L. and 5 lines were the double hybrids (three-generic derived with two related species, T. durum Desf. (AABB and Ae. speltoides Taush (BB.The anther culture method was used for obtaining DH lines from these interspecific and intergeneric hybrids. In in vitro culture 124 green plants were regenerated. The method of cluster analysis grouped hybrids in terms of comprehensive general similarity of the studied traits.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. Interspecific competition, hybridization, and reproductive isolation in secondary contact: missing perspectives on males and females.

    Science.gov (United States)

    Lipshutz, Sara E

    2018-02-01

    Research on sexual selection and hybridization has focused on female mate choice and male-male competition. While the evolutionary outcomes of interspecific female preference have been well explored, we are now gaining a better understanding of the processes by which male-male competition between species in secondary contact promotes reproductive isolation versus hybridization. What is relatively unexplored is the interaction between female choice and male competition, as they can oppose one another or align with similar outcomes for reproductive isolation. The role of female-female competition in hybridization is also not well understood, but could operate similarly to male-male competition in polyandrous and other systems where costs to heterospecific mating are low for females. Reproductive competition between either sex of sympatric species can cause the divergence and/or convergence of sexual signals and recognition, which in turn influences the likelihood for interspecific mating. Future work on species interactions in secondary contact should test the relative influences of both mate choice and competition for mates on hybridization outcomes, and should not ignore the possibilities that females can compete over mating resources, and males can exercise mate choice.

  11. 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

    influencing the number of pollen tubes germinating in the stigma. In relation to post-fertilization barriers, endosperm degeneration was a probable barrier hampering production of interspecific hybrids. Moreover, our results demonstrate the relation of genetic distance estimated by AFLP marker analysis...... of hybridization partners with cross-compatibility of Kalancho? species. At the same time, differences in ploidy did not influence the success of interspecific crosses.ConclusionsOur study presents the first comprehensive analysis of hybridization barriers occurring within Kalancho? genus. Reproductive barriers...... were detected on both, pre- and post-fertilization levels. This new knowledge will contribute to further understanding of reproductive isolation of Kalancho? species and facilitate breeding of new cultivars. For the first time, interspecific hybrids between K. nyikae as maternal plant and K...

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

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    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

  13. 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.

  14. Interspecific gene flow in a multispecies oak hybrid zone in the Sierra Tarahumara of Mexico.

    Science.gov (United States)

    Peñaloza-Ramírez, Juan Manuel; González-Rodríguez, Antonio; Mendoza-Cuenca, Luis; Caron, Henri; Kremer, Antoine; Oyama, Ken

    2010-03-01

    Interspecific gene flow can occur in many combinations among species within the genus Quercus, but simultaneous hybridization among more than two species has been rarely analysed. The present study addresses the genetic structure and morphological variation in a triple hybrid zone formed by Q. hypoleucoides, Q. scytophylla and Q. sideroxyla in north-western Mexico. A total of 247 trees from ten reference and 13 presumed intermediate populations were characterized using leaf shape variation and geometric morphometrics, and seven nuclear microsatellites as genetic markers. Discriminant function analysis was performed for leaf shape variation, and estimates of genetic diversity and structure, and individual Bayesian genetic assignments were obtained. Reference populations formed three completely distinct groups according to discriminant function analysis based on the morphological data, and showed low, but significant, genetic differentiation. Populations from the zone of contact contained individuals morphologically intermediate between pairs of species in different combinations, or even among the three species. The Bayesian admixture analysis found that three main genetic clusters best fitted the data, with good correspondence of reference populations of each species to one of the genetic clusters, but various degrees of admixture evidenced in populations from the contact area. The three oak species have formed a complex hybrid zone that is geographically structured as a mosaic, and comprising a wide range of genotypes, including hybrids between different species pairs, backcrosses and probable triple hybrids.

  15. 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.

  16. Plant regeneration and somatic embryogenesis from immature embryos derived through interspecific hybridization among different Carica species.

    Science.gov (United States)

    Azad, Md Abul Kalam; Rabbani, Md Golam; Amin, Latifah

    2012-12-12

    Plant regeneration and somatic embryogenesis through interspecific hybridization among different Carica species were studied for the development of a papaya ringspot virus-resistant variety. The maximum fruit sets were recorded from the cross of the native variety C. papaya cv. Shahi with the wild species C. cauliflora. The highest hybrid embryos were recorded at 90 days after pollination and the embryos were aborted at 150 days after pollination. The immature hybrid embryos were used for plant regeneration and somatic embryogenesis. The 90-day-old hybrid embryos from the cross of C. papaya cv. Shahi × C. cauliflora showed the highest percentage of germination, as well as plant regeneration on growth regulators free culture medium after 7 days pre-incubation on half-strength MS medium supplemented with 0.2 mg/L BAP, 0.5 mg/L NAA and 60 g/L sucrose. The 90-day-old hybrid embryos from the cross of C. papaya cv. Shahi × C. cauliflora produced maximum callus, as well as somatic embryos when cultured on half-strength MS medium containing 5 mg/L 2,4-D, 100 mg/L glutamine, 100 mg/L casein hydrolysate and 60 g/L sucrose. The somatic embryos were transferred into half-strength MS medium containing 0.5 mg/L BAP and 0.2 mg/L NAA and 60 g/L sucrose for maturation. The highest number of regenerated plants per hybrid embryo (10.33) was recorded from the cross of C. papaya cv. Shahi × C. cauliflora. Isoenzyme and dendrogram cluster analysis using UPGMA of the regenerated F(1) plantlets confirmed the presence of the hybrid plantlets.

  17. Plant Regeneration and Somatic Embryogenesis from Immature Embryos Derived through Interspecific Hybridization among Different Carica Species

    Directory of Open Access Journals (Sweden)

    Latifah Amin

    2012-12-01

    Full Text Available Plant regeneration and somatic embryogenesis through interspecific hybridization among different Carica species were studied for the development of a papaya ringspot virus-resistant variety. The maximum fruit sets were recorded from the cross of the native variety C. papaya cv. Shahi with the wild species C. cauliflora. The highest hybrid embryos were recorded at 90 days after pollination and the embryos were aborted at 150 days after pollination. The immature hybrid embryos were used for plant regeneration and somatic embryogenesis. The 90-day-old hybrid embryos from the cross of C. papaya cv. Shahi × C. cauliflora showed the highest percentage of germination, as well as plant regeneration on growth regulators free culture medium after 7 days pre-incubation on half-strength MS medium supplemented with 0.2 mg/L BAP, 0.5 mg/L NAA and 60 g/L sucrose. The 90-day-old hybrid embryos from the cross of C. papaya cv. Shahi × C. cauliflora produced maximum callus, as well as somatic embryos when cultured on half-strength MS medium containing 5 mg/L 2,4-D, 100 mg/L glutamine, 100 mg/L casein hydrolysate and 60 g/L sucrose. The somatic embryos were transferred into half-strength MS medium containing 0.5 mg/L BAP and 0.2 mg/L NAA and 60 g/L sucrose for maturation. The highest number of regenerated plants per hybrid embryo (10.33 was recorded from the cross of C. papaya cv. Shahi × C. cauliflora. Isoenzyme and dendrogram cluster analysis using UPGMA of the regenerated F1 plantlets confirmed the presence of the hybrid plantlets.

  18. 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.

  19. Volatiles emitted from single flower buds of the lilium longiflorum × L. callosum interspecific hybrid and its parents

    Science.gov (United States)

    This research was initiated to analyze the volatiles emitted from a single flower bud of Lilium longiflorum Thunb., L. callosum Sieb. et Zucc., and interspecific hybrids of L. longiflorum × L. callosum (L. longi × L. cal IH). Volatiles, collected automatically every 6-hour intervals at 20oC before ...

  20. Evaluation of the reaction oof interspecific hybrids of common bean and tepary bean to Bradyrhizobium y Rhizobium

    Science.gov (United States)

    Interspecific hybrids between common bean, Phaseolus vulgaris L., and tepary bean, Phaseolus acutifolius A. Gray, have the potential to increase bean production in regions where rainfall is limited. In 2014, an experiment was initiated using a split-plot design. The treatments included inoculation, ...

  1. 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.

  2. 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.

  3. Wood Quality and Growth Characterization across Intra- and Inter-Specific Hybrid Aspen Clones

    Directory of Open Access Journals (Sweden)

    Shawn D. Mansfield

    2013-09-01

    Full Text Available Trembling aspen (Populus tremuloides Michx. is one of the most abundant poplar species in North America; it is native, displays substantial breadth in distribution inhabiting several geographical and climatic ecoregions, is notable for its rapid growth, and is ecologically and economically important. As the demand for raw material continues to increase rapidly, there is a pressing need to improve both tree quality and growth rates via breeding efforts. Hybridization is considered one of the most promising options to simultaneously accelerate these tree characteristics, as it takes advantage of heterosis. Two aspen species showing particular promise for hybridization with trembling aspen are European aspen (P. tremula and Chinese aspen (P. davidiana because their native climates are similar to that of P. tremuloides and are also very easy to hybridize. In 2003, aspen clones were planted in Athabasca, Alberta from the following species crosses: open pollinated (OP P. tremuloides (NN, OP P. davidiana (CC, P. tremula × P. tremula (EE, P. tremula × P. tremuloides (EN, and P. tremuloides × P. davidiana (CN. In November 2010, growth measurements and core samples were taken from seven-year field grown clones. Comparisons of the mean growth and cell wall traits were made between crosses using generalized linear model least squares means tests for stem volume, fiber length, fiber width, coarseness, wood density, microfibril angle, total cell wall carbohydrate and lignin content, and lignin composition. The results clearly indicated that the inter-specific crosses offer a means to breed for more desirable wood characteristics than the intra-specific Populus spp. crosses.

  4. Species limits, interspecific hybridization and phylogeny in the cryptic land snail complex Pyramidula: The power of RADseq data.

    Science.gov (United States)

    Razkin, Oihana; Sonet, Gontran; Breugelmans, Karin; Madeira, María José; Gómez-Moliner, Benjamín Juan; Backeljau, Thierry

    2016-08-01

    Restriction site-associated DNA sequencing (RADseq) was used to jointly assess phylogenetic relationships, interspecific hybridization and species delimitation in the cryptic, non-model land snail complex Pyramidula. A robust phylogeny was inferred using a matrix of concatenated sequences of almost 1,500,000bp long, containing >97,000 polymorphic sites. Maximum likelihood analyses fully resolved the phylogenetic relationships among species and drastically improved phylogenetic trees obtained from mtDNA and nDNA gene trees (COI, 16S rRNA, 5.8S rRNA, ITS2 and 28S rRNA sequence data). The best species delimitation scenario was selected on the basis of 875 unlinked single nucleotide polymorphisms, showing that nine Pyramidula species should be distinguished in Europe. Applying D-statistics provided no or weak evidence of interspecific hybridization among Pyramidula, except for some evidence of gene flow between two species. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Rin4 Causes Hybrid Necrosis and Race-Specific Resistance in an Interspecific Lettuce Hybrid

    NARCIS (Netherlands)

    Jeuken, M.J.W.; Zhang, N.; McHale, L.K.; Pelgrom, K.T.B.; Boer, den E.; Lindhout, P.; Michelmore, R.; Visser, R.G.F.; Niks, R.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

  6. Evaluation of relationships between growth rate, tree size, lignocellulose composition and enzymatic saccharification in interspecific Corymbia hybrids and parental taxa.

    OpenAIRE

    Adam L Healey; David John Lee; David John Lee; Jason S Lupoi; Gabriella Papa; Joel M Guenther; Joel M Guenther; Luca Corno; Fabrizio Adani; Seema Singh; Seema Singh; Blake Simmons; Blake Simmons; Robert Henry

    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 C. torelliana (CT) and C. citr...

  7. Origin of new Brassica types from a single intergeneric hybrid ...

    Indian Academy of Sciences (India)

    Rieseberg L. H., Raymond O., Rosenthal D. M., Lai Z., Livingstone. K., Nakazato T. et al. 2003 Major ecological transition in wild sunflowers facilitated by hybridization. Science 301, 1211–1216. Snowdon R. J., Köhler W., Friedt W. and Köhler A. 1997 Genomic in situ hybridization in Brassica amphidiploids and interspecific.

  8. Interspecific hybridization as a tool to understand vocal divergence: the example of crowing in quail (Genus Coturnix.

    Directory of Open Access Journals (Sweden)

    Sébastien Derégnaucourt

    2010-02-01

    Full Text Available Understanding the mechanisms that lead organisms to be separated into distinct species remains a challenge in evolutionary biology. Interspecific hybridization, which results from incomplete reproductive isolation, is a useful tool to investigate such mechanisms. In birds, interspecific hybridization is relatively frequent, despite the fact that closed species exhibit morphological and behavioural differences. Evolution of behaviour is difficult to investigate on a large timescale since it does not 'fossilize'. Here I propose that calls of hybrid non-songbirds that develop without the influence of learning may help in understanding the gradual process that leads to vocal divergence during speciation. I recorded crows produced by the European quail (Coturnix c. coturnix, the domestic Japanese quail (Coturnix c. japonica and their hybrids (F1, F2 and backcrosses. Most crowing patterns were intermediate to those of the parental species; some were similar to one or the other parental species, or not present in either parental species. I also observed vocal changes in hybrid crows during the breeding season and from one year to the other. This vocal variability resembles those observed during the ontogeny of the crow in quails. It is likely that similar mechanisms involved in vocal changes during ontogeny might have driven vocal divergence in the species of Palearctic quails. I suggest that hybrid crows might have resembled those produced by intermediary forms of quails during speciation.

  9. 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.

  10. 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.

  11. Interspecific rice hybrid of Oryza sativa x Oryza nivara reveals a significant increase in seed protein content.

    Science.gov (United States)

    Mahmoud, Ahmed A; Sukumar, S; Krishnan, Hari B

    2008-01-23

    Wild species offer a potential reservoir of genetic variation for crop improvement. Besides the valuable genes for disease resistance that the wild species have provided for rice improvement, recent studies have shown that these wild species could also provide favorable alleles for the improvement of yield and yield-related traits. The present study reports yet another potential of wild relatives of rice, which involves the improvement of seed protein content. A significant increase in seed protein content was observed in an interspecific hybrid between Oryza sativa ssp. indica and the wild species Oryza nivara. The hybrid showed a protein content of 12.4%, which was 28 and 18.2% higher than those of the parents O. nivara and IR 64, respectively. The increase in protein content was dependent on the genetic background of the rice variety used in the hybridization. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of seed storage proteins demonstrated that a significant increase in prolamins and glutelins was mainly responsible for the elevated protein content of the hybrid. Amino acid analysis of seed proteins revealed that the hybrid had net gains of 19.5% in lysine and 19.4% in threonine over the O. nivara parent on a seed dry weight basis. Molecular analysis indicated that the increase in protein content of the hybrid was not a result of chromosomal rearrangements or transposable element activation, at least in the chromosomal regions containing seed storage protein genes. A preliminary genetic analysis of the F 2 segregating population showed that the inheritance of the increased protein content was polygenic in nature. The development of this interspecific hybrid offers a great potential for selecting new rice cultivars that combine the high yield and superior cooking quality of IR 64 with improved seed protein content.

  12. 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.

  13. 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

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, S. E-mail: kitamura@taka.jaeri.go.jp; Inoue, M.; Ohmido, N.; Fukui, K.; Tanaka, A

    2003-05-01

    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.

  14. 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

  15. The inter-specific hybrid Silene latifolia x S. viscosa reveals early events of sex chromosome evolution

    Czech Academy of Sciences Publication Activity Database

    Žlůvová, Jitka; Lengerová, Martina; Marková, Michaela; Hobza, Roman; Nicolas, Michael; Vyskot, Boris; Charlesworth, Deborah; Negrutiu, Ioan; Janoušek, Bohuslav

    2005-01-01

    Roč. 70, č. 4 (2005), s. 327-336 ISSN 1520-541X R&D Projects: GA ČR(CZ) GA522/02/1485; GA ČR(CZ) GA521/05/2076; GA ČR(CZ) GD204/05/H505; GA ČR(CZ) GP204/05/P505 Institutional research plan: CEZ:AV0Z50040507 Keywords : interspecific hybrid * sex chromosomes * Silene latifolia Subject RIV: BO - Biophysics Impact factor: 3.390, year: 2005

  16. Origin and genetic differentiation of pink-flowered Sorbus hybrids in the Western Carpathians.

    Science.gov (United States)

    Uhrinová, Veronika; Zozomová-Lihová, Judita; Bernátová, Dana; Paule, Juraj; Paule, Ladislav; Gömöry, Dušan

    2017-08-01

    Diversity of the genus Sorbus has been affected by interspecific hybridizations. Pink-flowered hybrid species have been insufficiently studied so far. They comprise bigenomic hybrid species derived from crosses S. aria s.l. × S. chamaemespilus and trigenomic ones, where S. aucuparia was involved as well. The main objective of the present study was to reconstruct their hybrid origins as well as to assess genetic distinction among several morphologically recognized hybrid species. Samples from putative maternal species and eight pink-flowered and two white-flowered hybrid species were collected in the Western Carpathians and the Sudetes. In total, 370 specimens were analysed. Six chloroplast microsatellites were used to infer parentage, whereas nuclear amplified fragment length polymorphism (AFLP) markers were employed for the identification of clones and patterns of genetic variation. Ploidy levels were estimated by flow cytometry on a subset of 140 individuals. Genetic data supported their hybrid origins proposed based on flower and leaf morphology, and chloroplast DNA (cpDNA) revealed recurrent origins ( S. caeruleomontana , S. haljamovae ), even from bidirectional hybridization events ( S. zuzanae ). All bigenomic and trigenomic hybrid species (except triploid S. zuzanae ) were found to be tetraploid. In addition to polyploidy, low genetic variation and the presence of clones within and among populations were observed, suggesting predominantly apomictic reproduction of the hybrid species. Most of the described hybrid species appeared also genetically distinct. The data suggest that multiple hybridization events in the Western Carpathian Sorbus have led to the formation of separate, partially reproductively isolated genetic lineages, which may or may not be discriminated morphologically. Even bidirectional hybridization can produce individuals classified to the same taxon based on phenotype. For some hybrid taxa, hybridization pathways were proposed based on

  17. Original Framework for Optimizing Hybrid Energy Supply

    Directory of Open Access Journals (Sweden)

    Amevi Acakpovi

    2016-01-01

    Full Text Available This paper proposes an original framework for optimizing hybrid energy systems. The recent growth of hybrid energy systems in remote areas across the world added to the increasing cost of renewable energy has triggered the inevitable development of hybrid energy systems. Hybrid energy systems always pose a problem of optimization of cost which has been approached with different perspectives in the recent past. This paper proposes a framework to guide the techniques of optimizing hybrid energy systems in general. The proposed framework comprises four stages including identification of input variables for energy generation, establishment of models of energy generation by individual sources, development of artificial intelligence, and finally summation of selected sources. A case study of a solar, wind, and hydro hybrid system was undertaken with a linear programming approach. Substantial results were obtained with regard to how load requests were constantly satisfied while minimizing the cost of electricity. The developed framework gained its originality from the fact that it has included models of individual sources of energy that even make the optimization problem more complex. This paper also has impacts on the development of policies which will encourage the integration and development of renewable energies.

  18. Comparison of major taste compounds and antioxidative properties of fruits and flowers of different Sambucus species and interspecific hybrids.

    Science.gov (United States)

    Mikulic-Petkovsek, Maja; Ivancic, Anton; Schmitzer, Valentina; Veberic, Robert; Stampar, Franci

    2016-06-01

    Differences in the content of sugars, organic acids, total phenolics and antioxidative activity have been evaluated among three different elderberry species (Sambucus nigra, Sambucus cerulea, Sambucus javanica) and seven interspecific hybrids. The highest content of sugars has been determined in the fruits of JA×CER hybrid and the lowest in fruits of (JA×NI)×cv. Black Beauty hybrid. S. nigra berries contained highest levels of total organic acids. S. nigra and (JA×NI)×CER flower extracts were characterized by 1.3- to 2.8-fold higher content of total sugars compared to other species/hybrids analyzed. Total phenolic content (TPC) in berries ranged from 3687 to 6831 mg GAE per kg FW. The highest TPC has been determined in S. nigra fruits and flowers. The ABTS scavenging activity differed significantly among species and hybrids and ranged from 3.2 to 39.59 mM trolox/kgF W in fruits and 44.87-118.26 mM trolox/kg DW in flowers. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. 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.

  20. The complex hybrid origins of the root knot nematodes revealed through comparative genomics

    Directory of Open Access Journals (Sweden)

    David H. Lunt

    2014-05-01

    Full Text Available Root knot nematodes (RKN can infect most of the world’s agricultural crop species and are among the most important of all plant pathogens. As yet however we have little understanding of their origins or the genomic basis of their extreme polyphagy. The most damaging pathogens reproduce by obligatory mitotic parthenogenesis and it has been suggested that these species originated from interspecific hybridizations between unknown parental taxa. We have sequenced the genome of the diploid meiotic parthenogen Meloidogyne floridensis, and use a comparative genomic approach to test the hypothesis that this species was involved in the hybrid origin of the tropical mitotic parthenogen Meloidogyne incognita. Phylogenomic analysis of gene families from M. floridensis, M. incognita and an outgroup species Meloidogyne hapla was carried out to trace the evolutionary history of these species’ genomes, and we demonstrate that M. floridensis was one of the parental species in the hybrid origins of M. incognita. Analysis of the M. floridensis genome itself revealed many gene loci present in divergent copies, as they are in M. incognita, indicating that it too had a hybrid origin. The triploid M. incognita is shown to be a complex double-hybrid between M. floridensis and a third, unidentified, parent. The agriculturally important RKN have very complex origins involving the mixing of several parental genomes by hybridization and their extreme polyphagy and success in agricultural environments may be related to this hybridization, producing transgressive variation on which natural selection can act. It is now clear that studying RKN variation via individual marker loci may fail due to the species’ convoluted origins, and multi-species population genomics is essential to understand the hybrid diversity and adaptive variation of this important species complex. This comparative genomic analysis provides a compelling example of the importance and complexity of

  1. A cold-tolerant evergreen interspecific hybrid of Ocimum kilimandscharicum and Ocimum basilicum: analyzing trichomes and molecular variations.

    Science.gov (United States)

    Dhawan, Sunita Singh; Shukla, Preeti; Gupta, Pankhuri; Lal, R K

    2016-05-01

    and cold. The analysis showed that O. kilimandscharicum and the hybrid were very close to each other but O. basilicum was more distinct in all respects. The overexpression of the WRKY coding gene showed high expression in the hybrid as compared to O. kilimandscharicum and O. basilicum and the transcription factor microspore-specific (MPS) promoter has also shown overexpression in the hybrid for its response against cold stress. The developed evergreen interspecific hybrid may thus provide a base to various industries which are dependent upon the bioactive constituents of Ocimum species.

  2. Mechanisms and genetic control of interspecific crossing barriers in Lycopersicon

    Energy Technology Data Exchange (ETDEWEB)

    Mutschler, M.A. (Cornell Univ., Ithaca, NY (United States)); McCormick, S. (Agricultural Research Service, Albany, CA (United States). Plant Gene Expression Center)

    1993-03-27

    This study employs Lycopersicon esculentum and L. pennellii as model systems to study the interspecific reproductive barriers unilateral incongruity (UI), hybrid breakdown and interspecific aberrant ratio syndrome (IARS).

  3. 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...

  4. Evolutionary impacts of hybridization and interspecific gene flow on an obligately estuarine fish.

    Science.gov (United States)

    Roberts, D G; Gray, C A; West, R J; Ayre, D J

    2009-01-01

    For free-spawning estuarine taxa, gene flow among estuaries may occur via hybridization with mobile congeners. This phenomenon has rarely been investigated, but is probably susceptible to anthropogenic disturbance. In eastern Australia, the estuarine Black Bream Acanthopagrus butcheri and marine Yellowfin Bream Acanthopagrus australis have overlapping distributions and the potential to hybridize. We used surveys of microsatellite and mtDNA variation in 565 adults from 25 estuaries spanning their distributional range to characterize the species and their putative hybrids. Hybrids were widespread (68% of estuaries) and hybrid frequencies varied greatly among estuaries (0-58%). Most (88%) were classed as advanced generation backcrosses with A. butcheri and displayed A. butcheri mtDNA haplotypes. We found most hybrids in the three estuaries within the zone of sympatry (57%). Our study highlights the underemphasized importance of estuaries as sites of hybridization and suggests that hybridization is driven both by opportunity for contact and human activity.

  5. BIOCHEMICAL AND PHYSIOLOGICAL CHARACTERIZATION OF OIL PALM INTERSPECIFIC HYBRIDS (Elaeis oleifera x Elaeis guineensis GROWN IN HYDROPONICS

    Directory of Open Access Journals (Sweden)

    Yurany Dayana Rivera

    2013-09-01

    Full Text Available 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 and hybrid crosses were established, 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.

  6. An interspecific barberry hybrid enables genetic dissection of non-host resistance to the stem rust pathogen Puccinia graminis.

    Science.gov (United States)

    Bartaula, Radhika; Melo, Arthur T O; Connolly, Bryan A; Jin, Yue; Hale, Iago

    2018-02-26

    Stem rust, caused by Puccinia graminis (Pg), remains a devastating disease of wheat; and the emergence of new Pg races virulent on deployed resistance genes fuels the ongoing search for sources of durable resistance. Despite its intrinsic durability, non-host resistance (NHR) is largely unexplored as a protection strategy against Pg, partly due to the inherent challenge of developing a genetically tractable system within which NHR segregates. Here we demonstrate that Pg's far less-studied ancestral host, barberry (Berberis spp.), provides such a unique pathosystem. Characterization of a natural population of B. ×ottawensis (B×o), an interspecific hybrid of Pg-susceptible B. vulgaris and Pg-resistant B. thunbergii (Bt), reveals that this uncommon nothospecies can be used to dissect the genetic mechanism(s) of Pg-NHR exhibited by Bt. Artificial inoculation of a natural population of B×o accessions, verified via genotyping-by-sequencing to be first generation hybrids, revealed 51% susceptible, 33% resistant, and 16% intermediate phenotypes. Characterization of a B×o full-sib family excluded the possibility of maternal inheritance of the resistance. By demonstrating segregation of Pg-NHR in a hybrid population, this study challenges the assumed irrelevance of Bt to Pg epidemiology and lays a novel foundation for the genetic dissection of NHR to one of agriculture's most studied pathogens.

  7. 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.

  8. 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.

  9. Change in male secondary sexual characters in artificial interspecific hybrid populations.

    OpenAIRE

    Carson, H L; Val, F C; Templeton, A R

    1994-01-01

    The interfertile Hawaiian species Drosophila silvestris and Drosophila heteroneura were hybridized, forming reciprocal populations; the SH hybrid line was begun with D. silvestris female parents, and the HS hybrid line was begun with D. heteroneura female parents. Mass laboratory cultures were maintained for 14 generations without artificial selection. The species differ strikingly in two male secondary sexual characters, head shape and foreleg tibial cilia number. These characters are known ...

  10. Comparative genomics among Saccharomyces cerevisiae × Saccharomyces kudriavzevii natural hybrid strains isolated from wine and beer reveals different origins

    Science.gov (United States)

    2012-01-01

    Background Interspecific hybrids between S. cerevisiae × S. kudriavzevii have frequently been detected in wine and beer fermentations. Significant physiological differences among parental and hybrid strains under different stress conditions have been evidenced. In this study, we used comparative genome hybridization analysis to evaluate the genome composition of different S. cerevisiae × S. kudriavzevii natural hybrids isolated from wine and beer fermentations to infer their evolutionary origins and to figure out the potential role of common S. kudriavzevii gene fraction present in these hybrids. Results Comparative genomic hybridization (CGH) and ploidy analyses carried out in this study confirmed the presence of individual and differential chromosomal composition patterns for most S. cerevisiae × S. kudriavzevii hybrids from beer and wine. All hybrids share a common set of depleted S. cerevisiae genes, which also are depleted or absent in the wine strains studied so far, and the presence a common set of S. kudriavzevii genes, which may be associated with their capability to grow at low temperatures. Finally, a maximum parsimony analysis of chromosomal rearrangement events, occurred in the hybrid genomes, indicated the presence of two main groups of wine hybrids and different divergent lineages of brewing strains. Conclusion Our data suggest that wine and beer S. cerevisiae × S. kudriavzevii hybrids have been originated by different rare-mating events involving a diploid wine S. cerevisiae and a haploid or diploid European S. kudriavzevii strains. Hybrids maintain several S. kudriavzevii genes involved in cold adaptation as well as those related to S. kudriavzevii mitochondrial functions. PMID:22906207

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. Regeneration and interspecific somatic hybridization in Allium for transfer of cytoplasmic male sterility to leek

    NARCIS (Netherlands)

    Buiteveld, J.

    1998-01-01

    The vast majority of the present day leek cultivars is of poor quality. The genetic constitution of leek makes it a difficult crop to breed and consequently mass, or family selection methods, both of which have a low efficiency, are mainly used. F 1 hybrid breeding

  16. The Role of Polyploidization and Interspecific Hybridization in the Breeding of Ornamental Crops

    NARCIS (Netherlands)

    Marasek-Ciolakowska, A.; Arens, P.F.P.; Tuyl, van J.M.

    2016-01-01

    Polyploidy and hybridisation are critical processes in plant evolution and speciation. Many current agricultural crops are either natural or agricultural hybrids or polyploids, including potato, sugarcane, wheat, strawberries, and banana. There is a great deal of potential to utilise these natural

  17. The use of ion beam to overcome interspecific hybrid inviability in plants

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Masayoshi [Kyoto Prefectural Univ. (Japan); Watanabe, Hiroshi

    1997-03-01

    In order to overcome sexual incompatibility between distantly related species in Nicotiana, the crosses with {sup 4}He{sup 2+} beam-irradiated pollen were carried out, and survival hybrids were obtained. They were resistant to tobacco mosaic virus and green peach aphid. (author)

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

    Indian Academy of Sciences (India)

    Unknown

    determinative asymmetry in the cell division at pollen mitosis I (PM I), which gives rise to a larger ... spindle, and an expected process of cytokinesis to form a hemispherical cell plate. Control of gametophytic cytoki- .... In the Brachiaria mutants affecting division symmetry at PM I, i.e. in the present hybrid and in the mutant de-.

  19. [Intergenomic chromosome substitutions in wheat interspecific hybrids and their use in the development of a genetic nomenclature of Triticum timopheevii chromosomes].

    Science.gov (United States)

    Badaeva, E D; Budashkina, E B; Bilinskaia, E N; Pukhal'skiĭ, V A

    2010-07-01

    The results of analysis of the genome formation in interspecific hybrids of Triticum aestivum with T. timopheevii are reviewed. The spectra of substitutions and rearrangements are shown to depend on the genotypes of the parental forms and on the direction of selection. The frequencies of substitutions of individual T. timopheevii chromosomes significantly vary and reflect the level of their divergence relative to the common wheat chromosomes. Some aspects of classification of the A(t)- and G-genome chromosomes are discussed.

  20. 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.

  1. Insights into Interspecific Hybridization Events in Allotetraploid Cotton Formation from Characterization of a Gene-Regulating Leaf Shape.

    Science.gov (United States)

    Chang, Lijing; Fang, Lei; Zhu, Yajuan; Wu, Huaitong; Zhang, Zhiyuan; Liu, Chunxiao; Li, Xinghe; Zhang, Tianzhen

    2016-10-01

    The morphology of cotton leaves varies considerably. Phenotypes, including okra, sea-island, super-okra, and broad leaf, are controlled by a multiple allele locus, L 2 Okra leaf (L 2 °) is an incomplete mutation that alters leaf shape by increasing the length of lobes with deeper sinuses. Using a map-based cloning strategy, we cloned the L 2 locus gene, which encodes a LATE MERISTEM IDENTITY 1 (LMI1)-like transcription factor (GhOKRA). Silencing GhOKRA leads to a change in phenotype from okra to broad leaf. Overexpression of GhOKRA in Arabidopsis thaliana greatly increases the degree of the leaf lobes and changes the leaf shape. Premature termination of translation in GhOKRA results in the production of broad leaves. The sequences of OKRA from diploid progenitor D-genome species, and wild races and domesticated allotetraploid cottons in Gossypium hirsutum show that a premature termination mutation occurred before and after the formation of tetraploid cotton, respectively. This study provides genomic insights into the two interspecific hybridization events: one produced the present broad leaf and another formed okra leaf phenotype with complete OKRA, that occurred during allotetraploid cotton formation. Copyright © 2016 by the Genetics Society of America.

  2. Sapogenin content variation in Medicago inter-specific hybrid derivatives highlights some aspects of saponin synthesis and control.

    Science.gov (United States)

    Carelli, Maria; Biazzi, Elisa; Tava, Aldo; Losini, Ilaria; Abbruscato, Pamela; Depedro, Claudia; Scotti, Carla

    2015-04-01

    In the Medicago genus, saponins are a complex mixture of triterpene glycosides showing a broad spectrum of biological properties. Here we analyzed the variation in the sapogenin content and composition of inter-specific hybrid Medicago sativa × Medicago arborea derivatives to highlight the pattern of this variation in plant organs (leaves/roots) and the possible mechanisms underlying it. In Sativa Arborea Cross (SAC) leaves and roots, saponins and sapogenins were evaluated using chromatographic methods. Phenotypic correlations between sapogenin content and bio-agronomic traits were examined. Expression studies on β-amyrin synthase and four cytochromes P450 (CYPs) involved in sapogenin biosynthesis and sequence analysis of the key gene of the hemolytic sapogenin pathway (CYP716A12) were performed. Chromatographic analyses revealed a different pattern of among-family variation for hemolytic and nonhemolytic sapogenins and saponins and for the two organs/tissues. Different correlation patterns of gene expression in roots and leaves were found. Diachronic analysis revealed a relationship between sapogenin content and gene transcriptional levels in the early stages of the productive cycle. The results suggest that there are different control mechanisms acting on sapogenin biosynthesis for leaves and roots, which are discussed. A key role for medicagenic acid in the control of sapogenin content in both the tissues is proposed and discussed. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  3. Change in male secondary sexual characters in artificial interspecific hybrid populations.

    Science.gov (United States)

    Carson, H L; Val, F C; Templeton, A R

    1994-07-05

    The interfertile Hawaiian species Drosophila silvestris and Drosophila heteroneura were hybridized, forming reciprocal populations; the SH hybrid line was begun with D. silvestris female parents, and the HS hybrid line was begun with D. heteroneura female parents. Mass laboratory cultures were maintained for 14 generations without artificial selection. The species differ strikingly in two male secondary sexual characters, head shape and foreleg tibial cilia number. These characters are known to be quantitative characters that are influenced by both sex-linked and autosomal factors and appear to be involved in sexual selection. In the later generations (4-14), head shape in SH flies changes significantly; cilia number changes in both SH and HS populations. In terms of the parental phenotypes, the SH population evolved toward a heteroneura-like head while simultaneously evolving toward a silvestris-like tibia. In the HS population, there was no significant change in head shape, but cilia number decreased, making it more like the parental heteroneura. Accordingly, these two secondary sexual characters pursue separate evolutionary pathways. We suggest that these changes are brought about by selection occurring naturally during the later generations.

  4. A comparative analysis of chromosome pairing at metaphase I in interspecific hybrids between durum wheat (Triticum turgidum L.) and the most widespread Aegilops species.

    Science.gov (United States)

    Cifuentes, M; Garcia-Agüero, V; Benavente, E

    2010-07-01

    Homoeologous metaphase I (MI) associations in hybrids between durum wheat and its wild allotetraploid relatives Aegilops neglecta, Ae. triuncialis and Ae. ventricosa have been characterized by a genomic in situ hybridization procedure that allows simultaneous discrimination of A, B and wild species genomes. Earlier results in equivalent hybrids with the wild species Ae. cylindrica and Ae. geniculata have also been considered to comparatively assay the MI pairing pattern of the durum wheat x Aegilops interspecific combinations more likely to occur in nature. The general picture can be drawn as follows. A and B wheat genomes pair with each other less than the 2 wild constituent genomes do in any of the hybrid combinations examined. Interspecific wheat-wild associations account for 60-70% of total MI pairing in all hybrids, except in that derived from Ae. triuncialis, but the A genome is always the wheat partner most frequently involved in MI pairing with the wild homoeologues. Hybrids with Ae. cylindrica, Ae. geniculata and Ae. ventricosa showed similar reduced levels of MI association and virtually identical MI pairing patterns. However, certain recurrent differences were found when the pattern of homoeologous pairing of hybrids from either Ae. triuncialis or Ae. neglecta was contrasted to that observed in the other durum wheat hybrid combinations. In the former case, a remarkable preferential pairing between the wild species constituent genomes U(t) and C(t) seems to be the reason, whereas a general promotion of homoeologous pairing, qualitatively similar to that observed under the effect of the ph1c mutation, appears to occur in the hybrid with Ae. neglecta. It is further discussed whether the results reported here can be extrapolated to the corresponding bread wheat hybrid combinations. Copyright 2010 S. Karger AG, Basel.

  5. 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

  6. Complex Interspecific Hybridization in Barley (Hordeum vulgare L.) and the Possible Occurrence of Apomixis

    DEFF Research Database (Denmark)

    Bothmer, R. von; Bengtsson, M.; Flink, J.

    1988-01-01

    mixoploid with respect to alien chromosomes (19-22). In one combination, chromosome no. 7 was duplicated. Meiosis in triple hybrids showed low, but variable pairing (1.3-5.5 chiasmata per cell). The syndesis probably did not include the barley chromosomes. Direct backcrosses to di- and tetraploid......-chromosomic plant in which the male parental genome was absent. We suspect that this plant may have arisen through parthenogenetic development of a reduced female gemete. The other cross with a diploid line ('9208/9') resulted in plant with 2n = 51-53. The most likely explanation for this second plant...... is that an unreduced gamete from the amphiploid was fertilized by a normal gamete from the backcross parent, and during early embryo development, some chromosomes were eliminated....

  7. MORPHOLOGICAL TRAITS AS TOOL TO VERIFY GENETIC VARIABILITY OF INTERSPECIFIC DRAGON FRUIT HYBRIDS

    Directory of Open Access Journals (Sweden)

    ADRIANA DE CASTRO CORREIA DA SILVA

    Full Text Available ABSTRACT With recent cultivation in Brazil, the dragon fruit still have lacks related to the selection of promising materials and there are not yet commercial varieties in the country. Therefore, manual pollination cross were held in 2010, between plants of H. undatus x H. polyrhizus and H. undatus x H. setaceus. Aiming evaluate the genetic diversity of the progenies for future use in breeding program, based on cladodes characteristics, six characters were assessed: length and diameter of stem, distance between areoles, arch height, number and size of spines/areole. From the Euclidean distance matrix analysis was constructed a dendrogram by the UPGMA method. There was great variability among hybrids, and eight of them have shown promise for use in breeding program.

  8. Interspecific and intergeneric hybridization as a source of variation for wheat grain quality improvement.

    Science.gov (United States)

    Alvarez, Juan B; Guzmán, Carlos

    2018-02-01

    The hybridization events with wild relatives and old varieties are an alternative source for enlarging the wheat quality variability. This review describes these process and their effects on the technological and nutritional quality. Wheat quality and its end-uses are mainly based on variation in three traits: grain hardness, gluten quality and starch. In recent times, the importance of nutritional quality and health-related aspects has increased the range of these traits with the inclusion of other grain components such as vitamins, fibre and micronutrients. One option to enlarge the genetic variability in wheat for all these components has been the use of wild relatives, together with underutilised or neglected wheat varieties or species. In the current review, we summarise the role of each grain component in relation to grain quality, their variation in modern wheat and the alternative sources in which wheat breeders have found novel variation.

  9. Genetic tests of ancient asexuality in Root Knot Nematodes reveal recent hybrid origins

    Directory of Open Access Journals (Sweden)

    Lunt David H

    2008-07-01

    has been maintained by selection. Conclusion The data strongly suggests the tropical root knot nematode apomicts have a recent origin and are not anciently asexual. The results support that interspecific hybridization has been involved in the origin of this asexual group and has played a role in shaping the patterns of genetic diversity observed. This study suggests that genetic signatures of ancient asexuality must be taken with caution due to the confounding effect of interspecific hybridization, which has long been implicated in the origins of apomictic species.

  10. Genetic divergence among interspecific Paspalum hybrids based on seed production traits

    Directory of Open Access Journals (Sweden)

    Rodrigo Ramos Lopes

    Full Text Available ABSTRACT The use of genetic divergence as a basis for identifying superior individuals, with greater heterozygosity, is important in view of the difficulty when selecting of dissimilar genotypes exhibiting high average for interest traits. The aim of this study was to evaluate the genetic divergence and the expression of seed production traits in seventeen apomictic Paspalum plicatulum × Paspalum guenoarum hybrids and two male parents (P. guenoarum. A randomized block design was used, with genotypes individually arranged into ten blocks. The following traits were assessed: total number of tillers/plant (TT, reproductive tiller/plant (RT, number of racemes per inflorescence (NRI, reproductive tiller height (RTH, inflorescence rachis length (IRL, number of seeds/inflorescence (NSI, weight of a thousand seeds (WTS and seed production (SP. Genetic divergence among the genotypes was estimated using the Tocher method and UPGMA clustering, based on the generalized Mahalanobis distance (D2 ii’. The Tocher and UPGMA optimization methods showed high concordance. The traits that most contributed to genetic divergence were RTH (23.59%, IRL (21.63%, WTS (16.67% and SP (14.23%. The presence of genetic diversity made it possible to identify divergent genotypes and those with high means for the traits studied, allowing the selection of genotypes with significant breeding potential. Repeated cross-breeding of female superior plants with the genotypes Azulão and H20 can result in a high heterosis effect on seed production characteristics.

  11. Distribution and Expression of Elicitin Genes in the Interspecific Hybrid Oomycete Phytophthora alni▿

    Science.gov (United States)

    Ioos, Renaud; Panabières, Franck; Industri, Benoît; Andrieux, Axelle; Frey, Pascal

    2007-01-01

    Phytophthora alni subsp. alni, P. alni subsp. multiformis, and P. alni subsp. uniformis are responsible for alder disease in Europe. Class I and II elicitin gene patterns of P. alni subsp. alni, P. alni subsp. multiformis, P. alni subsp. uniformis, and the phylogenetically close species P. cambivora and P. fragariae were studied through mRNA sequencing and 3′ untranslated region (3′UTR)-specific PCRs and sequencing. The occurrence of multiple 3′UTR sequences in association with identical elicitin-encoding sequences in P. alni subsp. alni indicated duplication/recombination events. The mRNA pattern displayed by P. alni subsp. alni demonstrated that elicitin genes from all the parental genomes are actually expressed in this allopolyploid taxon. The complementary elicitin patterns resolved confirmed the possible involvement of P. alni subsp. multiformis and P. alni subsp. uniformis in the genesis of the hybrid species P. alni subsp. alni. The occurrence of multiple and common elicitin gene sequences throughout P. cambivora, P. fragariae, and P. alni sensu lato, not observed in other Phytophthora species, suggests that duplication of these genes occurred before the radiation of these species. PMID:17601812

  12. Distribution and expression of elicitin genes in the interspecific hybrid oomycete Phytophthora alni.

    Science.gov (United States)

    Ioos, Renaud; Panabières, Franck; Industri, Benoît; Andrieux, Axelle; Frey, Pascal

    2007-09-01

    Phytophthora alni subsp. alni, P. alni subsp. multiformis, and P. alni subsp. uniformis are responsible for alder disease in Europe. Class I and II elicitin gene patterns of P. alni subsp. alni, P. alni subsp. multiformis, P. alni subsp. uniformis, and the phylogenetically close species P. cambivora and P. fragariae were studied through mRNA sequencing and 3' untranslated region (3'UTR)-specific PCRs and sequencing. The occurrence of multiple 3'UTR sequences in association with identical elicitin-encoding sequences in P. alni subsp. alni indicated duplication/recombination events. The mRNA pattern displayed by P. alni subsp. alni demonstrated that elicitin genes from all the parental genomes are actually expressed in this allopolyploid taxon. The complementary elicitin patterns resolved confirmed the possible involvement of P. alni subsp. multiformis and P. alni subsp. uniformis in the genesis of the hybrid species P. alni subsp. alni. The occurrence of multiple and common elicitin gene sequences throughout P. cambivora, P. fragariae, and P. alni sensu lato, not observed in other Phytophthora species, suggests that duplication of these genes occurred before the radiation of these species.

  13. 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.

  14. Evaluation of interspecific hybrids and cultivars of Brachiaria spp. submitted to sourcers and levels of nitrogen fertilization

    Directory of Open Access Journals (Sweden)

    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

  15. Genetic origin and composition of a natural hybrid poplar Populus × jrtyschensis from two distantly related species.

    Science.gov (United States)

    Jiang, Dechun; Feng, Jianju; Dong, Miao; Wu, Guili; Mao, Kangshan; Liu, Jianquan

    2016-04-18

    The factors that contribute to and maintain hybrid zones between distinct species are highly variable, depending on hybrid origins, frequencies and fitness. In this study, we aimed to examine genetic origins, compositions and possible maintenance of Populus × jrtyschensis, an assumed natural hybrid between two distantly related species. This hybrid poplar occurs mainly on the floodplains along the river valleys between the overlapping distributions of the two putative parents. We collected 566 individuals from 45 typical populations of P. × jrtyschensis, P. nigra and P. laurifolia. We genotyped them based on the sequence variations of one maternally inherited chloroplast DNA (cpDNA) fragment and genetic polymorphisms at 20 SSR loci. We further sequenced eight nuclear genes for 168 individuals from 31 populations. Two groups of cpDNA haplotypes characteristic of P. nigra and P. laurifolia respectively were both recovered for P. × jrtyschensis. Genetic structures and coalescent tests of two sets of nuclear population genetic data suggested that P. × jrtyschensis originated from hybridizations between the two assumed parental species. All examined populations of P. × jrtyschensis comprise mainly F1 hybrids from interspecific hybridizations between P. nigra and P. laurifolia. In the habitats of P. × jrtyschensis, there are lower concentrations of soil nitrogen than in the habitats occupied by the other two species. Our extensive examination of the genetic composition of P. × jrtyschensis suggested that it is typical of F1-dominated hybrid zones. This finding plus the low concentration of soil nitrogen in the floodplain soils support the F1-dominated bounded hybrid superiority hypothesis of hybrid zone maintenance for this particular hybrid poplar.

  16. Hybrid grating reflectors: Origin of ultrabroad stopband

    DEFF Research Database (Denmark)

    Park, Gyeong Cheol; Taghizadeh, Alireza; Chung, Il-Sug

    2016-01-01

    Hybrid grating (HG) reflectors with a high-refractive-index cap layer added onto a high contrast grating (HCG) provide a high reflectance close to 100% over a broader wavelength range than HCGs. The combination of a cap layer and a grating layer brings a strong Fabry-Perot (FP) resonance as well ...

  17. Differential susceptibility to the Withering Syndrome agent and renal coccidia in juvenile Haliotis rufescens, Haliotis discus hannai and the interspecific hybrid.

    Science.gov (United States)

    González, Roxana; Lohrmann, Karin B; Pizarro, Javiera; Brokordt, Katherina

    2014-02-01

    Withering Syndrome (WS) is a pathogenic chronic disease caused by the intracellular rickettsial-like bacterium "Candidatus Xenohaliotis californiensis" (WS-RLOs), which affects many abalone species. The renal coccidium (Margolisiella haliotis) has often been observed concurrent with WS infection. The red abalone Haliotis rufescens is a very susceptible species to WS and is also infected by the coccidium M. haliotis. In contrast, the Japanese abalone Haliotis discus hannai is not infected by these parasites. Interspecific hybridization is a method for improving important traits in animal husbandry. The objective of this study was to determine susceptibility to WS-RLO and M. haliotis infection in the hybrid generated from a cross between red and Japanese abalones. Juveniles from both species and the interspecific hybrid were challenged by exposure to effluent from red abalone adults infected with both parasites. The animals were analyzed by histology at 130days post-challenge. A 33% prevalence WS-RLOs was observed in the red abalone H. rufescens, whereas a 20% prevalence was observed in the hybrid. Infections were graded on a scale of 0-3. Of these red abalones infected, 53% presented grade 1 infection intensity, 10% had grade 2 infections, and 50% had grade 3 infections. However, the hybrids only presented intensities at the extremes of the scale; of those infected 33% showed grade 1 infections and 66% had grade 3 infections. The coccidium prevalence was 7% in red abalone individuals and 13% in the hybrid abalone. In contrast, the Japanese abalone did not present infections with either parasite. As with the prevalence, the infection intensities for the coccidium were higher in the hybrid abalone; of those infected 25% had grade 2 infections, and 75% had grade 3 infections, but the red abalone presented only grade 2 infection intensities. Therefore, the hybrid did not inherited non-susceptibility or resistance characteristics of the parental H. discus hannai and

  18. 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.

  19. Larval salivary glue protein heterosis and dosage compensation among the interspecific F1 hybrids of Drosophila nasuta nasuta and Drosophila nasuta albomicans

    Directory of Open Access Journals (Sweden)

    Raghavan Prithi

    2016-01-01

    Full Text Available Reciprocal cross effects with respect to larval salivary secretory protein levels were studied in the interspecific fertile reciprocal hybrids by crossing Drosophila nasuta nasuta, and Drosophila nasuta albomicans. These proteins are produced copiously during the third larval instar stage and are believed to play a role in the attachment of pupa to the substratum prior to pupariation as well as in insect immunity. Quantitative variations were encountered among the reciprocal hybrids. Significant heterosis was observed between D. n. nasuta and the F1 hybrid female of a cross between D. n. albomicans female and D. n. nasuta male (21.39% while the F1 hybrids of a cross between D. n. nasuta female and D. n. albomicans male showed a marginal increase (4.24% from the mid parent level. The glue secretions were correlated to total cell number but independent of gland size. SDS PAGE revealed a considerable heterosis with respect to X-linked protein fractions. Here we report sex specific biochemical heterosis. However the X-linked fractions undergo dosage compensation in both parents and hybrids indicating strict regulatory control.

  20. Use of eggs derived from the interspecific charr hybrids to induce androgenetic development of the brook charr (Salvelinus fontinalis Mitchill 1814).

    Science.gov (United States)

    Michalik, O; Dobosz, S; Wójcik, I; Zalewski, T; Ocalewicz, K

    2014-04-01

    Although, brook charr (Salvelinus fontinalis Mitchill 1814) and Arctic charr (Salvelinus alpinus Linnaeus 1758) are able to cross and give fertile offspring, their androgenetic nucleocytoplasmic hybrids are not viable. To overcome incompatibility between the egg cytoplasm of one charr species and the sperm nucleus of another charr species, application of F1 interspecific hybrids as egg donors for the purpose of androgenesis has been proposed. Here, androgenetic development of the brook charr was successfully induced in the brook charr eggs and the eggs derived from the reciprocal brook charr × Arctic charr F1 hybrids. A working androgenesis protocol included inactivation of the maternal nuclear DNA achieved by irradiation of the eggs with 420 Gy of X-rays, insemination of such treated eggs with the haploid sperm cells and exposition of the haploid androgenetic zygotes to the high hydrostatic pressure shock (51.711 MPa for 4 min) applied 420 min after insemination. Androgenetic larvae that hatched from the brook charr and the hybrid eggs were shown to be homozygous brook charr individuals. Androgenetic individuals exhibited 84 chromosomes and 100 chromosome arms (FN), values characteristic for the brook charr diploid cells. Strategy hybridize first than induce androgenesis should be tested in order to provide androgenetic offspring in other salmonids that are able to cross and produce fertile offspring. © 2013 Blackwell Verlag GmbH.

  1. Protein-precipitable tannin in wines from Vitis vinifera and interspecific hybrid grapes (Vitis ssp.): differences in concentration, extractability, and cell wall binding.

    Science.gov (United States)

    Springer, Lindsay F; Sacks, Gavin L

    2014-07-30

    Although they possess significant viticultural advantages, interspecific hybrid grapes (Vitis spp.) are reported to produce wine with lower tannin concentrations than European wine varieties (Vitis vinifera). However, extensive quantitative data on this phenomenon as well as mechanistic explanations for these differences are lacking. A survey of primarily commercial wines from the Finger Lakes American Viticultural Area (New York) using a protein precipitation method determined that hybrid-based wines had >4-fold lower tannin concentrations than vinifera wines. To elucidate factors responsible for differences in wine tannin, 24 wines were produced from both red hybrid and vinifera cultivars under identical conditions. Lower wine tannin in French-American hybrid- than vinifera-based wines could be partially explained by lower grape tannin. However, experiments in which cell wall material was incubated with tannin indicated that cell wall binding may be of equal or greater importance in explaining lower wine tannin concentrations in hybrid-based wines. Subsequent characterization of cell wall material revealed that protein in flesh cell walls and, to a lesser extent, pectin in skin cell walls were correlated with cell wall binding.

  2. Resolving incongruence: Species of hybrid origin in Columnea (Gesneriaceae).

    Science.gov (United States)

    Smith, James F; Clark, John L; Amaya-Márquez, Marisol; Marín-Gómez, Oscar H

    2017-01-01

    Speciation by hybridization has long been recognized among plants and includes both homoploid and allopolyploid speciation. The numbers of presumed hybrid species averages close to 11% and tends to be concentrated in a subset of angiosperm families. Recent advances in molecular methods have verified species of hybrid origin that had been presumed on the basis of morphology and have identified species that were not initially considered hybrids. Identifying species of hybrid origin is often a challenge and typically based on intermediate morphology, or discrepancies between molecular datasets. Discrepancies between data partitions may result from several factors including poor support, incomplete lineage sorting, or hybridization. A phylogenetic analysis of species in Columnea (Gesneriaceae) indicated significant incongruencies between the cpDNA and nrDNA datasets. Tests that examined whether one or both of the datasets had the phylogenetic signal to reject the topology of the alternate dataset (Shimodaira and Hasegawa [SH] and approximately unbiased [AU] tests) indicated significant differences between the topologies. Splitstree analyses also showed that there was support for the placement of the discrepant taxa in both datasets and that the combined data placed the putative hybrid species in an intermediate position between the two datasets. The genealogical sorting index (GSI) implied that coalescence in nrDNA had occurred in all species where more than a single individual had been sampled, but the GSI value was lower for the cpDNA of most of the putative hybrids, implying that these regions have not yet coalesced in these lineages despite being haploid. The JML test that evaluates simulated species pairwise distances against observed distances also implies that observed nrDNA data generate shorter distances than simulated data, implying hybridization. It is most likely that C. gigantifolia, C. rubriacuta, and C. sp. nov. represent a lineage from a hybrid ancestor

  3. Interspecific Hybridisation in Campanula

    DEFF Research Database (Denmark)

    Röper, Anna Catharina

    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......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...... was confirmed for most of the interspecific hybrids. Intermediate phenotypes compared to the parental species were found for several interspecific hybrids. The results from this PhD study demonstrated that the genetic viability could be increased in Campanula and reveal valuable information for interspecific...

  4. Interspecific hybridization as a source of novel genetic markers for the sterile insect technique in Bactrocera tryoni (Diptera: Tephritidae).

    Science.gov (United States)

    Shearman, D C A; Frommer, M; Morrow, J L; Raphael, K A; Gilchrist, A S

    2010-08-01

    Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) or "Qfly," is the most serious horticultural pest in Australia, with a bioclimatic range that extends from the tropical north to the temperate south. Various Australian horticultural exports depend on certification that they originated from B. tryoni-free areas. To eliminate, rather than suppress, B. tryoni in production areas, a sterile insect technique (SIT) campaign directed at B. tryoni has been in operation in southeastern Australia since 1997. Like many other SIT programs around the world, the B. tryoni SIT program relies on fluorescent dust to mark the sterile insects. However, fluorescent dust marking does not provide 100% accuracy in the identification of sterile insects, as required where the aim is to declare regions completely free of fruit fly. Here, we show that novel mitochondrial markers can be introduced into a strain of B. tryoni by interspecies hybridization between B. tryoni and a related but well-differentiated species, Bactrocera jarvisi (Tryon), followed by backcrossing of the hybrid strain with the parental B. tryoni strain. These novel markers do not affect the viability of the strain as measured by pupation and eclosion rates. A simple polymerase chain reaction-based test is described that distinguishes the marked B. tryoni from wild B. tryoni. As required in practice, the test was shown to work reliably on DNA extracted from dead flies that had remained in field traps for up to two weeks.

  5. Evidence for the hybrid origin of Nuphar xrubrodisca (Nymphaeaceae).

    Science.gov (United States)

    Padgett, D J; Les, D; Crow, G

    1998-10-01

    Plants intermediate in appearance between Nuphar microphyllaand N. variegata (Nymphaeaceae) have long been assumed to bethe result of hybridization. The evidence for this is based primarilyon field observations of morphology, poor fruit production, closegeographical proximity of presumed parent species, and limited pollensterility data. Fertile populations of the same plants have also beendocumented. We employed multivariate analyses of morphology, pollenfertility studies, and random amplified polymorphic DNA (RAPD) markersto test the hypothesis that Nuphar × rubrodiscarepresents a natural interspecific hybrid between N.microphylla and N. variegata. Examination of 15morphological characters demonstrated the intermediacy of N.× rubrodisca between N. microphylla and N.variegata, and the pollen data revealed a markedly lower meanpollen viability in N. × rubrodisca (23%)compared to the other two species (91 and 86%, respectively). Eight 10-mer primers produced 13 species-specific RAPD markers forN. microphylla and nine for N. variegata, with all 22markers present in N. × rubrodisca. The datafrom RAPDs are concordant with morphology in implicating N.microphylla and N. variegata as parents of N.×rubrodisca.

  6. Hybrid grating reflectors: Origin of ultrabroad stopband

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gyeong Cheol; Taghizadeh, Alireza; Chung, Il-Sug, E-mail: ilch@fotonik.dtu.dk [DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

    2016-04-04

    Hybrid grating (HG) reflectors with a high-refractive-index cap layer added onto a high contrast grating (HCG) provide a high reflectance close to 100% over a broader wavelength range than HCGs. The combination of a cap layer and a grating layer brings a strong Fabry-Perot (FP) resonance as well as a weak guided mode (GM) resonance. Most of the reflected power results from the FP resonance, while the GM resonance plays a key role in achieving a reflectance close to 100% as well as broadening the stopband. An HG sample with 7 InGaAlAs quantum wells included in the cap layer has been fabricated by directly wafer-bonding a III-V cap layer onto a Si grating layer. Its reflection property has been characterized. This heterogeneously integrated HG reflector may allow for a hybrid III-V on Si laser to be thermally efficient, which has promising prospects for silicon photonics light sources and high-speed operation.

  7. Evaluation of Relationships between Growth Rate, Tree Size, Lignocellulose Composition, and Enzymatic Saccharification in Interspecific Corymbia Hybrids and Parental Taxa

    OpenAIRE

    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

    © 2016 Healey,Lee,Lupoi,Papa,Guenther,Corno,Adani,Singh,Simmons and Henry. 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 h...

  8. Nonrandom patterns of genetic admixture expose the complex historical hybrid origin of unisexual leaf beetle species in the genus Calligrapha.

    Science.gov (United States)

    Montelongo, Tinguaro; Gómez-Zurita, Jesús

    2015-01-01

    Many unisexual animal lineages supposedly arose from hybridization. However, support for their putative hybrid origins mostly comes from indirect methodologies, which are rarely confirmatory. Here we provide compelling data indicating that tetraploid unisexual Calligrapha are true genetic mosaics obtained via analysis of mitochondrial DNA (mtDNA) and allelic variation and coalescence times for three single-copy nuclear genes (CPS, HARS, and Wg) in five of six unisexual Calligrapha and a representative sample of bisexual species. Nuclear allelic diversity in unisexuals consistently segregates in the gene pools of at least two but up to three divergent bisexual species, interpreted as putative parentals of interspecific hybridization crosses. Interestingly, their mtDNA diversity derives from an additional yet undiscovered older evolutionary lineage that is possibly the same for all independently originated unisexual species. One possibly extinct species transferred its mtDNA to several evolutionary lineages in a wave of hybridization events during the Pliocene, whereby descendant species retained a polymorphic mtDNA constitution. Recent hybridizations, in the Pleistocene and always involving females with the old introgressed mtDNA, seemingly occurred in the lineages leading to unisexual species, decoupling mtDNA introgression (and inferences derived from these data, such as timing and parentage) from subsequent acquisition of the new reproductive mode. These results illuminate an unexpected complexity in possible routes to animal unisexuality, with implications for the interpretation of ancient unisexuality. If the origin of unisexuality requires a mechanism where (1) hybridization is a necessary but insufficient condition and (2) multiple bouts of hybridization involving more than two divergent lineages are required, then the origins of several classical unisexual systems may have to be reassessed.

  9. Ancient Hybridization and an Irish Origin for the Modern Polar Bear Matriline

    Science.gov (United States)

    Edwards, Ceiridwen J.; Suchard, Marc A.; Lemey, Philippe; Welch, John J.; Barnes, Ian; Fulton, Tara L.; Barnett, Ross; O’Connell, Tamsin C.; Coxon, Peter; Monaghan, Nigel; Valdiosera, Cristina E.; Lorenzen, Eline D.; Willerslev, Eske; Baryshnikov, Gennady F.; Rambaut, Andrew; Thomas, Mark G.; Bradley, Daniel G.; Shapiro, Beth

    2015-01-01

    Summary Background Polar bears (Ursus maritimus) are among those species most susceptible to the rapidly changing arctic climate, and their survival is of global concern. Despite this, little is known about polar bear species history. Future conservation strategies would significantly benefit from an understanding of basic evolutionary information, such as the timing and conditions of their initial divergence from brown bears (U. arctos) or their response to previous environmental change. Results We used a spatially explicit phylogeographic model to estimate the dynamics of 242 brown bear and polar bear matrilines sampled throughout the last 120,000 years and across their present and past geographic ranges. Our results show that the present distribution of these matrilines was shaped by a combination of regional stability and rapid, long-distance dispersal from ice-age refugia. In addition, hybridization between polar bears and brown bears may have occurred multiple times throughout the Late Pleistocene. Conclusions The reconstructed matrilineal history of brown and polar bears has two striking features. First, it is punctuated by dramatic and discrete climate-driven dispersal events. Second, opportunistic mating between these two species as their ranges overlapped has left a strong genetic imprint. In particular, a likely genetic exchange with extinct Irish brown bears forms the origin of the modern polar bear matriline. This suggests that interspecific hybridization not only may be more common than previously considered but may be a mechanism by which species deal with marginal habitats during periods of environmental deterioration. PMID:21737280

  10. Accelerated Senescence and Enhanced Disease Resistance in Hybrid Chlorosis Lines Derived from Interspecific Crosses between Tetraploid Wheat and Aegilops tauschii

    OpenAIRE

    Nakano, Hiroki; Mizuno, Nobuyuki; 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 underlyin...

  11. On the origin of the sweet-smelling Parma violet cultivars (Violaceae): wide intraspecific hybridization, sterility, and sexual reproduction.

    Science.gov (United States)

    Malécot, Valéry; Marcussen, Thomas; Munzinger, Jérôme; Yockteng, Roxana; Henry, Max

    2007-01-01

    Parma violets are reputed for their double, fragrant flowers and have been cultivated for centuries in Europe. However, due to a rather atypical morphology their taxonomic affinity has not been clarified. Authors have proposed an origin from three possible species, Viola alba, V. odorata, or V. suavis, or a hybrid origin. Using both ITS sequence variation and allozyme variation in 14 putative loci, we showed that the Parma violet cultivars have their origin within Viola alba and that they are best included in the Mediterranean subsp. dehnhardtii. There is no trace of interspecific hybridization. However, the cultivars appear to have a single origin in a wide hybrid within V. alba, involving parental plants from the eastern and western Mediterranean region; historical literature sources seem to indicate Turkey and Italy, respectively. The Parma violet cultivars possess high levels of allozyme heterozygosity and to some extent also within-individual ITS sequence variation. Losses of heterozygosity and within-individual ITS sequence variation in some of the cultivars indicate subsequent rare events of sexual reproduction, presumably through cleistogamous seed set. We unambiguously identify the closest wild relative of this group of cultivars, allowing growers to develop new selection procedures, and show a peculiar molecular process associated with human selection.

  12. Homoploid hybrid origin of Yucca gloriosa: intersectional hybrid speciation in Yucca (Agavoideae, Asparagaceae).

    Science.gov (United States)

    Rentsch, Jeremy D; Leebens-Mack, Jim

    2012-09-01

    There is a growing appreciation for the importance of hybrid speciation in angiosperm evolution. Here, we show that Yucca gloriosa (Asparagaceae: Agavoideae) is the product of intersectional hybridization between Y. aloifolia and Y. filamentosa. These species, all named by Carl Linnaeus, exist in sympatry along the southeastern Atlantic coast of the United States. Yucca gloriosa was found to share a chloroplast haplotype with Y. aloifolia in all populations sampled. In contrast, nuclear gene-based microsatellite markers in Y. gloriosa are shared with both parents. The hybrid origin of Y. gloriosa is supported by multilocus analyses of the nuclear microsatellite markers including principal coordinates analysis (PCO), maximum-likelihood hybrid index scoring (HINDEX), and Bayesian cluster analysis (STRUCTURE). The putative parental species share only one allele at a single locus, suggesting there is little to no introgressive gene flow occurring between these species and Y. gloriosa. At the same time, diagnostic markers are segregating in Y. gloriosa populations. Lack of variation in the chloroplast of Y. aloifolia, the putative maternal parent, makes it difficult to rule out multiple hybrid origins of Y. gloriosa, but allelic variation at nuclear loci can be explained by a single hybrid origin of Y. gloriosa. Overall, these data provide strong support for the homoploid hybrid origin of Y. gloriosa.

  13. Genetic Diversity and Origins of the Homoploid-Type Hybrid Phytophthora ×alni.

    Science.gov (United States)

    Aguayo, Jaime; Halkett, Fabien; Husson, Claude; Nagy, Zoltán Á; Szigethy, András; Bakonyi, József; Frey, Pascal; Marçais, Benoit

    2016-12-15

    Assessing the process that gives rise to hybrid pathogens is central to understanding the evolution of emerging plant diseases. Phytophthora ×alni, a pathogen of alder, results from the homoploid hybridization of two related species, Phytophthora uniformis and Phytophthora ×multiformis Describing the genetic characteristics of P ×alni should help us understand how reproductive mechanisms and historical processes shaped the population structure of this emerging hybrid pathogen. The population genetic structure of P ×alni and the relationship with its parental species were investigated using 12 microsatellites and one mitochondrial DNA (mtDNA) marker on a European collection of 379 isolates. Populations of P ×alni were dominated by one multilocus genotype (MLG). The frequency of this dominant MLG increased after the disease emergence together with a decline in diversity, suggesting that it was favored by a genetic mechanism such as drift or selection. Combined microsatellite and mtDNA results confirmed that P ×alni originated from multiple hybridization events that involved different genotypes of the progenitors. Our detailed analyses point to a geographic structure that mirrors that observed for P. uniformis in Europe. The study provides more insights on the contribution of P. uniformis, an invasive species in Europe, to the emergence of Phytophthora-induced alder decline. Our study describes an original approach to assess the population genetics of polyploid organisms using microsatellite markers. By studying the parental subgenomes present in the interspecific hybrid P. ×alni, we were able to assess the geographical and temporal structure of European populations of the hybrid, shedding new light on the evolution of an emerging plant pathogen. In turn, the study of the parental subgenomes permitted us to assess some genetic characteristics of the parental species of P. ×alni, P. uniformis, and P ×multiformis, which are seldom sampled in nature. The

  14. Origin of new Brassica types from a single intergeneric hybrid ...

    Indian Academy of Sciences (India)

    Origin of new Brassica types from a single intergeneric hybrid between B. rapa and Orychophragmus violaceus by rapid chromosome evolution and introgression ... The lines with high productivity showed not only a wide spectrum of phenotypes but also obvious variations in fatty acid profiles of seed oil and glucosinolate ...

  15. The role of plastome-genome incompatibility and biparental plastid inheritance in interspecific hybridization in the genus Zantedeschia (Araceae)

    NARCIS (Netherlands)

    Snijder, R.C.; Santiago Brown, F.; Tuyl, van J.M.

    2007-01-01

    Mosquito plant (Pelargonium × citrosum Vanleenii) is a genetically engineered hybrid possessing the characteristics of geranium coupled with a sweet lemony citronella scent. As such, this hybrid has become much more popular as an ornamental plant with the added benefit of mosquito-repelling

  16. 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.

  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)

    Nakano, Hiroki; Mizuno, Nobuyuki; 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.

  18. Effects of the Fruit Ripening Stage on Antioxidant Capacity, Total Phenolics, and Polyphenolic Composition of Crude Palm Oil from Interspecific Hybrid Elaeis oleifera × Elaeis guineensis.

    Science.gov (United States)

    Rodríguez, Juanita C; Gómez, Daniela; Pacetti, Deborah; Núñez, Oscar; Gagliardi, Riccardo; Frega, Natale G; Ojeda, Myriam L; Loizzo, Monica R; Tundis, Rosa; Lucci, Paolo

    2016-02-03

    In the present study, we assessed for the first time the changes in the antioxidant capacity, total phenolic content, and polyphenolic composition of interspecific hybrid palm oil extracted from Elaeis oleifera × Elaeis guineensis (O × G, Coari × La Mé cultivar) during the fruit ripening process 18, 20, 22, and 24 weeks after anthesis. A progressive decrease (p fruit development together with marked changes in polyphenol profiles. Significant negative correlations were established between antioxidant activity measured by TEAC (R = -0.954; p fruit ripening stage, while a positive correlation between total phenolic content was found using either the TEAC assay or the ORAC assay. The highest DPPH radical scavenging activity was also obtained with oils extracted at 18 WAA. These results highlight that O × G fruits of early ripeness represent a better source of phenolic compounds and may provide extracts with higher antioxidant activities when hybrid palm oil is aimed to be used as a functional ingredient for the development of food or food products with antioxidant properties.

  19. Recent hybrid origin of three rare chinese turtles

    Energy Technology Data Exchange (ETDEWEB)

    Stuart, Bryan L.; Parham, James F.

    2006-02-07

    Three rare geoemydid turtles described from Chinese tradespecimens in the early 1990s, Ocadia glyphistoma, O. philippeni, andSacalia pseudocellata, are suspected to be hybrids because they are knownonly from their original descriptions and because they have morphologiesintermediate between other, better-known species. We cloned the allelesof a bi-parentally inherited nuclear intron from samples of these threespecies. The two aligned parental alleles of O. glyphistoma, O.philippeni, and S. pseudocellata have 5-11.5 times more heterozygouspositions than do 13 other geoemydid species. Phylogenetic analysis showsthat the two alleles from each turtle are strongly paraphyletic, butcorrectly match sequences of other species that were hypothesized frommorphology to be their parental species. We conclude that these rareturtles represent recent hybrids rather than valid species. Specifically,"O. glyphistoma" is a hybrid of Mauremys sinensis and M. cf. annamensis,"O. philippeni" is a hybrid of M. sinensis and Cuora trifasciata, and "S.pseudocellata" is a hybrid of C. trifasciata and S. quadriocellata.Conservation resources are better directed toward finding and protectingpopulations of other rare Southeast Asian turtles that do representdistinct evolutionary lineages.

  20. Interspecific hybridization and inbreeding effect in seed from a Eucalyptus grandis x E. urophylla clonal orchard in Brazil

    Directory of Open Access Journals (Sweden)

    Campinhos Eduardo N.

    1998-01-01

    Full Text Available We used allozyme markers to estimate the amount of natural hybridization between Eucalyptus grandis and E. urophylla in a 7.4-hectare commercial hybrid-seed orchard planted in Espírito Santo, Brazil. This orchard was planted in 1982 using a honeycomb design, with each hexagonal plot containing one E. grandis tree surrounded by six E. urophylla trees. There were 267 replicated hexagonal plots in the orchard. Seeds were harvested from the E. grandis clone only. The multilocus outcrossing rate estimated for the E. grandis clone averaged 70.2%, ranging from 33.0 to 99.0% among individual trees. Contaminant pollination, inferred from progeny genotypes containing alleles not present in the seven parental clones, accounted for 14.4% of the hybrid seed. Contaminant pollen was attributed to neighboring eucalyptus stands isolated from the orchard by a 400-m wide belt of native forest. Inbred and hybrid progenies were identified by their allozyme genotypes and transplanted to the field. Field growth of inbred progeny was 30% lower than that of hybrid plants at two and three years of age.

  1. Evaluation of Turf-type Interspecific Hybrids of Meadow Fescue with Perennial Ryegrass for Improved Stress Tolerance

    Czech Academy of Sciences Publication Activity Database

    Barnes, B.D.; Kopecký, David; Lukaszewski, A.J.; Baird, J. H.

    2014-01-01

    Roč. 54, č. 1 (2014), s. 355-365 ISSN 0011-183X R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : LOLIUM-FESTUCA COMPLEX * TALL FESCUE * INTERGENERIC HYBRIDS Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.575, year: 2014

  2. 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

  3. 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).

  4. Lotus tenuis x L. corniculatus interspecific hybridization as a means to breed bloat-safe pastures and gain insight into the genetic control of proanthocyanidin biosynthesis in legumes.

    Science.gov (United States)

    Escaray, Francisco J; Passeri, Valentina; Babuin, Florencia M; Marco, Francisco; Carrasco, Pedro; Damiani, Francesco; Pieckenstain, Fernando L; Paolocci, Francesco; Ruiz, Oscar A

    2014-02-03

    Proanthocyanidins (PAs) are secondary metabolites that strongly affect plant quality traits. The concentration and the structure of these metabolites influence the palatability and nutritional value of forage legumes. Hence, modulating PAs in the leaves of forage legumes is of paramount relevance for forage breeders worldwide. The lack of genetic variation in the leaf PA trait within the most important forage species and the difficulties in engineering this pathway via the ectopic expression of regulatory genes, prompted us to pursue alternative strategies to enhance this trait in forage legumes of agronomic interest. The Lotus genus includes forage species which accumulate PAs in edible organs and can thus be used as potential donor parents in breeding programs. We recovered a wild, diploid and PA-rich population of L. corniculatus and crossed with L. tenuis. The former grows in an alkaline-salty area in Spain while the latter is a diploid species, grown extensively in South American pastures, which does not accumulate PAs in the herbage. The resulting interspecific hybrids displayed several traits of outstanding agronomic relevance such as rhizome production, PA levels in edible tissues sufficient to prevent ruminal bloating (around 5 mg of PAs/g DW), biomass production similar to the cultivated parent and potential for adaptability to marginal lands. We show that PA levels correlate with expression levels of the R2R3MYB transcription factor TT2 and, in turn, with those of the key structural genes of the epicatechin and catechin biosynthetic pathways leading to PA biosynthesis. The L. tenuis x L. corniculatus hybrids, reported herein, represent the first example of the introgression of the PA trait in forage legumes to levels known to provide nutritional and health benefits to ruminants. Apart from PAs, the hybrids have additional traits which may prove useful to breed forage legumes with increased persistence and adaptability to marginal conditions. Finally, our

  5. 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)

  6. Recent, independent and anthropogenic origins of Trypanosoma cruzi hybrids.

    Directory of Open Access Journals (Sweden)

    Michael D Lewis

    2011-10-01

    Full Text Available The single celled eukaryote Trypanosoma cruzi, a parasite transmitted by numerous species of triatomine bug in the Americas, causes Chagas disease in humans. T. cruzi generally reproduces asexually and appears to have a clonal population structure. However, two of the six major circulating genetic lineages, TcV and TcVI, are TcII-TcIII inter-lineage hybrids that are frequently isolated from humans in regions where chronic Chagas disease is particularly severe. Nevertheless, a prevalent view is that hybridisation events in T. cruzi were evolutionarily ancient and that active recombination is of little epidemiological importance. We analysed genotypes of hybrid and non-hybrid T. cruzi strains for markers representing three distinct evolutionary rates: nuclear GPI sequences (n = 88, mitochondrial COII-ND1 sequences (n = 107 and 28 polymorphic microsatellite loci (n = 35. Using Maximum Likelihood and Bayesian phylogenetic approaches we dated key evolutionary events in the T. cruzi clade including the emergence of hybrid lineages TcV and TcVI, which we estimated to have occurred within the last 60,000 years. We also found evidence for recent genetic exchange between TcIII and TcIV and between TcI and TcIV. These findings show that evolution of novel recombinants remains a potential epidemiological risk. The clearly distinguishable microsatellite genotypes of TcV and TcVI were highly heterozygous and displayed minimal intra-lineage diversity indicative of even earlier origins than sequence-based estimates. Natural hybrid genotypes resembled typical meiotic F1 progeny, however, evidence for mitochondrial introgression, absence of haploid forms and previous experimental crosses indicate that sexual reproduction in T. cruzi may involve alternatives to canonical meiosis. Overall, the data support two independent hybridisation events between TcII and TcIII and a recent, rapid spread of the hybrid progeny in domestic transmission cycles

  7. Simultaneous delimitation of species and quantification of interspecific hybridization in Amazonian peacock cichlids (genus cichla) using multi-locus data.

    Science.gov (United States)

    Willis, Stuart C; Macrander, Jason; Farias, Izeni P; Ortí, Guillermo

    2012-06-22

    Introgression likely plays a significant role in evolution, but understanding the extent and consequences of this process requires a clear identification of species boundaries in each focal group. The delimitation of species, however, is a contentious endeavor. This is true not only because of the inadequacy of current tools to identify species lineages, but also because of the inherent ambiguity between natural populations and species paradigms. The result has been a debate about the supremacy of various species concepts and criteria. Here, we utilized multiple separate sources of molecular data, mtDNA, nuclear sequences, and microsatellites, to delimit species under a polytypic species concept (PTSC) and estimate the frequency and genomic extent of introgression in a Neotropical genus of cichlid fishes (Cichla). We compared our inferences of species boundaries and introgression under this paradigm to those when species are identified under a diagnostic species concept (DSC). We find that, based on extensive molecular data and an inclusive species concept, 8 separate biological entities should be recognized rather than the 15 described species of Cichla. Under the PTSC, fewer individuals are expected to exhibit hybrid ancestry than under the DSC (~2% vs. ~12%), but a similar number of the species exhibit introgression from at least one other species (75% vs. 60%). Under either species concept, the phylogenetic breadth of introgression in this group is notable, with both sister species and species from different major mtDNA clades exhibiting introgression. Introgression was observed to be a widespread phenomenon for delimited species in this group. While several instances of introgressive hybridization were observed in anthropogenically altered habitats, most were found in undisturbed natural habitats, suggesting that introgression is a natural but ephemeral part of the evolution of many tropical species. Nevertheless, even transient introgression may facilitate an

  8. Strongly asymmetric hybridization barriers shape the origin of a new polyploid species and its hybrid ancestor.

    Science.gov (United States)

    Vallejo-Marín, Mario; Cooley, Arielle M; Lee, Michelle Yuequi; Folmer, Madison; McKain, Michael R; Puzey, Joshua R

    2016-07-01

    Hybridization between diploids and tetraploids can lead to new allopolyploid species, often via a triploid intermediate. Viable triploids are often produced asymmetrically, with greater success observed for "maternal-excess" crosses where the mother has a higher ploidy than the father. Here we investigated the evolutionary origins of Mimulus peregrinus, an allohexaploid recently derived from the triploid M. ×robertsii, to determine whether reproductive asymmetry has shaped the formation of this new species. We used reciprocal crosses between the diploid (M. guttatus) and tetraploid (M. luteus) progenitors to determine the viability of triploid M. ×robertsii hybrids resulting from paternal- vs. maternal-excess crosses. To investigate whether experimental results predict patterns seen in the field, we performed parentage analyses comparing natural populations of M. peregrinus to its diploid, tetraploid, and triploid progenitors. Organellar sequences obtained from pre-existing genomic data, supplemented with additional genotyping was used to establish the maternal ancestry of multiple M. peregrinus and M. ×robertsii populations. We found strong evidence for asymmetric origins of M. peregrinus, but opposite to the common pattern, with paternal-excess crosses significantly more successful than maternal-excess crosses. These results successfully predicted hybrid formation in nature: 111 of 114 M. ×robertsii individuals, and 27 of 27 M. peregrinus, had an M. guttatus maternal haplotype. This study, which includes the first Mimulus chloroplast genome assembly, demonstrates the utility of parentage analysis through genome skimming. We highlight the benefits of complementing genomic analyses with experimental approaches to understand asymmetry in allopolyploid speciation. © 2016 Botanical Society of America.

  9. MITOCHONDRIAL DNA ANALYSES AND THE ORIGIN AND RELATIVE AGE OF PARTHENOGENETIC CNEMIDOPHORUS: PHYLOGENETIC CONSTRAINTS ON HYBRID ORIGINS.

    Science.gov (United States)

    Moritz, C; Wright, J W; Brown, W M

    1992-02-01

    Within the genus Cnemidophorus, parthenogenesis has arisen by hybridization several times. This provides the opportunity to investigate general features of hybridization events that result in the formation of parthenogenetic lineages. The relationships of mtDNA from all bisexual species of Cnemidophorus known to be parents of parthenogens were investigated to evaluate phylogenetic constraints on the hybrid-origin of parthenogenesis. No phylogenetic clustering of the parental species, either maternal or paternal, was apparent. However, the combination of bisexual species that have resulted in parthenogenetic lineages are generally distantly related or genetically divergent. This contrasts with the expectation if parthenogenesis in hybrids is due to the action of a single rare allele, but is consistent with the hypothesis that some minimal level of divergence is necessary to stimulate parthenogenetic reproduction in hybrids. © 1992 The Society for the Study of Evolution.

  10. Lipase activity, mesocarp oil content, and iodine value in oil palm fruits of Elaeis guineensis, Elaeis oleifera, and the interspecific hybrid O×G (E. oleifera × E. guineensis).

    Science.gov (United States)

    Cadena, Tatiana; Prada, Fausto; Perea, Aidé; Romero, Hernán Mauricio

    2013-02-01

    One factor affecting crude palm oil quality is the formation of free fatty acids (FFA), often attributed to the hydrolytic action of mesocarp lipase. The aim of this work was to evaluate the enzyme behavior and to look toward new genotypes with low FFA production, high yield, and better oil quality. Lipase activity was strongly activated at low temperatures (5 °C). At this temperature PLL, SOO, POL, and POO (P, palmitic; L, linoleic; S, stearic; O, oleic) were the most hydrolyzed triacylglycerols in Elaeis guineensis fruits. Ethylene production decreased from 36 nL g(-1) h(-1) at room temperature to 2 nL g(-1) h(-1) at 5 °C. Lipase activity of E. guineensis, the E. oleifera × E. guineensis (O×G) hybrid, and E. oleifera were 52.7%, 32.9%, and oil in the mesocarp of 54.7%, followed by the O×G hybrid (47.0%), and E. oleifera (13.6%), and the iodine values were 52.0, 66.3, and 77.4 g I(2) 100 g(-1), respectively. This work allowed the identification of interspecific O×G hybrids as promising crosses with less lipase activity and higher iodine value than E. guineensis. Although O×G crosses produce less oil in the mesocarp than commercial E. guineensis; this feature could be improved by further breeding to introduce new genes from E. oleifera into the hybrids. © 2012 Society of Chemical Industry.

  11. Characterization of interspecific hybrid dikaryons of the oyster mushrooms, Pleurotus florida PAU-5 and P. sajor-caju PAU-3 (higher Basidiomycetes) from India.

    Science.gov (United States)

    Jaswal, Ravinder Kumar; Sodhi, Harpreet Singh; Sharma, Shivani

    2014-01-01

    Five Pleurotus hybrid dikaryons, developed through cross-breeding of P. florida PAU-5 (PF-5) and P. sajor-caju PAU-3 (PSC-3) were characterized with respect to textural properties, color, and enzymatic and genetic variability. Texture profile revealed significant differences in springiness, resilience, cohesiveness, and chewiness between all hybrids compared to the parents. Among the hybrid cultures, maximum whiteness was reported in hybrid 37, whereas hybrid 8 had minimum whiteness. Three hybrids (16, 37, 42) showed an increased linear growth rate in relation to PF-5, whereas no hybrid showed a higher growth rate than PSC-3. Maximum endoglucanase and xylanase activity was observed in hybrid 46, whereas minimum activity occurred in hybrid 42. Laccase and protease activity was higher in hybrid 37 and 46, respectively. Four hybrids (16, 37, 42, 46) showed increased peroxidase activity in relation to PF-5, whereas hybrid 46 showed activity higher than the parent PSC-3. Comparison of isozyme patterns confirmed the hybrid nature of hybrid 16. The large variation in the intensity of bands could be a result of recombination. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of extracellular enzymes revealed 60.3- and 43-KDa bands in all the hybrids. An additional 25-KDa band was reported in hybrids 37, 42, and 46 and the parent PF-5, indicating their close relatedness. Parental strains showed higher divergence in small-subunit ribosomal DNA region compared with the internal transcribed spacer region, indicating their significance in varietal discrimination. Hybrid 46 had a small-subunit ribosomal DNA region more similar to that of PSC-3 compared with PF-5, whereas the internal transcribed spacer region of hybrids 42 and 46 revealed close resemblance to that of PF-5 and PSC-3, respectively.

  12. Fine mapping and genetic association analysis of Net2, the causative D-genome locus of low temperature-induced hybrid necrosis in interspecific crosses between tetraploid wheat and Aegilops tauschii.

    Science.gov (United States)

    Sakaguchi, Kouhei; Nishijima, Ryo; Iehisa, Julio Cesar Masaru; Takumi, Shigeo

    2016-10-01

    Hybrid necrosis has been observed in many interspecific hybrids from crosses between tetraploid wheat and the wheat D-genome donor Aegilops tauschii. Type II necrosis is a kind of hybrid incompatibility that is specifically characterized by low-temperature induction and growth suppression. Two complementary genes, Net1 on the AB genome and Net2 on the D genome, putatively control type II necrosis in ABD triploids and synthetic hexaploid wheat. Toward map-based cloning of Net2, a fine map around the Net2 region on 2DS was constructed in this study. Using the draft genome sequence of Ae. tauschii and the physical map of the barley genome, the Net2 locus was mapped within a 0.6 cM interval between two closely linked markers. Although local chromosomal rearrangements were observed in the Net2-corresponding region between the barley/Brachypodium and Ae. tauschii genomes, the two closely linked markers were significantly associated with type II necrosis in Ae. tauschii. These results suggest that these markers will aid efficient selection of Net2 non-carrier individuals from the Ae. tauschii population and intraspecific progeny, and could help with introgression of agriculturally important genes from Ae. tauschii to common wheat.

  13. Thermodynamic origin of instability in hybrid halide perovskites

    Science.gov (United States)

    Tenuta, E.; Zheng, C.; Rubel, O.

    2016-11-01

    Degradation of hybrid halide perovskites under the influence of environmental factors impairs future prospects of using these materials as absorbers in solar cells. First principle calculations can be used as a guideline in search of new materials, provided we can rely on their predictive capabilities. We show that the instability of perovskites can be captured using ab initio total energy calculations for reactants and products augmented with additional thermodynamic data to account for finite temperature effects. Calculations suggest that the instability of CH3NH3PbI3 in moist environment is linked to the aqueous solubility of the CH3NH3I salt, thus making other perovskite materials with soluble decomposition products prone to degradation. Properties of NH3OHPbI3, NH3NH2PbI3, PH4PbI3, SbH4PbI3, CsPbBr3, and a new hypothetical SF3PbI3 perovskite are studied in the search for alternative solar cell absorber materials with enhanced chemical stability.

  14. Fine mapping of Hch1, the causal D-genome gene for hybrid chlorosis in interspecific crosses between tetraploid wheat and Aegilops tauschii.

    Science.gov (United States)

    Hirao, Kana; Nishijima, Ryo; Sakaguchi, Kohei; Takumi, Shigeo

    2015-01-01

    Hybrid chlorosis, one of the reproductive barriers between tetraploid wheat and its D-genome progenitor, Aegilops tauschii, inhibits normal growth of synthetic wheat hexaploids. Hybrid chlorosis appears to be due to an epistatic interaction of two loci from the AB and D wheat genomes. Our previous study assigned the causal D-genome gene for hybrid chlorosis, Hch1, to the short arm of chromosome 7D. Here, we constructed a fine map of 7DS near Hch1 using 280 F2 individuals from a cross of two wheat synthetic lines, one showing normal growth and the other showing hybrid chlorosis. The hybrid chlorosis phenotype was controlled by a single dominant allele of the Hch1 locus in the synthetic hexaploids. Hch1 was closely linked to four new markers within 0.2 cM, and may be localized near or within the two Ae. tauschii scaffolds containing the linked markers on 7DS. Comparative analysis of the Hch1 chromosomal region for Ae. tauschii, barley and Brachypodium showed that a local inversion occurred in the region proximal to Hch1 during the divergence between barley and Ae. tauschii, and that the Hch1 region on wheat 7DS is syntenic to Brachypodium chromosome 1. These observations provide useful information for further studies toward map-based cloning of Hch1.

  15. Characterization of chromosome instability in interspecific somatic hybrids obtained by X-ray fusion between potato (Solanum tuberosum L.) and S. brevidens Phil

    International Nuclear Information System (INIS)

    Fehér, A.; Preiszner, J.; Litkey, Z.; Csanádi, G; Dudits, D.

    1992-01-01

    Asymmetric somatic hybrids between Solanum tuberosum L. and S. brevidens Phil. have been obtained via the fusion of protoplasts from potato leaves and from cell suspension culture of S. brevidens. The wild Solanum species served as donor after irradiation of its protoplasts with a lethal X-ray dose (200 Gy). Selection of the putative hybrids was based on the kanamycin-resistance marker gene previously introduced into the genome of Solanum brevidens by Agrobacterium-mediated gene transfer. Thirteen out of the 45 selected clones exhibited reduced morphogenic potential. The morphological abnormalities of the regenerated plantlets were gradually eliminated during the extended in vitro culture period. Cytological investigations revealed that the number of chromosomes in the cultured S. brevidens cells used as protoplast source ranged between 28-40 instead of the basic 2n=24 value. There was a high degree of aneuploidy in all of the investigated hybrid clones, and at least 12 extra chromosomes were observed in addition to the potato chromosomes (2n=48). Interand intraclonal variation and segregation during vegetative propagation indicated the genetic instability of the hybrids, which can be ascribed to the pre-existing and X-ray irradiation-induced chromosomal abnormalities in the donor S. brevidens cells. The detection of centromeric chromosome fragments and long, poly-constrictional chromosomes in cytological preparations as well as non-parental bands in Southern hybridizations with restriction fragment length polymorphism (RFLP) markers revealed extensive chromosome rearrangements in most of the regenerated clones. On the basis of the limited number of RFLP probes used, preferential loss of S. brevidens specific markers with a non-random elimination pattern could be detected in hybrid regenerants

  16. Interspecific hybridization contributes to high genetic diversity and apparent effective population size in an endemic population of mottled ducks (Anas fulvigula maculosa)

    Science.gov (United States)

    Peters, Jeffrey L.; Sonsthagen, Sarah A.; Lavretsky, Philip; Rezsutek, Michael; Johnson, William P.; McCracken, Kevin G.

    2014-01-01

    Under drift-mutation equilibrium, genetic diversity is expected to be correlated with effective population size (Ne). Changes in population size and gene flow are two important processes that can cause populations to deviate from this expected relationship. In this study, we used DNA sequences from six independent loci to examine the influence of these processes on standing genetic diversity in endemic mottled ducks (Anas fulvigula) and geographically widespread mallards (A. platyrhynchos), two species known to hybridize. Mottled ducks have an estimated census size that is about two orders-of-magnitude smaller than that of mallards, yet these two species have similar levels of genetic diversity, especially at nuclear DNA. Coalescent analyses suggest that a population expansion in the mallard at least partly explains this discrepancy, but the mottled duck harbors higher genetic diversity and apparent N e than expected for its census size even after accounting for a population decline. Incorporating gene flow into the model, however, reduced the estimated Ne of mottled ducks to 33 % of the equilibrium Ne and yielded an estimated Ne consistent with census size. We also examined the utility of these loci to distinguish among mallards, mottled ducks, and their hybrids. Most putatively pure individuals were correctly assigned to species, but the power for detecting hybrids was low. Although hybridization with mallards potentially poses a conservation threat to mottled ducks by creating a risk of extinction by hybridization, introgression of mallard alleles has helped maintain high genetic diversity in mottled ducks and might be important for the adaptability and survival of this species.

  17. Effects of temperature, pH and sugar concentration on the growth parameters of Saccharomyces cerevisiae, S. kudriavzevii and their interspecific hybrid.

    Science.gov (United States)

    Arroyo-López, F Noé; Orlić, Sandi; Querol, Amparo; Barrio, Eladio

    2009-05-31

    The effects of temperature, pH and sugar concentration (50% glucose+50% fructose) on the growth parameters of Saccharomyces cerevisiae T73, S. kudriavzevii IFO 1802(T) and the hybrid strain S. cerevisiae x S. kudriavzevii W27 were studied by means of response surface methodology based in a central composite circumscribed design. Lag phase could not be properly modelled in the wine model system, where yeasts started the fermentation in few hours after inoculation. In the case of the maximum specific growth rate (micro(max)), the temperature was the most important variable for three yeasts, although the effects of sugar concentration (in T73 and W27) and pH (W27 and 1802) were also significant (ptemperature and pH for yeast 1802. The polynomial equations built for micro(max) were used both to assess the behaviour of yeasts as a function of the factors and to predict their growth. In the case of temperature, the profiles obtained by the equations showed that response of the hybrid W27 was similar to T73 and different to 1802. When pH was the factor under study, the response of the hybrid W27 was closer to 1802 than yeast T73. For sugar concentration, the response of the hybrid W27 was similar to T73 but different to 1802. To the best of our knowledge, this is the first time that predictive models are used to assess and compare the response of a hybrid strain with respect to its parental species. The information obtained could also be useful to estimate the possible effect of climatic change on yeast growth.

  18. A phylogeographic investigation of the hybrid origin of a species of swordtail fish from Mexico.

    Science.gov (United States)

    Jones, Julia C; Perez-Sato, Juan-Antonio; Meyer, Axel

    2012-06-01

    Hybrid speciation may contribute significantly to generating biodiversity, but only a few well-documented examples for it exist so far that do not involve polyploidization as a mechanism. The swordtail fish, Xiphophorus clemenciae, shows common hallmarks of a hybrid origin and still overlaps in its current geographic distribution with its putative ancestral species (Xiphophorus hellerii and Xiphophorus maculatus). Xiphophorus clemenciae provides an ideal system for investigating the possible continued genetic interactions between a hybrid and its parental species. Here, we use microsatellite and mitochondrial markers to investigate the population structure of these species of swordtails and search for signs of recent hybridization. Individuals were sampled from 21 localities across the known range of X. clemenciae- the Isthmus of Tehuantepec (IT) Mexico, and several environmental parameters that might represent barriers to dispersal were recorded. The hybridization event that gave rise to X. clemenciae appears to be rather ancient, and a single origin is likely. We find negligible evidence for ongoing hybridization and introgression between the putative ancestral species, because they now occupy distinct ecological niches, and a common haplotype is shared by most populations of X. clemenciae. The population structure within these species shows an isolation-by-distance (IBD) pattern and genetic differentiation between most populations is significant and high. We infer that tectonic evolution in the Isthmus has greatly restricted gene flow between the southern and central IT populations of X. clemenciae and X. helleriii and provide preliminary information to aid in conservation management of this geographically restricted hybrid species, X. clemenciae. © 2012 Blackwell Publishing Ltd.

  19. Genetic Characterization of Bombyx mori (Lepidoptera: Bombycidae) Breeding and Hybrid Lines With Different Geographic Origins

    Science.gov (United States)

    Furdui, Emilia M.; Mărghitaş, Liviu A.; Dezmirean, Daniel S.; Paşca, Ioan; Pop, Iulia F.; Erler, Silvio; Schlüns, Ellen A.

    2014-01-01

    Abstract The domesticated silkworm Bombyx mori L. comprises a large number of geographical breeds and hybrid lines. Knowing the genetic structure of those may provide information to improve the conservation of commercial lines by estimating inbreeding over generations and the consequences of excessive use of those lineages. Here, we analyzed the genetic diversity of seven breeds and eight hybrid lines from Eastern Europe and Asia using highly polymorphic microsatellites markers to determine its genetical impact on their use in global breeding programs. No consistent pattern of deviation from Hardy–Weinberg equilibrium was found for most breed and hybrids; and the absence of a linkage disequilibrium also suggests that the strains are in equilibrium. A principal coordinate analysis revealed a clear separation of two silkworm breeds from the rest: one (IBV) originated from India and the other one (RG 90 ) from Romania/Japan. The tendency of the other breeds from different geographic origins to cluster together in a general mix might be due to similar selection pressures (climate and anthropogenic factors) in different geographic locations. Phylogenetic analyses grouped the different silkworm breeds but not the hybrids according to their geographic origin and confirmed the pattern found in the principal coordinate analysis. PMID:25502023

  20. Breaking and Fixing Origin-Based Access Control in Hybrid Web/Mobile Application Frameworks.

    Science.gov (United States)

    Georgiev, Martin; Jana, Suman; Shmatikov, Vitaly

    2014-02-01

    Hybrid mobile applications (apps) combine the features of Web applications and "native" mobile apps. Like Web applications, they are implemented in portable, platform-independent languages such as HTML and JavaScript. Like native apps, they have direct access to local device resources-file system, location, camera, contacts, etc. Hybrid apps are typically developed using hybrid application frameworks such as PhoneGap. The purpose of the framework is twofold. First, it provides an embedded Web browser (for example, WebView on Android) that executes the app's Web code. Second, it supplies "bridges" that allow Web code to escape the browser and access local resources on the device. We analyze the software stack created by hybrid frameworks and demonstrate that it does not properly compose the access-control policies governing Web code and local code, respectively. Web code is governed by the same origin policy, whereas local code is governed by the access-control policy of the operating system (for example, user-granted permissions in Android). The bridges added by the framework to the browser have the same local access rights as the entire application, but are not correctly protected by the same origin policy. This opens the door to fracking attacks, which allow foreign-origin Web content included into a hybrid app (e.g., ads confined in iframes) to drill through the layers and directly access device resources. Fracking vulnerabilities are generic: they affect all hybrid frameworks, all embedded Web browsers, all bridge mechanisms, and all platforms on which these frameworks are deployed. We study the prevalence of fracking vulnerabilities in free Android apps based on the PhoneGap framework. Each vulnerability exposes sensitive local resources-the ability to read and write contacts list, local files, etc.-to dozens of potentially malicious Web domains. We also analyze the defenses deployed by hybrid frameworks to prevent resource access by foreign-origin Web content

  1. Breaking and Fixing Origin-Based Access Control in Hybrid Web/Mobile Application Frameworks

    Science.gov (United States)

    Georgiev, Martin; Jana, Suman; Shmatikov, Vitaly

    2014-01-01

    Hybrid mobile applications (apps) combine the features of Web applications and “native” mobile apps. Like Web applications, they are implemented in portable, platform-independent languages such as HTML and JavaScript. Like native apps, they have direct access to local device resources—file system, location, camera, contacts, etc. Hybrid apps are typically developed using hybrid application frameworks such as PhoneGap. The purpose of the framework is twofold. First, it provides an embedded Web browser (for example, WebView on Android) that executes the app's Web code. Second, it supplies “bridges” that allow Web code to escape the browser and access local resources on the device. We analyze the software stack created by hybrid frameworks and demonstrate that it does not properly compose the access-control policies governing Web code and local code, respectively. Web code is governed by the same origin policy, whereas local code is governed by the access-control policy of the operating system (for example, user-granted permissions in Android). The bridges added by the framework to the browser have the same local access rights as the entire application, but are not correctly protected by the same origin policy. This opens the door to fracking attacks, which allow foreign-origin Web content included into a hybrid app (e.g., ads confined in iframes) to drill through the layers and directly access device resources. Fracking vulnerabilities are generic: they affect all hybrid frameworks, all embedded Web browsers, all bridge mechanisms, and all platforms on which these frameworks are deployed. We study the prevalence of fracking vulnerabilities in free Android apps based on the PhoneGap framework. Each vulnerability exposes sensitive local resources—the ability to read and write contacts list, local files, etc.—to dozens of potentially malicious Web domains. We also analyze the defenses deployed by hybrid frameworks to prevent resource access by foreign-origin

  2. Exploring the origin of the D genome of oat by fluorescence in situ hybridization.

    Science.gov (United States)

    Luo, Xiaomei; Zhang, Haiqin; Kang, Houyang; Fan, Xing; Wang, Yi; Sha, Lina; Zhou, Yonghong

    2014-09-01

    Further understanding of the origin of cultivated oat would accelerate its genetic improvement. In particular, it would be useful to clarify which diploid progenitor contributed the D genome of this allohexaploid species. In this study, we demonstrate that the landmarks produced by fluorescence in situ hybridization (FISH) of species of Avena using probes derived from Avena sativa can be used to explore the origin of the D genome. Selected sets of probes were hybridized in several sequential experiments performed on exactly the same chromosome spreads, with multiple probes of cytological preparations. Probes pITS and A3-19 showed there might be a similar distribution of pITS between the Ac and D genomes. These results indicated that the Ac genome is closely related to the D genome, and that Avena canariensis (AcAc) could be the D-genome donor of cultivated oat.

  3. 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 ...

  4. Interspecific hybridisation of Lathyrus sativus (Guaya) with wild ...

    African Journals Online (AJOL)

    Except for the reciprocal crosses of L. sativus and L. pseudo-cicera, others failed to develop viable seeds. In several of the interspecific hybrids, pod development was observed but embryos aborted during early stages of development. Embryo culture was attempted to rescue these immature embryos. The response of the ...

  5. Multiple and asymmetrical origin of polyploid dog rose hybrids (Rosa L. sect. Caninae (DC.) Ser.) involving unreduced gametes.

    Science.gov (United States)

    Herklotz, V; Ritz, C M

    2017-08-01

    Polyploidy and hybridization are important factors for generating diversity in plants. The species-rich dog roses ( Rosa sect. Caninae ) originated by allopolyploidy and are characterized by unbalanced meiosis producing polyploid egg cells (usually 4 x ) and haploid sperm cells (1 x ). In extant natural stands species hybridize spontaneously, but the extent of natural hybridization is unknown. The aim of the study was to document the frequency of reciprocal hybridization between the subsections Rubigineae and Caninae with special reference to the contribution of unreduced egg cells (5 x ) producing 6 x offspring after fertilization with reduced (1 x ) sperm cells. We tested whether hybrids arose by independent multiple events or via a single or few incidences followed by a subsequent spread of hybrids. Population genetics of 45 mixed stands of dog roses across central and south-eastern Europe were analysed using microsatellite markers and flow cytometry. Hybrids were recognized by the presence of diagnostic alleles and multivariate statistics were used to display the relationships between parental species and hybrids. Among plants classified to subsect. Rubigineae , 32 % hybridogenic individuals were detected but only 8 % hybrids were found in plants assigned to subsect. Caninae . This bias between reciprocal crossings was accompanied by a higher ploidy level in Rubigineae hybrids, which originated more frequently by unreduced egg cells. Genetic patterns of hybrids were strongly geographically structured, supporting their independent origin. The biased crossing barriers between subsections are explained by the facilitated production of unreduced gametes in subsect. Rubigineae . Unreduced egg cells probably provide the highly homologous chromosome sets required for correct chromosome pairing in hybrids. Furthermore, the higher frequency of Rubigineae hybrids is probably influenced by abundance effects because the plants of subsect. Caninae are much more abundant

  6. Role for RNA:DNA hybrids in origin-independent replication priming in a eukaryotic system.

    Science.gov (United States)

    Stuckey, Ruth; García-Rodríguez, Néstor; Aguilera, Andrés; Wellinger, Ralf Erik

    2015-05-05

    DNA replication initiates at defined replication origins along eukaryotic chromosomes, ensuring complete genome duplication within a single S-phase. A key feature of replication origins is their ability to control the onset of DNA synthesis mediated by DNA polymerase-α and its intrinsic RNA primase activity. Here, we describe a novel origin-independent replication process that is mediated by transcription. RNA polymerase I transcription constraints lead to persistent RNA:DNA hybrids (R-loops) that prime replication in the ribosomal DNA locus. Our results suggest that eukaryotic genomes have developed tools to prevent R-loop-mediated replication events that potentially contribute to copy number variation, particularly relevant to carcinogenesis.

  7. Nuclear glutamine synthetase evolution in Nicotiana: phylogenetics and the origins of allotetraploid and homoploid (diploid) hybrids.

    Science.gov (United States)

    Clarkson, James J; Kelly, Laura J; Leitch, Andrew R; Knapp, Sandra; Chase, Mark W

    2010-04-01

    Interspecies relationships in Nicotiana (Solanaceae) are complex because 40 species are diploid (two sets of chromosomes) and 35 species are allotetraploid (four sets of chromosomes, two from each progenitor diploid species). We sequenced a fragment (containing four introns) of the nuclear gene 'chloroplast-expressed glutamine synthetase' (ncpGS) in 65 species of Nicotiana. Here we present the first phylogenetic analysis based on a low-copy nuclear gene for this well studied and important genus. Diploid species have a single-copy of ncpGS, and allotetraploids as expected have two homeologous copies, each derived from their progenitor diploid. Results were particularly useful for determining the paternal lineage of previously enigmatic taxa (for which our previous analyses had revealed only the maternal progenitors). In particular, we were able to shed light on the origins of the two oldest and largest allotetraploid sections, N. sects. Suaveolentes and Repandae. All homeologues have an intact reading frame and apparently similar rates of divergence, suggesting both remain functional. Difficulties in fitting certain diploid species into the sectional classification of Nicotiana on morphological grounds, coupled with discordance between the ncpGS data and previous trees (i.e. plastid, nuclear ribosomal DNA), indicate a number of homoploid (diploid) hybrids in the genus. We have evidence for Nicotiana glutinosa and Nicotiana linearis being of hybrid origin and patterns of intra-allelic recombination also indicate the possibility of reticulate origins for other diploid species. (c) 2009 Elsevier Inc. All rights reserved.

  8. The role of hybridization in the origin and spread of asexuality in Daphnia

    Science.gov (United States)

    Xu, Sen; Innes, David J.; Lynch, Michael; Cristescu, Melania E.

    2014-01-01

    The molecular mechanisms leading to asexuality remain little understood despite their substantial bearing on why sexual reproduction is dominant in nature. Here we examine the role of hybridization in the origin and spread of obligate asexuality in Daphnia pulex, arguably the best-documented case of contagious asexuality. Obligately parthenogenetic (OP) clones of D. pulex have traditionally been separated into “hybrid” (Ldh SF) and “non-hybrid” (Ldh SS) forms because the lactase dehydrogenase (Ldh) locus distinguishes the cyclically parthenogenetic (CP) lake dwelling Daphnia pulicaria (Ldh FF) from its ephemeral pond dwelling sister species D. pulex (Ldh SS). The results of our population genetic analyses based on microsatellite loci suggest that both Ldh SS and SF OP individuals can originate from the crossing of CP female F1 (D. pulex × D. pulicaria) and backcrosses with males from OP lineages carrying genes that suppress meiosis specifically in female offspring. In previous studies, a suite of diagnostic markers was found to be associated with OP in Ldh SS D. pulex lineages. Our association mapping supports a similar genetic mechanism for the spread of obligate parthenogenesis in Ldh SF OP individuals. Interestingly, our study shows that CP D. pulicaria carry many of the diagnostic microsatellite alleles associated with obligate parthenogenesis. We argue that the assemblage of mutations that suppress meiosis and underlie obligate parthenogenesis in D. pulex originated due to a unique historical hybridization and introgression event between D. pulex and D. pulicaria. PMID:23879327

  9. Examining reproducibility in psychology: A hybrid method for combining a statistically significant original study and a replication.

    Science.gov (United States)

    van Aert, Robbie C M; van Assen, Marcel A L M

    2017-09-21

    The unrealistically high rate of positive results within psychology has increased the attention to replication research. However, researchers who conduct a replication and want to statistically combine the results of their replication with a statistically significant original study encounter problems when using traditional meta-analysis techniques. The original study's effect size is most probably overestimated because it is statistically significant, and this bias is not taken into consideration in traditional meta-analysis. We have developed a hybrid method that does take the statistical significance of an original study into account and enables (a) accurate effect size estimation, (b) estimation of a confidence interval, and (c) testing of the null hypothesis of no effect. We analytically approximate the performance of the hybrid method and describe its statistical properties. By applying the hybrid method to data from the Reproducibility Project: Psychology (Open Science Collaboration, 2015), we demonstrate that the conclusions based on the hybrid method are often in line with those of the replication, suggesting that many published psychological studies have smaller effect sizes than those reported in the original study, and that some effects may even be absent. We offer hands-on guidelines for how to statistically combine an original study and replication, and have developed a Web-based application ( https://rvanaert.shinyapps.io/hybrid ) for applying the hybrid method.

  10. Molecular evidence for the hybrid origin of Potamogeton ×subrufus Hagstr. (Potamogetonaceae

    Directory of Open Access Journals (Sweden)

    Joanna Zalewska-Gałosz

    2014-09-01

    Full Text Available Potamogeton ×subrufus Hagstr. was described as a hybrid between P. lucens L. and P. nodosus Poir.; however, the taxon had not been widely accepted and regarded as conspecific with P. ×fluitans Roth, the hybrid between P. lucens and P. natans L. The origin of P. ×subrufus had been obscured till 2010, when, based on morpho-anatomical treatment, it was shown that P. ×subrufus displays several characters consistently different from those of P. ×fluitans. Here we report a successful amplification and sequencing of nuclear ribosomal ITS1 region from a 115 year-old herbarium specimen of P. ×subrufus, collected in locus classicus by J. Baagöe and preserved in the Herbarium of the Institute of Botany, Jagiellonian University (KRA. Based on the additive polymorphism pattern expressed in the ITS1 sequences of P. ×subrufus, we demonstrate that one of the parents of this hybrid was P. nodosus, as was claimed by Hagström.

  11. Increased capacity for sustained locomotion at low temperature in parthenogenetic geckos of hybrid origin.

    Science.gov (United States)

    Kearney, Michael; Wahl, Rebecca; Autumn, Kellar

    2005-01-01

    The evolution of parthenogenesis is typically associated with hybridization and polyploidy. These correlates of parthenogenesis may have important physiological consequences that need be taken into account in understanding the relative merits of sexual and parthenogenetic reproduction. We compared the thermal sensitivity of aerobically sustained locomotion in hybrid/triploid parthenogenetic races of the gecko Heteronotia binoei and their diploid sexual progenitors. Endurance times at low temperature (10 degrees , 12.5 degrees , and 15 degrees C, 0.05 km h(-1)) were significantly greater in parthenogenetic females than in sexual females. Comparison of oxygen consumption rates during sustained locomotion at increasing speeds (0.05, 0.10, 0.15, 0.20, 0.25, and 0.30 km h(-1), 25 degrees C) indicated that parthenogenetic lizards have higher maximum oxygen consumption rates and maximum aerobic speeds than do female sexual geckos. In addition, parthenogenetic geckos showed greater levels of voluntary activity at 15 degrees C than did sexual geckos, although this pattern appears strongest in comparison to male sexual forms. Parthenogenetic lineages of Heteronotia thus have an advantage over sexual lineages in being capable of greater aerobic activity. This result is opposite of that found in prior studies of parthenogenetic teiid lizards (genus Cnemidophorus) and highlights the idiosyncratic nature of phenotypic evolution in parthenogens of hybrid origin.

  12. Hybridization within Saccharomyces Genus Results in Homoeostasis and Phenotypic Novelty in Winemaking Conditions

    Science.gov (United States)

    Dillmann, Christine; Bely, Marina; la Guerche, Stéphane; Giraud, Christophe; Huet, Sylvie; Sicard, Delphine; Masneuf-Pomarede, Isabelle; de Vienne, Dominique; Marullo, Philippe

    2015-01-01

    Despite its biotechnological interest, hybridization, which can result in hybrid vigor, has not commonly been studied or exploited in the yeast genus. From a diallel design including 55 intra- and interspecific hybrids between Saccharomyces cerevisiae and S. uvarum grown at two temperatures in enological conditions, we analyzed as many as 35 fermentation traits with original statistical and modeling tools. We first showed that, depending on the types of trait – kinetics parameters, life-history traits, enological parameters and aromas –, the sources of variation (strain, temperature and strain * temperature effects) differed in a large extent. Then we compared globally three groups of hybrids and their parents at two growth temperatures: intraspecific hybrids S. cerevisiae * S. cerevisiae, intraspecific hybrids S. uvarum * S. uvarum and interspecific hybrids S. cerevisiae * S. uvarum. We found that hybridization could generate multi-trait phenotypes with improved oenological performances and better homeostasis with respect to temperature. These results could explain why interspecific hybridization is so common in natural and domesticated yeast, and open the way to applications for wine-making. PMID:25946464

  13. Hybridization within Saccharomyces Genus Results in Homoeostasis and Phenotypic Novelty in Winemaking Conditions.

    Directory of Open Access Journals (Sweden)

    Telma da Silva

    Full Text Available Despite its biotechnological interest, hybridization, which can result in hybrid vigor, has not commonly been studied or exploited in the yeast genus. From a diallel design including 55 intra- and interspecific hybrids between Saccharomyces cerevisiae and S. uvarum grown at two temperatures in enological conditions, we analyzed as many as 35 fermentation traits with original statistical and modeling tools. We first showed that, depending on the types of trait--kinetics parameters, life-history traits, enological parameters and aromas -, the sources of variation (strain, temperature and strain * temperature effects differed in a large extent. Then we compared globally three groups of hybrids and their parents at two growth temperatures: intraspecific hybrids S. cerevisiae * S. cerevisiae, intraspecific hybrids S. uvarum * S. uvarum and interspecific hybrids S. cerevisiae * S. uvarum. We found that hybridization could generate multi-trait phenotypes with improved oenological performances and better homeostasis with respect to temperature. These results could explain why interspecific hybridization is so common in natural and domesticated yeast, and open the way to applications for wine-making.

  14. Interspecific aggression and character displacement in the damselfly Calopteryx splendens.

    Science.gov (United States)

    Tynkkynen, K; Rantala, M J; Suhonen, J

    2004-07-01

    Problems in species recognition are thought to affect the evolution of secondary sexual characters mainly through avoidance of maladaptive hybridization. Another, but much less studied avenue for the evolution of sexual characters due to species recognition problems is through interspecific aggression. In the damselfly, Calopteryx splendens, males have pigmented wing spots as a sexual character. Large-spotted males resemble males of another species, Calopteryx virgo, causing potential problems in species recognition. In this study, we investigate whether there is character displacement in wing spot size and whether interspecific aggression could cause this pattern. We found first that wing spot size of C. splendens in populations decreased with increasing relative abundance of C. virgo. Secondly, C. virgo males were more aggressive towards large- than small-spotted C. splendens males. Thirdly, in interspecific contests C. virgo males had better territory holding ability than C. splendens males. These results suggest that interspecific aggression may have caused character displacement in wing spot size of C. splendens, because the intensity of aggression towards large-spotted males is likely to increase with relative abundance of C. virgo males. Thus, interspecific aggression may be an evolutionarily significant force that is able to cause divergence in secondary sexual characters. Copyright 2004 Blackwell Publishing Ltd

  15. Interspecific hybridization in the genus Tulipa L.

    NARCIS (Netherlands)

    Creij, van M.G.M.

    1997-01-01

    The genus Tulipa L. comprises about 55 species. The tulip species are classified in two subgenera, Tulipa and Eriostemones, which are subdivided into five and three sections respectively. Commercial tulips are mainly cultivars

  16. Hybrid Origins of Carex rostrata var. borealis and C. stenolepis, Two Problematic Taxa in Carex Section Vesicariae (Cyperaceae).

    Science.gov (United States)

    M Pedersen, A Tiril; Nowak, Michael D; Brysting, Anne K; Elven, Reidar; Bjorå, Charlotte S

    2016-01-01

    Hybridization is frequent in the large and ecologically significant genus Carex (Cyperaceae). In four important sections of the northern regions (Ceratocystis, Glareosae, Phacocystis and Vesicariae), the frequent occurrence of hybrids often renders the identification of "pure" species and hybrids difficult. In this study we address the origins and taxonomic rank of two taxa of section Vesicariae: Carex rostrata var. borealis and C. stenolepis. The origin and taxonomic status of C. stenolepis has been the subject of substantial debate over the years, whereas C. rostrata var. borealis has received very little attention in the years since its first description in the 19th century. By performing an extensive sampling of relevant taxa from a broad distribution range, and analyzing data from fifteen microsatellite loci developed specifically for our study together with pollen stainability measures, we resolve the hybrid origins of C. rostrata var. borealis and C. stenolepis and provide new insights into this taxonomically challenging group of sedges. Our results are in accordance with previous findings suggesting that C. stenolepis is a hybrid between C. vesicaria and C. saxatilis. They are also in accordance with a previous proposition that C. rostrata var. borealis is a hybrid between C. rostrata and C. rotundata, and furthermore suggest that both hybrids are the result of multiple, recent (i.e., postglacial) hybridization events. We found little evidence for successful sexual reproduction within C. rostrata var. borealis and C. stenolepis, but conclude that the common and recurrent, largely predictable occurrence of these taxa justifies accepting both hybrids as hybrid species with binomial names. There are, however, complications as to types and priority names, and we therefore choose to address these problems in a separate paper.

  17. 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.

  18. Production of intergeneric hybrid between dwarfing polish wheat (Triticum polonicum L.) and Aegilops tauschii Cosson. with reference to wheat origin.

    Science.gov (United States)

    Kang, H Y; Wang, Y; Yuan, H J; Jiang, Y; Zhou, Y H

    2009-06-01

    Dwarfing polish wheat is a dwarfing accession of Triticum polonicum L. from Xinjiang of China. In the present study, the artificial hybridization between dwarfing polish wheat and two accessions of Aegilops tauschii Cosson. (AS60 and AS65) was carried out, and the F1 hybrids were obtained successfully without using embryo rescue techniques for the first time. The crossabilities of hybrids T. polonicum x Ae. tauschii (AS60) and T. polonicum x Ae. tauschii (AS65) were 1.67% and 0.60% respectively. Only the hybrids of T. polonicum x Ae. tauschii (AS60) germinated well, and 24 Fl hybrid plants were obtained. All the F1 hybrid plants grew vigorously, and the morphological traits were similar to bread wheat. The F1 plants had some obvious traits inherited from T. polonicum and Ae. tauschii and were completely sterile. Chromosome pairing in the hybrid was characterized by a large number of univalents, with an average of 20.56 and 0.22 bivalents per PMC, and no ring bivalents and multivalents were observed. Furthermore, the potential value of the F1 hybrids between T. polonicum and Ae. tauschii for studying wheat origin and breeding are discussed.

  19. Interspecific aggression causes negative selection on sexual characters.

    Science.gov (United States)

    Tynkkynen, Katja; Kotiaho, Janne S; Luojumäki, Mari; Suhonen, Jukka

    2005-08-01

    Interspecific aggression originating from mistaken species recognition may cause selection on secondary sexual characters, but this hypothesis has remained untested. Here we report a field experiment designed to test directly whether interspecific aggression causes selection on secondary sexual characters, wing spots, in wild damselfly populations. Males of Calopteryx virgo are more aggressive toward males of C. splendens with large than with small wing spots. This differential interspecific aggression may cause negative selection on wing spot size. Indeed, our results show that directional survival selection on wing spot size of C. splendens males was changed by experimental removal of C. virgo males. Without removal, directional selection went from positive to negative with increasing relative abundance of C. virgo males. In populations where C. virgo males were removed, this relationship disappeared. These results verify that interspecific aggression can cause negative selection on sexual characters. Thus, interspecific aggression has the potential to cause divergence on these characters between two species offering an alternative explanation for reinforcement for generating character displacement in secondary sexual characters.

  20. Genetic loci with parent-of-origin effects cause hybrid seed lethality in crosses between Mimulus species.

    Science.gov (United States)

    Garner, Austin G; Kenney, Amanda M; Fishman, Lila; Sweigart, Andrea L

    2016-07-01

    In flowering plants, F1 hybrid seed lethality is a common outcome of crosses between closely related diploid species, but the genetic basis of this early-acting and potentially widespread form of postzygotic reproductive isolation is largely unknown. We intercrossed two closely related species of monkeyflower, Mimulus guttatus and Mimulus tilingii, to characterize the mechanisms and strength of postzygotic reproductive isolation. Then, using a reciprocal backcross design, we performed high-resolution genetic mapping to determine the genetic architecture of hybrid seed lethality and directly test for loci with parent-of-origin effects. We found that F1 hybrid seed lethality is an exceptionally strong isolating barrier between Mimulus species, with reciprocal crosses producing species. It is also primarily caused by genetic loci with parent-of-origin effects, suggesting a possible role for imprinted genes in the evolution of Mimulus hybrid seed lethality. Our findings suggest that divergence in loci with parent-of-origin effects, which is probably driven by genomic coevolution within lineages, might be an important source of hybrid incompatibilities between flowering plant species. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  1. Interspecific Resource Competition in Antelopes

    NARCIS (Netherlands)

    Prins, Herbert H.T.

    2016-01-01

    Intraspecific or interspecific competition is then fundamentally the same: scramble competition is a good example of this type of competition. Modern ecology increasingly is faced with the question whether the data or a paper provide evidence for the statement that is made or for testing the

  2. CHARACTERISATION OF Phaseolus coccineus INTERSPECIFIC ...

    African Journals Online (AJOL)

    ACSS

    2018-02-20

    Feb 20, 2018 ... ACCESSIONS FOR DISEASE RESISTANCE, GRAIN MARKET CLASS AND. YIELD ... genetic base of this crop, especially for adaptation to extreme environments. The runner bean ( ..... Analysis of Variance (ANOVA) of reaction to field occurring diseases and yield performance of 186 interspecific lines at ...

  3. Hybrid origin of Asian aspermic Fasciola flukes is confirmed by analyzing two single-copy genes, pepck and pold.

    Science.gov (United States)

    Hayashi, Kei; Ichikawa-Seki, Madoka; Mohanta, Uday Kumar; Shoriki, Takuya; Chaichanasak, Pannigan; Itagaki, Tadashi

    2018-01-27

    Nuclear gene markers, phosphoenolpyruvate carboxykinase (pepck) and DNA polymerase delta (pold), have been developed for precise discrimination of Fasciola flukes instead of internal transcribed spacer 1. In this study, these two genes of 730 Fasciola flukes from eight Asian countries were analyzed. The results were compared with their mitochondrial NADH dehydrogenase subunit 1 (nad1) lineages for obtaining a definitive evidence of the hybrid origin of aspermic Fasciola flukes. All the flukes categorized into the aspermic nad1 lineages possessed both the fragment patterns of F. hepatica and F. gigantica (mixed types) in pepck and/or pold. These findings provide clear evidence for the hybrid origin of aspermic Fasciola lineages and suggest that "aspermic Fasciola flukes" should hereafter be called "hybrid Fasciola flukes".

  4. Floral Biology and Hybridization Potential of Nine Accessions of Physic Nut Jatropha curcas L. originating from Three Continents

    Directory of Open Access Journals (Sweden)

    Ahoton, LE.

    2012-01-01

    Full Text Available Jatropha curcas is a shrub which has an important economic and medicinal role in tropical and subtropical zones of the world. The oil of its kernels can serve as fuel feedstock to produce diesel, indicating its potential as a renewable source of energy. In an attempt to introduce new variation into cultivated Jatropha curcas, a program of intraspecific hybridization with several ecotypes originating from Africa, Asia and America was undertaken. Field studies were performed over three years 2009, 2010 and 2011. Before achieving hybridization, the floral ratio and the breeding system of physic nut were studied in Southern Benin ecological conditions. Significant differences (P< 0.05 were observed between the analysed ecotypes regarding the number of female flowers. This study has also confirmed that the breeding system of Jatropha curcas is essentially outcrossing and that foraging insects are the main pollination actors of female flowers. New intraspecific hybrid combinations were produced involving nine accessions. Crosses results varied according to the origin and the direction of the hybridization. Crosses between accessions of J. curcas originating from Africa and Asia gave hybrids without difficulty. The data obtained confirm that apomixis might play a major role in J. curcas a reproductive biology. Considering the high number of female flowers per inflorescence produced by the accession from Ecuador, and the large genetic distance existing between this accession and those from Africa and Asia, it should constitute a valuable genetic stock for the development of F1 hybrids with local ecotypes of J. curcas. However, the use of growth regulators might be necessary to improve the hybridization success rate when it is used as female parent.

  5. Allopolyploidy in bryophytes: Multiple origins of Plagiomnium medium

    Science.gov (United States)

    Wyatt, Robert; Odrzykoski, Ireneusz J.; Stoneburner, Ann; Bass, Henry W.; Galau, Glenn A.

    1988-01-01

    Bryophytes are thought to be unique among land plants in lacking the important evolutionary process of allopolyploidy, which involves interspecific hybridization and chromosome doubling. Electrophoretic data show, however, that the polyploid moss Plagiomnium medium is an allopolyploid derivative of Plagiomnium ellipticum and Plagiomnium insigne, that P. medium has originated more than once from these progenitors, and that cross-fertilization results in interlocus genetic recombination. Evidence from restriction fragment length polymorphisms in chloroplast DNA implicates P. insigne as the female parent in interspecific hybridizations with P. ellipticum. Contrary to prevailing views, it appears that those evolutionary processes responsible for genetic differentiation and speciation in other land plants occur in the bryophytes as well. Images PMID:16593968

  6. 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.

  7. A bicontinental origin of polyploid Australian/New Zealand Lepidium species (Brassicaceae)? Evidence from genomic in situ hybridization.

    Science.gov (United States)

    Dierschke, Tom; Mandáková, Terezie; Lysak, Martin A; Mummenhoff, Klaus

    2009-09-01

    Incongruence between chloroplast and nuclear DNA phylogenies, and single additive nucleotide positions in internal transcribed spacer (ITS) sequences of polyploid Australian/New Zealand (NZ) Lepidium species have been used to suggest a bicontinental hybrid origin. This pattern was explained by two trans-oceanic dispersals of Lepidium species from California and Africa and subsequent hybridization followed by homogenization of the ribosomal DNA sequence either to the Californian (C-clade) or to the African ITS-type (A-clade) in two different ITS-lineages of Australian/NZ Lepidium polyploids. Genomic in situ hybridization (GISH) was used to unravel the genomic origin of polyploid Australian/NZ Lepidium species. Fluorescence in situ hybridization (FISH) with ribosomal DNA (rDNA) probes was applied to test the purported ITS evolution, and to facilitate chromosome counting in high-numbered polyploids. In Australian/NZ A-clade Lepidium polyploids, GISH identified African and Australian/NZ C-clade species as putative ancestral genomes. Neither the African nor the Californian genome were detected in Australian/NZ C-clade species and the Californian genome was not detected in Australian/NZ A-clade species. Five of the eight polyploid species (from 7x to 11x) displayed a diploid-like set of rDNA loci. Even the undecaploid species Lepidium muelleriferdinandi (2n = 11x = 88) showed only one pair of each rDNA repeat. In A-clade allopolyploids, in situ rDNA localization combined with GISH corroborated the presence of the African ITS-type. The nuclear genomes of African and Australian/NZ C-clade species were detected by GISH in allopolyploid Australian/NZ Lepidium species of the A-clade, supporting their hybrid origin. The presumed hybrid origin of Australian/NZ C-clade taxa could not be confirmed. Hence, it is assumed that Californian ancestral taxa experienced rapid radiation in Australia/NZ into extant C-clade polyploid taxa followed by hybridization with African species. As a

  8. On the origins and industrial applications of Saccharomyces cerevisiae × Saccharomyces kudriavzevii hybrids.

    Science.gov (United States)

    Peris, David; Pérez-Torrado, Roberto; Hittinger, Chris Todd; Barrio, Eladio; Querol, Amparo

    2018-01-01

    Companies based on alcoholic fermentation products, such as wine, beer and biofuels, use yeasts to make their products. Each industrial process utilizes different media conditions, which differ in sugar content, the presence of inhibitors and fermentation temperature. Saccharomyces cerevisiae has traditionally been the main yeast responsible for most fermentation processes. However, the market is changing due to consumer demand and external factors such as climate change. Some processes, such as biofuel production or winemaking, require new yeasts to solve specific challenges, especially those associated with sustainability, novel flavours and altered alcohol content. One of the proposed solutions is the application of yeast hybrids. The lager beer market has been dominated by S. cerevisiae × S. eubayanus hybrids. However, several less thoroughly studied hybrids have been isolated from other diverse industrial processes. Here we focus on S. cerevisiae × S. kudriavzevii hybrids, which have been isolated from diverse industrial conditions that include wine, ale beer, cider and dietary supplements. Emerging data suggest an extended and complex story of adaptation of these hybrids to traditional industrial conditions. S. cerevisiae × S. kudriavzevii hybrids are also being explored for new industrial applications, such as biofuels. This review describes the past, present and future of S. cerevisiae × S. kudriavzevii hybrids. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  9. Chromosomal distribution of pTa-535, pTa-86, pTa-713, 35S rDNA repetitive sequences in interspecific hexaploid hybrids of common wheat (Triticum aestivum L.) and spelt (Triticum spelta L.).

    Science.gov (United States)

    Goriewa-Duba, Klaudia; Duba, Adrian; Kwiatek, Michał; Wiśniewska, Halina; Wachowska, Urszula; Wiwart, Marian

    2018-01-01

    Fluorescent in situ hybridization (FISH) relies on fluorescent-labeled probes to detect specific DNA sequences in the genome, and it is widely used in cytogenetic analyses. The aim of this study was to determine the karyotype of T. aestivum and T. spelta hybrids and their parental components (three common wheat cultivars and five spelt breeding lines), to identify chromosomal aberrations in the evaluated wheat lines, and to analyze the distribution of polymorphisms of repetitive sequences in the examined hybrids. The FISH procedure was carried out with four DNA clones, pTa-86, pTa-535, pTa-713 and 35S rDNA used as probes. The observed polymorphisms between the investigated lines of common wheat, spelt and their hybrids was relatively low. However, differences were observed in the distribution of repetitive sequences on chromosomes 4A, 6A, 1B and 6B in selected hybrid genomes. The polymorphisms observed in common wheat and spelt hybrids carry valuable information for wheat breeders. The results of our study are also a valuable source of knowledge about genome organization and diversification in common wheat, spelt and their hybrids. The relevant information is essential for common wheat breeders, and it can contribute to breeding programs aimed at biodiversity preservation.

  10. Chromosomal distribution of pTa-535, pTa-86, pTa-713, 35S rDNA repetitive sequences in interspecific hexaploid hybrids of common wheat (Triticum aestivum L. and spelt (Triticum spelta L..

    Directory of Open Access Journals (Sweden)

    Klaudia Goriewa-Duba

    Full Text Available Fluorescent in situ hybridization (FISH relies on fluorescent-labeled probes to detect specific DNA sequences in the genome, and it is widely used in cytogenetic analyses. The aim of this study was to determine the karyotype of T. aestivum and T. spelta hybrids and their parental components (three common wheat cultivars and five spelt breeding lines, to identify chromosomal aberrations in the evaluated wheat lines, and to analyze the distribution of polymorphisms of repetitive sequences in the examined hybrids. The FISH procedure was carried out with four DNA clones, pTa-86, pTa-535, pTa-713 and 35S rDNA used as probes. The observed polymorphisms between the investigated lines of common wheat, spelt and their hybrids was relatively low. However, differences were observed in the distribution of repetitive sequences on chromosomes 4A, 6A, 1B and 6B in selected hybrid genomes. The polymorphisms observed in common wheat and spelt hybrids carry valuable information for wheat breeders. The results of our study are also a valuable source of knowledge about genome organization and diversification in common wheat, spelt and their hybrids. The relevant information is essential for common wheat breeders, and it can contribute to breeding programs aimed at biodiversity preservation.

  11. Kondo Hybridization and the Origin of Metallic States at the (001 Surface of SmB_{6}

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    E. Frantzeskakis

    2013-12-01

    Full Text Available SmB_{6}, a well-known Kondo insulator, has been proposed to be an ideal topological insulator with states of topological character located in a clean, bulk electronic gap, namely, the Kondo-hybridization gap. Since the Kondo gap arises from many-body electronic correlations, SmB_{6} would be placed at the head of a new material class: topological Kondo insulators. Here, for the first time, we show that the k-space characteristics of the Kondo-hybridization process is the key to unraveling the origin of the two types of metallic states experimentally observed by angle-resolved photoelectron spectroscopy (ARPES in the electronic band structure of SmB_{6}(001. One group of these states is essentially of bulk origin and cuts the Fermi level due to the position of the chemical potential 20 meV above the lowest-lying 5d-4f hybridization zone. The other metallic state is more enigmatic, being weak in intensity, but represents a good candidate for a topological surface state. However, before this claim can be substantiated by an unequivocal measurement of its massless dispersion relation, our data raise the bar in terms of the ARPES resolution required, as we show there to be a strong renormalization of the hybridization gaps by a factor 2–3 compared to theory, following from the knowledge of the true position of the chemical potential and a careful comparison with the predictions from recent local-density-approximation (LDA+Gutzwiller calculations. All in all, these key pieces of evidence act as triangulation markers, providing a detailed description of the electronic landscape in SmB_{6} and pointing the way for future, ultrahigh-resolution ARPES experiments to achieve a direct measurement of the Dirac cones in the first topological Kondo insulator.

  12. Demographic modelling with whole-genome data reveals parallel origin of similar Pundamilia cichlid species after hybridization.

    Science.gov (United States)

    Meier, Joana I; Sousa, Vitor C; Marques, David A; Selz, Oliver M; Wagner, Catherine E; Excoffier, Laurent; Seehausen, Ole

    2017-01-01

    Modes and mechanisms of speciation are best studied in young species pairs. In older taxa, it is increasingly difficult to distinguish what happened during speciation from what happened after speciation. Lake Victoria cichlids in the genus Pundamilia encompass a complex of young species and polymorphic populations. One Pundamilia species pair, P. pundamilia and P. nyererei, is particularly well suited to study speciation because sympatric population pairs occur with different levels of phenotypic differentiation and reproductive isolation at different rocky islands within the lake. Genetic distances between allopatric island populations of the same nominal species often exceed those between the sympatric species. It thus remained unresolved whether speciation into P. nyererei and P. pundamilia occurred once, followed by geographical range expansion and interspecific gene flow in local sympatry, or if the species pair arose repeatedly by parallel speciation. Here, we use genomic data and demographic modelling to test these alternative evolutionary scenarios. We demonstrate that gene flow plays a strong role in shaping the observed patterns of genetic similarity, including both gene flow between sympatric species and gene flow between allopatric populations, as well as recent and early gene flow. The best supported model for the origin of P. pundamilia and P. nyererei population pairs at two different islands is one where speciation happened twice, whereby the second speciation event follows shortly after introgression from an allopatric P. nyererei population that arose earlier. Our findings support the hypothesis that very similar species may arise repeatedly, potentially facilitated by introgressed genetic variation. © 2016 John Wiley & Sons Ltd.

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

    International Nuclear Information System (INIS)

    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

  14. Hybridization and management of oak populations

    Science.gov (United States)

    Oliver Gailing

    2017-01-01

    Hybridization can result in the transfer of adaptations among species and may contribute to speciation processes. On the other hand, hybridization can also result in a loss of species diversity due to asymmetric gene flow between species (genetic swamping) and in low hybrid fitness. An understanding of the outcomes of interspecific hybridization is crucial for the...

  15. Ultrafast optical snapshots of hybrid perovskites reveal the origin of multiband electronic transitions

    Science.gov (United States)

    Appavoo, Kannatassen; Nie, Wanyi; Blancon, Jean-Christophe; Even, Jacky; Mohite, Aditya D.; Sfeir, Matthew Y.

    2017-11-01

    Connecting the complex electronic excitations of hybrid perovskites to their intricate organic-inorganic lattice structure has critical implications for energy conversion and optoelectronic technologies. Here we detail the multiband, multivalley electronic structure of a halide hybrid perovskite by measuring the absorption transients of a millimeter-scale-grain thin film as it undergoes a thermally controlled reversible tetragonal-to-orthogonal phase transition. Probing nearly single grains of this hybrid perovskite, we observe an unreported energy splitting (degeneracy lifting) of the high-energy 2.6 eV band in the tetragonal phase that further splits as the rotational degrees of freedom of the disordered C H3N H3 + molecules are reduced when the sample is cooled. This energy splitting drastically increases during an extended phase-transition coexistence region that persists from 160 to 120 K, becoming more pronounced in the orthorhombic phase. By tracking the temperature-dependent optical transition energies and using symmetry analysis that describes the evolution of electronic states from the tetragonal phase to the orthorhombic phase, we assign this energy splitting to the nearly degenerate transitions in the tetragonal phase from both the R - and M -point-derived states. Importantly, these assignments explain how momentum conservation effects lead to long hot-carrier lifetimes in the room-temperature tetragonal phase, with faster hot-carrier relaxation when the hybrid perovskite structurally transitions to the orthorhombic phase due to enhanced scattering at the Γ point.

  16. 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.

  17. STUDY ON THE BEHAVIOUR OF THE DIFFERENT ORIGIN SILKWORM HYBRIDS UNDER THE CLIMATIC CONDITIONS OF BULGARIA

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    ALEXANDRA MATEI

    2007-10-01

    Full Text Available Romania, Ukraine, Turkey and Uzbekistan as countries placed in the Black, Caspian Seasand Central Asia (BACSA region, in comparison with hybrids from China, Japan, Italy andKorea has been carried out in Sericulture Station Vratza – Bulgaria.The study pointed out the superiority of the Japanese hybrid Shunrei + Shogetsu which hadthe highest cocoon yield by one box of eggs (41,10 kg and the highest raw silk productivity(7,05 kg/box of eggs.The silkworm hybrids produced in BACSA members countries had ahatching percentage ranged from 77,50% to 98,50%, a high pupation percentage (72,86 –96,91%, cocoon weight (1,892 – 2,319 g and fresh cocoon yield by one box of silkwormvaried from 29,894 kg to 40,982 kg.The Romanian hybrids had high values of the rawcocoon weight (2,307 g Record and 2,194 g Baneasa Super, the appreciable values of thecocoon yield/box of eggs (36,135 kg Record and 39,168 kg Baneasa Super, but low valuesof the silk content (20,38% Record and 20,51% Baneasa Super and of the raw silkproductivity/box of eggs (4,33 kg Record and 4,80 kg Baneasa Super.The breeding works inthe BACSA member countries, should be directed towards improvement of the silkproductivity of the hybrids and the qualities of the silk fibre, by the same time preservingtheir comparatively high pupation rate and cocoon yield.

  18. Origin,

    Directory of Open Access Journals (Sweden)

    Artur de Vargas Giorgi

    2011-02-01

    Full Text Available This essay tightens the “origin” concept, its manifestation through puzzles and their relationship to techniques of reproduction. Contrary to the hegemonic critique of aesthetic and cultural objects – critique that, settled on the appearance and notions of identity, tradition, canon, etc., undervalues the reproductions of "originals" –, the aim is to deliver these objects from formal hierarchization dispositives, that is, release them of what is ideal and positively imposed, so that the reproducibility is potentiated as producer of singularities, of apparitions. The effort is to keep the undecided character of puzzles (bodies, texts, images in which the origin is manifest, so that the logic of the spectacle is reverted into sense opening, instance in which the aesthetic becomes a “performance” before contemporary complexity. With the reproducibility, an origin survives in passage: continually restored, but incomplete, present in trace, in absence.

  19. Some rare Indo-Pacific coral species are probable hybrids.

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    Zoe T Richards

    Full Text Available BACKGROUND: Coral reefs worldwide face a variety of threats and many coral species are increasingly endangered. It is often assumed that rare coral species face higher risks of extinction because they have very small effective population sizes, a predicted consequence of which is decreased genetic diversity and adaptive potential. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that some Indo-Pacific members of the coral genus Acropora have very small global population sizes and are likely to be unidirectional hybrids. Whether this reflects hybrid origins or secondary hybridization following speciation is unclear. CONCLUSIONS/SIGNIFICANCE: The interspecific gene flow demonstrated here implies increased genetic diversity and adaptive potential in these coral species. Rare Acropora species may therefore be less vulnerable to extinction than has often been assumed because of their propensity for hybridization and introgression, which may increase their adaptive potential.

  20. A general model of distant hybridization reveals the conditions for extinction in Atlantic salmon and brown trout.

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    Claudio S Quilodrán

    Full Text Available Interspecific hybridization is common in nature but can be increased in frequency or even originated by human actions, such as species introduction or habitat modification, which may threaten species persistence. When hybridization occurs between distantly related species, referred to as "distant hybridization," the resulting hybrids are generally infertile or fertile but do not undergo chromosomal recombination during gametogenesis. Here, we present a model describing this frequent but poorly studied interspecific hybridization to assess its consequences on parental species and to anticipate the conditions under which they can reach extinction. Our general model fully incorporates three important processes: density-dependent competition, dominance/recessivity inheritance of traits and assortative mating. We demonstrate its use and flexibility by assessing population extinction risk between Atlantic salmon and brown trout in Norway, whose interbreeding has recently increased due to farmed fish releases into the wild. We identified the set of conditions under which hybridization may threaten salmonid species. Thanks to the flexibility of our model, we evaluated the effect of an additional risk factor, a parasitic disease, and showed that the cumulative effects dramatically increase the extinction risk. The consequences of distant hybridization are not genetically, but demographically mediated. Our general model is useful to better comprehend the evolution of such hybrid systems and we demonstrated its importance in the field of conservation biology to set up management recommendations when this increasingly frequent type of hybridization is in action.

  1. Origin of year-long bean (Phaseolus dumosus Macfady, Fabaceae) from reticulated hybridization events between multiple Phaseolus species.

    Science.gov (United States)

    Mina-Vargas, Angela M; McKeown, Peter C; Flanagan, Nicola S; Debouck, Daniel G; Kilian, Andrzej; Hodkinson, Trevor R; Spillane, Charles

    2016-08-06

    Improved understanding of the secondary gene pools of crops is essential for advancing genetic gain in breeding programmes. Common bean, Phaseolus vulgaris, is a staple crop with several wild relatives in its secondary gene pool. The year-long bean, P. dumosus, an important crop in Guatemala, is considered particularly closely related to P. vulgaris and a potential source of novel variation. However, the genetic diversity and relationship to other Phaseolus species of P. dumosus remain unclear. We conducted the first comprehensive investigation of P. dumosus genetic diversity using both nuclear and chloroplast genome markers. Our nuclear marker set included over 700 markers present within the Phaseolus DArT (Diversity Arrays Technology) array, which we applied to P. dumosus and other relatives of P. vulgaris (including every secondary gene pool species: P. acutifolius, P. albescens, P. coccineus and P. costaricensis). Phaseolus dumosus arose from hybridization of P. vulgaris and P. coccineus, followed by at least two later hybridizations with sympatric congener populations. Existing P. dumosus collections have low genetic diversity. The under-utilized crop P. dumosus has a complex hybrid origin. Further sampling in the region in which it arose may uncover additional germplasm for introgressing favourable traits into crops within the P. vulgaris gene pool. © 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.

  2. Interspecific Resource Competition Effects on Fisheres Revenue

    NARCIS (Netherlands)

    Wolfshaar, van de K.E.; Schellekens, T.; Poos, J.J.; Kooten, van T.

    2012-01-01

    In many fisheries multiple species are simultaneously caught while stock assessments and fishing quota are defined at species level. Yet species caught together often share habitat and resources, resulting in interspecific resource competition. The consequences of resource competition on population

  3. 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

  4. 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.

  5. Extensive hybridization and introgression between Melastoma candidum and M. sanguineum.

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    Ting Liu

    Full Text Available Natural hybridization can lead to various evolutionary outcomes in plants, including hybrid speciation and interspecific gene transfer. It can also cause taxonomic problems, especially in plant genera containing multiple species. In this study, the hybrid status of Melastoma affine, the most widespread taxon in this genus, and introgression between its putative parental species, M. candidum and M. sanguineum, were assessed on two sites, Hainan and Guangdong, using 13 SSR markers and sequences of a chloroplast intergenic spacer. Bayesian-based STRUCTURE analysis detected two most likely distinct clusters for the three taxa, and 76.0% and 73.9% of the morphologically identified individuals of M. candidum and M. sanguineum were correctly assigned, respectively. 74.5% of the M. affine individuals had a membership coefficient to either parental species between 0.1 and 0.9, suggesting admixture between M. candidum and M. sanguineum. Furthermore, NewHybrids analysis suggested that most individuals of M. affine were F2 hybrids or backcross hybrids to M. candidum, and that there was extensive introgression between M. candidum and M. sanguineum. These SSR data thus provides convincing evidence for hybrid origin of M. affine and extensive introgression between M. candidum and M. sanguineum. Chloroplast DNA results were consistent with this conclusion. Much higher hybrid frequency on the more disturbed Guangdong site suggests that human disturbance might offer suitable habitats for the survival of hybrids, a hypothesis that is in need of further testing.

  6. Viabilidade do grão de pólen de acessos de capim-elefante, milheto - DOI: 10.4025/actascibiolsci.v28i1.1052 Pollen viability in elephantgrass, pearl millet and interspecific hybrids - DOI: 10.4025/actascibiolsci.v28i1.1052

    Directory of Open Access Journals (Sweden)

    Antônio Vander Pereira

    2006-03-01

    Full Text Available O objetivo deste trabalho foi estimar a viabilidade do pólen em acessos de capim-elefante, milheto e híbridos interespecíficos por meio de germinação in vitro e coloração com carmim propiônico, orceína acética e corante de Alexander. Os testes de germinação foram realizados com grãos de pólen frescos e armazenados por 30 dias. Os acessos de capim-elefante e de milheto apresentaram alta viabilidade de pólen. Apenas um deles, quando avaliado com o corante de Alexander, mostrou baixa fertilidade. Para os híbridos, observou-se alta taxa de pólens funcionais com os corantes nucleares. Entretanto, o corante de Alexander confirmou a completa esterilidade desses acessos. Os acessos de capim-elefante e milheto apresentaram baixa porcentagem de pólens viáveis quando induzidos à germinação em meio de cultura. Nos híbridos foi constatada completa esterilidade do grão de pólen, condizente com as anormalidades meióticas relatadas na literatura. Quanto ao armazenamento, os grãos de pólen de todos os acessos perderam completamente o poder germinativoThe aim of this work was to estimate the pollen viability in elephantgrass, pearl millet and interspecific hybrids accessions through in vitro germination and staining with propionic carmine, acetic orcein and Alexander’s stain. The germination tests were accomplished with fresh pollen grains and stored for 30 days. The elephantgrass and peare millet accessions presented a high pollen viability. Just one of the accessions, when evaluated with Alexander's stain, showed low fertility. For the hybrid, a high rate of functional pollen was observed with the nuclear stain. However, Alexander's stain confirmed the complete sterility of those accessions. Elephantgrass and pearl millet accessions presented a low percentage of viable pollen grain, when induced to germination in culture medium. Complete sterility of the pollen grain was verified in the hybrid, agreeing with the meiotic

  7. The close relationship between estimated divergent selection and observed differentiation supports the selective origin of a marine snail hybrid zone.

    Science.gov (United States)

    Cruz, R; Vilas, C; Mosquera, J; García, C

    2004-11-01

    To study the role of divergent selection in the differentiation of the two morphs in a hybrid zone of the intertidal snail Littorina saxatilis, we compared the strength of the divergent selection acting on a series of shell characters (as estimated by the viability of snails in a reciprocal transplant experiment) with the contribution of these characters to the phenotypic differences between the morphs. We found a close correlation between selection and differentiation, which suggests a cause-effect relationship, i.e. that all present differentiation is the result of past divergent selection. In addition, divergent selection was a very important component of the total natural selection acting on shell measures. These novel results support previous evidence, based on allozyme analysis, of a parapatric origin for this hybrid zone. We discuss possible limitations of this interpretation and the circumstances under which allopatric differentiation would produce the same results. Phenotypic analysis of divergent selection may be a useful method of investigating the evolutionary mechanisms involved in differentiation processes.

  8. Tools for assessing kinship, population structure, phylogeography, and interspecific hybridization in Asian carps invasive to the Mississippi River, USA: isolation and characterization of novel tetranucleotide microsatellite DNA loci in silver carp Hypophthalmichthys molitrix

    Science.gov (United States)

    King, T.L.; Eackles, M.S.; Chapman, D.C.

    2011-01-01

    We document the isolation and characterization of novel tetranucleotide microsatellite DNA markers for the invasive silver carp Hypophthalmichthys molitrix and provide the results of cross-species amplification for three additional invasive carp species: bighead (H. nobilis), grass (Ctenopharyngodon idella) and black (Mylopharyngodon piceus). In the target species these markers yielded levels of allelic diversity (average 4.4 alleles/locus) and heterozygosity (average 54.7%) sufficient to: (1) provide unique multilocus genotypes; (2) delineate kinship relationships; (3) differentiate populations/species; (4) estimate effective population sizes; and (5) provide unique demographic perspectives for control or eradication. Currently these markers are being utilized to determine the degree of introgressive hybridization between H. molitrix and H. nobilis, to quantify gene flow between different sub-basins established in the central United States, and to assess the demographic status of sub-basin groups. This information will be critically important in the management/control of these invasive species.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. Identification of Persistent RNA-DNA Hybrid Structures within the Origin of Replication of Human Cytomegalovirus

    OpenAIRE

    Prichard, Mark N.; Jairath, Sanju; Penfold, Mark E. T.; Jeor, Stephen St.; Bohlman, Marlene C.; Pari, Gregory S.

    1998-01-01

    Human cytomegalovirus (HCMV) lytic-phase DNA replication initiates at the cis-acting origin of replication, oriLyt. oriLyt is a structurally complex region containing repeat elements and transcription factor binding sites. We identified two site-specific alkali-labile regions within oriLyt which flank an alkali-resistant DNA segment. These alkali-sensitive regions were the result of the degradation of two RNA species embedded within oriLyt and covalently linked to viral DNA. The virus-associa...

  11. A Role for CHH Methylation in the Parent-of-Origin Effect on Altered Circadian Rhythms and Biomass Heterosis in Arabidopsis Intraspecific Hybrids[W][OPEN

    Science.gov (United States)

    Ng, Danny W.-K.; Miller, Marisa; Yu, Helen H.; Huang, Tien-Yu; Kim, Eun-Deok; Lu, Jie; Xie, Qiguang; McClung, C. Robertson; Chen, Z. Jeffrey

    2014-01-01

    Hybrid plants and animals often show increased levels of growth and fitness, a phenomenon known as hybrid vigor or heterosis. Circadian rhythms optimize physiology and metabolism in plants and animals. In plant hybrids and polyploids, expression changes of the genes within the circadian regulatory network, such as CIRCADIAN CLOCK ASSOCIATED1 (CCA1), lead to heterosis. However, the relationship between allelic CCA1 expression and heterosis has remained elusive. Here, we show a parent-of-origin effect on altered circadian rhythms and heterosis in Arabidopsis thaliana F1 hybrids. This parent-of-origin effect on biomass heterosis correlates with altered CCA1 expression amplitudes, which are associated with methylation levels of CHH (where H = A, T, or C) sites in the promoter region. The direction of rhythmic expression and hybrid vigor is reversed in reciprocal F1 crosses involving mutants that are defective in the RNA-directed DNA methylation pathway (argonaute4 and nuclear RNA polymerase D1a) but not in the maintenance methylation pathway (methyltransferase1 and decrease in DNA methylation1). This parent-of-origin effect on circadian regulation and heterosis is established during early embryogenesis and maintained throughout growth and development. PMID:24894042

  12. A Role for CHH Methylation in the Parent-of-Origin Effect on Altered Circadian Rhythms and Biomass Heterosis in Arabidopsis Intraspecific Hybrids.

    Science.gov (United States)

    Ng, Danny W-K; Miller, Marisa; Yu, Helen H; Huang, Tien-Yu; Kim, Eun-Deok; Lu, Jie; Xie, Qiguang; McClung, C Robertson; Chen, Z Jeffrey

    2014-06-01

    Hybrid plants and animals often show increased levels of growth and fitness, a phenomenon known as hybrid vigor or heterosis. Circadian rhythms optimize physiology and metabolism in plants and animals. In plant hybrids and polyploids, expression changes of the genes within the circadian regulatory network, such as CIRCADIAN CLOCK ASSOCIATED1 (CCA1), lead to heterosis. However, the relationship between allelic CCA1 expression and heterosis has remained elusive. Here, we show a parent-of-origin effect on altered circadian rhythms and heterosis in Arabidopsis thaliana F1 hybrids. This parent-of-origin effect on biomass heterosis correlates with altered CCA1 expression amplitudes, which are associated with methylation levels of CHH (where H = A, T, or C) sites in the promoter region. The direction of rhythmic expression and hybrid vigor is reversed in reciprocal F1 crosses involving mutants that are defective in the RNA-directed DNA methylation pathway (argonaute4 and nuclear RNA polymerase D1a) but not in the maintenance methylation pathway (methyltransferase1 and decrease in DNA methylation1). This parent-of-origin effect on circadian regulation and heterosis is established during early embryogenesis and maintained throughout growth and development. © 2014 American Society of Plant Biologists. All rights reserved.

  13. Meiotic behavior of interspecific hybrids between artificially tetraploidized sexual Brachiaria ruziziensis and tetraploid apomictic B. brizantha (Poaceae Comportamento meiótico de híbridos interespecíficos entre tetraplóides artificiais de Brachiaria ruziziensis e tetraplóides apomíticos de B. brizantha (Poaceae

    Directory of Open Access Journals (Sweden)

    Mariana Ferrari Felismino

    2010-04-01

    Full Text Available The meiotic behavior of four interspecific promising hybrids was evaluated by conventional cytological methods. The female genitors were two artificially tetraploidized sexual accessions of B. ruziziensis (R41 and R44, 2n = 4χ = 36, which were crossed to an agronomically superior natural tetraploid apomictic genotype of B. brizantha (B140 - BRA003395. Three of them (HBGC313, HBGC 315, and HBGC324 were sexual and one (HBGC325 apomictic. Analyses of some cells in diakinesis revealed multivalent chromosome configurations, suggesting that genetic recombination and introgression of some genes could be present. The four hybrids had different types of meiotic abnormalities at various frequencies. Abnormalities related to irregular chromosome segregation due to polyploidy were common among these hybrids, and characterized by precocious chromosome migration to the poles, laggard chromosomes, both generating micronuclei in telophases and tetrads and, as a consequence, unbalanced gametes. One abnormality genotype-specific, related to spindle orientation (a putative divergent spindle mutation, was recorded for the first time in two of the hybrids, HBGC313 and HBGC325. The sexual hybrid HBGC324 had the lower rate of abnormalities, and it could be used as a female genitor in future crosses in the breeding program. The abnormalities present in these hybrids may impact fertility and affect seed production. Based on the results, HBGC324 is the single hybrid recommended to the breeding program. Hybrids must produce a good amount of viable seeds, besides good overall dry matter production and nutritive value, in order to be widely utilized and adopted in production systems. Due to pseudogamy, the desirable superior apomictic hybrids need viable pollen grains to fertilize the secondary nucleus of the embryo sac and thus ensure normal and vigorous endosperm development and plenty of seed set.O comportamento meiótico de quatro híbridos interespec

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

    Indian Academy of Sciences (India)

    2011). However, to develop efficient interspecific crosses it is essential to determine their phy- logenetic relationships. Although some workers have tried nuclear ribosomal DNA internal transcribed spacer (ITS) regions for this purpose (Ronsted et al. 2002; Dhar et al. 2006), it would be worthwhile to use molecular markers,.

  15. Volatiles in inter-specific bacterial interactions

    NARCIS (Netherlands)

    Tyc, Olaf; Zweers, H.; Boer, de W.; Garbeva, P.

    2015-01-01

    The importance of volatile organic compounds for functioning of microbes is receiving increased research attention. However, to date very little is known on how inter-specific bacterial interactions effect volatiles production as most studies have been focused on volatiles produced by monocultures

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

    Indian Academy of Sciences (India)

    Molecular markers unravel intraspecific and interspecific genetic variability in Plantago ovata and some of its wild allies. Shivanjali Kotwal, Manoj K. Dhar, Balbir Kour, Kuldeep Raj and Sanjana Kaul. J. Genet. 92, 293–298. Table 1. Jaccard's similarity matrix of AFLP analysis of Plantago species. P. coronopus P. lanceolata ...

  17. 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 ...

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

    Science.gov (United States)

    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

  19. Reproduction and hybrid load in all-hybrid populations of Rana esculenta water frogs in Denmark

    DEFF Research Database (Denmark)

    Christiansen, Ditte Guldager; Fog, Kåre; Pedersen, Bo Vest

    2005-01-01

    All-hybrid populations of the water frog, Rana esculenta, are exceptional in consisting of independently and to some extent sexually reproducing interspecific hybrids. In most of its range R. esculenta reproduces hemiclonally with one of the parental species, R. lessonae or R. ridibunda, but viable...... gametogenesis and mating between frogs with incompatible gametes induce a significant hybrid load in all-hybrid populations of R. esculenta, and we discuss compensating advantages and potential evolutionary trajectories to reduce this hybrid load....

  20. Hybridization in geese: a review.

    Science.gov (United States)

    Ottenburghs, Jente; van Hooft, Pim; van Wieren, Sipke E; Ydenberg, Ronald C; Prins, Herbert H T

    2016-01-01

    The high incidence of hybridization in waterfowl (ducks, geese and swans) makes this bird group an excellent study system to answer questions related to the evolution and maintenance of species boundaries. However, knowledge on waterfowl hybridization is biased towards ducks, with a large knowledge gap in geese. In this review, we assemble the available information on hybrid geese by focusing on three main themes: (1) incidence and frequency, (2) behavioural mechanisms leading to hybridization, and (3) hybrid fertility. Hybridization in geese is common on a species-level, but rare on a per-individual level. An overview of the different behavioural mechanisms indicates that forced extra-pair copulations and interspecific nest parasisitm can both lead to hybridization. Other sources of hybrids include hybridization in captivity and vagrant geese, which may both lead to a scarcity of conspecifics. The different mechanisms are not mutually exclusive and it is currently not possible to discriminate between the different mechanisms without quantitative data. Most hybrid geese are fertile; only in crosses between distantly related species do female hybrids become sterile. This fertility pattern, which is in line with Haldane's Rule, may facilitate interspecific gene flow between closely related species. The knowledge on hybrid geese should be used, in combination with the information available on hybridization in ducks, to study the process of avian speciation.

  1. Testing the SI × SC rule: Pollen-pistil interactions in interspecific crosses between members of the tomato clade (Solanum section Lycopersicon, Solanaceae).

    Science.gov (United States)

    Baek, You Soon; Covey, Paul A; Petersen, Jennifer J; Chetelat, Roger T; McClure, Bruce; Bedinger, Patricia A

    2015-02-01

    Interspecific reproductive barriers (IRBs) act to ensure species integrity by preventing hybridization. Previous studies on interspecific crosses in the tomato clade have focused on the success of fruit and seed set. The SI × SC rule (SI species × SC species crosses are incompatible, but the reciprocal crosses are compatible) often applies to interspecific crosses. Because SI systems in the Solanaceae affect pollen tube growth, we focused on this process in a comprehensive study of interspecific crosses in the tomato clade to test whether the SI × SC rule was always followed. Pollen tube growth was assessed in reciprocal crosses between all 13 species of the tomato clade using fluorescence microscopy. In crosses between SC and SI species, pollen tube growth follows the SI × SC rule: interspecific pollen tube rejection occurs when SI species are pollinated by SC species, but in the reciprocal crosses (SC × SI), pollen tubes reach ovaries. However, pollen tube rejection occurred in some crosses between pairs of SC species, demonstrating that a fully functional SI system is not necessary for pollen tube rejection in interspecific crosses. Further, gradations in the strength of both pistil and pollen IRBs were revealed in interspecific crosses using SC populations of generally SI species. The SI × SC rule explains many of the compatibility relations in the tomato clade, but exceptions occur with more recently evolved SC species and accessions, revealing differences in strength of both pistil and pollen IRBs. © 2015 Botanical Society of America, Inc.

  2. [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.

  3. Hybrid origin of European commercial pigs examined by an in-depth haplotype analysis on chromosome 1

    Directory of Open Access Journals (Sweden)

    Mirte eBosse

    2015-01-01

    Full Text Available Although all farm animals have an original source of domestication, a large variety of modern breeds exists that are phenotypically highly distinct from the ancestral wild population. This phenomenon can be the result of artificial selection or gene flow from other sources into the domesticated population. The Eurasian wild boar (Sus scrofa has been domesticated at least twice in two geographically distinct regions during the Neolithic revolution when hunting shifted to farming. Prior to the establishment of the commercial European pig breeds we know today, some 200 years ago Chinese pigs were imported into Europe to improve local European pigs. Commercial European domesticated pigs are genetically more diverse than European wild boars, although historically the latter represents the source population for domestication. In this study we examine the cause of the higher diversity within the genomes of European commercial pigs compared to their wild ancestors by testing two different hypotheses. In the first hypothesis we consider that European commercial pigs are a mix of different European wild populations as a result of movement throughout Europe, hereby acquiring haplotypes from all over the European continent. As an alternative hypothesis, we examine whether the introgression of Asian haplotypes into European breeds during the Industrial Revolution caused the observed increase in diversity. By using re-sequence data for chromosome 1 of 136 pigs and wild boars, we show that an Asian introgression of about 20% into the genome of European commercial pigs explains the majority of the increase in genetic diversity. These findings confirm that the Asian hybridization, that was used to improve production traits of local breeds, left its signature in the genome of the commercial pigs we know today.

  4. Reconstruction of the evolutionary history of Saccharomyces cerevisiae x S. kudriavzevii hybrids based on multilocus sequence analysis.

    Science.gov (United States)

    Peris, David; Lopes, Christian A; Arias, Armando; Barrio, Eladio

    2012-01-01

    In recent years, interspecific hybridization and introgression are increasingly recognized as significant events in the evolution of Saccharomyces yeasts. These mechanisms have probably been involved in the origin of novel yeast genotypes and phenotypes, which in due course were to colonize and predominate in the new fermentative environments created by human manipulation. The particular conditions in which hybrids arose are still unknown, as well as the number of possible hybridization events that generated the whole set of natural hybrids described in the literature during recent years. In this study, we could infer at least six different hybridization events that originated a set of 26 S. cerevisiae x S. kudriavzevii hybrids isolated from both fermentative and non-fermentative environments. Different wine S. cerevisiae strains and European S. kudriavzevii strains were probably involved in the hybridization events according to gene sequence information, as well as from previous data on their genome composition and ploidy. Finally, we postulate that these hybrids may have originated after the introduction of vine growing and winemaking practices by the Romans to the present Northern vine-growing limits and spread during the expansion of improved viticulture and enology practices that occurred during the Late Middle Ages.

  5. Reconstruction of the Evolutionary History of Saccharomyces cerevisiae x S. kudriavzevii Hybrids Based on Multilocus Sequence Analysis

    Science.gov (United States)

    Peris, David; Lopes, Christian A.; Arias, Armando; Barrio, Eladio

    2012-01-01

    In recent years, interspecific hybridization and introgression are increasingly recognized as significant events in the evolution of Saccharomyces yeasts. These mechanisms have probably been involved in the origin of novel yeast genotypes and phenotypes, which in due course were to colonize and predominate in the new fermentative environments created by human manipulation. The particular conditions in which hybrids arose are still unknown, as well as the number of possible hybridization events that generated the whole set of natural hybrids described in the literature during recent years. In this study, we could infer at least six different hybridization events that originated a set of 26 S. cerevisiae x S. kudriavzevii hybrids isolated from both fermentative and non-fermentative environments. Different wine S. cerevisiae strains and European S. kudriavzevii strains were probably involved in the hybridization events according to gene sequence information, as well as from previous data on their genome composition and ploidy. Finally, we postulate that these hybrids may have originated after the introduction of vine growing and winemaking practices by the Romans to the present Northern vine-growing limits and spread during the expansion of improved viticulture and enology practices that occurred during the Late Middle Ages. PMID:23049811

  6. Reconstruction of the evolutionary history of Saccharomyces cerevisiae x S. kudriavzevii hybrids based on multilocus sequence analysis.

    Directory of Open Access Journals (Sweden)

    David Peris

    Full Text Available In recent years, interspecific hybridization and introgression are increasingly recognized as significant events in the evolution of Saccharomyces yeasts. These mechanisms have probably been involved in the origin of novel yeast genotypes and phenotypes, which in due course were to colonize and predominate in the new fermentative environments created by human manipulation. The particular conditions in which hybrids arose are still unknown, as well as the number of possible hybridization events that generated the whole set of natural hybrids described in the literature during recent years. In this study, we could infer at least six different hybridization events that originated a set of 26 S. cerevisiae x S. kudriavzevii hybrids isolated from both fermentative and non-fermentative environments. Different wine S. cerevisiae strains and European S. kudriavzevii strains were probably involved in the hybridization events according to gene sequence information, as well as from previous data on their genome composition and ploidy. Finally, we postulate that these hybrids may have originated after the introduction of vine growing and winemaking practices by the Romans to the present Northern vine-growing limits and spread during the expansion of improved viticulture and enology practices that occurred during the Late Middle Ages.

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

    Indian Academy of Sciences (India)

    Chromosome paired predominantly as multivalents suggesting that genetic recombination and introgression of specific target genes from B. brizantha into B. ruziziensis can be expected. Arrangement of parental genomes in distinct metaphase plates was observed in H27 and H34, which have different male genitors.

  8. field reactions of interspecific hybrids of tomato (solanum

    African Journals Online (AJOL)

    User

    2014-09-03

    Sep 3, 2014 ... Leaf spot is a major disease of tomato causing reduction in fruit yield under humid environments. It's control using some of the major systemic fungicides available is environmentally unfriendly and costly. Heterosis known to increase productivity in crops was used to assess improvement in tomato yield and ...

  9. Intra and interspecific hybridization in the genus "capsicum" | Falusi ...

    African Journals Online (AJOL)

    African Crop Science Journal. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 2, No 2 (1994) >. Log in or Register to get access to full text downloads.

  10. field reactions of interspecific hybrids of tomato (solanum ...

    African Journals Online (AJOL)

    User

    2014-09-03

    Sep 3, 2014 ... The leaves were assayed at the vegetative and reproductive stages for leaf spot infection and some phytochemicals content. Data obtained were subjected to analysis of ... caused by the fungi. Septoria lycopersici and Cercospora spp., respectively. The spread of the diseases is encouraged by excessive.

  11. Field Reactions of Segregating Populations of Interspecific Hybrids ...

    African Journals Online (AJOL)

    The progenies arising from crosses between cultivated tomatoes and a wild relative were screened with their parents for resistance to bacterial leaf spot disease. The aim is to develop a tolerant variety that is well adapted to humid forest ecology where the disease is endemic. The results obtained showed that the cultivated ...

  12. Interspecific differentiation and hybridization in vanilla species (Orchidaceae)

    DEFF Research Database (Denmark)

    Nielsen, Lene Rostgaard; Siegismund

    1999-01-01

    Vanilla claviculata, V. barbellata and V. dilloniana are distributed throughout the Caribbean islands and are all found in Puerto Rico. The vegetative parts of the species are similar; however, their conspicuous flowers easily distinguish them. Electrophoresis of seven polymorphic enzymes reveale...

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

    Indian Academy of Sciences (India)

    combination and the number of pollen tubes at the base of the style was low. In these combinations, postzygotic barriers ranging through embryo abortion and a failure of endosperm development, nongermination of seeds to when germination occurred the plants were subviable. The per- centage of unfilled seeds ranged ...

  14. Experimental hybridization of species in the genus Rorippa

    Czech Academy of Sciences Publication Activity Database

    Jarolímová, Vlasta

    2005-01-01

    Roč. 77, - (2005), s. 277-296 ISSN 0032-7786 Institutional research plan: CEZ:AV0Z60050516 Keywords : Brassicaceae * interspecific hybridization * ploidy level Subject RIV: EF - Botanics Impact factor: 1.545, year: 2005

  15. 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.

  16. Volatiles in Inter-Specific Bacterial Interactions.

    Science.gov (United States)

    Tyc, Olaf; Zweers, Hans; de Boer, Wietse; Garbeva, Paolina

    2015-01-01

    The importance of volatile organic compounds for functioning of microbes is receiving increased research attention. However, to date very little is known on how inter-specific bacterial interactions effect volatiles production as most studies have been focused on volatiles produced by monocultures of well-described bacterial genera. In this study we aimed to understand how inter-specific bacterial interactions affect the composition, production and activity of volatiles. Four phylogenetically different bacterial species namely: Chryseobacterium, Dyella, Janthinobacterium, and Tsukamurella were selected. Earlier results had shown that pairwise combinations of these bacteria induced antimicrobial activity in agar media whereas this was not the case for monocultures. In the current study, we examined if these observations were also reflected by the production of antimicrobial volatiles. Thus, the identity and antimicrobial activity of volatiles produced by the bacteria were determined in monoculture as well in pairwise combinations. Antimicrobial activity of the volatiles was assessed against fungal, oomycetal, and bacterial model organisms. Our results revealed that inter-specific bacterial interactions affected volatiles blend composition. Fungi and oomycetes showed high sensitivity to bacterial volatiles whereas the effect of volatiles on bacteria varied between no effects, growth inhibition to growth promotion depending on the volatile blend composition. In total 35 volatile compounds were detected most of which were sulfur-containing compounds. Two commonly produced sulfur-containing volatile compounds (dimethyl disulfide and dimethyl trisulfide) were tested for their effect on three target bacteria. Here, we display the importance of inter-specific interactions on bacterial volatiles production and their antimicrobial activities.

  17. Volatiles in inter-specific bacterial interactions

    Directory of Open Access Journals (Sweden)

    Olaf eTyc

    2015-12-01

    Full Text Available The importance of volatile organic compounds for functioning of microbes is receiving increased research attention. However, to date very little is known on how inter-specific bacterial interactions effect volatiles production as most studies have been focused on volatiles produced by monocultures of well described bacterial genera. In this study we aimed to understand how inter-specific bacterial interactions affect the composition, production and activity of volatiles. Four phylogenetically different bacterial species namely: Chryseobacterium, Dyella, Janthinobacterium and Tsukamurella were selected. Earlier results had shown that pairwise combinations of these bacteria induced antimicrobial activity in agar media whereas this was not the case for monocultures. In the current study, we examined if these observations were also reflected by the production of antimicrobial volatiles. Thus, the identity and antimicrobial activity of volatiles produced by the bacteria were determined in monoculture as well in pairwise combinations. Antimicrobial activity of the volatiles was assessed against fungal, oomycetal and bacterial model organisms. Our results revealed that inter-specific bacterial interactions affected volatiles blend composition. Fungi and oomycetes showed high sensitivity to bacterial volatiles whereas the effect of volatiles on bacteria varied between no effects, growth inhibition to growth promotion depending on the volatile blend composition. In total 35 volatile compounds were detected most of which were sulfur-containing compounds. Two commonly produced sulfur-containing volatile compounds (dimethyl disulfide and dimethyl trisulfide were tested for their effect on three target bacteria. Here we display the importance of inter-specific interactions on bacterial volatiles production and their antimicrobial activities.

  18. 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.

  19. 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.

  20. Rapid radiations of both kiwifruit hybrid lineages and their parents shed light on a two-layer mode of species diversification.

    Science.gov (United States)

    Liu, Yifei; Li, Dawei; Zhang, Qiong; Song, Chi; Zhong, Caihong; Zhang, Xudong; Wang, Ying; Yao, Xiaohong; Wang, Zupeng; Zeng, Shaohua; Wang, Ying; Guo, Yangtao; Wang, Shuaibin; Li, Xinwei; Li, Li; Liu, Chunyan; McCann, Honour C; He, Weiming; Niu, Yan; Chen, Min; Du, Liuwen; Gong, Junjie; Datson, Paul M; Hilario, Elena; Huang, Hongwen

    2017-07-01

    Reticulate speciation caused by interspecific hybridization is now recognized as an important mechanism in the creation of biological diversity. However, depicting the patterns of phylogenetic networks for lineages that have undergone interspecific gene flow is challenging. Here we sequenced 25 taxa representing natural diversity in the genus Actinidia with an average mapping depth of 26× on the reference genome to reconstruct their reticulate history. We found evidence, including significant gene tree discordance, cytonuclear conflicts, and changes in genome-wide heterozygosity across taxa, collectively supporting extensive reticulation in the genus. Furthermore, at least two separate parental species pairs were involved in the repeated origin of the hybrid lineages, in some of which a further phase of syngameon was triggered. On the basis of the elucidated hybridization relationships, we obtained a highly resolved backbone phylogeny consisting of taxa exhibiting no evidence of hybrid origin. The backbone taxa have distinct demographic histories and are the product of recent rounds of rapid radiations via sorting of ancestral variation under variable climatic and ecological conditions. Our results suggest a mode for consecutive plant diversification through two layers of radiations, consisting of the rapid evolution of backbone lineages and the formation of hybrid swarms derived from these lineages. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  1. Evaluation of different genetic procedures for the generation of artificial hybrids in Saccharomyces genus for winemaking.

    Science.gov (United States)

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

    2012-05-15

    Several methods based on recombinant DNA techniques have been proposed for yeast strain improvement; however, the most relevant oenological traits depend on a multitude of loci, making these techniques difficult to apply. In this way, hybridization techniques involving two complete genomes became interesting. Natural hybrid strains between different Saccharomyces species have been detected in diverse fermented beverages including wine, cider and beer. These hybrids seem to be better adapted to fluctuating situations typically observed in fermentations due to the acquisition of particular physiological properties of both parental strains. In this work we evaluated the usefulness of three different hybridization methods: spore to spore mating, rare-mating and protoplast fusion for the generation of intra- and inter-specific stable hybrids, being the first report about the comparison of different methods to obtain artificial hybrids to be used in fermentations. Spore to spore mating is an easy but time-consuming method; hybrids generated with this technique could lack some of the industrially relevant traits present in the parental strains because of the segregation occurred during meiosis and spore generation prior to hybridization. Hybrids obtained by protoplast fusion get the complete information of both parents but they are currently considered as genetically modified organisms (GMOs). Finally, hybrids obtained by rare-mating are easily obtained by the optimized methodology described in this work, they originally contain a complete set of chromosomes of both parents and they are not considered as GMOs. Hybrids obtained by means of the three methodological approaches showed a high genetic variability; however, a loss of genetic material was detected in most of them. Based on these results, it became evident that a last crucial aspect to be considered in every hybridization program is the genetic stabilization of recently generated hybrids that guarantee its

  2. Hybrid CCTA/SPECT myocardial perfusion imaging findings in patients with anomalous origin of coronary arteries from the opposite sinus and suspected concomitant coronary artery disease.

    Science.gov (United States)

    Gräni, Christoph; Benz, Dominik C; Schmied, Christian; Vontobel, Jan; Mikulicic, Fran; Possner, Mathias; Clerc, Olivier F; Stehli, Julia; Fuchs, Tobias A; Pazhenkottil, Aju P; Gaemperli, Oliver; Buechel, Ronny R; Kaufmann, Philipp A

    2017-02-01

    Anomalous coronary arteries originating from the opposite sinus of Valsalva (ACAOS) are associated with adverse cardiac events. Discrimination between ACAOS and coronary artery disease (CAD)-related perfusion defects may be difficult. The aim of the present study was to investigate the value of hybrid coronary computed tomography angiography (CCTA)/SPECT-MPI in patients with ACAOS and possible concomitant CAD. We retrospectively identified 46 patients (mean age 56 ± 12 years) with ACAOS revealed by CCTA who underwent additional SPECT-MPI. ACAOS with an interarterial course were classified as malignant, whereas all other variants were considered benign. CCTA/SPECT-MPI hybrid imaging findings (ischemia or scar) were analyzed according to the territory subtended by an anomalous vessel or a stenotic coronary artery. Twenty-six (57%) patients presented with malignant ACAOS. Myocardial ischemia or scar was found only in patients who had concomitant obstructive CAD in the vessel matching the perfusion defect as evidenced by hybrid CCTA/SPECT imaging. Hybrid CCTA/SPECT-MPI represents a valuable non-invasive tool to discriminate the impact of ACAOS from concomitant CAD on myocardial ischemia. Our results suggest that in a middle-aged population myocardial ischemia due to ACAOS per se may be exceedingly rare and is more likely attributable to concomitant CAD.

  3. Non-parent of Origin Expression of Numerous Effector Genes Indicates a Role of Gene Regulation in Host Adaption of the Hybrid Triticale Powdery Mildew Pathogen

    Science.gov (United States)

    Praz, Coraline R.; Menardo, Fabrizio; Robinson, Mark D.; Müller, Marion C.; Wicker, Thomas; Bourras, Salim; Keller, Beat

    2018-01-01

    Powdery mildew is an important disease of cereals. It is caused by one species, Blumeria graminis, which is divided into formae speciales each of which is highly specialized to one host. Recently, a new form capable of growing on triticale (B.g. triticale) has emerged through hybridization between wheat and rye mildews (B.g. tritici and B.g. secalis, respectively). In this work, we used RNA sequencing to study the molecular basis of host adaptation in B.g. triticale. We analyzed gene expression in three B.g. tritici isolates, two B.g. secalis isolates and two B.g. triticale isolates and identified a core set of putative effector genes that are highly expressed in all formae speciales. We also found that the genes differentially expressed between isolates of the same form as well as between different formae speciales were enriched in putative effectors. Their coding genes belong to several families including some which contain known members of mildew avirulence (Avr) and suppressor (Svr) genes. Based on these findings we propose that effectors play an important role in host adaptation that is mechanistically based on Avr-Resistance gene-Svr interactions. We also found that gene expression in the B.g. triticale hybrid is mostly conserved with the parent-of-origin, but some genes inherited from B.g. tritici showed a B.g. secalis-like expression. Finally, we identified 11 unambiguous cases of putative effector genes with hybrid-specific, non-parent of origin gene expression, and we propose that they are possible determinants of host specialization in triticale mildew. These data suggest that altered expression of multiple effector genes, in particular Avr and Svr related factors, might play a role in mildew host adaptation based on hybridization. PMID:29441081

  4. Non-parent of Origin Expression of Numerous Effector Genes Indicates a Role of Gene Regulation in Host Adaption of the Hybrid Triticale Powdery Mildew Pathogen

    Directory of Open Access Journals (Sweden)

    Coraline R. Praz

    2018-01-01

    Full Text Available Powdery mildew is an important disease of cereals. It is caused by one species, Blumeria graminis, which is divided into formae speciales each of which is highly specialized to one host. Recently, a new form capable of growing on triticale (B.g. triticale has emerged through hybridization between wheat and rye mildews (B.g. tritici and B.g. secalis, respectively. In this work, we used RNA sequencing to study the molecular basis of host adaptation in B.g. triticale. We analyzed gene expression in three B.g. tritici isolates, two B.g. secalis isolates and two B.g. triticale isolates and identified a core set of putative effector genes that are highly expressed in all formae speciales. We also found that the genes differentially expressed between isolates of the same form as well as between different formae speciales were enriched in putative effectors. Their coding genes belong to several families including some which contain known members of mildew avirulence (Avr and suppressor (Svr genes. Based on these findings we propose that effectors play an important role in host adaptation that is mechanistically based on Avr-Resistance gene-Svr interactions. We also found that gene expression in the B.g. triticale hybrid is mostly conserved with the parent-of-origin, but some genes inherited from B.g. tritici showed a B.g. secalis-like expression. Finally, we identified 11 unambiguous cases of putative effector genes with hybrid-specific, non-parent of origin gene expression, and we propose that they are possible determinants of host specialization in triticale mildew. These data suggest that altered expression of multiple effector genes, in particular Avr and Svr related factors, might play a role in mildew host adaptation based on hybridization.

  5. [The demonstration of natural hybridization between two swallowtail species Parnassius nomion and Parnassius bremeri (Lepidoptera, Papilionidae) using RAPD-PCR technique].

    Science.gov (United States)

    Zakharov, E V

    2001-04-01

    Genetic evidence for interspecific hybridization between Parnassius nomion and Parnassius bremeri in nature is presented. To demonstrate hybridization between these species, RAPD analysis was used. By testing 25 decamer primers, three and two diagnostic markers were revealed for P. nomion and P. bremeri, respectively. Out of 28 animals examined, 4 were shown to be interspecific hybrids. According to the distribution of diagnostic markers, the interspecific hybrids were intermediate with regard to the parental species. Ecological and biological characteristics of two swallowtail species that promote their hybridization in nature are discussed.

  6. Variation in the relative magnitude of intraspecific and interspecific ...

    Indian Academy of Sciences (India)

    While there was considerable variation in the relative magnitude of intraspecific and interspecific competitive effects over generations, among both populations and environments, there was no clear evidence supporting the genetic feedback hypothesis. Intraspecific and interspecific competitive effects on population growth ...

  7. Molecular profiling of an interspecific rice population derived from a ...

    African Journals Online (AJOL)

    NERICA rices are interspecific inbred progeny derived from crosses between Oryza sativa x O. glaberrima. In this study, we evaluated 70 BC2 interspecific lines, developed by crossing a tropical japonica variety (WAB 56-104) as the recurrent parent to an O. glaberrima variety (CG 14) as the donor parent, followed by the ...

  8. 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.

  9. Cloth-based hybridization array system for expanded identification of the animal species origin of derived materials in feeds.

    Science.gov (United States)

    Murphy, Johanna; Armour, Jennifer; Blais, Burton W

    2007-12-01

    A cloth-based hybridization array system (CHAS) previously developed for the detection of animal species for which prohibited materials have been specified (cattle, sheep, goat, elk, and deer) has been expanded to include the detection of animal species for which there are no prohibitions (pig and horse) in Canadian and American animal feeds. Animal species were identified by amplification of mitochondrial DNA sequences by PCR and subsequent hybridization of the amplicons with an array of species-specific oligonucleotide capture probes immobilized on a polyester cloth support, followed by an immunoenzymatic assay of the bound PCR products. The CHAS permitted sensitive and specific detection of meat meals from different animal species blended in a grain-based feed and should provide a useful adjunct to microscopic examination for the identification of prohibited materials in animal feeds.

  10. Parental partners effects on progenies characteristics on hybridization within the Larix genus

    Energy Technology Data Exchange (ETDEWEB)

    Sindelar, J.; Frydl, J. [Forestry and Game Management Research Inst., Jiloviste (Czech Republic)

    1995-12-31

    Larch progenies of maternal clone No. 52-4-11 (Larix decidua Mill.) combined with the series of paternal clones of the same species and further of the Larix leptolepis Gord. and L. gmelini (Rupr.) Ledeb. species were evaluated on three research plots with larch (Larix sp.). Growth in height and thickness as well as stem forming were monitored at the age of 11 and 22 years. There was found out a significant share of variance falling on the action of mother, hence the existence of extra-nuclear heredity can be anticipated, particularly in interspecific hybrids. Comparing with the control in interspecific hybrids mostly luxuriant growth is displayed. On one of the studied plots there was found out the assumed growth depression in the quantitative characters of progenies originated from self-pollination. Some results of the research can be used as an auxiliary criterion in the selection of progenies and trees within the progenies for the establishment of seed orchards to produce hybrid seed of F2 generation. 24 refs, 6 figs, 6 tabs

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

    Science.gov (United States)

    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.

  12. Quantifying interspecific coagulation efficiency of phytoplankton

    DEFF Research Database (Denmark)

    Hansen, J.L.S.; Kiørboe, Thomas

    1997-01-01

    Non-sticky latex beads and sticky diatoms were used as models to describe mutual coagulation between sticky and non-sticky particles. in mixed suspensions of beads and Thalassiosira nordenskjoeldii, both types of particles coagulated into mixed aggregates at specific rates, from which...... the interspecific coagulation efficiency could be calculated. Stickiness between beads and T. nordenskjoeldii was 50% of that of T. nordenskjoeldii in monospecific suspensions, and this ratio remained constant throughout 12 experiments covering 1 order of magnitude variation in the stickiness level of T....... nordenskjoeldii. Mutual coagulation between Skeletonema costatum and the non-sticky cel:ls of Ditylum brightwellii also proceeded with hall the efficiency of S. costatum alone. The latex beads were suitable to be used as 'standard particles' to quantify the ability of phytoplankton to prime aggregation...

  13. Genome reorganization in F1 hybrids uncovers the role of retrotransposons in reproductive isolation

    Science.gov (United States)

    Senerchia, Natacha; Felber, François; Parisod, Christian

    2015-01-01

    Interspecific hybridization leads to new interactions among divergent genomes, revealing the nature of genetic incompatibilities having accumulated during and after the origin of species. Conflicts associated with misregulation of transposable elements (TEs) in hybrids expectedly result in their activation and genome-wide changes that may be key to species boundaries. Repetitive genomes of wild wheats have diverged under differential dynamics of specific long terminal repeat retrotransposons (LTR-RTs), offering unparalleled opportunities to address the underpinnings of plant genome reorganization by selfish sequences. Using reciprocal F1 hybrids between three Aegilops species, restructuring and epigenetic repatterning was assessed at random and LTR-RT sequences with amplified fragment length polymorphism and sequence-specific amplified polymorphisms as well as their methylation-sensitive counterparts, respectively. Asymmetrical reorganization of LTR-RT families predicted to cause conflicting interactions matched differential survival of F1 hybrids. Consistent with the genome shock model, increasing divergence of merged LTR-RTs yielded higher levels of changes in corresponding genome fractions and lead to repeated reorganization of LTR-RT sequences in F1 hybrids. Such non-random reorganization of hybrid genomes is coherent with the necessary repression of incompatible TE loci in support of hybrid viability and indicates that TE-driven genomic conflicts may represent an overlooked factor supporting reproductive isolation. PMID:25716787

  14. Examining reproducibility in psychology : A hybrid method for combining a statistically significant original study and a replication

    NARCIS (Netherlands)

    Van Aert, Robbie C M; van Assen, Marcel A.L.M.

    2017-01-01

    The unrealistically high rate of positive results within psychology has increased the attention to replication research. However, researchers who conduct a replication and want to statistically combine the results of their replication with a statistically significant original study encounter

  15. Examining reproducibility in psychology : A hybrid method for combining a statistically significant original study and a replication

    NARCIS (Netherlands)

    Van Aert, R.C.M.; Van Assen, M.A.L.M.

    2018-01-01

    The unrealistically high rate of positive results within psychology has increased the attention to replication research. However, researchers who conduct a replication and want to statistically combine the results of their replication with a statistically significant original study encounter

  16. Recurrent hybridization and recent origin obscure phylogenetic relationships within the ‘white-headed’ gull (Larus sp.) complex

    Science.gov (United States)

    Sonsthagen, Sarah A.; Wilson, Robert E.; Chesser, Terry; Pons, Jean-Marc; Crochet, Pierre-Andre; Driscoll, Amy; Dove, Carla

    2016-01-01

    Species complexes that have undergone recent radiations are often characterized by extensive allele sharing due to recent ancestry and (or) introgressive hybridization. This can result in discordant evolutionary histories of genes and heterogeneous genomes, making delineating species limits difficult. Here we examine the phylogenetic relationships among a complex group of birds, the white-headed gulls (Aves: Laridae), which offer a unique window into the speciation process due to their recent evolutionary history and propensity to hybridize. Relationships were examined among 17 species (61 populations) using a multilocus approach, including mitochondrial and nuclear intron DNA sequences and microsatellite genotype information. Analyses of microsatellite and intron data resulted in some species-based groupings, although most species were not represented by a single cluster. Considerable allele and haplotype sharing among white-headed gull species was observed; no locus contained a species-specific clade. Despite this, our multilocus approach provided better resolution among some species than previous studies. Interestingly, most clades appear to correspond to geographic locality: our BEAST analysis recovered strong support for a northern European/Icelandic clade, a southern European/Russian clade, and a western North American/canus clade, with weak evidence for a high latitude clade spanning North America and northwestern Europe. This geographical structuring is concordant with behavioral observations of pervasive hybridization in areas of secondary contact. The extent of allele and haplotype sharing indicates that ecological and sexual selection are likely not strong enough to complete reproductive isolation within several species in the white-headed gull complex. This suggests that just a few genes are driving the speciation process.

  17. Y-chromosome status identification suggests a recipient origin of posttransplant non-small cell lung carcinomas: chromogenic in situ hybridization analysis.

    Science.gov (United States)

    Chen, Wei; Brodsky, Sergey V; Zhao, Weiqiang; Otterson, Gregory A; Villalona-Calero, Miguel; Satoskar, Anjali A; Hasan, Ayesha; Pelletier, Ronald; Ivanov, Iouri; Ross, Patrick; Nadasdy, Tibor; Shilo, Konstantin

    2014-05-01

    Owing to the need of lifelong immunosuppression, solid-organ transplant recipients are known to have an increased risk of posttransplant malignancies including lung cancer. Posttransplant neoplastic transformation of donor-derived cells giving rise to hematopoietic malignancies, Kaposi sarcoma, and basal cell carcinoma in nongraft tissues has been reported. The goal of this study was to assess the cell origin (donor versus recipient derived) of posttransplant non-small cell lung carcinomas (NSCLCs) in kidney and heart transplant recipients. An institutional database search identified 2557 kidney and heart transplant recipients in 8 consecutive years. Among this cohort, 20 (0.8%) renal and 18 (0.7%) heart transplant recipients developed NSCLC. The study cohort comprised 6 of 38 NSCLCs arising in donor-recipient sex-mismatched transplant patients. The tumor cell origin was evaluated by chromogenic in situ hybridization with Y-chromosome probe on formalin-fixed, paraffin-embedded tissues. Y-chromosome was identified in 97% ± 1% (range from 92% to 99%) of all types of nucleated cells in male control tissues. In all 5 NSCLCs from male recipients of female donor organ, Y-chromosome was identified in 97% ± 2% (range from 92% to 100%) of tumor cells, statistically equivalent to normal control (P recipient of male kidney. These findings suggest a recipient derivation of NSCLC arising in kidney and heart transplant recipients. A combination of histologic evaluation and chromogenic in situ hybridization with Y-chromosome analysis allows reliable determination of tissue origin in sex-mismatched solid-organ transplant recipients and may aid in management of posttransplant malignancy in such cases. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Selection of Gossypium hirsutum genotypes for interspecific ...

    African Journals Online (AJOL)

    FORRESTER

    ARS), Crop Genetics Research Unit in. Stoneville, Mississippi ... Key words: Cotton, germplasm, immature embryo, tissue culture, wide-hybridization. INTRODUCTION. Tetraploid upland cotton, Gossypium hirsutum L., is comprised of over 90% ...

  19. Coexistence facilitates interspecific biofilm formation in complex microbial communities.

    Science.gov (United States)

    Madsen, Jonas S; Røder, Henriette L; Russel, Jakob; Sørensen, Helle; Burmølle, Mette; Sørensen, Søren J

    2016-09-01

    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 biofilm formation among co-cultured bacteria that have coexisted in their original environment. Conversely, when randomly co-culturing bacteria across these five consortia, we found less biofilm induction and a prevalence of biofilm reduction. Reduction in biofilm formation was even more predominant when co-culturing bacteria from environments where long-term coexistence was unlikely to have occurred. Phylogenetic diversity was not found to be a strong underlying factor but a relation between biofilm induction and phylogenetic history was found. The data indicates that biofilm reduction is typically correlated with an increase in planktonic cell numbers, thus implying a behavioral response rather than mere growth competition. Our findings suggest that an increase in biofilm formation is a common adaptive response to long-term coexistence. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. Hybrid origin of European commercial pigs examined by an in-depth haplotype analysis on chromosome 1

    NARCIS (Netherlands)

    Bosse, M.; Madsen, O.; Megens, H.J.W.C.; Frantz, L.A.F.; Paudel, Y.; Crooijmans, R.P.M.A.; Groenen, M.

    2015-01-01

    Although all farm animals have an original source of domestication, a large variety of modern breeds exist that are phenotypically highly distinct from the ancestral wild population. This phenomenon can be the result of artificial selection or gene flow from other sources into the domesticated

  1. Genomic characterization of a South American Phytophthora hybrid mandates reassessment of the geographic origins of Phytophthora infestans

    DEFF Research Database (Denmark)

    Martin, Michael David; Garrett Vieira, Filipe Jorge; Ho, Simon Y. W.

    2016-01-01

    As the oomycete pathogen causing potato late blight disease, Phytophthora infestans triggered the famous 19th-century Irish potato famine and remains the leading cause of global commercial potato crop destruction. But the geographic origin of the genotype that caused this devastating initial...

  2. Tumor formation in hybrids between Solanum lycopersicum and S ...

    African Journals Online (AJOL)

    Genetic tumors are neoplastic growths that arise spontaneously in particular genotypes in plants. In the present study, we observed the occurrence of tumors in interspecific hybrids between Solanum lycopersicum L. and Solanum habrochaites S. Knapp and D. M. Spooner. The hybridity of these plants was confirmed based ...

  3. Genotype as a New Interspesific Hybrid Rootstock for Stone Fruit

    African Journals Online (AJOL)

    ADOWIE PERE

    ABSTRACT: Interspecific hybrids, especially in prunus genus, are used as rootstocks for stone fruit trees in the world, in recent decades. In this research, 106 interspesific hybrids including: almond × peach (P. amygdalus ×P. persica ) , almond × prune (P. amygdalus × P. cerasifera ), apricot × prune (P. armeniaca × P.

  4. 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)

  5. Interspecific aggression in hermatypic corals from Bermuda

    Science.gov (United States)

    Logan, A.

    1984-11-01

    Interspecific aggression between hermatypic corals on Bermudian reefs has been investigated by aquarium and field studies, the latter involving induced interactions, observations from 30 m-2 transects and random SCUBA traverses. Resultant hierarchies, constructed by ranking the abilities of species to damage competitors, show close similarities with each other and with the Jamaican hierarchy at the family level, notwithstanding some differences in the ranking of some species. Only 11% of natural-occurring interactions depart from the aquarium-derived results; in terms of species-pair combinations, 30% show partial or complete inversions from aquarium to field, with most changes involving species close together in the field hierarchy. Circular (intransitive) interactions occur mostly within a network of weakly-aggressive species in both aquarium- and fieldderived hierarchies. While number of potential interactions m-2 varies directly with density, frequency of aggression is positively correlated with coral diversity (species richness), while frequency of “no reactions” and conspecific fusion (combined) shows a correspondingly negative correlation with diversity. Frequency of aggression does not appear to be depth related. Comparison of aquarium and field hierarchies suggest that digestion by mesenterial filaments is the most important mechanism of aggression under natural conditions. Sweeper tentacle activity is the most likely cause of field reversals involving Madracis mirabilis and Montastrea cavernosa. Other factors, such as stress caused by seasonal environmental extremes, may be responsible for reversals or inconsistent behaviour in other species.

  6. Phylogenetic analyses suggest a hybrid origin of the figs (Moraceae: Ficus) that are endemic to the Ogasawara (Bonin) Islands, Japan.

    Science.gov (United States)

    Kusumi, Junko; Azuma, Hiroshi; Tzeng, Hsy-Yu; Chou, Lien-Siang; Peng, Yan-Qiong; Nakamura, Keiko; Su, Zhi-Hui

    2012-04-01

    The Ogasawara Islands are oceanic islands and harbor a unique endemic flora. There are three fig species (Ficus boninsimae, F. nishimurae and F. iidaiana) endemic to the Ogasawara Islands, and these species have been considered to be closely related to Ficus erecta, and to have diverged within the islands. However, this hypothesis remains uncertain. To investigate this issue, we assessed the phylogenetic relationships of the Ogasawara figs and their close relatives occurring in Japan, Taiwan and South China based on six plastid genome regions, nuclear ITS region and two nuclear genes. The plastid genome-based tree indicated a close relationship between the Ogasawara figs and F. erecta, whereas some of the nuclear gene-based trees suggested this relationship was not so close. In addition, the phylogenetic analyses of the pollinating wasps associated with these fig species based on the nuclear 28S rRNA and mitochondrial cytB genes suggested that the fig-pollinating wasps of F. erecta are not sister to those of the Ogasawara figs These results suggest the occurrence of an early hybridization event(s) in the lineage leading to the Ogasawara figs. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Effect of gamma-ray irradiation on hybridization between Chamaecyparis obtusa S. et Z. and C. pisifera S. et Z

    International Nuclear Information System (INIS)

    Maeta, Takehiko

    1980-01-01

    The effect of gamma irradiation on the interspecific hybridization between Chamaecyparis obtusa and C. pisifera was investigated, and F 1 seedlings were examined cytologically. Acute gamma irradiation and chronic gamma irradiation given throughout annual growing seasons on male flowers were effective in producing hybrids between these two species. The crossing of C. obtusa x C. pisifera was better than the reverse crossing because the pollen of C. obtusa rapidly loses its fertility, and C. pisifera blooms earlier than C. obtusa. Chronic gamma irradiation of male flowers throughout the annual growing season was slightly effective for producing the hybrids, but that of female flowers was not. Acute gamma irradiation of male flowers at the first to second telophase (300 R) was considered to be desirable for hybrid production. However, it was confirmed by cytological observation that all of the hybrids produced were triploid which had two identical genomes originated from either parent. Therefore, the unreduced male gametophytes or unreduced eggs seem to participate in the formation of the hybrids. It seems difficult to produce diploid hybrids between C. obtusa and C. pisifera. (Kaihara, S.)

  8. Cytoplasmic and Genomic Effects on Meiotic Pairing in Brassica Hybrids and Allotetraploids from Pair Crosses of Three Cultivated Diploids

    Science.gov (United States)

    Cui, Cheng; Ge, Xianhong; Gautam, Mayank; Kang, Lei; Li, Zaiyun

    2012-01-01

    Interspecific hybridization and allopolyploidization contribute to the origin of many important crops. Synthetic Brassica is a widely used model for the study of genetic recombination and “fixed heterosis” in allopolyploids. To investigate the effects of the cytoplasm and genome combinations on meiotic recombination, we produced digenomic diploid and triploid hybrids and trigenomic triploid hybrids from the reciprocal crosses of three Brassica diploids (B. rapa, AA; B. nigra, BB; B. oleracea, CC). The chromosomes in the resultant hybrids were doubled to obtain three allotetraploids (B. juncea, AA.BB; B. napus, AA.CC; B. carinata, BB.CC). Intra- and intergenomic chromosome pairings in these hybrids were quantified using genomic in situ hybridization and BAC-FISH. The level of intra- and intergenomic pairings varied significantly, depending on the genome combinations and the cytoplasmic background and/or their interaction. The extent of intragenomic pairing was less than that of intergenomic pairing within each genome. The extent of pairing variations within the B genome was less than that within the A and C genomes, each of which had a similar extent of pairing. Synthetic allotetraploids exhibited nondiploidized meiotic behavior, and their chromosomal instabilities were correlated with the relationship of the genomes and cytoplasmic background. Our results highlight the specific roles of the cytoplasm and genome to the chromosomal behaviors of hybrids and allopolyploids. PMID:22505621

  9. The perils of pathogen discovery: origin of a novel parvovirus-like hybrid genome traced to nucleic acid extraction spin columns.

    Science.gov (United States)

    Naccache, Samia N; Greninger, Alexander L; Lee, Deanna; Coffey, Lark L; Phan, Tung; Rein-Weston, Annie; Aronsohn, Andrew; Hackett, John; Delwart, Eric L; Chiu, Charles Y

    2013-11-01

    Next-generation sequencing was used for discovery and de novo assembly of a novel, highly divergent DNA virus at the interface between the Parvoviridae and Circoviridae. The virus, provisionally named parvovirus-like hybrid virus (PHV), is nearly identical by sequence to another DNA virus, NIH-CQV, previously detected in Chinese patients with seronegative (non-A-E) hepatitis. Although we initially detected PHV in a wide range of clinical samples, with all strains sharing ∼99% nucleotide and amino acid identity with each other and with NIH-CQV, the exact origin of the virus was eventually traced to contaminated silica-binding spin columns used for nucleic acid extraction. Definitive confirmation of the origin of PHV, and presumably NIH-CQV, was obtained by in-depth analyses of water eluted through contaminated spin columns. Analysis of environmental metagenome libraries detected PHV sequences in coastal marine waters of North America, suggesting that a potential association between PHV and diatoms (algae) that generate the silica matrix used in the spin columns may have resulted in inadvertent viral contamination during manufacture. The confirmation of PHV/NIH-CQV as laboratory reagent contaminants and not bona fide infectious agents of humans underscores the rigorous approach needed to establish the validity of new viral genomes discovered by next-generation sequencing.

  10. Interspecific visual signalling in animals and plants: a functional classification.

    Science.gov (United States)

    Caro, Tim; Allen, William L

    2017-07-05

    Organisms frequently gain advantages when they engage in signalling with individuals of other species. Here, we provide a functionally structured framework of the great variety of interspecific visual signals seen in nature, and then describe the different signalling mechanisms that have evolved in response to each of these functional requirements. We propose that interspecific visual signalling can be divided into six major functional categories: anti-predator, food acquisition, anti-parasite, host acquisition, reproductive and agonistic signalling, with each function enabled by several distinct mechanisms. We support our classification by reviewing the ecological and behavioural drivers of interspecific signalling in animals and plants, principally focusing on comparative studies that address large-scale patterns of diversity. Collating diverse examples of interspecific signalling into an organized set of functional and mechanistic categories places anachronistic behavioural and morphological labels in fresh context, clarifies terminology and redirects research effort towards understanding environmental influences driving interspecific signalling in nature.This article is part of the themed issue 'Animal coloration: production, perception, function and application'. © 2017 The Author(s).

  11. Genetic variation and origin of parthenogenesis in the Aspidoscelis cozumela complex: evidence from mitochondrial genes.

    Science.gov (United States)

    Manríquez-Morán, Norma L; Cruz, Fausto R Méndez-de la; Murphy, Robert W

    2014-01-01

    Parthenogenesis is a form of clonal reproduction. Eggs develop in the absence of sperm and offspring are genetically identical to their mother. Although common in invertebrates, it occurs in only a few species of squamate reptiles. Parthenogenetic reptiles have their origin in interspecific hybridization, and their populations are exclusively female. Because of its high mutation rate and maternal inheritance, mitochondrial DNA sequence data can evaluate the origin and evolution of all-female vertebrates. Partial sequences from two mitochondrial genes, Cytb and ND4, were analyzed to investigate questions about the origin of parthenogenesis in the Aspidoscelis cozumela complex, which includes A. cozumela, A. maslini and A. rodecki. Low levels of divergence were detected among parthenogenetic species, and between them and A. angusticeps, confirming it as the maternal species of the parthenoforms. A gene tree was constructed using sequences from three populations of A. angusticeps and nine of its unisexual daughter species. The phylogeny suggests that two independent hybridization events between A. angusticeps and A. deppii formed three unisexual species. One hybridization resulted in A. rodecki and the other formed A. maslini and A. cozumela. Although A. cozumela has the haplotype characteristic of A. maslini from Puerto Morelos, it is considered to be a different species based on karyological and morphological characteristics and its geographical isolation.

  12. Expression of the Retrotransposon Helena Reveals a Complex Pattern of TE Deregulation in Drosophila Hybrids.

    Directory of Open Access Journals (Sweden)

    Valèria Romero-Soriano

    Full Text Available Transposable elements (TEs, repeated mobile sequences, are ubiquitous in the eukaryotic kingdom. Their mobilizing capacity confers on them a high mutagenic potential, which must be strongly regulated to guarantee genome stability. In the Drosophila germline, a small RNA-mediated silencing system, the piRNA (Piwi-interacting RNA pathway, is the main responsible TE regulating mechanism, but some stressful conditions can destabilize it. For instance, during interspecific hybridization, genomic stress caused by the shock of two different genomes can lead, in both animals and plants, to higher transposition rates. A recent study in D. buzatii-D. koepferae hybrids detected mobilization of 28 TEs, yet little is known about the molecular mechanisms explaining this transposition release. We have characterized one of the mobilized TEs, the retrotransposon Helena, and used quantitative expression to assess whether its high transposition rates in hybrids are preceded by increased expression. We have also localized Helena expression in the gonads to see if cellular expression patterns have changed in the hybrids. To give more insight into changes in TE regulation in hybrids, we analysed Helena-specific piRNA populations of hybrids and parental species. Helena expression is not globally altered in somatic tissues, but male and female gonads have different patterns of deregulation. In testes, Helena is repressed in F1, increasing then its expression up to parental values. This is linked with a mislocation of Helena transcripts along with an increase of their specific piRNA levels. Ovaries have additive levels of Helena expression, but the ping-pong cycle efficiency seems to be reduced in F1 hybrids. This could be at the origin of new Helena insertions in hybrids, which would be transmitted to F1 hybrid female progeny.

  13. Hybridization success is largely limited to homoploid Prunus hybrids: a multidisciplinary approach

    Czech Academy of Sciences Publication Activity Database

    Macková, L.; Vít, Petr; Ďurišová, Ľ.; Eliáš, P. Jr.; Urfus, T.

    2017-01-01

    Roč. 303, č. 4 (2017), s. 481-495 ISSN 0378-2697 Institutional support: RVO:67985939 Keywords : absolute genome size * interspecific hybridization * embryology Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 1.239, year: 2016

  14. Nuclear and mitochondrial DNA analysis reveals that hybridization between Fasciola hepatica and Fasciola gigantica occurred in China.

    Science.gov (United States)

    Ichikawa-Seki, Madoka; Peng, Mao; Hayashi, Kei; Shoriki, Takuya; Mohanta, Uday Kumar; Shibahara, Toshiyuki; Itagaki, Tadashi

    2017-02-01

    The well-known pathogens of fasciolosis, Fasciola hepatica (Fh) and Fasciola Gigantica (Fg), possess abundant mature sperms in their seminal vesicles, and thus, they reproduce bisexually. On the other hand, aspermic Fasciola flukes reported from Asian countries, which have no sperm in their seminal vesicles, probably reproduce parthenogenetically. The aim of this study was to reveal the origin of aspermic Fasciola flukes. The nuclear single copy markers, phosphoenolpyruvate carboxykinase and DNA polymerase delta, were employed for analysis of Fasciola species from China. The hybrid origin of aspermic Fasciola flukes was strongly suggested by the presence of the Fh/Fg type, which includes DNA fragments of both F. hepatica and F. gigantica. China can be regarded as the cradle of the interspecific hybridization because F. hepatica and F. gigantica were detected in the northern and southern parts of China, respectively, and hybrids flukes were distributed between the habitats of the two species. The Chinese origin was supported by the fact that a larger number of mitochondrial NADH dehydrogenase subunit 1 (nad1) haplotypes was detected in Chinese aspermic Fasciola populations than in aspermic populations from the neighbouring countries. Hereafter, 'aspermic' Fasciola flukes should be termed as 'hybrid' Fasciola flukes.

  15. New insights into the origin of visible-light photocatalytic activity in Se-modified anatase TiO2 from screened coulomb hybrid DFT calculations

    KAUST Repository

    Harb, Moussab

    2013-12-05

    We report a systematic study on the optoelectronic properties of Se-modified anatase TiO2 investigated by DFT (including the perturbation theory approach DFPT) within the screened coulomb hybrid HSE06 formalism to guarantee accurate band gap and electronic excitation predictions. Various selenium species at substitutional sites for O or Ti, at interstitial sites, as well as at mixed substitutional/interstitial sites are studied. Among the explored structures, Ti(1-2x)O2Se2x (containing Se4+ species), TiO(2-x)Sex (containing Se2- species), and TiO(2-x)Se2x (containing Se2 2- species) reveal significant enhanced visible-light optical absorption spectra with new absorption features appearing at 500, 600, and 690 nm, respectively. Our calculated spectra are found to be in good agreement with those obtained in available experimental works. The band gap narrowing in these materials originates from incorporation of newly occupied electronic levels within 0.5-1.5 eV above the original valence band of TiO 2, leading to new narrowed band gaps of 2.5, 2.0, and 1.8 eV respectively. Our calculations also reveal suitable band positions of Ti (1-2x)O2Se2x and TiO(2-x)Se x for overall water splitting, whereas TiO(2-x)Se 2x shows an unsuitable valence band position for the oxygen evolution reaction. In contrast, the localized electronic character of the new occupied states on the Se 4p orbitals and only on the O 2p orbitals linked to the Se species makes the holes mobility limited in this material and the recombination rate of charge carriers greatly increased in the bulk. © 2013 American Chemical Society.

  16. Strategy for comparative untargeted metabolomics reveals honey markers of different floral and geographic origins using ultrahigh-performance liquid chromatography-hybrid quadrupole-orbitrap mass spectrometry.

    Science.gov (United States)

    Li, Yi; Jin, Yue; Yang, Shupeng; Zhang, Wenwen; Zhang, Jinzhen; Zhao, Wen; Chen, Lanzhen; Wen, Yaqin; Zhang, Yongxin; Lu, Kaizhi; Zhang, Yaping; Zhou, Jinhui; Yang, Shuming

    2017-05-26

    Honey discrimination based on floral and geographic origins is limited by the ability to determine reliable markers because developing hypothetical substances in advance considerably limits the throughput of metabolomics studies. Here, we present a novel approach to screen and elucidate honey markers based on comparative untargeted metabolomics using ultrahigh-performance liquid chromatography-hybrid quadrupole-orbitrap mass spectrometry (UHPLC-Q-Orbitrap). To reduce metabolite information losses during sample preparation, the honey samples were dissolved in water and centrifuged to remove insoluble particles prior to UHPLC-Q-Orbitrap analysis in positive and negative electrospray ionization modes. The data were pretreated using background subtraction, chromatographic peak extraction, normalization, transformation and scaling to remove interferences from unwanted biases and variance in the experimental data. The pretreated data were further processed using principal component analysis (PCA) and a three-stage approach (t-test, volcano plot and variable importance in projection (VIP) plot) to ensure marker authenticity. A correlation between the molecular and fragment ions with a mass accuracy of less than 1.0ppm was used to annotate and elucidate the marker structures, and the marker responses in real samples were used to confirm the effectiveness of the honey discrimination. Moreover, we evaluated the data quality using blank and quality control (QC) samples based on PCA clustering, retention times, normalized levels and peak areas. This strategy will help guide standardized, comparative untargeted metabolomics studies of honey and other agro-products from different floral and geographic origins. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Upscaling the niche variation hypothesis from the intra- to the inter-specific level.

    Science.gov (United States)

    Bison, Marjorie; Ibanez, Sébastien; Redjadj, Claire; Boyer, Frédéric; Coissac, Eric; Miquel, Christian; Rioux, Delphine; Said, Sonia; Maillard, Daniel; Taberlet, Pierre; Yoccoz, Nigel Gilles; Loison, Anne

    2015-11-01

    The "niche variation hypothesis" (NVH) predicts that populations with wider niches should display higher among-individual variability. This prediction originally stated at the intra-specific level may be extended to the inter-specific level: individuals of generalist species may differ to a greater extent than individuals of a specialist species. We tested the NVH at intra- and inter-specific levels based on a large diet database of three large herbivore feces collected in the field and analyzed using DNA metabarcoding. The three herbivores (roe deer Capreolus capreolus, chamois Rupicapra rupicapra and mouflon Ovis musimon) are highly contrasted in terms of sociality (solitary to highly gregarious) and diet. The NVH at the intraspecific level was tested by relating, for the same population, diet breadth and inter-individual variation across the four seasons. Compared to null models, our data supported the NVH both at the intra- and inter-specific levels. Inter-individual variation of the diet of solitary species was not larger than in social species, although social individuals feed together and could therefore have more similar diets. Hence, the NVH better explained diet breadth than other factors such as sociality. The expansion of the population niche of the three species was driven by resource availability, and achieved by an increase in inter-individual variation, and the level of inter-individual variability was larger in the generalist species (mouflon) than in the specialist one (roe deer). This mechanism at the base of the NVH appears at play at different levels of biological organization, from populations to communities.

  18. Transposable Element Misregulation Is Linked to the Divergence between Parental piRNA Pathways in Drosophila Hybrids.

    Science.gov (United States)

    Romero-Soriano, Valèria; Modolo, Laurent; Lopez-Maestre, Hélène; Mugat, Bruno; Pessia, Eugénie; Chambeyron, Séverine; Vieira, Cristina; Garcia Guerreiro, Maria Pilar

    2017-06-01

    Interspecific hybridization is a genomic stress condition that leads to the activation of transposable elements (TEs) in both animals and plants. In hybrids between Drosophila buzzatii and Drosophila koepferae, mobilization of at least 28 TEs has been described. However, the molecular mechanisms underlying this TE release remain poorly understood. To give insight on the causes of this TE activation, we performed a TE transcriptomic analysis in ovaries (notorious for playing a major role in TE silencing) of parental species and their F1 and backcrossed (BC) hybrids. We find that 15.2% and 10.6% of the expressed TEs are deregulated in F1 and BC1 ovaries, respectively, with a bias toward overexpression in both cases. Although differences between parental piRNA (Piwi-interacting RNA) populations explain only partially these results, we demonstrate that piRNA pathway proteins have divergent sequences and are differentially expressed between parental species. Thus, a functional divergence of the piRNA pathway between parental species, together with some differences between their piRNA pools, might be at the origin of hybrid instabilities and ultimately cause TE misregulation in ovaries. These analyses were complemented with the study of F1 testes, where TEs tend to be less expressed than in D. buzzatii. This can be explained by an increase in piRNA production, which probably acts as a defence mechanism against TE instability in the male germline. Hence, we describe a differential impact of interspecific hybridization in testes and ovaries, which reveals that TE expression and regulation are sex-biased. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  19. Chronobiology of interspecific interactions in a changing world

    NARCIS (Netherlands)

    Kronfeld-Schor, Noga; Visser, Marcel E.; Salis, Lucia; van Gils, Jan A.

    2017-01-01

    Animals should time activities, such as foraging, migration and reproduction, as well as seasonal physiological adaptation, in a way that maximizes fitness. The fitness outcome of such activities depends largely on their interspecific interactions; the temporal overlap with other species determines

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

    Directory of Open Access Journals (Sweden)

    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.

  1. Variation in the relative magnitude of intraspecific and interspecific ...

    Indian Academy of Sciences (India)

    Administrator

    Models of competitor coevolution, especially the genetic feedback hypothesis, suggest that a negative correlation be- tween intraspecific and interspecific competitive effects may be important in sustaining competitor coexistence, and can give rise to oscillatory dynamics with repeated reversals of competitive superiority.

  2. Ants exhibit asymmetric hybridization in a mosaic hybrid zone.

    Science.gov (United States)

    Purcell, Jessica; Zahnd, Sacha; Athanasiades, Anouk; Türler, Rebecca; Chapuisat, Michel; Brelsford, Alan

    2016-10-01

    Research on hybridization between species provides unparalleled insights into the pre- and postzygotic isolating mechanisms that drive speciation. In social organisms, colony-level incompatibilities may provide additional reproductive barriers not present in solitary species, and hybrid zones offer an opportunity to identify these barriers. Here, we use genotyping-by-sequencing to sequence hundreds of markers in a hybrid zone between two socially polymorphic ant species, Formica selysi and Formica cinerea. We characterize the zone, determine the frequency of hybrid workers, infer whether hybrid queens or males are produced and investigate whether hybridization is influenced by colony social organization. We also compare cuticular hydrocarbon profiles and aggression levels between the two species. The hybrid zone exhibits a mosaic structure. The asymmetric distribution of hybrids skewed towards F. cinerea suggests a pattern of unidirectional nuclear gene flow from F. selysi into F. cinerea. The occurrence of backcrossed individuals indicates that hybrid queens and/or males are fertile, and the presence of the F. cinerea mitochondrial haplotype in 97% of hybrids shows that successful F1 hybrids will generally have F. cinerea mothers and F. selysi fathers. We found no evidence that social organization contributes to speciation, because hybrids occur in both single-queen and multiple-queen colonies. Strongly differentiated cuticular hydrocarbon profiles and heightened interspecific aggression further reveal that species recognition cues are both present and perceived. The discovery of fertile hybrids and asymmetrical gene flow is unusual in ants, and this hybrid zone will therefore provide an ideal system with which to investigate speciation in social insects. © 2016 John Wiley & Sons Ltd.

  3. Enhanced Wort Fermentation withDe NovoLager Hybrids Adapted to High-Ethanol Environments.

    Science.gov (United States)

    Krogerus, Kristoffer; Holmström, Sami; Gibson, Brian

    2018-02-15

    Interspecific hybridization is a valuable tool for developing and improving brewing yeast in a number of industry-relevant aspects. However, the genomes of newly formed hybrids can be unstable. Here, we exploited this trait by adapting four brewing yeast strains, three of which were de novo interspecific lager hybrids with different ploidy levels, to high ethanol concentrations in an attempt to generate variant strains with improved fermentation performance in high-gravity wort. Through a batch fermentation-based adaptation process and selection based on a two-step screening process, we obtained eight variant strains which we compared to the wild-type strains in 2-liter-scale wort fermentations replicating industrial conditions. The results revealed that the adapted variants outperformed the strains from which they were derived, and the majority also possessed several desirable brewing-relevant traits, such as increased ester formation and ethanol tolerance, as well as decreased diacetyl formation. The variants obtained from the polyploid hybrids appeared to show greater improvements in fermentation performance than those derived from diploid strains. Interestingly, it was not only the hybrid strains, but also the Saccharomyces cerevisiae parent strain, that appeared to adapt and showed considerable changes in genome size. Genome sequencing and ploidy analysis revealed that changes had occurred at both the chromosome and single nucleotide levels in all variants. Our study demonstrates the possibility of improving de novo lager yeast hybrids through adaptive evolution by generating stable and superior variants that possess traits relevant to industrial lager beer fermentation. IMPORTANCE Recent studies have shown that hybridization is a valuable tool for creating new and diverse strains of lager yeast. Adaptive evolution is another strain development tool that can be applied in order to improve upon desirable traits. Here, we apply adaptive evolution to newly

  4. Effects of environmental stress on mRNA expression levels of seven genes related to oxidative stress and growth in Atlantic salmon Salmo salar L. of farmed, hybrid and wild origin.

    Science.gov (United States)

    Solberg, Monica F; Kvamme, Bjørn Olav; Nilsen, Frank; Glover, Kevin A

    2012-12-05

    Ten generations of domestication selection has caused farmed Atlantic salmon Salmo salar L. to deviate from wild salmon in a range of traits. Each year hundreds of thousands of farmed salmon escape into the wild. Thus, interbreeding between farmed escapees and wild conspecifics represents a significant threat to the genetic integrity of wild salmon populations. In a previous study we demonstrated how domestication has inadvertently selected for reduced responsiveness to stress in farmed salmon. To complement that study, we have evaluated the expression of seven stress-related genes in head kidney of salmon of farmed, hybrid and wild origin exposed to environmentally induced stress. In general, the crowding stressor used to induce environmental stress did not have a strong impact on mRNA expression levels of the seven genes, except for insulin-like growth factor-1 (IGF-1) that was downregulated in the stress treatment relative to the control treatment. mRNA expression levels of glutathione reductase (GR), Cu/Zn superoxide dismutase (Cu/Zn SOD), Mn superoxide dismutase (Mn SOD), glutathione peroxidase (GP) and IGF-1 were affected by genetic origin, thus expressed significantly different between the salmon of farmed, hybrid or wild origin. A positive relationship was detected between body size of wild salmon and mRNA expression level of the IGF-1 gene, in both environments. No such relationship was observed for the hybrid or farmed salmon. Farmed salmon in this study displayed significantly elevated mRNA levels of the IGF-1 gene relative to the wild salmon, in both treatments, while hybrids displayed a non additive pattern of inheritance. As IGF-1 mRNA levels are positively correlated to growth rate, the observed positive relationship between body size and IGF-1 mRNA levels detected in the wild but neither in the farmed nor the hybrid salmon, could indicate that growth selection has increased IGF-1 levels in farmed salmon to the extent that they may not be limiting

  5. Natural hybrids in the genus of Aloe (Aloeaceae) in East Africa ...

    African Journals Online (AJOL)

    Natural hybrids can arise in the genus Aloe because their chief pollinators, sunbirds, are not species-specific when feeding on nectar. From literature and the observations of the writer and others, 16 cases of known or suspected natural interspecific hybrids in East Africa are recorded. Journal of East African Natural History ...

  6. Hybridization between invasive populations of Dalmatian toadflax (Linaria dalmatica) and yellow toadflax (Linaria vulgaris)

    Science.gov (United States)

    Sarah M. Ward; Caren E. Fleischmann; Marie F. Turner; Sharlene E. Sing

    2009-01-01

    Although there is evidence that interspecific hybridization can initiate invasion by nonnative plants, there are few documented examples of novel hybridization events between introduced plant species already exhibiting invasive behavior. We conducted morphometric and molecular analyses of toadflax plants with intermediate morphology found at two sites in Montana, which...

  7. Evaluating hybridization as a potential facilitator of successful cogongrass (Imperata cylindrica) invasion in Florida, USA

    Science.gov (United States)

    Rima Lucardi; L.E. Wallace; G.N. Ervin

    2014-01-01

    Interspecific hybridization is cited as one potential mechanism for increased invasiveness, particularly among some grass species. In the southeastern United States, the successful invasion of cogongrass (Imperata cylindrica) has sometimes been attributed to hybridization with the previously naturalized Imperata brasiliensis. This...

  8. Phylogenetic origin of limes and lemons revealed by cytoplasmic and nuclear markers.

    Science.gov (United States)

    Curk, Franck; Ollitrault, Frédérique; Garcia-Lor, Andres; Luro, François; Navarro, Luis; Ollitrault, Patrick

    2016-04-01

    The origin of limes and lemons has been a source of conflicting taxonomic opinions. Biochemical studies, numerical taxonomy and recent molecular studies suggested that cultivated Citrus species result from interspecific hybridization between four basic taxa (C. reticulata,C. maxima,C. medica and C. micrantha). However, the origin of most lemons and limes remains controversial or unknown. The aim of this study was to perform extended analyses of the diversity, genetic structure and origin of limes and lemons. The study was based on 133 Citrus accessions. It combined maternal phylogeny studies based on mitochondrial and chloroplastic markers, and nuclear structure analysis based on the evaluation of ploidy level and the use of 123 markers, including 73 basic taxa diagnostic single nucleotide polymorphism (SNP) and indel markers. The lime and lemon horticultural group appears to be highly polymorphic, with diploid, triploid and tetraploid varieties, and to result from many independent reticulation events which defined the sub-groups. Maternal phylogeny involves four cytoplasmic types out of the six encountered in the Citrus genus. All lime and lemon accessions were highly heterozygous, with interspecific admixture of two, three and even the four ancestral taxa genomes. Molecular polymorphism between varieties of the same sub-group was very low. Citrus medica contributed to all limes and lemons and was the direct male parent for the main sub-groups in combination with C. micrantha or close papeda species (for C. aurata, C. excelsa, C. macrophylla and C. aurantifolia--'Mexican' lime types of Tanaka's taxa), C. reticulata(for C. limonia, C. karna and C. jambhiri varieties of Tanaka's taxa, including popular citrus rootstocks such as 'Rangpur' lime, 'Volkamer' and 'Rough' lemons), C. aurantium (for C. limetta and C. limon--yellow lemon types--varieties of Tanaka's taxa) or the C. maxima × C. reticulate hybrid (for C. limettioides--'Palestine sweet' lime types--and C

  9. 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.

  10. Aggregation Behaviour and Interspecific Responses in Three Species of Triatominae

    Directory of Open Access Journals (Sweden)

    Lorenzo Figueiras Alicia N

    1998-01-01

    Full Text Available The response to intra- and interspecific assembling signals was tested in three species of Chagas' disease vectors. As previously described for Triatoma infestans, larvae of both species, T. sordida and T. guasayana, aggregated on papers impregnated with their own excrement. Moreover, bugs belonging to each of the three species also aggregated on papers contaminated with faeces from the other two, with the only exception of the larvae of T. guasayana, which did not assemble on faeces of T. sordida. In all cases, the response to interspecific excrement was as strong as that to the intraspecific one. The non-specificity of the signal is discussed in the context of the ecological association of the three species and their role as vectors of Chagas' disease

  11. L’hybridation interspécifique chez les champignons phytopathogènes à l’origine de nouvelles maladies

    OpenAIRE

    Frey, Pascal

    2009-01-01

    Mécanisme évolutif bien connu chez les plantes, l’hybridation interspécifique a été relativement peu étudiée dans certains groupes taxonomiques, comme les champignons. Chez les champignons phytopathogènes, l’hybridation entre une espèce indigène et une espèce exotique peut pourtant conduire à l’émergence de nouvelles maladies des plantes.

  12. Interspecific Larval Competition Differentially Impacts Adult Survival in Dengue Vectors.

    Science.gov (United States)

    Alto, Barry W; Bettinardi, David J; Ortiz, Sara

    2015-03-01

    Mosquitoes often experience intraspecific and interspecific competition among larvae attributable to high densities and nutrient limitation, especially container mosquitoes including Aedes aegypti (L.) and Aedes albopictus (Skuse). Density-dependent effects on larvae impact adult production and adult traits that influence transmission of arboviruses. To improve our understanding of the mechanisms by which density-dependence influences transmission and identify species-specific traits, we tested the hypotheses: 1) Competitive asymmetry in favor of Ae. albopictus over Ae. aegypti translates to altered adult female survival, and 2) Ae. aegypti adult females are more resistant to life-shortening effects of low-humidity conditions than Ae. albopictus. We gauged the relative impact of inter- and intraspecific larval competition on adult survival in high- and low-humidity regimes (77 and 44% relative humidity, respectively). For Ae. albopictus, intraspecific but not interspecific competition usually reduced adult survival under both humidity regimes. For Ae. aegypti, both intraspecific and interspecific competition reduced adult survival. Ae. albopictus adult survival was minimally influenced by interspecific competition with Ae. aegypti, consistent with observations that Ae. albopictus is the superior competitor. A species comparison indicated that Ae. aegypti exhibited a survival advantage relative to Ae. albopictus under both low- and high-humidity conditions. However, similar survival of these Aedes species was observed in some cases depending on conditions experienced in both the aquatic and terrestrial environments. These results demonstrate plasticity in survival rates of dengue and chikungunya vectors and the significance of considering the influence of biological interactions during the immature stages and abiotic conditions during the adult stage. © The Author 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights

  13. Chronobiology of interspecific interactions in a changing world.

    Science.gov (United States)

    Kronfeld-Schor, Noga; Visser, Marcel E; Salis, Lucia; van Gils, Jan A

    2017-11-19

    Animals should time activities, such as foraging, migration and reproduction, as well as seasonal physiological adaptation, in a way that maximizes fitness. The fitness outcome of such activities depends largely on their interspecific interactions; the temporal overlap with other species determines when they should be active in order to maximize their encounters with food and to minimize their encounters with predators, competitors and parasites. To cope with the constantly changing, but predictable structure of the environment, organisms have evolved internal biological clocks, which are synchronized mainly by light, the most predictable and reliable environmental cue (but which can be masked by other variables), which enable them to anticipate and prepare for predicted changes in the timing of the species they interact with, on top of responding to them directly. Here, we review examples where the internal timing system is used to predict interspecific interactions, and how these interactions affect the internal timing system and activity patterns. We then ask how plastic these mechanisms are, how this plasticity differs between and within species and how this variability in plasticity affects interspecific interactions in a changing world, in which light, the major synchronizer of the biological clock, is no longer a reliable cue owing to the rapidly changing climate, the use of artificial light and urbanization.This article is part of the themed issue 'Wild clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals'. © 2017 The Author(s).

  14. Host Adaptation and Speciation through Hybridization and Polyploidy in Phytophthora

    Science.gov (United States)

    Bertier, Lien; Leus, Leen; D’hondt, Liesbet; de Cock, Arthur W. A. M.; Höfte, Monica

    2013-01-01

    It is becoming increasingly evident that interspecific hybridization is a common event in phytophthora evolution. Yet, the fundamental processes underlying interspecific hybridization and the consequences for its ecological fitness and distribution are not well understood. We studied hybridization events in phytophthora clade 8b. This is a cold-tolerant group of plant pathogenic oomycetes in which six host-specific species have been described that mostly attack winter-grown vegetables. Hybrid characterization was done by sequencing and cloning of two nuclear (ITS and Ypt1) and two mitochondrial loci (Cox1 and Nadh1) combined with DNA content estimation using flow cytometry. Three different mtDNA haplotypes were recovered among the presumed hybrid isolates, dividing the hybrids into three types, with different parental species involved. In the nuclear genes, additivity, i.e. the presence of two alleles coming from different parents, was detected. Hybrid isolates showed large variations in DNA content, which was positively correlated with the additivity in nuclear loci, indicating allopolyploid hybridization followed by a process of diploidization. Moreover, indications of homeologous recombination were found in the hybrids by cloning ITS products. The hybrid isolates have been isolated from a range of hosts that have not been reported previously for clade 8b species, indicating that they have novel pathogenic potential. Next to this, DNA content measurements of the non-hybrid clade 8b species suggest that polyploidy is a common feature of this clade. We hypothesize that interspecific hybridization and polyploidy are two linked phenomena in phytophthora, and that these processes might play an important and ongoing role in the evolution of this genus. PMID:24386473

  15. Asexual Reproduction Does Not Apparently Increase the Rate of Chromosomal Evolution: Karyotype Stability in Diploid and Triploid Clonal Hybrid Fish (Cobitis, Cypriniformes, Teleostei).

    Science.gov (United States)

    Majtánová, Zuzana; Choleva, Lukáš; Symonová, Radka; Ráb, Petr; Kotusz, Jan; Pekárik, Ladislav; Janko, Karel

    2016-01-01

    Interspecific hybridization, polyploidization and transitions from sexuality to asexuality considerably affect organismal genomes. Especially the last mentioned process has been assumed to play a significant role in the initiation of chromosomal rearrangements, causing increased rates of karyotype evolution. We used cytogenetic analysis and molecular dating of cladogenetic events to compare the rate of changes of chromosome morphology and karyotype in asexually and sexually reproducing counterparts in European spined loach fish (Cobitis). We studied metaphases of three sexually reproducing species and their diploid and polyploid hybrid clones of different age of origin. The material includes artificial F1 hybrid strains, representatives of lineage originated in Holocene epoch, and also individuals of an oldest known age to date (roughly 0.37 MYA). Thereafter we applied GISH technique as a marker to differentiate parental chromosomal sets in hybrids. Although the sexual species accumulated remarkable chromosomal rearrangements after their speciation, we observed no differences in chromosome numbers and/or morphology among karyotypes of asexual hybrids. These hybrids possess chromosome sets originating from respective parental species with no cytogenetically detectable recombinations, suggesting their integrity even in a long term. The switch to asexual reproduction thus did not provoke any significant acceleration of the rate of chromosomal evolution in Cobitis. Asexual animals described in other case studies reproduce ameiotically, while Cobitis hybrids described here produce eggs likely through modified meiosis. Therefore, our findings indicate that the effect of asexuality on the rate of chromosomal change may be context-dependent rather than universal and related to particular type of asexual reproduction.

  16. Asexual Reproduction Does Not Apparently Increase the Rate of Chromosomal Evolution: Karyotype Stability in Diploid and Triploid Clonal Hybrid Fish (Cobitis, Cypriniformes, Teleostei.

    Directory of Open Access Journals (Sweden)

    Zuzana Majtánová

    Full Text Available Interspecific hybridization, polyploidization and transitions from sexuality to asexuality considerably affect organismal genomes. Especially the last mentioned process has been assumed to play a significant role in the initiation of chromosomal rearrangements, causing increased rates of karyotype evolution. We used cytogenetic analysis and molecular dating of cladogenetic events to compare the rate of changes of chromosome morphology and karyotype in asexually and sexually reproducing counterparts in European spined loach fish (Cobitis. We studied metaphases of three sexually reproducing species and their diploid and polyploid hybrid clones of different age of origin. The material includes artificial F1 hybrid strains, representatives of lineage originated in Holocene epoch, and also individuals of an oldest known age to date (roughly 0.37 MYA. Thereafter we applied GISH technique as a marker to differentiate parental chromosomal sets in hybrids. Although the sexual species accumulated remarkable chromosomal rearrangements after their speciation, we observed no differences in chromosome numbers and/or morphology among karyotypes of asexual hybrids. These hybrids possess chromosome sets originating from respective parental species with no cytogenetically detectable recombinations, suggesting their integrity even in a long term. The switch to asexual reproduction thus did not provoke any significant acceleration of the rate of chromosomal evolution in Cobitis. Asexual animals described in other case studies reproduce ameiotically, while Cobitis hybrids described here produce eggs likely through modified meiosis. Therefore, our findings indicate that the effect of asexuality on the rate of chromosomal change may be context-dependent rather than universal and related to particular type of asexual reproduction.

  17. McGISH identification and phenotypic description of leaf rust and yellow rust resistant partial amphiploids originating from a wheat × Thinopyrum synthetic hybrid cross.

    Science.gov (United States)

    Kruppa, Klaudia; Türkösi, Edina; Mayer, Marianna; Tóth, Viola; Vida, Gyula; Szakács, Éva; Molnár-Láng, Márta

    2016-11-01

    A Thinopyrum intermedium × Thinopyrum ponticum synthetic hybrid wheatgrass is an excellent source of leaf and stem rust resistance produced by N.V.Tsitsin. Wheat line Mv9kr1 was crossed with this hybrid (Agropyron glael) in Hungary in order to transfer its advantageous agronomic traits into wheat. As the wheat parent was susceptible to leaf rust, the transfer of resistance was easily recognizable in the progenies. Three different partial amphiploid lines with leaf rust resistance were selected from the wheat/Thinopyrum hybrid derivatives by multicolour genomic in situ hybridization. Chromosome counting on the partial amphiploids revealed 58 chromosomes (18 wheatgrass) in line 194, 56 (14 wheatgrass) in line 195 and 54 (12 wheatgrass) in line 196. The wheat chromosomes present in these lines were identified and the wheatgrass chromosomes were characterized by fluorescence in situ hybridization using the repetitive DNA probes Afa-family, pSc119.2 and pTa71. The 3D wheat chromosome was missing from the lines. Molecular marker analysis showed the presence of the Lr24 leaf rust resistance gene in lines 195 and 196. The morphological traits were evaluated in the field during two consecutive seasons in two different locations.

  18. Effects of intra- and interspecific competition on the sensitivity of Daphnia magna populations to the fungicide carbendazim.

    Science.gov (United States)

    Del Arco, Ana Isabel; Rico, Andreu; van den Brink, Paul J

    2015-08-01

    The ecological risk assessment of pesticides is generally based on toxicity data obtained from single-species laboratory experiments and does not take into account ecological interactions such as competition or predation. Intraspecific and interspecific competition are expected to result in additional stress and might increase the sensitivity of aquatic populations to pesticide contamination. To test this hypothesis, the effects of the fungicide carbendazim were assessed on the population dynamics of the micro-crustacean Daphnia magna under different levels of intraspecific and interspecific competition for an algal food resource, using the rotifer Brachionus calyciflorus as competing species. The experiments were performed in glass jars with three different carbendazim concentrations (i.e., 50, 100 and 150 µg/L), and had a duration of 25 days, with a 4-day pre-treatment period in which competition was allowed to take place and a 21-day exposure period. The endpoints evaluated were D. magna total population abundance and population structure. Results of these experiments show that competition stress on its own had a significant influence on shaping D. magna population's structure, however, a different response was observed in the intraspecific and interspecific competition experiments. The use of a 4-day pre-treatment period in the intraspecific experiment already led to an absence of interactive effects due to the quick abundance confluence between the different intraspecific treatments, thus not allowing the observation of interactive effects between competition and carbendazim stress. Results of the interspecific competition experiment showed that rotifers were quickly outcompeted by D. magna and that D. magna even profited from the rotifer presence through exploitative competition, which alleviated the original stress caused by the algal resource limitation. These experiments suggest that competition interactions play an important role in defining population

  19. Hybrid Action Systems

    DEFF Research Database (Denmark)

    Ronkko, Mauno; Ravn, Anders P.

    1997-01-01

    a differential action, which allows differential equations as primitive actions. The extension allows us to model hybrid systems with both continuous and discrete behaviour. The main result of this paper is an extension of such a hybrid action system with parallel composition. The extension does not change...... the original meaning of the parallel composition, and therefore also the ordinary action systems can be composed in parallel with the hybrid action systems....

  20. Evidence for the hybrid origin of Potamogeton ×cooperi (Potamogetonaceae): traditional morphology-based taxonomy and molecular techniques in concert

    Czech Academy of Sciences Publication Activity Database

    Kaplan, Zdeněk; Fehrer, Judith

    2004-01-01

    Roč. 39, - (2004). s. 431-453 ISSN 1211-9520 R&D Projects: GA ČR(CZ) GP206/03/P156; GA ČR(CZ) GA206/02/0773 Institutional research plan: CEZ:AV0Z6005908 Keywords : Potamogeton * hybridization * DNA Subject RIV: EF - Botanics Impact factor: 0.968, year: 2004

  1. Geographically extensive hybridization between the forest trees American butternut and Japanese walnut

    OpenAIRE

    Hoban, Sean M.; McCleary, Tim S.; Schlarbaum, Scott E.; Romero-Severson, Jeanne

    2009-01-01

    We investigate the question of naturally occurring interspecific hybrids between two forest trees: the native North American butternut (Juglans cinerea L.) and the introduced Japanese walnut (Juglans ailantifolia Carrière). Using nuclear and chloroplast DNA markers, we provide evidence for 29 F1 and 22 advanced generation hybrids in seven locations across the eastern and southern range of the native species. Two locations show extensive admixture (95% J. ailantifolia and hybrids) while other ...

  2. 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.

  3. A report on the hybridization between two species of threatenedAsian box turtles (Testudines: Cuora) in the wild on Hainan Island(China) with comments on the origin of 'Serrata'-like turtles.

    Energy Technology Data Exchange (ETDEWEB)

    Shi, H.; Parham, James F.; Simison, W. Brian; Wang, J.; Gong, S.; Fu, B.

    2004-03-01

    Ten new turtle taxa were described from pet trade specimens from China since the 1980s (see Fritz and Obst, 1998; Fritz and Obst, 1999; Parham et al., 2001 for a review). Specimens similar to one of these taxa, Cuora serrata Iverson and McCord, 1992 (originally Cuora galbinifrons serrata, elevated by Fritz and Obst, 1997), were shown to be hybrids of male Cuora mouhotii (Gray, 1862; formerly Pyxidea, but see Stuart and Parham, 2004) and females of Cuora galbinifrons Bourret, 1939 or Cuora bourreti Obst and Reimann, 1994 (Parham et al., 2001; and Stuart and Parham, 2004).

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

    DEFF Research Database (Denmark)

    Galatius-Jørgensen, Anders; Berta, Annalisa; Frandsen, Marie Michele Schou

    2011-01-01

    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. J. Morphol., 2011. © 2010 Wiley-Liss, Inc........ 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...

  5. Loss of Heterozygosity Drives Adaptation in Hybrid Yeast

    Science.gov (United States)

    Smukowski Heil, Caiti S.; DeSevo, Christopher G.; Pai, Dave A.; Tucker, Cheryl M.; Hoang, Margaret L.

    2017-01-01

    Abstract Hybridization is often considered maladaptive, but sometimes hybrids can invade new ecological niches and adapt to novel or stressful environments better than their parents. The genomic changes that occur following hybridization that facilitate genome resolution and/or adaptation are not well understood. Here, we examine hybrid genome evolution using experimental evolution of de novo interspecific hybrid yeast Saccharomyces cerevisiae × Saccharomyces uvarum and their parentals. We evolved these strains in nutrient-limited conditions for hundreds of generations and sequenced the resulting cultures identifying numerous point mutations, copy number changes, and loss of heterozygosity (LOH) events, including species-biased amplification of nutrient transporters. We focused on a particularly interesting example, in which we saw repeated LOH at the high-affinity phosphate transporter gene PHO84 in both intra- and interspecific hybrids. Using allele replacement methods, we tested the fitness of different alleles in hybrid and S. cerevisiae strain backgrounds and found that the LOH is indeed the result of selection on one allele over the other in both S. cerevisiae and the hybrids. This is an example where hybrid genome resolution is driven by positive selection on existing heterozygosity and demonstrates that even infrequent outcrossing may have lasting impacts on adaptation. PMID:28369610

  6. Sample size for estimating average trunk diameter and plant height in eucalyptus hybrids

    OpenAIRE

    Alberto Cargnelutti Filho; Rafael Beltrame; Dilson Antônio Bisognin; Marília Lazarotto; Clovis Roberto Haselein; Darci Alberto Gatto; Gleison Augusto dos Santos

    2016-01-01

    ABSTRACT: In eucalyptus crops, it is important to determine the number of plants that need to be evaluated for a reliable inference of growth. The aim of this study was to determine the sample size needed to estimate average trunk diameter at breast height and plant height of inter-specific eucalyptus hybrids. In 6,694 plants of twelve inter-specific hybrids it was evaluated trunk diameter at breast height at three (DBH3) and seven years (DBH7) and tree height at seven years (H7) of age. The ...

  7. INTERSPECIFIC ANALYSIS OF GENETIC DIVERSITY IN Pyrus spp. and Malus spp

    Directory of Open Access Journals (Sweden)

    ANA CRUZ MORILLO CORONADO

    2017-01-01

    Full Text Available Boyacá is one of the departments of Colombia pioneer in the national production of deciduous, especially peaches, plums, pears and apples. Eight Random Amplified Microsatellite primers (RAMs were evaluated in eleven apple (Malus communis, seven pears (Pyrus communis, two apricots (Prunus armeniaca L. and one almond (Prunus amigdalus L. materials from deciduous collection of the Pedagogical and Technological University of Colombia. A total of 128 bands were generated with molecular weights ranging between 250 and 1300 Kb. Two groups and subgroups were formed, a similarity coefficient of 0,55, according to specie and fruit characteristics. The number of polymorphic loci ranged between 96 and 123 for CGA and ACA primers, respectively. The average value of heterozygosity was 0,34, much lower than values found in other genetic diversity studies in the genus Malus and Pyrus. Similarity index and genetic distances corrobate the synteny between these genomes which can be taken advantage for identifying of genes, comparative mapping and interspecific hybridization.

  8. Making it on their own: sperm-dependent hybrid fishes (Cobitis) switch the sexual hosts and expand beyond the ranges of their original sperm donors

    Czech Academy of Sciences Publication Activity Database

    Choleva, Lukáš; Apostolou, A.; Ráb, Petr; Janko, Karel

    2008-01-01

    Roč. 363, - (2008), s. 2911-2919 ISSN 0962-8436 R&D Projects: GA ČR GP206/05/P586; GA ČR GA206/06/1763; GA MŠk LC06073 Grant - others:GA MŽP(CZ) SM/6/3/05 Program:SM Institutional research plan: CEZ:AV0Z50450515 Keywords : hybridization * gynogenesis * polyploidy Subject RIV: EG - Zoology Impact factor: 5.556, year: 2008

  9. 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...

  10. 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...

  11. Comprehensive phylogenetic analysis of all species of swordtails and platies (Pisces: Genus Xiphophorus) uncovers a hybrid origin of a swordtail fish, Xiphophorus monticolus, and demonstrates that the sexually selected sword originated in the ancestral lineage of the genus, but was lost again secondarily.

    Science.gov (United States)

    Kang, Ji Hyoun; Schartl, Manfred; Walter, Ronald B; Meyer, Axel

    2013-01-29

    Males in some species of the genus Xiphophorus, small freshwater fishes from Meso-America, have an extended caudal fin, or sword - hence their common name "swordtails". Longer swords are preferred by females from both sworded and - surprisingly also, non-sworded (platyfish) species that belong to the same genus. Swordtails have been studied widely as models in research on sexual selection. Specifically, the pre-existing bias hypothesis was interpreted to best explain the observed bias of females in presumed ancestral lineages of swordless species that show a preference for assumed derived males with swords over their conspecific swordless males. However, many of the phylogenetic relationships within this genus still remained unresolved. Here we construct a comprehensive molecular phylogeny of all 26 known Xiphophorus species, including the four recently described species (X. kallmani, X. mayae, X. mixei and X. monticolus). We use two mitochondrial and six new nuclear markers in an effort to increase the understanding of the evolutionary relationships among the species in this genus. Based on the phylogeny, the evolutionary history and character state evolution of the sword was reconstructed and found to have originated in the common ancestral lineage of the genus Xiphophorus and that it was lost again secondarily. We estimated the evolutionary relationships among all known species of the genus Xiphophorus based on the largest set of DNA markers so far. The phylogeny indicates that one of the newly described swordtail species, Xiphophorus monticolus, is likely to have arisen through hybridization since it is placed with the southern platyfish in the mitochondrial phylogeny, but with the southern swordtails in the nuclear phylogeny. Such discordance between these two types of markers is a strong indication for a hybrid origin. Additionally, by using a maximum likelihood approach the possession of the sexually selected sword trait is shown to be the most likely

  12. Comprehensive phylogenetic analysis of all species of swordtails and platies (Pisces: Genus Xiphophorus uncovers a hybrid origin of a swordtail fish, Xiphophorus monticolus, and demonstrates that the sexually selected sword originated in the ancestral lineage of the genus, but was lost again secondarily

    Directory of Open Access Journals (Sweden)

    Kang Ji Hyoun

    2013-01-01

    Full Text Available Abstract Background Males in some species of the genus Xiphophorus, small freshwater fishes from Meso-America, have an extended caudal fin, or sword – hence their common name “swordtails”. Longer swords are preferred by females from both sworded and – surprisingly also, non-sworded (platyfish species that belong to the same genus. Swordtails have been studied widely as models in research on sexual selection. Specifically, the pre-existing bias hypothesis was interpreted to best explain the observed bias of females in presumed ancestral lineages of swordless species that show a preference for assumed derived males with swords over their conspecific swordless males. However, many of the phylogenetic relationships within this genus still remained unresolved. Here we construct a comprehensive molecular phylogeny of all 26 known Xiphophorus species, including the four recently described species (X. kallmani, X. mayae, X. mixei and X. monticolus. We use two mitochondrial and six new nuclear markers in an effort to increase the understanding of the evolutionary relationships among the species in this genus. Based on the phylogeny, the evolutionary history and character state evolution of the sword was reconstructed and found to have originated in the common ancestral lineage of the genus Xiphophorus and that it was lost again secondarily. Results We estimated the evolutionary relationships among all known species of the genus Xiphophorus based on the largest set of DNA markers so far. The phylogeny indicates that one of the newly described swordtail species, Xiphophorus monticolus, is likely to have arisen through hybridization since it is placed with the southern platyfish in the mitochondrial phylogeny, but with the southern swordtails in the nuclear phylogeny. Such discordance between these two types of markers is a strong indication for a hybrid origin. Additionally, by using a maximum likelihood approach the possession of the sexually

  13. 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

    The Bactrocera dorsalis species complex, which taxonomically resembles the Oriental fruit fly, B. dorsalis (Hendel), comprises at least 52 species. Two closely related members of the complex, namely B. papayae Drew and Hancock and B. carambolae Drew and Hancock, were recently reclassified as new species (Drew and Hancock 1994). Under this taxonomic revision, B. papayae is now regarded as a distinct species from B. carambolae based on the differences of: 1) wing pattern of the costal band at apex R4+5, 2) the presence of a dark spot on the fore femora and, 3) the pattern of the transverse black band on terga III-V. Chemical examination of the volatile components produced by the males of both species also revealed pronounced differences in the chemistry of their rectal gland secretions (Perkins et al. 1990). In Malaysia, B. papayae has a wider distribution and a larger host range compared with B. carambolae. Starfruit (Averrhoa carambola L.) and various species of wax apple (Syzygium spp.) are the preferred hosts of B. carambolae whilst B. papayae attacks over 150 species but preferentially 'attacks' banana (Musa spp.), starfruit, mango (Mangifera indica L.), papaya (Carica papaya L.) and guava (Psidium guajava L.) in decreasing order (Tan 1997). Recently, data from field trapping studies using methyl eugenol (ME) in Penang Island, Malaysia, showed the presence of male flies with intermediate morphological characteristics between B. papayae and B. carambolae. Laboratory testing showed that these two species are able to interbreed and produce viable offspring. The hybrids also possess a variety of intermediate characteristics between the two species (Wee and Tan, unpublished data). Therefore, the question arises as to whether B. papayae and B. carambolae should be categorised as different species, subspecies or even as different strains. And before a satisfactory conclusion can be achieved, there are some key issues that need to be addressed. Firstly, after ME

  14. Molecular characterization of enterohemorrhagic Escherichia coli hemolysin gene (EHEC-hlyA)-harboring isolates from cattle reveals a diverse origin and hybrid diarrheagenic strains.

    Science.gov (United States)

    Askari Badouei, Mahdi; Morabito, Stefano; Najafifar, Arash; Mazandarani, Emad

    2016-04-01

    In the present study we investigated the occurrence of Escherichia coli strains harboring the gene encoding enterohemorrhagic E. coli hemolysin (EHEC-HlyA) in cattle and the association of this gene with various diarrheagenic E. coli (DEC) pathotypes. First, the bovine E. coli isolates were screened for EHEC-hlyA gene by PCR, and then they were characterized for the phylogenetic groups and the presence of the major virulence genes of different DEC pathotypes. In total, 25 virulence gene profiles were observed in 54 EHEC-hlyA+ isolates that reflect a considerable heterogeneity. The EHEC-hlyA+ strains were mostly associated with EHEC (72%), while only 7.4% were enteropathogenic E. coli (EPEC). We also showed the presence of estA gene of enterotoxigenic E. coli (ETEC) in 6 isolates (11.1%). Interestingly, two of the estA+ strains showed hybrid pathotypes with one carrying eae/estA (EPEC/ETEC), and the other one stx2/astA/estA (EHEC/ETEC). None of the isolates were related to enteroaggregative E. coli (EAggEC), enteroinvasive E. coli (EIEC), and necrotoxigenic E. coli (NTEC). The EHEC-plasmid encoded genes occurred in seven different combinations with EHEC-hlyA/saa/subA/espP being the most prevalent (46.3%). All stx-/eae+ strains carried O island 57 (OI-57) molecular marker(s) that may indicate these to be the progenitors of EHEC or strains losing stx. The most prevalent phylogroup was B1 (61.1%), but the most heterogeneous strains including the hybrid strains belonged to A phylogroup. Overall, our results indicate that cattle EHEC-hlyA encoding E. coli isolates consist of diverse diarrheagenic strains with the possible existence of hybrid pathotypes. Future studies are required to clarify the evolutionary aspects and clinical significance of these strains in humans and domestic animals. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. KARYOTYPE ALTERATIONS AFTER HYBRIDIZATION BETWEEN Pennisetum purpureum AND Pennisetum glaucum

    Directory of Open Access Journals (Sweden)

    Gabriela Barreto dos Reis

    2015-10-01

    Full Text Available ABSTRACTNapier grass and pearl millet are tropical forages from the genus Pennisetum. The variability in those species is explored in breeding programs of forages, as well as in the production of interspecific hybrids. Hybridization is a phenomenon that leads to intergenomic conflicts following the elimination of genomic sequences. In this sense, the present work aimed to study the genomic alterations occurring after interspecific hybridization of pearl millet and Napier grass with the use of cytogenetics and flow cytometry tools. These methods allowed the evaluation of chromosome morphometry, DNA content and genomic ratio in pearl millet, Napier grass and hybrids. It was observed that pearl millet and Napier grass have chromosomes with superposed size. The hybrid presents chromosomes that are smaller than expected, leading to karyotype alterations. Additionally, comparing the DNA content of parents and hybrids, loss of DNA content was demonstrated. Further, changes in the pearl millet and Napier grass genome ratio were also verified in the hybrid nucleus. Moreover, genomic rearrangements were shown to occur through karyotype alterations in the hybrid.

  16. 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

  17. Genome-wide comparative analysis reveals similar types of NBS genes in hybrid Citrus sinensis genome and original Citrus clementine genome and provides new insights into non-TIR NBS genes.

    Directory of Open Access Journals (Sweden)

    Yunsheng Wang

    Full Text Available In this study, we identified and compared nucleotide-binding site (NBS domain-containing genes from three Citrus genomes (C. clementina, C. sinensis from USA and C. sinensis from China. Phylogenetic analysis of all Citrus NBS genes across these three genomes revealed that there are three approximately evenly numbered groups: one group contains the Toll-Interleukin receptor (TIR domain and two different Non-TIR groups in which most of proteins contain the Coiled Coil (CC domain. Motif analysis confirmed that the two groups of CC-containing NBS genes are from different evolutionary origins. We partitioned NBS genes into clades using NBS domain sequence distances and found most clades include NBS genes from all three Citrus genomes. This suggests that three Citrus genomes have similar numbers and types of NBS genes. We also mapped the re-sequenced reads of three pomelo and three mandarin genomes onto the C. sinensis genome. We found that most NBS genes of the hybrid C. sinensis genome have corresponding homologous genes in both pomelo and mandarin genomes. The homologous NBS genes in pomelo and mandarin suggest that the parental species of C. sinensis may contain similar types of NBS genes. This explains why the hybrid C. sinensis and original C. clementina have similar types of NBS genes in this study. Furthermore, we found that sequence variation amongst Citrus NBS genes were shaped by multiple independent and shared accelerated mutation accumulation events among different groups of NBS genes and in different Citrus genomes. Our comparative analyses yield valuable insight into the structure, organization and evolution of NBS genes in Citrus genomes. Furthermore, our comprehensive analysis showed that the non-TIR NBS genes can be divided into two groups that come from different evolutionary origins. This provides new insights into non-TIR genes, which have not received much attention.

  18. On the allopolyploid origin and genome structure of the closely related species Hordeum secalinum and Hordeum capense inferred by molecular karyotyping.

    Science.gov (United States)

    Cuadrado, Ángeles; de Bustos, Alfredo; Jouve, Nicolás

    2017-08-01

    To provide additional information to the many phylogenetic analyses conducted within Hordeum , here the origin and interspecific affinities of the allotetraploids Hordeum secalinum and Hordeum capense were analysed by molecular karyotyping. Karyotypes were determined using genomic in situ hybridization (GISH) to distinguish the sub-genomes and , plus fluorescence in situ hybridization (FISH)/non-denaturing (ND)-FISH to determine the distribution of ten tandem repetitive DNA sequences and thus provide chromosome markers. Each chromosome pair in the six accessions analysed was identified, allowing the establishment of homologous and putative homeologous relationships. The low-level polymorphism observed among the H. secalinum accessions contrasted with the divergence recorded for the sub-genome of the H. capense accessions. Although accession H335 carries an intergenomic translocation, its chromosome structure was indistinguishable from that of H. secalinum . Hordeum secalinum and H. capense accession H335 share a hybrid origin involving Hordeum marinum subsp. gussoneanum as the genome donor and an unidentified genome progenitor. Hordeum capense accession BCC2062 either diverged, with remodelling of the sub-genome, or its genome was donated by a now extinct ancestor. A scheme of probable evolution shows the intricate pattern of relationships among the Hordeum species carrying the genome (including all H. marinum taxa and the hexaploid Hordeum brachyantherum ). © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  19. Interspecific androgenetic restoration of rosy barb using cadaveric sperm.

    Science.gov (United States)

    Kirankumar, S; Pandian, T J

    2004-02-01

    Interspecific androgenetic rosy barb (Puntius conchonius) was generated using its cadaveric (-20 degrees C) or fresh sperm to activate nuclear genome inactivated oocytes of gray tiger barb (Puntius tetrazona). UV irradiation was used to inactivate nuclear genome of tiger barb oocytes. Thermal shock restored diploidy of rosy barb in the oocytes of tiger barb. Survival of androgenotes was 14% or 7% when fresh or cadaveric sperm was used. The diploid or haploid nuclear genome of rosy barb, individually or jointly with that of tiger barb, regulated the time sequence of embryonic development in an alien cytoplasm of tiger barb oocytes. Androgenetic males (Y2Y2) attained sexual maturity earlier and had significantly higher gonadosomatic index and sperm concentration, albeit suffering a slight decrease in fertilizing ability. Conversely, androgenetic females (X2X2) suffered extended interspawning period, reduced fecundity, and poor hatchability of their progenies. These results are discussed with respect to their significance for conservation biology.

  20. Confirmation of cross-fertilization using molecular markers in ornamental passion flower hybrids.

    Science.gov (United States)

    Conceição, L D H C S; Belo, G O; Souza, M M; Santos, S F; Cerqueira-Silva, C B M; Corrêa, R X

    2011-01-11

    Several interspecific Passiflora hybrids are produced in the northern hemisphere for the ornamental plant market. In Brazil, production of passion flower hybrids is limited to the introgression of genes into the main cultivated species, yellow passion fruit, to be used as rootstocks. Confirmation of hybridization in the initial developmental stage is important for breeding perennial and sub-perennial plants, such as passion flowers, reducing time and costs in plant stock maintenance. In order to obtain F₁ hybrids with ornamental potential, four species of Passiflora (P. alata, P. gardneri, P. gibertii, and P. watsoniana) from the Active Germplasm Bank at UESC were hybridized. Flower buds, in pre-anthesis, of the genitors were previously protected, and the female buds were emasculated. To confirm hybridization, the genomic DNA of the genitor species and the supposed hybrids was extracted and RAPD primers were used to obtain molecular markers and select passion flower interspecific hybrids. Eight primers were used to confirm hybrids derived from P. gardneri with P. alata, P. watsoniana with P. alata, P. watsoniana with P. gardneri, and P. gardneri with P. gibertii; 75, 50, 45, and 46% of the informative bands, respectively, confirmed the hybrid nature of these plants. The RAPD technique was effective in the early identification of hybrids; this will be useful for development of hybrid Passiflora progeny.

  1. .i.Daphnia./i. hybridization along ecological gradients in pelagic environments: the potential for the presence of hybrid zones in plankton

    Czech Academy of Sciences Publication Activity Database

    Petrusek, A.; Seďa, Jaromír; Macháček, Jiří; Ruthová, Š.; Šmilauer, P.

    2008-01-01

    Roč. 363, č. 1505 (2008), s. 2931-2941 ISSN 0962-8436 R&D Projects: GA ČR(CZ) GA206/04/0190 Institutional research plan: CEZ:AV0Z60170517 Keywords : interspecific hybridization * Daphnia longispina complex * hybrid zones * canyon-shaped reservoirs * ITS-RFLP * allozyme electrophoresis Subject RIV: EH - Ecology, Behaviour Impact factor: 5.556, year: 2008

  2. Fine mapping of dominant X-linked incompatibility alleles in Drosophila hybrids.

    Science.gov (United States)

    Matute, Daniel R; Gavin-Smyth, Jackie

    2014-04-01

    Sex chromosomes have a large effect on reproductive isolation and play an important role in hybrid inviability. In Drosophila hybrids, X-linked genes have pronounced deleterious effects on fitness in male hybrids, which have only one X chromosome. Several studies have succeeded at locating and identifying recessive X-linked alleles involved in hybrid inviability. Nonetheless, the density of dominant X-linked alleles involved in interspecific hybrid viability remains largely unknown. In this report, we study the effects of a panel of small fragments of the D. melanogaster X-chromosome carried on the D. melanogaster Y-chromosome in three kinds of hybrid males: D. melanogaster/D. santomea, D. melanogaster/D. simulans and D. melanogaster/D. mauritiana. D. santomea and D. melanogaster diverged over 10 million years ago, while D. simulans (and D. mauritiana) diverged from D. melanogaster over 3 million years ago. We find that the X-chromosome from D. melanogaster carries dominant alleles that are lethal in mel/san, mel/sim, and mel/mau hybrids, and more of these alleles are revealed in the most divergent cross. We then compare these effects on hybrid viability with two D. melanogaster intraspecific crosses. Unlike the interspecific crosses, we found no X-linked alleles that cause lethality in intraspecific crosses. Our results reveal the existence of dominant alleles on the X-chromosome of D. melanogaster which cause lethality in three different interspecific hybrids. These alleles only cause inviability in hybrid males, yet have little effect in hybrid females. This suggests that X-linked elements that cause hybrid inviability in males might not do so in hybrid females due to differing sex chromosome interactions.

  3. The origin of the C-genome and cytoplasm of Avena polyploids.

    Science.gov (United States)

    Nikoloudakis, N; Katsiotis, A

    2008-07-01

    The contribution of C-genome diploid species to the evolution of polyploid oats was studied using C-genome ITS-specific primers. SCAR analysis among Avena accessions confirmed the presence of C-genome ITS1-5.8S-ITS2 sequences in the genome of AACC and AACCDD polyploids. In situ hybridization and screening of more than a thousand rRNA clones in Avena polyploid species containing the C-genome revealed substantial C-genome rRNA sequence elimination. C-genome clones sequenced and Maximum Likelihood Parsimony analysis revealed close proximity to Avena ventricosa ITS1-5.8S-ITS2 sequences, providing strong evidence of the latter's active role in the evolution of tetraploid and hexaploid oats. In addition, cloning and sequencing of the chloroplastic trnL intron among the most representative Avena species verified the maternal origin of A-genome for the AACC interspecific hybrid formation, which was the genetic bridge for the establishment of cultivated hexaploid oats.

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

    Science.gov (United States)

    Baah-Acheamfour, Mark; Bourque, Charles P-A; Meng, Fan-Rui; Swift, D Edwin

    2017-01-01

    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.

  5. 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.

  6. ‘Hapa White’, 'Hapa Pink', and 'Hapa Red' interspecific hybrid hibiscus cultivars

    Science.gov (United States)

    Hibiscus mutabilis, also known as confederate rose, is native to southeastern China, but it is also grown as an ornamental throughout the southeastern United States and is hardy in USDA zone 7 to 9. It is popular for its large, soft, gray-green foliage during the summer, and large, showy flowers pro...

  7. Production of interspecific Campanula hybrids by ovule culture: exploring the effecto of ovule isolation time

    NARCIS (Netherlands)

    Röper, A.C.; Lütken, H.; Christensen, B.; Boutilier, K.A.; Petersen, K.K.; Müller, R.

    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 the

  8. Susceptibility of Juglans Species andInterspecific Hybrids to Agrobacterium tumefaciens

    Science.gov (United States)

    James R. McKenna; Lynn Epstein

    2003-01-01

    Crown gall, caused by the common soil-borne bacterium Agrobacterium tumefaciens, can be an economic problem in walnut nurseries and production orchards in Caliiornia. The principal rootstocks used for commercial walnut production in California are the native Northern California black walnut, Juglans hindsii, and "Paradox,...

  9. High capacity of plant regeneration from callus of interspecific hybrids with cultivated barley (Hordeum vulgare L.)

    DEFF Research Database (Denmark)

    Bagger Jørgensen, Rikke; Jensen, C. J.; Andersen, B.

    1986-01-01

    explants of young spikes on the barley medium J 25-8. The capacity for plant regeneration was dependent on the wild parental species. In particular, combinations with four related wild species, viz. H. jubatum, H. roshevitzii, H. lechleri, and H. procerum, regenerated high numbers of plants from calli....

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

    Indian Academy of Sciences (India)

    Unknown

    and the typical hemispherical cell plate was not detected as well. The usual asymmetry was not seen at first pollen mitosis (PM I), and microspores therefore lacked differ- entiation between the vegetative and the generative cell. After telophase, each cell entered PM II, but this was not always followed by cytokinesis. Tripolar ...

  11. Composition of Essential Oil, Radical Scavenging and Antibacterial Properties of Interspecific Hybrid Thymus × oblongifolius Opiz

    Directory of Open Access Journals (Sweden)

    Kristina Lo žienė

    2012-01-01

    Full Text Available Radical scavenging and antibacterial properties of thyme extracts isolated from the two different Thymus × oblongifolius Opiz samples (TO1 and TO2 were studied. The oil of the TO1 was constituted mainly of hydrocarbon terpenes (83.4%, while the oil of the TO2 was composed mainly of oxygenated compounds with a -terpenyl acetate (37.9% being the major one. The extracts isolated with hexane, acetone and ethanol from the whole and deodorized herb were tested for their radical scavenging capacity (RSC in the model reaction systems containing stable radical DPPH • and cation radical ABTS •+. The extracts isolated with ethanol from undeodorized herb possessed the strongest RSC, while hexane extracts were not active. Undeodorized acetone extracts of the TO1 possessed higher RSC than those of the TO2, while undeodorized ethanol extracts of the TO2 were stronger radical scavengers than similar extracts of the TO1. The antibacterial activity of the extracts tested by using seven food pathogenic species depended on the species, extract concentration and extract type. Bacillus cereus, Staphylococcus aureus and St. epidermidis were more sensitive to plant extracts than Micrococcus luteus, Esherichia coli, Salmonella typhimurium and Enterobacter aerogenes.

  12. Genomic in situ hybridization reveals both auto- and allopolyploid origins of different North and Central American hexaploid potato (Solanum sect. Petota) species.

    Science.gov (United States)

    Pendinen, Galina; Spooner, David M; Jiang, Jiming; Gavrilenko, Tatjana

    2012-06-01

    Wild potato ( Solanum L. sect. Petota Dumort.) species contain diploids (2n = 2x = 24) to hexaploids (2n = 6x = 72). J.G. Hawkes classified all hexaploid Mexican species in series Demissa Bukasov and, according to a classic five-genome hypothesis of M. Matsubayashi in 1991, all members of series Demissa are allopolyploids. We investigated the genome composition of members of Hawkes's series Demissa with genomic in situ hybridization (GISH), using labeled DNA of their putative progenitors having diploid AA, BB, or PP genome species or with DNA of tetraploid species having AABB or AAA(a)A(a) genomes. GISH analyses support S. hougasii Correll as an allopolyploid with one AA component genome and another BB component genome. Our results also indicate that the third genome of S. hougasii is more closely related to P or a P genome-related species. Solanum demissum Lindl., in contrast, has all three chromosome sets related to the basic A genome, similar to the GISH results of polyploid species of series Acaulia Juz. Our results support a more recent taxonomic division of the Mexican hexaploid species into two groups: the allopolyploid Iopetala group containing S. hougasii, and an autopolyploid Acaulia group containing S. demissum with South American species S. acaule Bitter and S. albicans (Ochoa) Ochoa.

  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. Segregation of Fusarium resistance in an interspecific cross between Lilium longiflorum and Lilium dauricum

    NARCIS (Netherlands)

    Löffler, H.J.M.; Meijer, H.; Straathof, Th.P.; Tuyl, van J.M.

    1996-01-01

    Using interspecific hybridisation techniques, a resistant accession of L. dauricum (section Sinomartagon), was crossed with the susceptible L. longiflorum cultivars 'Gelria' and 'Flevo' (section Leucolirion). The progeny was tested for Fusarium resistance in a standardised scale-bulblet assay. Both

  15. Study of turbulence of Lower Hybrid Drift Instability origin with the Multi Level Multi Domain semi-implicit adaptive PIC method

    Science.gov (United States)

    Innocenti, Maria Elena; Beck, Arnaud; Markidis, Stefano; Lapenta, Giovanni

    2015-04-01

    We study turbulence generated by the Lower Hybrid Drift Instability (LHDI [1]) in the terrestrial magnetosphere. The problem is not only of interest per se, but also for the implications it can have for the so-called turbulent reconnection. The LHDI evolution is simulated with the PIC Multi Level Multi Domain code Parsek2D-MLMD [2,3], which simulates different parts of the domain with different spatial and temporal resolutions. This allows to satisfy, at a low computing cost, the two necessary requirements for LHDI turbulence simulations: 1) a large domain, to capture the high wavelength branch of the LHDI and of the secondary kink instability and 2) high resolution, to cover the high wavenumber part of the power spectrum and to capture the wavenumber at which the turbulent cascade ends. The turbulent cascade proceeds seamlessly from the coarse (low resolution) to the refined (high resolution) grid, the only one resolved enough to capture its end, which is studied here and related to wave-particle interaction processes. We also comment upon the role of smoothing (a common technique used in PIC simulations to reduce particle noise, [4]) in simulations of turbulence and on how its effects on power spectra may be easily mistaken, in absence of accurate convergence studies, for the end of the inertial range. [1] P. Gary, Theory of space plasma microinstabilities, Cambridge Atmospheric and Space Science Series, 2005. [2] M. E. Innocenti, G. Lapenta, S. Markidis, A. Beck, A. Vapirev, Journal of Computational Physics 238 (2013) 115 - 140. [3] M. E. Innocenti, A. Beck, T. Ponweiser, S. Markidis, G. Lapenta, Computer Physics Communications (accepted) (2014). [4] C. K. Birdsall, A. B. Langdon, Plasma physics via computer simulation, Taylor and Francis, 2004.

  16. The role of mating preferences in shaping interspecific divergence in mating signals in vertebrates.

    Science.gov (United States)

    Ptacek

    2000-10-05

    Vertebrates represent one of the best-studied groups in terms of the role that mating preferences have played in the evolution of exaggerated secondary sexual characters and mating behaviours within species. Vertebrate species however, also exhibit enormous interspecific diversity in features of mating signals that has potentially led to reproductive isolation and speciation in many groups. The role that sexual selection has played in interspecific divergence in mating signals has been less fully explored. This review summarizes our current knowledge of how mating preferences within species have shaped interspecific divergence in mate recognition signals among the major vertebrate groups. Certain signal modalities appear to characterize mating signal diversification among different vertebrate taxa. Acoustic signals play an important role in mating decisions in anuran amphibians and birds. Here, different properties of the signal may convey information regarding individual, neighbor and species recognition. Mating preferences for particular features of the acoustic signal have led to interspecific divergence in calls and songs. Divergence in morphological traits such as colouration or ornamentation appears to be important in interspecific diversity in certain groups of fishes and birds. Pheromonal signals serve as the primary basis for species-specific mating cues in many salamander species, most mammals and even some fishes. The evolution of interspecific divergence in elaborate courtship displays may have played an important role in speciation of lizards, and particular groups of fishes, salamanders, birds and mammals. While much research has focused on the importance of mating preferences in shaping the evolution of these types of mating signals within species, the link between intraspecific preferences and interspecific divergence and speciation remains to be more fully tested. Future studies should focus on identifying how variation in mating preferences within

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

    Science.gov (United States)

    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.

  18. Interspecific parasite exchange in a mixed colony of birds.

    Science.gov (United States)

    Valera, Francisco; Casas-Crivillé, Alejandro; Hoi, Herbert

    2003-04-01

    Studies of avian host-parasite interactions rarely include consequences of relationships among hosts for either the host or parasite species. In this study, we examine the ectoparasitic burden of adult and nestling European bee-eaters (Merops apiaster) and rock sparrows (Petronia petronia) in a mixed colony. We found that (1) each bird species had its own species of lice; (2) hematophagous mites parasitized both adults and nestlings of both bird species; (3) Carnus hemapterus, a common parasite of nestling bee-eaters, also infested rock sparrow nestlings, a species not previously described as a host for this dipteran; and (4) whereas C. hemapterus did not show high host specificity within the colony, the emergence of adult flies was synchronized with the start of hatching in bee-eater nests. We suggest that coexistence of these 2 bird species results in parasite exchange, bee-eaters obtaining mites from sparrows and sparrows becoming infested by C. hemapterus. Differences in the detrimental effects of parasite transfer for each host species may result in a process of apparent competition mediated by shared parasites. Interspecific parasite exchange is an important aspect of host-parasite relationships in mixed colonies, which requires further attention.

  19. Interspecific variation for thermal dependence of glutathione reductase in sainfoin.

    Science.gov (United States)

    Kidambi, S P; Mahan, J R; Matches, A G

    1990-05-01

    Understanding the biochemical and physiological consequences of species variation would expedite improvement in agronomically useful genotypes of sainfoin (Onobrychis spp.) Information on variation among sainfoin species is lacking on thermal dependence of glutathione reductase (B.C. 1.6.4.2.), which plays an important role in the protection of plants from both high and low temperature stresses by preventing harmful oxidation of enzymes and membranes. Our objective was to investigate the interspecific variation for thermal dependency of glutathione reductase in sainfoin. Large variation among species was found for: (i) the minimum apparent Km (0.4-2.5 μM NADPH), (ii) the temperature at which the minimum apparent Km was observed (15°-5°C), and (iii) the thermal kinetic windows (2°-30°C width) over a 15°-45°C temperature gradient. In general, tetraploid species had narrower (≤17°C) thermal kinetic windows than did diploid species (∼30°C), with one exception among the diploids. Within the tetraploid species, the cultivars of O. viciifolia had a broader thermal kinetic window (≥7°C) than the plant introduction (PI 212241, >2 °C) itself.

  20. 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.

  1. Interspecific differences revealed with in Drosophila Photometric Analysis

    Directory of Open Access Journals (Sweden)

    Hoenigsberg H. F.

    1964-12-01

    Full Text Available The above refer to experiments present a new method which permits the study of philogenesis in the genus Drosophila. There are several types of results: a close kinship among the various geographical races of  D. melanogaster in the neo-tropics coincides with their spectrophotometric similarities; b the interspecific differences are also identified with the photometric analysis; c finally there are optical density affinities among the various species which belong to the same taxonomic groups.  Acknowledgment. The authors want to express their gratitude to Professor Everet of the physico-chemical laboratory of the National University for the use of his Beckman DU spectrophotometer and for his generous advice. This research is supported by the American Agricultural Research Service grant F. G. Co 107. For technical assistance we are indebted to Miss B. I. Cortés and to Mr. L. Castro.

  2. Triple Hybridization with Cultivated Barley (Hordeum vulgare L.)

    DEFF Research Database (Denmark)

    Bothmer, R. von; Claesson, L.; Flink, J.

    1989-01-01

    A crossing programme for trispecific hybridization including cultivated barely (Hordeum vulgare L.) as the third parent was carried out. The primary hybrids comprised 11 interspecific combinations, each of which had either H. jabatum or H. lechleri as one of the parents. The second parent......' and 'Vada'. Generally, cv 'Gull' had high crossability in crosses with related species in the primary hybrid. It is suggested that 'Gull' has a genetic factor for crossability not present in cv 'Vada' and cv 'Golden Promise'. One accession of H. brachyantherum used in the primary hybrid had a very high...... crossability (seed set 54.7%) in combination with cv 'Vada' but no viable offspring was produced. In all, two trispecific hybrids were raised, viz. (H. lechleri .times. H. brevisubulatum) .times. 'Gull' (2n = 27-30) and (H. jubatum .times. H. lechleri) .times. 'Gull' (2n = 20-22). The first combination...

  3. Origin, divergence, and phylogeny of asexual Epichloe endophyte in Elymus species from western China.

    Directory of Open Access Journals (Sweden)

    Hui Song

    Full Text Available Asexual Epichloë species are likely derived directly from sexual Epichloë species that then lost their capacity for sexual reproduction or lost sexual reproduction because of interspecific hybridization between distinct lineages of sexual Epichloë and/or asexual Epichloë species. In this study we isolated asexual Epichloë endophytes from Elymus species in western China and sequenced intron-rich regions in the genes encoding β-tubulin (tubB and translation elongation factor 1-α (tefA. Our results showed that there are no gene copies of tubB and tefA in any of the isolates. Phylogenetic analysis showed that sequences in this study formed a single clade with asexual Epichloë bromicola from Hordeum brevisubulatum, which implies asexual Epichloë endophytes that are symbionts in a western Chinese Elymus species likely share a common ancestor with asexual E. bromicola from European H. brevisubulatum. In addition, our results revealed that asexual E. bromicola isolates that are symbionts in a western Chinese Elymus species and sexual Epichloë species that are symbionts in a North American Elymus species have a different origin. Further analysis found that Epichloë species likely originated in Eurasia. In addition, the results support the hypothesis that migratory birds or humans might have aided the dispersal of these fungal endophytes to other continents.

  4. Origin, divergence, and phylogeny of asexual Epichloë endophyte in Elymus species from western China.

    Science.gov (United States)

    Song, Hui; Nan, Zhibiao

    2015-01-01

    Asexual Epichloë species are likely derived directly from sexual Epichloë species that then lost their capacity for sexual reproduction or lost sexual reproduction because of interspecific hybridization between distinct lineages of sexual Epichloë and/or asexual Epichloë species. In this study we isolated asexual Epichloë endophytes from Elymus species in western China and sequenced intron-rich regions in the genes encoding β-tubulin (tubB) and translation elongation factor 1-α (tefA). Our results showed that there are no gene copies of tubB and tefA in any of the isolates. Phylogenetic analysis showed that sequences in this study formed a single clade with asexual Epichloë bromicola from Hordeum brevisubulatum, which implies asexual Epichloë endophytes that are symbionts in a western Chinese Elymus species likely share a common ancestor with asexual E. bromicola from European H. brevisubulatum. In addition, our results revealed that asexual E. bromicola isolates that are symbionts in a western Chinese Elymus species and sexual Epichloë species that are symbionts in a North American Elymus species have a different origin. Further analysis found that Epichloë species likely originated in Eurasia. In addition, the results support the hypothesis that migratory birds or humans might have aided the dispersal of these fungal endophytes to other continents.

  5. Hybrid Warfare

    Science.gov (United States)

    2013-08-01

    Office, Title 10, U.S. Code ; Act of 5 May 1960. 3. 2010 Quadrennial Defense Review Report, February 2010, 8. 4. Hybrid Warfare, Global Accountability...Rise of Hybrid Wars.” Proceedings 132 (November 2005); William J. Nemeth , Future War and Chechnya: A Case for Hybrid War- fare (master’s thesis, U.S...William J. Nemeth which represents the earliest scholarly work on the subject, in which the emergence of devolved hybrid societies gives rise to hybrid

  6. Original Researc Original Research

    African Journals Online (AJOL)

    RAGHAVENDRA

    equalizer and tasseled cap transformation were employed to the image data. RGB to IHS conversions and color combination of the original image data have also been made. The Vegetation index, NDVI, has also been used to measure the presence and state of vegetation so as to distinguish vegetated areas from others.

  7. Original Research Original Research

    African Journals Online (AJOL)

    User

    2013-03-28

    Mar 28, 2013 ... food production in sub-Saharan Africa coun. (Sanchez, 2010). Soil is the most precious vital natural resource and it must be mana. Original Research .... Exchangeable K and Na were measured by fl photometer. Exchangeable acidity determined by saturating the samples with. KCl solution and titrated with ...

  8. Original Research Original Research

    African Journals Online (AJOL)

    User

    questionnaires and analyzed using cross tab revealed the transfer of ... informal enterprises with the rural economy. Original Research. 95 ... ise from the formal sectors ew (1994) accepts these is study of the dynamics of lared the informal tailoring inputs from intermediary of and this is economic of inputs. According to.

  9. Original Research Original Research

    African Journals Online (AJOL)

    User

    2013-06-20

    Jun 20, 2013 ... great value in Ethiopian socio-economic growt requires small capital, promote inter linkages as it is a base for medium and large enterprises, increased domestic saving investment. Also they help for bal development provision of goods and services. Original Research. 123. 3327 (Online) esearch Journal.

  10. Original Research Original Research

    African Journals Online (AJOL)

    User

    , fatty makeup of compost and raised the tempera of composting dairy manure and bedding by average of 3.4°C during an 8-wk developm period. BD compost preparation are used to. Original Research. 32. 3327 (Online) esearch Journal.

  11. Original Research Original Research

    African Journals Online (AJOL)

    User

    2013-06-25

    Jun 25, 2013 ... the feeding practices (Kassahun, 2000). This involves the use of fodder bank, f trees, agro-industrial by-products such as, seed cake and urea to overcome CP shor. (ILCA, 1990). Supplementation of poor q roughage feed with suitable energy and p. Original Research. 38. 3327 (Online) esearch Journal.

  12. Original Research Original Research

    African Journals Online (AJOL)

    User

    2013-03-24

    Mar 24, 2013 ... approach is to create a pseudo alignment by taking random positions of the original alignment. Some columns of the alignment ... Table 1: Sequences selected for MSA: Inform contains the organism name from wh sequences. Sequence format. Sequence number. Sequence 1. Sequence 2. Sequence 3.

  13. 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.

  14. Original Researc Original Research

    African Journals Online (AJOL)

    RAGHAVENDRA

    introdution of defects during the synthesis proces growth of the films. But, still the origin of ferromag is in debate. ... se (Mn), cobalt (Co) and nickel (Ni) doped zinc oxide (ZnO) ndidates for variety of practical application due to their spin of ... hexhydrate (Zn (NO3)26H2O), mangane hydrate (Co(NO3)2.6H2O), cobalt nitrate he.

  15. Assignment of peptidase S (PEPS) to chromosome 4 in man using somatic cell hybrids.

    Science.gov (United States)

    Shows, T B; Brown, J A; Eddy, R L; Byers, M G; Haley, L L; Cooper, E S; Goggin, A P

    1978-08-31

    A starch gel electrophoretic procedure is described that resolves peptidase S (PEPS) as well as the peptidases A, B, and C in man-rodent, rodent-rodent, and primate-rodent interspecific somatic cell hybrids. The interspecific PEPS cell hybrid phenotype can be resolved into a pattern which suggests that PEPS is composed of five or six identical subunits. Results are presented supporting assignment of the PEPS locus to chromosome 4 in man using man-mouse and man-Chinese hamster somatic cell hybrids. Human genes coding for peptidases A, B, C, and D were assigned to chromosome 18, 12, 1, and 19, respectively, confirming previous assignments. These somatic cell genetic data demonstrate the independent genetic control of the several human peptidases.

  16. Indexical Hybrid Tense Logic

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Jørgensen, Klaus Frovin

    2012-01-01

    In this paper we explore the logic of now, yesterday, today and tomorrow by combining the semantic approach to indexicality pioneered by Hans Kamp [9] and refined by David Kaplan [10] with hybrid tense logic. We first introduce a special now nominal (our @now corresponds to Kamp’s original now...

  17. Interspecific interactions drive cultural co-evolution and acoustic convergence in syntopic species.

    Science.gov (United States)

    Laiolo, Paola

    2012-05-01

    1. Antagonistic interactions have been favourite subjects of studies on species co-evolution, because coexistence among competing species often results in quantifiable character displacement. A common output for competitive interactions is trait divergence, although the opposite phenomenon, convergence, has been proposed to evolve in some instances, for example in the communication behaviour of species that maintain mutually exclusive territories. 2. I use here experimental and observational evidence to study how species interactions drive heterospecific signal convergence and analyse how convergence feeds back to the interaction itself, in the form of aggressive behaviour. I recorded the learned territorial signals of two non-hybridizing larks, Galerida cristata and G. theklae, and used allopatric populations as controls for evaluating acoustic convergence in syntopy. Acoustic variation was analysed with respect to social conditions controlling for other potential agents of natural selection, habitat and climate. 3. Interspecific convergence of Galerida calls peaked in syntopy. Although call acoustic structure was affected by climate and habitat, it matched gradients of density and proximity to congeners even at small local scales. The process of cultural transmission, in which individuals may acquire components of behaviour by copying neighbours, enhances the correlation between call acoustics and the local social milieu. 4. Territories were defended against both species, but playback stimuli of convergent congener calls elicited a stronger aggressive reaction than congener calls from allopatric locations. 5. This study shows that learned behaviours may co-evolve as a consequence of antagonistic interactions, determining reciprocal cultural evolution or cultural co-evolution. As for (biological) co-evolution, the distribution of competing species influences whether a particular area becomes a syntopic environment in which convergence is occurring, or

  18. 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...

  19. Genetic identification of F1 and post-F1 serrasalmid juvenile hybrids in Brazilian aquaculture.

    Directory of Open Access Journals (Sweden)

    Diogo Teruo Hashimoto

    Full Text Available Juvenile fish trade monitoring is an important task on Brazilian fish farms. However, the identification of juvenile fish through morphological analysis is not feasible, particularly between interspecific hybrids and pure species individuals, making the monitoring of these individuals difficult. Hybrids can be erroneously identified as pure species in breeding facilities, which might reduce production on farms and negatively affect native populations due to escapes or stocking practices. In the present study, we used a multi-approach analysis (molecular and cytogenetic markers to identify juveniles of three serrasalmid species (Colossoma macropomum, Piaractus mesopotamicus and Piaractus brachypomus and their hybrids in different stocks purchased from three seed producers in Brazil. The main findings of this study were the detection of intergenus backcrossing between the hybrid ♀ patinga (P. mesopotamicus×P. brachypomus×♂ C. macropomum and the occurrence of one hybrid triploid individual. This atypical specimen might result from automixis, a mechanism that produces unreduced gametes in some organisms. Moreover, molecular identification indicated that hybrid individuals are traded as pure species or other types of interspecific hybrids, particularly post-F1 individuals. These results show that serrasalmid fish genomes exhibit high genetic heterogeneity, and multi-approach methods and regulators could improve the surveillance of the production and trade of fish species and their hybrids, thereby facilitating the sustainable development of fish farming.

  20. Genetic identification of F1 and post-F1 serrasalmid juvenile hybrids in Brazilian aquaculture.

    Science.gov (United States)

    Hashimoto, Diogo Teruo; Senhorini, José Augusto; Foresti, Fausto; Martínez, Paulino; Porto-Foresti, Fábio

    2014-01-01

    Juvenile fish trade monitoring is an important task on Brazilian fish farms. However, the identification of juvenile fish through morphological analysis is not feasible, particularly between interspecific hybrids and pure species individuals, making the monitoring of these individuals difficult. Hybrids can be erroneously identified as pure species in breeding facilities, which might reduce production on farms and negatively affect native populations due to escapes or stocking practices. In the present study, we used a multi-approach analysis (molecular and cytogenetic markers) to identify juveniles of three serrasalmid species (Colossoma macropomum, Piaractus mesopotamicus and Piaractus brachypomus) and their hybrids in different stocks purchased from three seed producers in Brazil. The main findings of this study were the detection of intergenus backcrossing between the hybrid ♀ patinga (P. mesopotamicus×P. brachypomus)×♂ C. macropomum and the occurrence of one hybrid triploid individual. This atypical specimen might result from automixis, a mechanism that produces unreduced gametes in some organisms. Moreover, molecular identification indicated that hybrid individuals are traded as pure species or other types of interspecific hybrids, particularly post-F1 individuals. These results show that serrasalmid fish genomes exhibit high genetic heterogeneity, and multi-approach methods and regulators could improve the surveillance of the production and trade of fish species and their hybrids, thereby facilitating the sustainable development of fish farming.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    Kullan, Anand Raj Kumar; van Dyk, Maria M; Hefer, Charles A; Jones, Nicoletta; Kanzler, Arnulf; Myburg, Alexander A

    2012-07-20

    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. 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. 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 study provide a resource for

  3. Absence of hypomethylation and LINE-1 amplification in a white x black rhinoceros hybrid.

    Science.gov (United States)

    Dobigny, Gauthier; Waters, Paul D; Robinson, Terence J

    2006-05-01

    Genomic stress resulting from the interspecific hybridization of marsupials has been shown to lead to hypomethylation and transposable element over-amplification. Here we investigated both methylation status and transposable element (LINE-1) activity in an F1 hybrid between the black (Diceros bicornis) and white rhinoceros (Ceratotherium simum). Our data show that in this instance the hybrid genome was not characterised by gross hypomethylation and LINE-1 over-amplification thus extending previous investigations on eutherian mammals. These findings underscore observations that wide-scale genomic instability involving hypomethylation and mobile element release may be marsupial specific phenomena within Mammalia.

  4. Badania mieszańców w rodzaju Trifolium L. IV. Cytogenetyka mieszańca Trifolium repens L. × T. isthomocarpum Brot. [Investigations on hybrids of the genus Trifolium L. P. IV. Cytogenetics of the cross T. repens L. × T. isthomocarpum Brot.

    Directory of Open Access Journals (Sweden)

    T. Kazimierski

    2015-01-01

    Full Text Available Interspecific F1 hybrid between Trifolium repens (2n = 32 and T. isthomocarpum (2n = 16 was obtained. The hybrid is sterile and its disturbed meiotic divisions are described. It is suggested from cytogenetic evidence that one of the genomes of T. repens is similar to the genome of T. isthomacarpum.

  5. 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

  6. Interspecific competition influences fitness benefits of assortative mating for territorial aggression in eastern bluebirds (Sialia sialis.

    Directory of Open Access Journals (Sweden)

    Morgan R Harris

    Full Text Available Territorial aggression influences fitness and, in monogamous pairs, the behavior of both individuals could impact reproductive success. Moreover, territorial aggression is particularly important in the context of interspecific competition. Tree swallows and eastern bluebirds are highly aggressive, secondary cavity-nesting birds that compete for limited nesting sites. We studied eastern bluebirds at a field site in the southern Appalachian Mountains that has been recently colonized (<40 yr by tree swallows undergoing a natural range expansion. The field site is composed of distinct areas where bluebirds compete regularly with tree swallows and areas where there is little interaction between the two species. Once birds had settled, we measured how interspecific competition affects the relationship between assortative mating (paired individuals that behave similarly and reproductive success in eastern bluebirds. We found a strong tendency toward assortative mating throughout the field site. In areas of high interspecific competition, pairs that behaved the most similarly and displayed either extremely aggressive or extremely non-aggressive phenotypes experienced higher reproductive success. Our data suggest that interspecific competition with tree swallows may select for bluebirds that express similar behavior to that of their mate. Furthermore, animal personality may be an important factor influencing the outcome of interactions between native and aggressive, invasive species.

  7. 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...

  8. 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.

  9. 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.

  10. 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...

  11. Habitat fragmentation and interspecific competition: Implications for lynx conservation [Chapter 4

    Science.gov (United States)

    Steven W. Buskirk

    2000-01-01

    Habitat fragmentation and interspecific competition are two important forces that potentially affect lynx populations. Fragmentation operates by various mechanisms, including direct habitat loss, vehicle collisions and behavioral disturbance from roads, and changes in landscape features such as edges. Competition takes two forms: Exploitation competition involves...

  12. Effects of intra- and interspecific competition on the sensitivity of aquatic macroinvertebrates to carbendazim.

    Science.gov (United States)

    Del Arco, Ana Isabel; Parra, Gema; Rico, Andreu; Van den Brink, Paul J

    2015-10-01

    The Ecological Risk Assessment of pesticides and other potentially toxic chemicals is generally based on toxicity data obtained from single-species laboratory experiments. In the field, however, contaminant effects are ubiquitously co-occurring with ecological interactions such as species competition and predation, which might influence the sensitivity of the individuals exposed to toxicants. The present experimental study investigated how intra- and interspecific competition influence the response of sensitive aquatic organisms to a pesticide. For this, the effects of the fungicide carbendazim were assessed on the mortality and growth of the snail Bithynia tentaculata and the crustacean Gammarus pulex under different levels of intraspecific and interspecific competition for a food resource. Interspecific competition was created by adding individuals of Radix peregra and Asellus aquaticus, respectively. The interaction of competition and carbendazim exposure significantly influenced B. tentaculata growth, however, combined effects on survival and immobility were considered transient and were less easily demonstrated. Positive influence of competition on G. pulex survival was observed under low-medium carbendazim concentrations and under medium-high density pressures, being partly related to cannibalistic and predation compensatory mechanisms, enhanced under food limiting conditions. This study shows that intra- and interspecific competition pressure may influence the response of sensitive aquatic organisms in a more complex way (positive, non-significant and negative effects were observed) than just increasing the sensitivity of the studied species, as has generally been hypothesized. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Interspecific plasmid transfer between Streptococcus pneumoniae and Bacillus subtilis

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, M. (Inst. de Immunologia y Biologia Microbiana, Velazquez, Madrid, Spain); Lopez, P.; Perez-Urena, M.T.; Lacks, S.A.

    1982-01-01

    The streptococcal plasmids pMV158 and pLS1, grown in Streptococcus pneumoniae, were transformed to Bacillus subtilis by DNA-mediated transformation.The plasmids were unchanged in the new host; no deletions were observed in 80 instances of transfer. Hybrid plasmids were produced by recombining the EcoRI fragment of pBD6 that confers Km/sup r/ with EcoRI-cut pLS1, which confers Tc/sup r/. The simple hybrid, pMP2, was transferable to both species and expressed Tc/sup r/ and Km/sup r/ in both. A derivative, pMP5, which contained an insertion in the pBD6 component, expressed a higher level of kanomycin resistance and was more easily selected in S. pneumoniae. Another derivative, pMP3, which contained an additional EcoRI fragment, presumably of pneumococcal chromosomal DNA, could not be transferred to B. subtilis. Previous findings that monomeric plasmid forms could transform S. pneumoniae but not B. subtilis were confirmed using single plasmid preparations. Although plasmids extracted from either species were readily transferred to S. pneumoniae, successive passage in B. subtilis increased the ability of plasmid extracts to transfer the plasmid to a B. subtilis recipient. This adaptation was tentatively ascribed to an enrichment of multimeric forms in extracts of B. subtilis as compared to S. pneumoniae. A review of host ranges exhibited by plasmids of Gram-positive bacteria suggested differences in their ability to use particular host replication functions. (JMT)

  14. 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.

  15. Intraspecific and interspecific competition induces density-dependent habitat niche shifts in an endangered steppe bird.

    Science.gov (United States)

    Tarjuelo, Rocío; Morales, Manuel B; Arroyo, Beatriz; Mañosa, Santiago; Bota, Gerard; Casas, Fabián; Traba, Juan

    2017-11-01

    Interspecific competition is a dominant force in animal communities that induces niche shifts in ecological and evolutionary time. If competition occurs, niche expansion can be expected when the competitor disappears because resources previously inaccessible due to competitive constraints can then be exploited (i.e., ecological release). Here, we aimed to determine the potential effects of interspecific competition between the little bustard ( Tetrax tetrax ) and the great bustard ( Otis tarda ) using a multidimensional niche approach with habitat distribution data. We explored whether the degree of niche overlap between the species was a density-dependent function of interspecific competition. We then looked for evidences of ecological release by comparing measures of niche breadth and position of the little bustard between allopatric and sympatric situations. Furthermore, we evaluated whether niche shifts could depend not only on the presence of great bustard but also on the density of little and great bustards. The habitat niches of these bustard species partially overlapped when co-occurring, but we found no relationship between degree of overlap and great bustard density. In the presence of the competitor, little bustard's niche was displaced toward increased use of the species' primary habitat. Little bustard's niche breadth decreased proportionally with great bustard density in sympatric sites, in consistence with theory. Overall, our results suggest that density-dependent variation in little bustard's niche is the outcome of interspecific competition with the great bustard. The use of computational tools like kernel density estimators to obtain multidimensional niches should bring novel insights on how species' ecological niches behave under the effects of interspecific competition in ecological communities.

  16. Origins and domestication of cultivated banana inferred from chloroplast and nuclear genes.

    Directory of Open Access Journals (Sweden)

    Lin-Feng Li

    Full Text Available Cultivated bananas are large, vegetatively-propagated members of the genus Musa. More than 1,000 cultivars are grown worldwide and they are major economic and food resources in numerous developing countries. It has been suggested that cultivated bananas originated from the islands of Southeast Asia (ISEA and have been developed through complex geodomestication pathways. However, the maternal and parental donors of most cultivars are unknown, and the pattern of nucleotide diversity in domesticated banana has not been fully resolved.We studied the genetics of 16 cultivated and 18 wild Musa accessions using two single-copy nuclear (granule-bound starch synthase I, GBSS I, also known as Waxy, and alcohol dehydrogenase 1, Adh1 and two chloroplast (maturase K, matK, and the trnL-F gene cluster genes. The results of phylogenetic analyses showed that all A-genome haplotypes of cultivated bananas were grouped together with those of ISEA subspecies of M. acuminata (A-genome. Similarly, the B- and S-genome haplotypes of cultivated bananas clustered with the wild species M. balbisiana (B-genome and M. schizocarpa (S-genome, respectively. Notably, it has been shown that distinct haplotypes of each cultivar (A-genome group were nested together to different ISEA subspecies M. acuminata. Analyses of nucleotide polymorphism in the Waxy and Adh1 genes revealed that, in comparison to the wild relatives, cultivated banana exhibited slightly lower nucleotide diversity both across all sites and specifically at silent sites. However, dramatically reduced nucleotide diversity was found at nonsynonymous sites for cultivated bananas.Our study not only confirmed the origin of cultivated banana as arising from multiple intra- and inter-specific hybridization events, but also showed that cultivated banana may have not suffered a severe genetic bottleneck during the domestication process. Importantly, our findings suggested that multiple maternal origins and a reduction in

  17. Phylogeny of Opuntia s.s. (Cactaceae): clade delineation, geographic origins, and reticulate evolution.

    Science.gov (United States)

    Majure, Lucas C; Puente, Raul; Griffith, M Patrick; Judd, Walter S; Soltis, Pamela S; Soltis, Douglas E

    2012-05-01

    The opuntias (nopales, prickly pears) are not only culturally, ecologically, economically, and medicinally important, but are renowned for their taxonomic difficulty due to interspecific hybridization, polyploidy, and morphological variability. Evolutionary relationships in these stem succulents have been insufficiently studied; thus, delimitation of Opuntia s.s. and major subclades, as well as the biogeographic history of this enigmatic group, remain unresolved. We sequenced the plastid intergenic spacers atpB-rbcL, ndhF-rpl32, psbJ-petA, and trnL-trnF, the plastid genes matK and ycf1, the nuclear gene ppc, and ITS to reconstruct the phylogeny of tribe Opuntieae, including Opuntia s.s. We used phylogenetic hypotheses to infer the biogeographic history, divergence times, and potential reticulate evolution of Opuntieae. Within Opuntieae, a clade of Tacinga, Opuntia lilae, Brasiliopuntia, and O. schickendantzii is sister to a well-supported Opuntia s.s., which includes Nopalea. Opuntia s.s. originated in southwestern South America (SA) and then expanded to the Central Andean Valleys and the desert region of western North America (NA). Two major clades evolved in NA, which subsequently diversified into eight subclades. These expanded north to Canada and south to Central America and the Caribbean, eventually returning back to SA primarily via allopolyploid taxa. Dating approaches suggest that most of the major subclades in Opuntia s.s. originated during the Pliocene. Opuntia s.s. is a well-supported clade that includes Nopalea. The clade originated in southwestern SA, but the NA radiation was the most extensive, resulting in broad morphological diversity and frequent species formation through reticulate evolution and polyploidy.

  18. Patterns of parasite distribution in the hybrids of non-congeneric cyprinid fish species: is asymmetry in parasite infection the result of limited coadaptation?

    Czech Academy of Sciences Publication Activity Database

    Krasnovyd, V.; Vetešník, Lukáš; Gettová, L.; Civáňová, K.; Šimková, A.

    2017-01-01

    Roč. 47, č. 8 (2017), s. 471-483 ISSN 0020-7519 R&D Projects: GA ČR GAP505/12/0375 Institutional support : RVO:68081766 Keywords : Interspecific hybrids * Cyprinid fish * Parasite communities * Host specificity * Maternal ancestry Subject RIV: EG - Zoology OBOR OECD: Parasitology Impact factor: 3.730, year: 2016

  19. Fine-scale temporal and spatial variation of taxon and clonal structure in the Daphnia longispina hybrid complex in heterogeneous environments

    Czech Academy of Sciences Publication Activity Database

    Yin, M.; Petrusek, A.; Seďa, Jaromír; Wolinska, J.

    2012-01-01

    Roč. 12, January (2012), s. 1-12 ISSN 1471-2148 R&D Projects: GA AV ČR(CZ) IAA600960901 Institutional support: RVO:60077344 Keywords : species complex * genetic-structure * interspecific hybridization * cyclic parthenogenesis * population-dynamics Subject RIV: EG - Zoology Impact factor: 3.285, year: 2012

  20. Rare occurrence of reciprocal hybridization in a sympatric population of the Czech stenoendemic Dianthus arenarius subsp. bohemicus and widespread D. carthusianorum

    Czech Academy of Sciences Publication Activity Database

    Vítová, Jana; Vít, Petr; Suda, Jan

    2015-01-01

    Roč. 87, č. 3 (2015), s. 329-345 ISSN 0032-7786 R&D Projects: GA ČR GB14-36079G Institutional support: RVO:67985939 Keywords : conservation * Dianthus * interspecific hybridization Subject RIV: EF - Botanics Impact factor: 2.711, year: 2015

  1. Evolutionary Origins and Dynamics of Octoploid Strawberry Subgenomes Revealed by Dense Targeted Capture Linkage Maps

    Science.gov (United States)

    Tennessen, Jacob A.; Govindarajulu, Rajanikanth; Ashman, Tia-Lynn; Liston, Aaron

    2014-01-01

    Whole-genome duplications are radical evolutionary events that have driven speciation and adaptation in many taxa. Higher-order polyploids have complex histories often including interspecific hybridization and dynamic genomic changes. This chromosomal reshuffling is poorly understood for most polyploid species, despite their evolutionary and agricultural importance, due to the challenge of distinguishing homologous sequences from each other. Here, we use dense linkage maps generated with targeted sequence capture to improve the diploid strawberry (Fragaria vesca) reference genome and to disentangle the subgenomes of the wild octoploid progenitors of cultivated strawberry, Fragaria virginiana and Fragaria chiloensis. Our novel approach, POLiMAPS (Phylogenetics Of Linkage-Map-Anchored Polyploid Subgenomes), leverages sequence reads to associate informative interhomeolog phylogenetic markers with linkage groups and reference genome positions. In contrast to a widely accepted model, we find that one of the four subgenomes originates with the diploid cytoplasm donor F. vesca, one with the diploid Fragaria iinumae, and two with an unknown ancestor close to F. iinumae. Extensive unidirectional introgression has converted F. iinumae-like subgenomes to be more F. vesca-like, but never the reverse, due either to homoploid hybridization in the F. iinumae-like diploid ancestors or else strong selection spreading F. vesca-like sequence among subgenomes through homeologous exchange. In addition, divergence between homeologous chromosomes has been substantially augmented by interchromosomal rearrangements. Our phylogenetic approach reveals novel aspects of the complicated web of genetic exchanges that occur during polyploid evolution and suggests a path forward for unraveling other agriculturally and ecologically important polyploid genomes. PMID:25477420

  2. Effects of natural hybrid and non-hybrid Epichloë endophytes on the response of Hordelymus europaeus to drought stress.

    Science.gov (United States)

    Oberhofer, Martina; Güsewell, Sabine; Leuchtmann, Adrian

    2014-01-01

    Interspecific hybrid endophytes of the genus Epichloë (Ascomycota, Clavicipitaceae) are prevalent in wild grass populations, possibly because of their larger gene variation, resulting in increased fitness benefits for host plants; however, the reasons are not yet known. We tested hypotheses regarding niche expansion mediated by hybrid endophytes, population-dependent interactions and local co-adaptation in the woodland grass Hordelymus europaeus, which naturally hosts both hybrid and non-hybrid endophyte taxa. Seedlings derived from seeds of four grass populations made endophyte free were re-inoculated with hybrid or non-hybrid endophyte strains, or left endophyte free. Plants were grown in the glasshouse with or without drought treatment. Endophyte infection increased plant biomass and tiller production by 10-15% in both treatments. Endophyte types had similar effects on growth, but opposite effects on reproduction: non-hybrid endophytes increased seed production, whereas hybrid endophytes reduced or prevented it completely. The results are consistent with the observation that non-hybrid endophytes in H. europaeus prevail at dry sites, but cannot explain the prevalence of hybrid endophytes. Thus, our results do not support the hypothesis of niche expansion of hybrid-infected plants. Moreover, plants inoculated with native relative to foreign endophytes yielded higher infections, but both showed similar growth and survival, suggesting weak co-adaptation. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  3. Hybrid reactors

    International Nuclear Information System (INIS)

    Moir, R.W.

    1980-01-01

    The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of 233 U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW.m -2 , and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are usually rapid

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

    Science.gov (United States)

    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.

  5. The Role of Hybridization in the Evolution and Emergence of New Fungal Plant Pathogens.

    Science.gov (United States)

    Stukenbrock, Eva H

    2016-02-01

    Hybridization in fungi has recently been recognized as a major force in the generation of new fungal plant pathogens. These include the grass pathogen Zymoseptoria pseudotritici and the powdery mildew pathogen Blumeria graminis triticale of triticale. Hybridization also plays an important role in the transfer of genetic material between species. This process is termed introgressive hybridization and involves extensive backcrossing between hybrid and the parental species. Introgressive hybridization has contributed substantially to the successful spread of plant pathogens such as Ophiostoma ulmi and O. novo-ulmi, the causal agents of Dutch elm disease, and other tree pathogens such as the rust pathogen Melampsora. Hybridization occurs more readily between species that have previously not coexisted, so-called allopatric species. Reproductive barriers between allopatric species are likely to be more permissive allowing interspecific mating to occur. The bringing together of allopatric species of plant pathogens by global agricultural trade consequently increases the potential for hybridization between pathogen species. In light of global environmental changes, agricultural development, and the facilitated long-distance spread of fungal plant pathogens, hybridization should be considered an important mechanism whereby new pathogens may emerge. Recent studies have gained insight into the genetics and biology of fungal hybrids. Here I summarize current knowledge about hybrid speciation and introgressive hybridization. I propose that future studies will benefit greatly from the availability of large genome data sets and that genome data provide a powerful resource in combination with experimental approaches for analyses of hybrid species.

  6. Embryonic development and inviability phenotype of chicken-Japanese quail F1 hybrids

    Science.gov (United States)

    Ishishita, Satoshi; Kinoshita, Keiji; Nakano, Mikiharu; Matsuda, Yoichi

    2016-01-01

    Interspecific hybrid incompatibility, including inviability and sterility, is important in speciation; however, its genetic basis remains largely unknown in vertebrates. Crosses between male chickens and female Japanese quails using artificial insemination can generate intergeneric hybrids; however, the hatching rate is low, and hatched hybrids are only sterile males. Hybrid development is arrested frequently during the early embryonic stages, and the sex ratio of living embryos is male-biased. However, the development and sex ratio of hybrid embryos have not been comprehensively analyzed. In the present study, we observed delayed embryonic development of chicken-quail hybrids during the early stage, compared with that of chickens and quails. The survival rate of hybrids decreased markedly during the blastoderm-to-pre-circulation stage and then decreased gradually through the subsequent stages. Hybrid females were observed at more than 10 d of incubation; however, the sex ratio of hybrids became male-biased from 10 d of incubation. Severely malformed embryos were observed frequently in hybrids. These results suggest that developmental arrest occurs at various stages in hybrid embryos, including a sexually non-biased arrest during the early stage and a female-biased arrest during the late stage. We discuss the genetic basis for hybrid inviability and its sex bias. PMID:27199007

  7. Effet de l'hybridation interspecifique sur la teneur et la composition chimique des huiles essentielles d'eucalyptus cultivés au Maroc

    OpenAIRE

    Farah A.; Fechtal M.; Chaouch A.

    2002-01-01

    Interspecific hybridization effect on the content and the chemical composition of essential oils of eucalyptus grown in Morocco. In this work, the quality and quantity of the leave essential oils of five Eucalyptus hybrids were determined. The crosses of Eucalyptus globulus ssp. maideni, Eucalyptus globulus ssp. globulus, Eucalyptus grandis, Eucalyptus cladocalyx and Eucalyptus diversicolor with Eucalyptus camaldulensis have been studied. The average yield of parental species samples varies a...

  8. Original Research

    African Journals Online (AJOL)

    2013-12-27

    Dec 27, 2013 ... based, machine learning and hybrid approaches (Diriba. Megersa, 2002; Mesifin Getachew, 2001). The rule-based approach is one of the earliest approaches in developing morphological synthesis systems. The rule based approach uses rules created by linguists or by a computer program to generate.

  9. 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

    Energy Technology Data Exchange (ETDEWEB)

    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

  10. Intra-generic and interspecific karyotype patterns of Leptodactylus and Adenomera (Anura, Leptodactylidae) with inclusion of five species from Central Amazonia.

    Science.gov (United States)

    Coelho, Ana Carolina; de Mattos, Thais Lemos; Viana, Patrik; Terencio, Maria Leandra; Schneider, Carlos Henrique; Menin, Marcelo; Gross, Maria Claudia

    2016-02-01

    The genera Leptodactylus and Adenomera comprise 92 species distributed throughout the Neotropical region. These species have a modal diploid chromosome number 2n = 22. However, chromosome rearrangements are evident in the differentiation of five intra-generic groups in the genus Leptodactylus (L. fuscus, L. latrans, L. marmoratus (formally composed by the species of the genus Adenomera), L. melanonotus, L. pentadactylus), yet it is not clear if there is a karyotype pattern for each group. Aiming to understand the intra-generic and interspecific karyotype patterns of Leptodactylus and Adenomera, cytogenetic analyses were performed in A. andreae, L. macrosternum, L. pentadactylus, L. petersii, and L. riveroi using conventional staining, C-banding, nucleolus organizer region (NOR) and hybridization in situ fluorescent (FISH). The karyotype of Leptodactylus riveroi was described for the first time. Adenomera andreae had 2n = 26, while the remaining species 2n = 22. The NOR was found on pair No. 8 of A. andreae, L. macrosternum, L. pentadactylus, and L. riveroi, whereas L. petersii had it on pairs Nos. 6 and 10. These locations were confirmed by the FISH with 18S rDNA probe, except for pair No. 10 of L. petersii. The C-banding pattern was evident at the centromeres of chromosomes of all species and some interspecific variations were also observed. 2n = 22 was observed in the species of the L. latrans group, as well as in the intra-generic groups L. fuscus and L. pentadactylus; in the L. melanonotus group there were three diploid chromosome numbers 2n = 20, 22 and 24; and a larger variation in 2n was also evident in the L. marmoratus group.

  11. Hybrid Metaheuristics

    CERN Document Server

    2013-01-01

    The main goal of this book is to provide a state of the art of hybrid metaheuristics. The book provides a complete background that enables readers to design and implement hybrid metaheuristics to solve complex optimization problems (continuous/discrete, mono-objective/multi-objective, optimization under uncertainty) in a diverse range of application domains. Readers learn to solve large scale problems quickly and efficiently combining metaheuristics with complementary metaheuristics, mathematical programming, constraint programming and machine learning. Numerous real-world examples of problems and solutions demonstrate how hybrid metaheuristics are applied in such fields as networks, logistics and transportation, bio-medical, engineering design, scheduling.

  12. Sample size for estimating average trunk diameter and plant height in eucalyptus hybrids

    Directory of Open Access Journals (Sweden)

    Alberto Cargnelutti Filho

    2016-01-01

    Full Text Available ABSTRACT: In eucalyptus crops, it is important to determine the number of plants that need to be evaluated for a reliable inference of growth. The aim of this study was to determine the sample size needed to estimate average trunk diameter at breast height and plant height of inter-specific eucalyptus hybrids. In 6,694 plants of twelve inter-specific hybrids it was evaluated trunk diameter at breast height at three (DBH3 and seven years (DBH7 and tree height at seven years (H7 of age. The statistics: minimum, maximum, mean, variance, standard deviation, standard error, and coefficient of variation were calculated. The hypothesis of variance homogeneity was tested. The sample size was determined by re sampling with replacement of 10,000 re samples. There was an increase in the sample size from DBH3 to H7 and DBH7. A sample size of 16, 59 and 31 plants is adequate to estimate DBH3, DBH7 and H7 means, respectively, of inter-specific hybrids of eucalyptus, with amplitude of confidence interval of 95% equal to 20% of the estimated mean.

  13. Coexistence facilitates interspecific biofilm formation in complex microbial communities

    DEFF Research Database (Denmark)

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

    2016-01-01

    , 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...... biofilm formation among co-cultured bacteria that have coexisted in their original environment. Conversely, when randomly co-culturing bacteria across these five consortia, we found less biofilm induction and a prevalence of biofilm reduction. Reduction in biofilm formation was even more predominant when...... co-culturing bacteria from environments where long-term coexistence was unlikely to have occurred. Phylogenetic diversity was not found to be a strong underlying factor but a relation between biofilm induction and phylogenetic history was found. The data indicates that biofilm reduction is typically...

  14. Interpopulation hybridization generates meiotically stable rDNA epigenetic variants in allotetraploid Tragopogon mirus.

    Science.gov (United States)

    Matyášek, Roman; Dobešová, Eva; Húska, Dalibor; Ježková, Ivana; Soltis, Pamela S; Soltis, Douglas E; Kovařík, Aleš

    2016-02-01

    Uniparental silencing of 35S rRNA genes (rDNA), known as nucleolar dominance (ND), is common in interspecific hybrids. Allotetraploid Tragopogon mirus composed of Tragopogon dubius (d) and Tragopogon porrifolius (p) genomes shows highly variable ND. To examine the molecular basis of such variation, we studied the genetic and epigenetic features of rDNA homeologs in several lines derived from recently and independently formed natural populations. Inbred lines derived from T. mirus with a dominant d-rDNA homeolog transmitted this expression pattern over generations, which may explain why it is prevalent among natural populations. In contrast, lines derived from the p-rDNA dominant progenitor were meiotically unstable, frequently switching to co-dominance. Interpopulation crosses between progenitors displaying reciprocal ND resulted in d-rDNA dominance, indicating immediate suppression of p-homeologs in F1 hybrids. Original p-rDNA dominance was not restored in later generations, even in those segregants that inherited the corresponding parental rDNA genotype, thus indicating the generation of additional p-rDNA and d-rDNA epigenetic variants. Despite preserved intergenic spacer (IGS) structure, they showed altered cytosine methylation and chromatin condensation patterns, and a correlation between expression, hypomethylation of RNA Pol I promoters and chromatin decondensation was apparent. Reversion of such epigenetic variants occurred rarely, resulting in co-dominance maintained in individuals with distinct genotypes. Generally, interpopulation crosses may generate epialleles that are not present in natural populations, underlying epigenetic dynamics in young allopolyploids. We hypothesize that highly expressed variants with distinct IGS features may induce heritable epigenetic reprogramming of the partner rDNA arrays, harmonizing the expression of thousands of genes in allopolyploids. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  15. Hybrid dwarfness in crosses between wheat (Triticum aestivum L.) and rye (Secale cereale L.): a new look at an old phenomenon.

    Science.gov (United States)

    Tikhenko, N; Rutten, T; Tsvetkova, N; Voylokov, A; Börner, A

    2015-03-01

    The existence of hybrid dwarfs from intraspecific crosses in wheat (Triticum aestivum) was described 100 years ago, and the genetics underlying hybrid dwarfness are well understood. In this study, we report a dwarf phenotype in interspecific hybrids between wheat and rye (Secale cereale). We identified two rye lines that produce hybrid dwarfs with wheat and have none of the hitherto known hybrid dwarfing genes. Genetic analyses revealed that both rye lines carry a single allelic gene responsible for the dwarf phenotype. This gene was designated Hdw-R1 (Hybrid dwarf-R1). Application of gibberellic acid (GA3 ) to both intraspecific (wheat-wheat) and interspecific (wheat-rye) hybrids showed that hybrid dwarfness cannot be overcome by treatment with this phytohormone. Histological analysis of shoot apices showed that wheat-rye hybrids with the dwarf phenotype at 21 and 45 days after germination failed to develop further. Shoot apices of dwarf plants did not elongate, did not form new primordia and had a dome-shaped appearance in the seed. The possible relationship between hybrid dwarfness and the genes responsible for the transition from vegetative to generative growth stage is discussed. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  16. Reproductive isolation and the expansion of an invasive hybrid swarm

    Science.gov (United States)

    Blum, Michael J.; Walters, David M.; Burkhead, Noel M.; Freeman, Byron J.; Porter, Brady A.

    2010-01-01

    Biological invasions involving hybridization proceed according to prezygotic and postzygotic reproductive isolating mechanisms. Yet few comparisons of reproductive isolation have been carried out to understand how different mechanisms prevent or promote invasions involving hybridization. Here we present a study of prezygotic and postzygotic isolation between non-native red shiner (Cyprinella lutrensis) and native blacktail shiner (C. venusta stigmatura) from the Coosa River basin (USA) to better understand the formation and expansion of invasive hybrid swarms. We conducted spawning trials to measure mating preferences and raised broods from crosses to assay hybrid viability through early juvenile development. Females of both species were more responsive to conspecific mates, although blacktail shiner females responded more often to heterospecific mates than did red shiner females. Fecundity of red shiner females was also higher than blacktail shiner females. Heterospecific crosses resulted in lower fertilization and egg hatching rates, but we found no other evidence of inviability. Rather, we found comparatively low larval mortality of F1 hybrids, which is suggestive of heterosis. These findings support prior inferences of assortative mating from genetic descriptions of hybridization, and that the invasion in the Coosa River is likely proceeding due to interspecific competition and intrinsic hybrid viability.

  17. Species interactions and chemical stress combined effects of intraspecific and interspecific interactions and pyrene n Daphnia magna populations dynamics

    NARCIS (Netherlands)

    Viaene, K.P.J.; Laender, de F.; Rico, A.; Brink, van den P.J.; Guardo, Di A.; Morselli, M.; Janssen, C.R.

    2015-01-01

    Species interactions are often suggested as an important factor when assessing the effects of chemicals on higher levels of biological organization. Nevertheless, the contribution of intraspecific and interspecific interactions to chemical effects on populations is often overlooked. In the present

  18. 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.

  19. Species coexistence under resource competition with intraspecific and interspecific direct competition in a chemostat.

    Science.gov (United States)

    Saito, Yasuhisa; Miki, Takeshi

    2010-11-01

    Competition theory has developed separately for direct competition and for exploitative competition. However, the combined effects of the two types of competition on species coexistence remain unclear. To examine how intraspecific and interspecific direct competition contributes to the coexistence of species competing for a single resource, we constructed a chemostat-type resource competition model. With general functions for intraspecific and interspecific direct competition, we derived necessary and sufficient conditions (except for a critical case that rarely occurs in a biological sense) that determine the number of stably coexisting species. From these conditions, we found that the number of coexisting species is determined just by the invasibility of each species into subcommunities with a smaller number of species. In addition, using a combination of rigorous mathematical theory and a simple graphical method, we can demonstrate how the stronger intraspecific direct competition facilitates species invasion, leading to a larger number of coexisting species. Copyright 2010 Elsevier Inc. All rights reserved.

  20. 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.

  1. Interspecific interactions between wild felids vary across scales and levels of urbanization.

    Science.gov (United States)

    Lewis, Jesse S; Bailey, Larissa L; VandeWoude, Sue; Crooks, Kevin R

    2015-12-01

    Ongoing global landscape change resulting from urbanization is increasingly linked to changes in species distributions and community interactions. However, relatively little is known about how urbanization influences competitive interactions among mammalian carnivores, particularly related to wild felids. We evaluated interspecific interactions between medium- and large-sized carnivores across a gradient of urbanization and multiple scales. Specifically, we investigated spatial and temporal interactions of bobcats and pumas by evaluating circadian activity patterns, broad-scale seasonal interactions, and fine-scale daily interactions in wildland-urban interface (WUI), exurban residential development, and wildland habitats. Across levels of urbanization, interspecific interactions were evaluated using two-species and single-species occupancy models with data from motion-activated cameras. As predicted, urbanization increased the opportunity for interspecific interactions between wild felids. Although pumas did not exclude bobcats from areas at broad spatial or temporal scales, bobcats responded behaviorally to the presence of pumas at finer scales, but patterns varied across levels of urbanization. In wildland habitat, bobcats avoided using areas for short temporal periods after a puma visited an area. In contrast, bobcats did not appear to avoid areas that pumas recently visited in landscapes influenced by urbanization (exurban development and WUI habitat). In addition, overlap in circadian activity patterns between bobcats and pumas increased in exurban development compared to wildland habitat. Across study areas, bobcats used sites less frequently as the number of puma photographs increased at a site. Overall, bobcats appear to shape their behavior at fine spatial and temporal scales to reduce encounters with pumas, but residential development can potentially alter these strategies and increase interaction opportunities. We explore three hypotheses to explain our

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

    Science.gov (United States)

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

    2014-01-01

    Snakes often occur in species-rich assemblages, and sympatry is thought to be facilitated primarily by low diet overlap, not interspecific interactions. 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 examined a large-scale database of snake detection/nondetection data and used occupancy modelling to determine whether these species occur together more or less frequently than expected by chance while accounting for variation in detection probability among species and incorporating important habitat categories in the models. For some snakes, we obtained evidence that the probabilities that habitat patches are used are influenced by the presence of potentially competing congeneric species. Specifically, timber rattlesnakes (Crotalus horridus) were less likely than expected by chance to use areas that also contained eastern diamond-backed rattlesnakes (Crotalus adamanteus) when the proportion of evergreen forest was relatively high. Otherwise, they occurred together more often than expected by chance. Complex relationships were revealed between habitat use, detection probabilities and occupancy probabilities of North American racers (Coluber constrictor) and coachwhips (Coluber flagellum) that indicated the probability of competitive exclusion increased with increasing area of grassland habitat, although there was some model uncertainty. Cornsnakes (Pantherophis guttatus or Pantherophis slowinskii) and ratsnakes (Pantherophis alleghaniensis, Pantherophis spiloides, or Pantherophis obsoletus) exhibited differences in habitat selection, but we obtained no evidence that patterns of use for this species pair were influenced by current interspecific interactions. Overall, our results are consistent with the hypothesis that competitive interactions influence snake assemblage composition; the strength of these effects was

  3. Improved cider fermentation performance and quality with newly generated Saccharomyces cerevisiae × Saccharomyces eubayanus hybrids.

    Science.gov (United States)

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

    2017-08-01

    Yeast cryotolerance may be advantageous for cider making, where low temperatures are usually employed. Here, we crossed the cryotolerant S. eubayanus with a S. cerevisiae wine strain and assessed the suitability of the hybrids for low-temperature cider fermentation. All strains fermented the juice to 5% ABV, but at different rates; hybrid strains outperformed S. cerevisiae, which was sensitive to low temperatures. The best hybrid fermented similarly to S. eubayanus. S. eubayanus produced sulphurous off flavours which masked a high concentration of fruity ester notes. This phenotype was absent in the hybrid strains, resulting in distinctly fruitier ciders. Aroma was assessed by an independent consumer panel, which rated the hybrid ciders as identical to the wine strain cider. Both were significantly more pleasant than the S. eubayanus cider. Interspecific hybridization can apparently be used effectively to improve low-temperature fermentation performance without compromising product quality.

  4. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. PREVALENCE OF ANDROGENIC-. ANABOLIC STEROID USE IN. ADOLESCENTS IN TWO REGIONS. OF SOUTH AFRICA. Michael I lambert, Steven D Titlestad, Martin P Schwellnus. Objective. To determine the prevalence of androgenic- anabolic steroid (AAS) use among schoolchildren in two.

  5. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    siderosomes), Golgi complex and ... containing proteins, ferritin and haemosiderin, in the jejunal epithelial cells of black children with pellagra as well as ... from 10 of the original 16 patients showed adequate ultrastructural preservation; tissue blocks of ...

  6. Eukaryotic origins

    OpenAIRE

    Lake, James A.

    2015-01-01

    The origin of the eukaryotes is a fundamental scientific question that for over 30 years has generated a spirited debate between the competing Archaea (or three domains) tree and the eocyte tree. As eukaryotes ourselves, humans have a personal interest in our origins. Eukaryotes contain their defining organelle, the nucleus, after which they are named. They have a complex evolutionary history, over time acquiring multiple organelles, including mitochondria, chloroplasts, smooth and rough endo...

  7. Agronomic potentials of quality protein maize hybrids developed in ...

    African Journals Online (AJOL)

    A quality protein maize (QPM) hybrid programme was started in 1991 to develop and promote high and stableyielding QPM hybrids to increase production of nutritionally superior maize varieties in Ghana. Six 3- way QPM hybrids developed from inbred lines originating from germplasm of the International Centre for Maize

  8. 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. 

  9. Hybrid stars

    Indian Academy of Sciences (India)

    physics pp. 753-756. Hybrid stars. AsHOK GOYAL. Department of Physics and Astrophysics, University of Delhi, Delhi 110 007, India. Abstract. Recently there have been important developments in the determination of neutron ... be composed of normal nuclear matter with hyperons and/or condensed mesons. The matter at ...

  10. Hybrid composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

    Full Text Available balance between the inherent advantages and disadvantages. Also, using a hybrid composite that contains two or more types of fibre, the advantages of one type of fibre could complement with what are lacking in the other. As a consequence, a balance in cost...

  11. Hybrid Qualifications

    DEFF Research Database (Denmark)

    has turned out as a major focus of European education and training policies and certainly is a crucial principle underlying the European Qualifications Framework (EQF). In this context, «hybrid qualifications» (HQ) may be seen as an interesting approach to tackle these challenges as they serve «two...

  12. Hybrid stars

    Indian Academy of Sciences (India)

    Hybrid stars. AsHOK GOYAL. Department of Physics and Astrophysics, University of Delhi, Delhi 110 007, India. Abstract. Recently there have been important developments in the determination of neutron ... number and the electric charge. ... available to the system to rearrange concentration of charges for a given fraction of.

  13. Shape Grammars for Innovative Hybrid Typological Design

    DEFF Research Database (Denmark)

    Al-kazzaz, Dhuha; Bridges, Alan; Chase, Scott Curland

    2010-01-01

    This paper describes a new methodology of deriving innovative hybrid designs using shape grammars of heterogeneous designs. The method is detailed within three phases of shape grammars: analysis, synthesis and evaluation. In the analysis phase, the research suggests that original rules of each...... design component are grouped in subclass rule sets to facilitate rule choices. Additionally, adding new hybrid rules to original rules expands the options available to the grammar user. In the synthesis phase, the research adopts state labels and markers to drive the design generation. The former...... is implemented with a user guide grammar to ensure hybridity in the generated design, while the latter aims to ensure feasible designs. Lastly evaluation criteria are added to measure the degree of innovation of the hybrid designs. This paper describes the derivation of hybrid minaret designs from a corpus...

  14. Giemsa C-banded karyotypes of Hordeum secalinum, H. capense and their interspecific hybrids with H. vulgare

    DEFF Research Database (Denmark)

    Linde-Laursen, Ib; Bothmer, R. von; Jacobsen, N.

    1986-01-01

    The European H. secalinum (2n = 4x = 48) and the South African H. capense (2n = 4x = 28) had similar karyotypes with ten pairs of metacentrics, three of submetacentrics, and one of SAT-chromosomes. The C-banded karyotypes of H. secalinum from northern Europe were characterized by banding patterns...... reproductive system. No banding pattern polymorphism was present within plants of H. secalinum from Spain and H. capense, suggesting self-pollination. In both species banding pattern polymorphism was prevalent among plants. Together with other evidence the fairly similar basic C-banded karyotypes of the two...

  15. Interspecific hybrid of xeric Shepherdia rotundifolia and riparian Shepherdia argentea: description, and traits suitable for low-water urban landscapes

    Science.gov (United States)

    Shepherdia rotundifolia Parry (roundleaf buffaloberry), a shrub endemic to the U.S. Colorado Plateau high desert, has aesthetic and drought tolerance qualities desirable for low-water urban landscapes. However, slow growth and too often fatal sensitivity to wet or disturbed soil stymies nursery pro...

  16. The ecology of white-handed and pileated gibbons in a zone of overlap and hybridization in Thailand.

    Science.gov (United States)

    Asensio, Norberto; José-Domínguez, Juan Manuel; Kongrit, Chalita; Brockelman, Warren Y

    2017-08-01

    The study of related species in contact zones can elucidate what factors mediate species coexistence and geographical distributions. We investigated niche overlap and group interactions of two gibbon species and their hybrids co-occurring in a zone of overlap and hybridization. The location, composition and behavior of white-handed, pileated, and mixed-species gibbon groups were studied by following them during 31 consecutive months in a relatively large part of the contact zone. Twenty groups of white-handed gibbon were mapped followed by nine groups of pileated gibbons and five mixed-species groups. White-handed, pileated and mixed-species groups had similar sizes and composition, ate a high proportion of fruits, shared a large number of species in their diets, and presented similar habitat preferences. Group home range sizes did not differ between species and overlapped little with neighboring groups irrespective of species, and intraspecific and interspecific encounter rates were similar. Ecological similarities support that competition between the gibbon species exists and takes the form of interspecific territoriality. However, we could not find any clear mechanism of niche partitioning favoring coexistence between species. Our findings suggest that the contact zone is unstable and is maintained by dispersal inward from groups of the parental species. The relatively low numbers of mixed-species groups and hybrids found suggests a high degree of premating reproductive isolation, perhaps mediated by interspecific miscommunication. The existence of hybrids and backcrosses potentially undetectable from phenotypic characters alone raises the possibility of more widespread introgression than has been evident. Hence, while interspecific territoriality should reduce the rate of gene transfer, it would not necessarily present a barrier to introgression into contiguous populations of the opposite species. © 2017 Wiley Periodicals, Inc.

  17. Identifying hybridizing taxa within the Daphnia longispina species complex: a comparison of genetic methods and phenotypic approaches

    Czech Academy of Sciences Publication Activity Database

    Dlouhá, Š.; Thielsch, A.; Kraus, R.H.S.; Seďa, Jaromír; Schwenk, K.; Petrusek, A.

    2010-01-01

    Roč. 643, č. 1 (2010), s. 107-122 ISSN 0018-8158. [International Symposium on Cladocera /8./. Aguascalientes, 21.10.2008-25.10.2008] R&D Projects: GA ČR(CZ) GA206/04/0190; GA AV ČR(CZ) IAA600960901 Institutional research plan: CEZ:AV0Z60170517 Keywords : Daphnia * interspecific hybridization * internal transcribed spacer * allozyme electrophoresis * microsatellite s Subject RIV: DA - Hydrology ; Limnology Impact factor: 1.964, year: 2010

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

    Directory of Open Access Journals (Sweden)

    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

  19. Genetic engineering with tobacco protoplasts. [Hybridization by fusion of leaf protoplasts

    Energy Technology Data Exchange (ETDEWEB)

    Smith, H H

    1976-01-01

    Interspecific hybridization by fusion of leaf protoplasts of Nicotiana glauca (GG) and N. langsdorffii (LL) was confirmed and extended. Enzymatic digestion of leaf tissues to obtain protoplats was followed by fusion with the aid of polyethylene glycol. The hybrid calli were selected by their better growth on defined culture media. Mature hybrid plants were identified by their morphology and tumor formation. Cytological examination revealed a range in chromosome numbers from 56 to 64 rather than the amphiploid GGLL number of 42. About 75 percent of the hybrids were fertile. The potential range in combining widely disparate genotypes by somatic cell fusion was demonstrated by fusing tobacco GGLL protoplasts with human HeLa cells. The HeLa nucleus was observed inside the plant protoplasts, thus forming an interkingdom heterokaryon.

  20. Differential effects of climate and species interactions on range limits at a hybrid zone: potential direct and indirect impacts of climate change.

    Science.gov (United States)

    McQuillan, Michael A; Rice, Amber M

    2015-11-01

    The relative contributions of climate versus interspecific interactions in shaping species distributions have important implications for closely related species at contact zones. When hybridization occurs within a contact zone, these factors regulate hybrid zone location and movement. While a hybrid zone's position may depend on both climate and interactions between the hybridizing species, little is known about how these factors interact to affect hybrid zone dynamics. Here, we utilize SDM (species distribution modeling) both to characterize the factors affecting the current location of a moving North American avian hybrid zone and to predict potential direct and indirect effects of climate change on future distributions. We focus on two passerine species that hybridize where their ranges meet, the Black-capped (Poecile atricapillus) and Carolina (P. carolinensis) chickadee. Our contemporary climate models predict the occurrence of climatically suitable habitat extending beyond the hybrid zone for P. atricapillus only, suggesting that interspecific interactions primarily regulate this range boundary in P. atricapillus, while climatic factors regulate P. carolinensis. Year 2050 climate models predict a drastic northward shift in suitable habitat for P. carolinensis. Because of the greater importance of interspecific interactions for regulating the southern range limit of P. atricapillus, these climate-mediated shifts in the distribution of P. carolinensis may indirectly lead to a range retraction in P. atricapillus. Together, our results highlight the ways climate change can both directly and indirectly affect species distributions and hybrid zone location. In addition, our study lends support to the longstanding hypothesis that abiotic factors regulate species' poleward range limits, while biotic factors shape equatorial range limits.

  1. Unreduced gamete formation in wheat × Aegilops spp. hybrids is genotype specific and prevented by shared homologous subgenomes.

    Science.gov (United States)

    Fakhri, Zhaleh; Mirzaghaderi, Ghader; Ahmadian, Samira; Mason, Annaliese S

    2016-05-01

    The presence of homologous subgenomes inhibited unreduced gamete formation in wheat × Aegilops interspecific hybrids. Unreduced gamete rates were under the control of the wheat nuclear genome. Production of unreduced gametes is common among interspecific hybrids, and may be affected by parental genotypes and genomic similarity. In the present study, five cultivars of Triticum aestivum and two tetraploid Aegilops species (i.e. Ae. triuncialis and Ae. cylindrica) were reciprocally crossed to produce 20 interspecific hybrid combinations. These hybrids comprised two different types: T. aestivum × Aegilops triuncialis; 2n = ABDU(t)C(t) (which lack a common subgenome) and T. aestivum × Ae. cylindrica; 2n = ABDD(c)C(c) (which share a common subgenome). The frequency of unreduced gametes in F1 hybrids was estimated in sporads from the frequency of dyads, and the frequency of viable pollen, germinated pollen and seed set were recorded. Different meiotic abnormalities recorded in the hybrids included precocious chromosome migration to the poles at metaphase I and II, laggards in anaphase I and II, micronuclei and chromosome stickiness, failure in cell wall formation, premature cytokinesis and microspore fusion. The mean frequency of restitution meiosis was 10.1 %, and the mean frequency of unreduced viable pollen was 4.84 % in T. aestivum × Ae. triuncialis hybrids. By contrast, in T. aestivum × Ae. cylindrica hybrids no meiotic restitution was observed, and a low rate of viable gametes (0.3 %) was recorded. This study present evidence that high levels of homologous pairing between the D and D(c) subgenomes may interfere with meiotic restitution and the formation of unreduced gametes. Variation in unreduced gamete production was also observed between T. aestivum × Ae. triuncialis hybrid plants, suggesting genetic control of this trait.

  2. 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

  3. Avaliação de linhagens de trigo originárias de hibridação com e sem irradiação gama Evaluation of wheat inbred lines originated from hybridizations with and without gamma irradiation

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo de Oliveira Camargo

    2005-01-01

    Full Text Available O emprego da técnica de indução de mutação associada à hibridação tem contribuído para a obtenção de novos genótipos de trigo com características agronômicas desejáveis. Avaliaram-se 18 linhagens de trigo, sendo dez oriundas de seleção de plantas do híbrido Kauz "S"x IAC-24 que tiveram as sementes, em geração F2, irradiadas (I com raios gama e oito não irradiadas (NI, além das cultivares IAC-24 e IAC-289, em seis experimentos instalados no período 1997-99. Foram analisadas a produção de grãos, a resistência a doenças e outras características agronômicas. Em condições de laboratório, estudou-se a tolerância ao alumínio em soluções nutritivas, utilizando-se as cultivares BH-1146 (tolerante e Anahuac (sensível, como controles. A linhagem L18-I destacou-se quanto à produção de grãos em condição de irrigação por aspersão e solo corrigido, nos três anos considerados. Em solo ácido e condição de sequeiro, L20-I, tolerante à toxicidade de Al3+, em soluções nutritivas, destacou-se quanto à produção de grãos, diferindo somente da IAC-289, a mais sensível à toxicidade de Al3+. IAC-289 e L9-NI destacaram-se na condição de sequeiro e solo corrigido, diferindo somente das linhagens L3-NI e L11-I. Na linhagem L11-I, observou-se porte mais baixo em todos os experimentos associado à resistência ao acamamento e à tolerância à toxicidade de Al3+. Todos os genótipos foram suscetíveis ao agente causal da mancha-da-folha. L9-NI tem potencial como fonte de genes em programas de melhoramento genético dada sua resistência à ferrugem-da-folha. Com exceção de Anahuac, IAC-289 e da L3-NI, todos os genótipos foram tolerantes à presença de 10 mg L-1 de Al3+ em soluções nutritivas.The mutation induction technique associated with hybridization has provided the development of new genotypes with desirable agronomic traits. Seeds of eighteen F2 wheat lines being ten originated by plant selections of

  4. Original Research

    African Journals Online (AJOL)

    2013-12-17

    .starjournal.org ... Soil pH can vary from 7 to 8.3 when only. Original Research. DOI: http://dx.doi.org/10.4314/star.v2i4.9 ...... to solve fertility management related problems in the area. Thus identification of the reasons behind.

  5. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. FIREARM-RELATED INJURIES AND. DEATHS AMONG CHILDREN AND. ADOLESCENTS IN CAPE TOWN -. 1992 -1996. Alyssa Wigton. Objective. To determ.i.lle the epidemiological profile of fireann- related injuries among children and adolescents in Cape. Town during recent years in order to ...

  6. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. References. 1. UNAIDS. Report on the Global HTV/AIDS Epidemic. Geneva: June 2000. 2. Connor E..\\1, Sperling RS, Gelber R. et al. Reduction of maternal-infant transmission of human immunodeficiency virus type 1 with zidovu dine treatment. N Eng! J Med 1994; 331:1173-1180. 3. Undegren ML ...

  7. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. PEAK RATES OF DIURESIS IN. HEALTHY HUMANS DURING ORAL. FLUID OVERLOAD. Timothy D Noakes, Gary Wilson, David A Gray,. Michael I Lambert, Steven C Dennis. Objective. To determine whether rates of intestinal fluid absorption and renal diuresis can match high rates of fluid ingestion ...

  8. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. CRITICAL CARE FOCUS. AETIOLOGY AND OUTCOME OF. SEVERE COMMUNITY-ACQUIRED. PNEUMONIA IN CHILDREN. ADMITTED TO A PAEDIATRIC. INTENSIVE CARE UNIT. S D Delport, T Brisley. Objective. To determine the aetiological agents and outcome of severe community-acquired ...

  9. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. UNPAID COMMUNITY. VOLUNTEERS - EFFECTIVE. PROVIDERS OF DIRECTLY. OBSERVED THERAPY (DOT) IN. RURAL SOUTH AFRICA. R D Barker, F J C Millard, M E Nthangeni. Objective. To il).ustrate successes and difficulties for the South. African National Tuberculosis Progranune in a ...

  10. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. Dual protection in sexually active women. Immo Kleinschmidt, Baker Ndugga Maggwa, Jennifer Smit,Mags E Beksinska, Helen Rees. Objective. To determine the prevalence and co-factors associated with the practice of dual protection against sexually transmitted infections (STis) and unwanted.

  11. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. EARLY DIAGNOSIS OF PROSTATE. CANCER IN THE WESTERN CAPE. C F Heyns, AM Naude, A J Visser, D C Marais,. H B Stopforth, J K Nyarko, G A Stellmacher. Background. Early stage prostate cancer does not cause symptoms, and even metastatic disease may exist for years without causing ...

  12. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. Nutritional variation and cardiovascular risk factors in. Tanzania - rural-urban difference. Marina Njelekela, Toshiaki Sato, Yasuo Nara, Tomohiro Miki, Sachiko Kuga, Takanori Noguchi, Torno Kanda, Masashi Yamori,. Josiah Ntogwisangu, Zablon Masesa, Yohana Mashalla, Jacob Mtabaji, Yukio ...

  13. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. Formative assessment promotes learning in undergraduate clinical clerkships. V C Burch, J L Seggie, N E Gary. Introduction. Clinical clerkships, typically situated in environments lacking educational structure, form the backbone of undergraduate medical training. The imperative to develop strategies ...

  14. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES c(~rvical spine injury outcome- a review of 101 cases treated in a tertiary referral unit. K Friielingsdorf, R N Dunn. Cervical spinal cord injury (SCI) is a devastating event for the patient and family. It has a huge impact on society because of the intensive resources required to manage the patient in both.

  15. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. OCCUPATIONAL EXPOSURE OF. INTERNS TO BLOOD IN AN AREA. OF HIGH HIV SEROPREVALENCE. A S Karstaedt, L Pantanowitz. Objective. To determine the epidemiology of work-related exposure to blood among interns. Design. Interns were invited to complete anonymously a questionnaire ...

  16. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. HISTORY OF MEDICINE. ELIM HOSPITAL - THE FIRST 100. YEARS. Part 2. C F van der Merwe. THE JAQUES ERA. The year 1957 saw the arrival of another giant in the history of. Elim Hospital. During this year Dr Pierre Jaques returned from postgraduate work in the UK. This son of the North was.

  17. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. References. 1. Raftery J. Mental health services in transition: the United States and the United Kingdom. Br. J Psychiatry 1992; 161: 589-593. 2. Sainsbury Centre for Mental Health. The Mental Health Services Workforce: Present and Future. A Report for the NHS Executive. London: The Sainsbury ...

  18. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. NUTRITIONAL STATUS AND. DENTAL CARIES IN A LARGE. SAMPLE OF 4- AND 5-YEAR-OLD. SOUTH AFRICAN CHILDREN. Peter Cleaton-Jones, Barbara D Richardson, Lars Granath,. L raul Fatti, Ruth SinweU, Alexander R Walker, Mirriam. Mogotsi. Background. Evidence from studies involving ...

  19. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. WHAT IS THE INFANT MORTALITY. RATE IN SOUTH AFRICA? THE NEED FOR IMPROVED DATA. Nadine Nannan, Debbie Bradshaw, Robert Mazur, Sim.phiwe. Maphumulo. Objectives. To review recent infant mortality and birth registration data in South Africa and to investigate geographical ...

  20. ORIGINAL ARTICLE

    African Journals Online (AJOL)

    boaz

    ORIGINAL ARTICLE. AFRICAN JOURNAL OF CLINICAL AND EXPERIMENTAL MICROBIOLOGY MAY 2017 ISBN 1595-689X VOL18 No. 2 ... aquaculture in particular is of great concern to environmental and public health. In Nigeria, regulation ..... Occupational and Environmental Hygiene, 7 (2): 66-71. 29. Adebowale O.O ...

  1. Original Article

    African Journals Online (AJOL)

    Administratör

    Stroke in Palestine www.ljm.org.ly. Libyan J Med, AOP: 080920. Page 39. Original Article. Characterization of Hospitalized Ischemic Stroke Patients in. Palestine. Sawalha AF ... Key words: Ischemic stroke, Risk factors, In-hospital mortality, Palestine. ABSTRACT .... stroke in young patients seems to vary between different ...

  2. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    alternatives to conventional care (homoeopathy, chiropractic, acupuncture, etc.), and also recognise the groundswell of interest in and support for inclusion of benefits for services provided by traditional healers. The transition from the original, relatively restricted approach which was concerned with established, mainstream.

  3. original research

    African Journals Online (AJOL)

    jenny

    Original Research: Computer-based learning for the enhancement of breastfeeding training. 2009;22(3) ... Conclusion: It is recommended that validated computer-based breastfeeding training modules be integrated as part of multi-media methods .... training and consultations at community and individual level. 3. 0.

  4. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES failure, breath-holding spells and even strokeY The decreased attention span and learning associated with iron deficiency may have adverse effects on cognitive and psychomotor development.'-' Furthermore, appropriate treatment of iron deficiency is effective and safe, It would therefore seem worth.

  5. ORIGINAL ARTICLE

    African Journals Online (AJOL)

    2011-04-01

    Apr 1, 2011 ... also trained as VCT counsellors by the Foundation for ... of VCT. As a further response to reaching the NSP target, the national HIV counselling and testing campaign3 was launched in April 2010 with a focus on mobilising all South Africans to be ... origin of HIV/AIDS, HIV as an infectious disease, stigma,.

  6. original articles

    African Journals Online (AJOL)

    reliably measured by double-beam X-ray absorptiometry. (DEXA), which ... The diagnosis of osteoporosis is based on BMD relative to that of healthy young adults and criteria for diagnosis are arbritary. The original 'normal' BMD data published by some ..... measurement error and were regarded as unchanged, but 10%.

  7. Original Article

    African Journals Online (AJOL)

    102640

    stress and aspirin-induced gastric ulcer in rats. Jamahiriya Medical Journal 2003; 2:43-46. 13. Trease G and Evans W. Drugs of biological origin. In: Trease and Evans, 11th ed. Bailliere. Tindall. London 1980; pp 319-320, 741. 14. Cunnane SC, Ganguli S, Menard C, et al. High α-linolenic acid flaxseed (Linum usitatissimum):.

  8. Original Research

    African Journals Online (AJOL)

    2013-09-18

    Sep 18, 2013 ... 1998) and involves the movement of water along evapotranspiration, precipitation, surface runoff, subsurface flow, and groundwater pathways. Evapotranspiration (ET) is usually the largest component of the hydrologic cycle, given that most precipitation that falls on land is returned to the. Original Research ...

  9. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    warrant delivery:. was made in the presence of fetal heart rate baseline variability of less than 5 beats per minute continuing for at least 60 minutes, or repeated late decelerations. 4. Antepartum haemorrhage included bleeding due to abruptio placentae, placenta praevia and antepartum haemorrhage of unknown origin.

  10. ORIGINAL ARTICLE

    African Journals Online (AJOL)

    number of MTB strain is less than 39,062,500 and. 4,444,444,444 with selective effect to INH and RIF ..... random generated cycles was used as the empirical data to further assess the simulated results of the ... Basically, the process is a form of pseudo sampling from the original dataset to determine the variability.

  11. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. Paediatric immunity. The immaturity of the infant immune system is demonstrated by the increased susceptibility of children to infections by both viral and bacterial pathogens. The humoral arm of the immune system is underdeveloped and differs greatly from that of adults. Infants only develop the ...

  12. Cultural Originality

    African Journals Online (AJOL)

    of originality for the concept of alterity (or difference) and endorse it rather than rejecting it as the bedrock of a ..... economies and tax-paying dynamics of established nation-states. How then do we ~ and people .... The book demonstrates particularly clearly certain features of the intellec- tual artisanship of anthropological ...

  13. Original Article

    African Journals Online (AJOL)

    2010 May;3(2):25-9. Original Article. AJNT. Abstract. Introduction: Several reports described an association between type 2 diabetes mellitus (DM) and chronic hepatitis C virus (HCV) infection. Chronic HCV infection is prevalent in Egypt. The present work aimed to evaluate the prevalence of proteinuria and neuropathy.

  14. Demonstration of paternal inheritance of plastids in Picea (Pinaceae). [Hybridization of cloned, sup 32 -P labeled, petunia cpDNA

    Energy Technology Data Exchange (ETDEWEB)

    Stine, M.

    1988-01-01

    Chloroplast DNA (cpDNA) was purified from Picea glauca, P. pungens, P. engelmannii, and P. omorika, and was digested with several restriction endonucleases. Interspecific restriction fragment length polymorphisms (RFLPs) of cpDNA were identified. The RFLPs were identified as cpDNA by the hybridization of cloned, {sup 32}-P labeled, petunia cpDNA to the polymorphic bands, and by the lack of hybridization of a cloned and labeled mtDNA probe from maize. Chloroplast DNA RFLPs that showed no intraspecific variation when examined across the natural range for each species, were used as markers to follow the inheritance of plastids in interspecific hybrids. The inheritance of plastids was determined for F{sub 1}-hybrids from reciprocal crosses of P. glauca and P. pungens, P. glauca and P. omorika, and F{sub 1}-hybrids of P. engelmannii x pungens. All 31 F{sub 1}-hybrids examined showed the cpDNA genotypes of the pollen parent, or the paternal species.

  15. Is Hybridization a Source of Adaptive Venom Variation in Rattlesnakes? A Test, Using a Crotalus scutulatus × viridis Hybrid Zone in Southwestern New Mexico

    Directory of Open Access Journals (Sweden)

    Giulia Zancolli

    2016-06-01

    Full Text Available Venomous snakes often display extensive variation in venom composition both between and within species. However, the mechanisms underlying the distribution of different toxins and venom types among populations and taxa remain insufficiently known. Rattlesnakes (Crotalus, Sistrurus display extreme inter- and intraspecific variation in venom composition, centered particularly on the presence or absence of presynaptically neurotoxic phospholipases A2 such as Mojave toxin (MTX. Interspecific hybridization has been invoked as a mechanism to explain the distribution of these toxins across rattlesnakes, with the implicit assumption that they are adaptively advantageous. Here, we test the potential of adaptive hybridization as a mechanism for venom evolution by assessing the distribution of genes encoding the acidic and basic subunits of Mojave toxin across a hybrid zone between MTX-positive Crotalus scutulatus and MTX-negative C. viridis in southwestern New Mexico, USA. Analyses of morphology, mitochondrial and single copy-nuclear genes document extensive admixture within a narrow hybrid zone. The genes encoding the two MTX subunits are strictly linked, and found in most hybrids and backcrossed individuals, but not in C. viridis away from the hybrid zone. Presence of the genes is invariably associated with presence of the corresponding toxin in the venom. We conclude that introgression of highly lethal neurotoxins through hybridization is not necessarily favored by natural selection in rattlesnakes, and that even extensive hybridization may not lead to introgression of these genes into another species.

  16. Giemsa C-banding in two polyploid, South American Hordeum species, H. tetraploidum and H. lechleri, and their aneuploid hybrids with H. vulgare

    DEFF Research Database (Denmark)

    Linde-Laursen, Ib; Bothmer, R. von

    1986-01-01

    American taxa of the same sections suggest a rather close relationship and support that the biological basis for their classification with different sections is questionable. C-banding patterns identified the chromosomes of parental genomes in interspecific hybrids between the two species and H. vulgare....... The hybrids were stably aneuploid. Both had lost and acquired H. vulgare chromosomes. Thus, somatic elimination of chromosomes was combined with multiplication of chromosomes. The observations of stably aneuploid hybrids have implications for the exploitation of alien germplasm. The activity of non-H. vulgare...

  17. Differential pollinator effectiveness and importance in a milkweed (Asclepias, Apocynaceae) hybrid zone.

    Science.gov (United States)

    Stoepler, Teresa M; Edge, Andrea; Steel, Anna; O'Quinn, Robin L; Fishbein, Mark

    2012-03-01

    Exceptions to the ideal of complete reproductive isolation between species are commonly encountered in diverse plant, animal, and fungal groups, but often the causative ecological processes are poorly understood. In flowering plants, the outcome of hybridization depends in part on the effectiveness of pollinators in interspecific pollen transport. In the Asclepias exaltata and A. syriaca (Apocynaceae) hybrid zone in Shenandoah National Park, Virginia, extensive introgression has been documented. The objectives of this study were to (1) determine the extent of pollinator overlap among A. exaltata, A. syriaca, and their hybrids and (2) identify the insect taxa responsible for hybridization and introgression. We observed focal plants of parental species and hybrids to measure visitation rate, visit duration, and per-visit pollinia removal and deposition, and we calculated pollinator effectiveness and importance. Visitation rates varied significantly between the 2 yr of the study. Overall, Apis mellifera, Bombus sp., and Epargyreus clarus were the most important pollinators. However, Bombus sp. was the only visitor that was observed to both remove and insert pollinia for both parent species as well as hybrids. We conclude that Bombus may be a key agent of hybridization and introgression in these sympatric milkweed populations, and hybrids are neither preferred nor selected against by pollinators. Thus, we have identified a potential mechanism for how hybrids act as bridges to gene flow between A. exaltata and A. syriaca. These results provide insights into the breakdown of prezygotic isolating mechanisms.

  18. Testing a hypothesis of unidirectional hybridization in plants: Observations on Sonneratia, Bruguiera and Ligularia

    Directory of Open Access Journals (Sweden)

    Wu Chung-I

    2008-05-01

    Full Text Available Abstract Background When natural hybridization occurs at sites where the hybridizing species differ in abundance, the pollen load delivered to the rare species should be predominantly from the common species. Previous authors have therefore proposed a hypothesis on the direction of hybridization: interspecific hybrids are more likely to have the female parent from the rare species and the male parent from the common species. We wish to test this hypothesis using data of plant hybridizations both from our own experimentation and from the literature. Results By examining the maternally inherited chloroplast DNA of 6 cases of F1 hybridization from four genera of plants, we infer unidirectional hybridization in most cases. In all 5 cases where the relative abundance of the parental species deviates from parity, however, the direction is predominantly in the direction opposite of the prediction based strictly on numerical abundance. Conclusion Our results show that the observed direction of hybridization is almost always opposite of the predicted direction based on the relative abundance of the hybridizing species. Several alternative hypotheses, including unidirectional postmating isolation and reinforcement of premating isolation, were discussed.

  19. Analysis of the meiotic segregation in intergeneric hybrids of tilapias.

    Science.gov (United States)

    Bezault, Etienne; Rognon, Xavier; Clota, Frederic; Gharbi, Karim; Baroiller, Jean-Francois; Chevassus, Bernard

    2012-01-01

    Tilapia species exhibit a large ecological diversity and an important propensity to interspecific hybridisation. This has been shown in the wild and used in aquaculture. However, despite its important evolutionary implications, few studies have focused on the analysis of hybrid genomes and their meiotic segregation. Intergeneric hybrids between Oreochromis niloticus and Sarotherodon melanotheron, two species highly differentiated genetically, ecologically, and behaviourally, were produced experimentally. The meiotic segregation of these hybrids was analysed in reciprocal second generation hybrid (F2) and backcross families and compared to the meiosis of both parental species, using a panel of 30 microsatellite markers. Hybrid meioses showed segregation in accordance to Mendelian expectations, independent from sex and the direction of crosses. In addition, we observed a conservation of linkage associations between markers, which suggests a relatively similar genome structure between the two parental species and the apparent lack of postzygotic incompatibility, despite their important divergence. These results provide genomics insights into the relative ease of hybridisation within cichlid species when prezygotic barriers are disrupted. Overall our results support the hypothesis that hybridisation may have played an important role in the evolution and diversification of cichlids.

  20. Selfish evolution of cytonuclear hybrid incompatibility in Mimulus.

    Science.gov (United States)

    Case, Andrea L; Finseth, Findley R; Barr, Camille M; Fishman, Lila

    2016-09-14

    Intraspecific coevolution between selfish elements and suppressors may promote interspecific hybrid incompatibility, but evidence of this process is rare. Here, we use genomic data to test alternative models for the evolution of cytonuclear hybrid male sterility in Mimulus In hybrids between Iron Mountain (IM) Mimulus guttatus × Mimulus nasutus, two tightly linked M. guttatus alleles (Rf1/Rf2) each restore male fertility by suppressing a local mitochondrial male-sterility gene (IM-CMS). Unlike neutral models for the evolution of hybrid incompatibility loci, selfish evolution predicts that the Rf alleles experienced strong selection in the presence of IM-CMS. Using whole-genome sequences, we compared patterns of population-genetic variation in Rf at IM to a neighbouring population that lacks IM-CMS. Consistent with local selection in the presence of IM-CMS, the Rf region shows elevated FST, high local linkage disequilibrium and a distinct haplotype structure at IM, but not at Cone Peak (CP), suggesting a recent sweep in the presence of IM-CMS. In both populations, Rf2 exhibited lower polymorphism than other regions, but the low-diversity outliers were different between CP and IM. Our results confirm theoretical predictions of ubiquitous cytonuclear conflict in plants and provide a population-genetic mechanism for the evolution of a common form of hybrid incompatibility. © 2016 The Author(s).

  1. 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.

  2. Ecological, morphological and phylogenetic correlates of interspecific variation in plasma carotenoid concentration in birds.

    Science.gov (United States)

    Tella, J L; Figuerola, J; Negro, J J; Blanco, G; Rodríguez-Estrella, R; Forero, M G; Blázquez, M C; Green, A J; Hiraldo, F

    2004-01-01

    Carotenoids are important as pigments for bright coloration of animals, and as physiologically active compounds with a wide array of health-related benefits. However, the causes of variation in carotenoid acquisition and physiology among species are poorly known. We measured the concentration of carotenoids in the blood of 80 wild bird species differing in diet, body size and the extent of carotenoid-based traits. Preliminary analyses showed that diet significantly explains interspecific variability in plasma carotenoids. However, dietary influences were apparently overridden by phylogenetic relationships among species, which explained most (65%) of this variability. This phylogenetic effect could be due partly to its covariation with diet, but may also be caused by interspecific differences in carotenoid absorption from food to the blood stream, mediated, for example by endothelial carriers or gut parasites. Carotenoid concentrations also decreased with body size (which may be explained by the allometric relationship between ingestion rate and body mass), and correlated positively with the extent of carotenoid-dependent coloration of plumage and bare parts. Therefore, the acquisition of carotenoids from the diet and their use for both health and display functions seem to be constrained by ecological and physiological aspects linked to the phylogeny and size of the species.

  3. 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).

  4. 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.

  5. 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.

  6. Can we predict diatoms herbicide sensitivities with phylogeny? Influence of intraspecific and interspecific variability.

    Science.gov (United States)

    Esteves, Sara M; Keck, François; Almeida, Salomé F P; Figueira, Etelvina; Bouchez, Agnès; Rimet, Frédéric

    2017-10-01

    Diatoms are used as indicators of freshwater ecosystems integrity. Developing diatom-based tools to assess impact of herbicide pollution is expected by water managers. But, defining sensitivities of all species to multiple herbicides would be unattainable. The existence of a phylogenetic signal of herbicide sensitivity was shown among diatoms and should enable prediction of new species sensitivity. However, diatoms present a cryptic diversity that may lead to variation in their sensitivity to herbicides that would need to be taken into account. Using bioassays, the sensitivity to four herbicides (Atrazine, Terbutryn, Diuron, Isoproturon) was evaluated for 11 freshwater diatom taxa and intraspecific variability was assessed for two of them (Nitzschia palea and Achnanthidium spp.). Intraspecific variability of herbicide sensitivity was always smaller than interspecific variability, but intraspecific variability was more important in N. palea than in Achnanthidium spp. Indeed, one species showed no intraspecific phylogenetic signal (N. palea) whereas the other did (Achnanthidium spp.). On one hand, species boundaries are not set properly for Achnanthidium spp. which encompass several taxa. On the other hand, there is a higher phenotypic plasticity for N. palea. Finally, a phylogenetic signal of herbicide sensitivity was measured at the interspecific level, opening up prospects for setting up reliable biomonitoring tools based on sensitivity prediction, insofar as species boundaries are correctly defined.

  7. Inheritance of anthocyanin pigmentation in interspecific cross of rice (Oryza sativa L. × O. rufipogon Griff

    Directory of Open Access Journals (Sweden)

    Deepak Pandey

    2016-09-01

    Full Text Available An inheritance study of the anthocyanin pigmentation in the inter-specific cross of O. sativa × O. rufipogon was conducted in the greenhouse of the Institute of Agriculture and Animal Science (IAAS, Rampur, Chitwan, including the parents, F1 and subsequent F2 segregants in the rice growing season of the year 2012. The study was done in the segregating generation of the inter-specific cross of O. sativa cv. Pokhreli Palele × O. rufipogon. The inheritance of anthocyanin pigmentation pattern in the different plant parts was found to be complicated. The segregation of pigmented: non-pigmented for basal leaf sheath, stigma and leaf apex was digenic with complementary gene action (9: 7. Digenic inheritance of the pigmentation in the awn and lemma and palea was found with the segregation ratio of 11 pigmented: 5 non-pigmented. A tetragenic ratio with inhibitory gene action (81 pigmented: 175 non-pigmented was observed for the internode colour. A pleiotropic gene action of one of the basal leaf sheath pigmentation with that for the stigma and internode pigmentation was found.

  8. Evolutionary stability of mutualism: interspecific population regulation as an evolutionarily stable strategy

    Science.gov (United States)

    Holland, J. Nathaniel; DeAngelis, Donald L.; Schultz, Stewart T.

    2004-01-01

    Interspecific mutualisms are often vulnerable to instability because low benefit : cost ratios can rapidly lead to extinction or to the conversion of mutualism to parasite–host or predator–prey interactions. We hypothesize that the evolutionary stability of mutualism can depend on how benefits and costs to one mutualist vary with the population density of its partner, and that stability can be maintained if a mutualist can influence demographic rates and regulate the population density of its partner. We test this hypothesis in a model of mutualism with key features of senita cactus (Pachycereus schottii) – senita moth (Upiga virescens) interactions, in which benefits of pollination and costs of larval seed consumption to plant fitness depend on pollinator density. We show that plants can maximize their fitness by allocating resources to the production of excess flowers at the expense of fruit. Fruit abortion resulting from excess flower production reduces pre–adult survival of the pollinating seed–consumer, and maintains its density beneath a threshold that would destabilize the mutualism. Such a strategy of excess flower production and fruit abortion is convergent and evolutionarily stable against invasion by cheater plants that produce few flowers and abort few to no fruit. This novel mechanism of achieving evolutionarily stable mutualism, namely interspecific population regulation, is qualitatively different from other mechanisms invoking partner choice or selective rewards, and may be a general process that helps to preserve mutualistic interactions in nature.

  9. Optional Endoreplication and Selective Elimination of Parental Genomes during Oogenesis in Diploid and Triploid Hybrid European Water Frogs.

    Science.gov (United States)

    Dedukh, Dmitry; Litvinchuk, Spartak; Rosanov, Juriy; Mazepa, Glib; Saifitdinova, Alsu; Shabanov, Dmitry; Krasikova, Alla

    2015-01-01

    Incompatibilities between parental genomes decrease viability of interspecific hybrids; however, deviations from canonical gametogenesis such as genome endoreplication and elimination can rescue hybrid organisms. To evaluate frequency and regularity of genome elimination and endoreplication during gametogenesis in hybrid animals with different ploidy, we examined genome composition in oocytes of di- and triploid hybrid frogs of the Pelophylax esculentus complex. Obtained results allowed us to suggest that during oogenesis the endoreplication involves all genomes occurring before the selective genome elimination. We accepted the hypothesis that only elimination of one copied genome occurs premeiotically in most of triploid hybrid females. At the same time, we rejected the hypothesis stating that the genome of parental species hybrid frogs co-exist with is always eliminated during oogenesis in diploid hybrids. Diploid hybrid frogs demonstrate an enlarged frequency of deviations in oogenesis comparatively to triploid hybrids. Typical for hybrid frogs deviations in gametogenesis increase variability of produced gametes and provide a mechanism for appearance of different forms of hybrids.

  10. A New Sythetic Hybrid (A1D5 between Gossypium herbaceum and G. raimondii and Its Morphological, Cytogenetic, Molecular Characterization.

    Directory of Open Access Journals (Sweden)

    Yuxiang Wu

    Full Text Available The diploid species G. herbaceum (A1 and G. raimondii (D5 are the progenitors of allotetraploid cotton, respectively. However, hybrids between G. herbaceum and G. raimondii haven't been reported. In the present study, hybridization between G. herbaceum and G. raimondii was explored. Morphological, cytogenetic and molecular analyses were used to assess the hybridity. The interspecific hybrid plants were successfully obtained. Most of the morphological characteristics of the hybrids were intermediate between G. herbaceum and G. raimondii. However, the color of glands, anther cases, pollen and corolla, and the state of bracteoles in hybrids were associated with the G. herbaceum. The color of staminal columns and filaments in hybrids were associated with G. raimondii. Cytogenetic analysis confirmed abnormal meiotic behavior existed in hybrids. The hybrids couldn't produce boll-set. Simple sequence repeat results found that besides the fragments inherited from the two parents, some novel bands were amplified in hybrids, indicating that potential mutations and chromosomal recombination occurred between parental genomes during hybridization. These results may provide some novel insights in speciation, genome interaction, and evolution of the tetraploid cotton species.

  11. In vitro establishment of the hybrid rootstock ‘Garfi x Nemared’ (Garnem for peach

    Directory of Open Access Journals (Sweden)

    Limberg Guevara Salguero

    2016-04-01

    Full Text Available The interspecific hybrid between almond and peach, ‘Garfield x Nemared’ (Prunus dulcis (Mill D.A.Webb x Prunus persica (L. Batsch. has become very important as rootstocks for peach in Bolivia, but propagation by traditional methods of this hybrid has been very difficult. In the present study the aim was to in vitro establishment of this hybrid. As initial explants, nodal segments from mother plants, growing under controlled culture conditions, were used. For disinfection two concentrations of sodium hypochlorite (0.5 and 0.75% and time (10 and 12 min were tested. The greatest percentage of establishment was achieved using 0.75% NaClO for 12 min in an MS culture medium free of growth regulators. A 100% control of the phenols oxidation was achieved with the combination of mother plants growing under 50% shade, young buds, use of 150 mg l-1 citric acid at the end of the disinfection process and into the culture medium and then place the test tubes with the nodal segments one week in the dark.   Keywords: interspecific hybrid, Prunus, tissue culture

  12. Detection of Alien Oryza punctata Kotschy Chromosomes in Rice, Oryza sativa L., by Genomic in situ Hybridization

    OpenAIRE

    Yasui, Hideshi; Nonomura, Ken-ichi; Iwata, Nobuo; 安井, 秀; 野々村, 賢一; 岩田, 伸夫

    1997-01-01

    Genomic in situ hybridization (GIS H) using total Oryza punctata Kotschy genomic DNA as a probe was applied to detect alien chromosomes transferred from O. punctata (W1514: 2n=2x=24: BB) to O. sativa Japonica cultivar, Nipponbare (2n=2x=24: AA). Only 12 chromosomes in the interspecific hybrids (2n=3x=36: AAB) between autotetraploid of O. sativa cultivar Nipponbare and a diploid strain of O. punctata (W1514) showed intense staining by FITC in mitotic metaphase spreads. Only one homologous pair...

  13. Time course of programmed cell death, which included autophagic features, in hybrid tobacco cells expressing hybrid lethality.

    Science.gov (United States)

    Ueno, Naoya; Nihei, Saori; Miyakawa, Naoto; Hirasawa, Tadashi; Kanekatsu, Motoki; Marubashi, Wataru; van Doorn, Wouter G; Yamada, Tetsuya

    2016-12-01

    PCD with features of vacuolar cell death including autophagy-related features were detected in hybrid tobacco cells, and detailed time course of features of vacuolar cell death were established. A type of interspecific Nicotiana hybrid, Nicotiana suaveolens × N. tabacum exhibits temperature-sensitive lethality. This lethality results from programmed cell death (PCD) in hybrid seedlings, but this PCD occurs only in seedlings and suspension-cultured cells grown at 28 °C, not those grown at 36 °C. Plant PCD can be classified as vacuolar cell death or necrotic cell death. Induction of autophagy, vacuolar membrane collapse and actin disorganization are each known features of vacuolar cell death, but observed cases of PCD showing all these features simultaneously are rare. In this study, these features of vacuolar cell death were evident in hybrid tobacco cells expressing hybrid lethality. Ion leakage, plasma membrane disruption, increased activity of vacuolar processing enzyme, vacuolar membrane collapse, and formation of punctate F-actin foci were each evident in these cells. Transmission electron microscopy revealed that macroautophagic structures formed and tonoplasts ruptured in these cells. The number of cells that contained monodansylcadaverine (MDC)-stained structures and the abundance of nine autophagy-related gene transcripts increased just before cell death at 28 °C; these features were not evident at 36 °C. We assessed whether an autophagic inhibitor, wortmannin (WM), influenced lethality in hybrid cells. After the hybrid cell began to die, WM suppressed increases in ion leakage and cell deaths, and it decreased the number of cells containing MDC-stained structures. These results showed that several features indicative of autophagy and vacuolar cell death were evident in the hybrid tobacco cells subject to lethality. In addition, we documented a detailed time course of these vacuolar cell death features.

  14. Original pedagogues

    DEFF Research Database (Denmark)

    Schmidt, Christina Haandbæk

    authenticity in professional judgment and identity building. I argue that this should be seen in the context that the professional status of the Danish pedagogues is being challenged by the current restructuring of public services with reference to knowledge economy discourse. Furthermore there is remarkable...... and professional autonomy in exercising judgment concerning pedagogical situations. To understand how pedagogues can struggle the distention between being competent and being original the project draws on both Michel Foucault and Charles Taylor as two incompatible theories on modern identity. The study...

  15. DNA-based hybrid catalysis.

    Science.gov (United States)

    Rioz-Martínez, Ana; Roelfes, Gerard

    2015-04-01

    In the past decade, DNA-based hybrid catalysis has merged as a promising novel approach to homogeneous (asymmetric) catalysis. A DNA hybrid catalysts comprises a transition metal complex that is covalently or supramolecularly bound to DNA. The chiral microenvironment and the second coordination sphere interactions provided by the DNA are key to achieve high enantioselectivities and, often, additional rate accelerations in catalysis. Nowadays, current efforts are focused on improved designs, understanding the origin of the enantioselectivity and DNA-induced rate accelerations, expanding the catalytic scope of the concept and further increasing the practicality of the method for applications in synthesis. Herein, the recent developments will be reviewed and the perspectives for the emerging field of DNA-based hybrid catalysis will be discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Original Thinking

    Directory of Open Access Journals (Sweden)

    Ashok Natarajan

    2012-04-01

    Full Text Available History that comes to us as a chronology of events is really a collective existence that is evolving through several stages to develop Individuality in all members of the society. The human community, nation states, linguistic groups, local castes and classes, and families are the intermediate stages in development of the Individual. The social process moves through phases of survival, growth, development and evolution. In the process it organizes the consciousness of its members at successive levels from social external manners, formed behavior, value-based character and personality to culminate in the development of Individuality. Through this process, society evolves from physicality to Mentality. The power of accomplishment in society and its members develops progressively through stages of skill, capacity, talent, and ability. Original thinking is made possible by the prior development of thinking that organizes facts into information. The immediate result of the last world war was a shift in reliance from physical force and action to mental conception and mental activity on a global scale. At such times no problem need defy solution, if only humanity recognizes the occasion for thinking and Original Thinking. The apparently insoluble problems we confront are an opportunity to formulate a comprehensive theory of social evolution. The immediate possibility is to devise complete solutions to all existing problems, if only we use the right method of thought development.

  17. SPECIES SPECIFICITY OF BIOTOPIC PREFERENCES AS A FACTOR IN INTERSPECIFIC ISOLATION IN MAMMALS (BY THE EXAMPLE OF GENUS SPERMOPHILUS

    Directory of Open Access Journals (Sweden)

    S. V. Titov

    2017-12-01

    Full Text Available Background. Biotopical preferences of contact species are the first-level factors of hybridization. They provide the «primary contact» of heterospecifics individuals. All subsequent events depend on the degree of heterospecifics «mixing»: whether the contact will be short-term and accidental or the mixed population with a particular spatial structure will form. The research was aimed at studying the species specificity of biotopic preferences as a factor in interspecific isolation by the example of single-species colonies consisting of three members of the genus Spermophilus (russet (Spermophilus major, yellow (S. fulvus and spotted (S. suslicus ground squirrels inhabiting the Volga region in the areas of simpatry. Materials and methods. Analysis of biotopical preferences of ground squirrels was carried out in 10 model colonies. The geobotanical sites were described using the method of random squares. The discount areas (75×75 m were laid out for geobotanical descriptions, where the mapping of contours was conducted. The parameters of the environment and the number of holes were defined there. In total 705 holes were recorded, 536 of which belonged to spotted ground squirrel, 129 – to russet ground squirrel, and 40 – to yellow ground squirrel. The preferences in microbiotopes demonstrated by ground squirrels were evaluated according to the density of holes per the contour. The coefficient (RS of Spearman’s rank correlation was calculated to determine the influence of these factors on the preferences of ground squirrels in the particular areas of the biotope. The factorial and stepwise discriminant analyses were carried out to define the influence of these factors on the preferences of ground squirrels in the particular areas of the biotope and to highlight the habitat niches of species. Results. The analysis of indicators in biotopical preferences of spotted, russet and yellow ground squirrels revealed valid differences. Based on the

  18. Hybrid Gear

    Science.gov (United States)

    Handschuh, Robert F. (Inventor); Roberts, Gary D. (Inventor)

    2016-01-01

    A hybrid gear consisting of metallic outer rim with gear teeth and metallic hub in combination with a composite lay up between the shaft interface (hub) and gear tooth rim is described. The composite lay-up lightens the gear member while having similar torque carrying capability and it attenuates the impact loading driven noise/vibration that is typical in gear systems. The gear has the same operational capability with respect to shaft speed, torque, and temperature as an all-metallic gear as used in aerospace gear design.

  19. A genetic basis for the inviability of hybrids between sibling species of Drosophila

    International Nuclear Information System (INIS)

    Hutter, P.; Roote, J.; Ashburner, M.

    1990-01-01

    An X-ray induced mutation of Drosophila melanogaster whose only known effect is the rescue of otherwise lethal interspecific hybrids has been characterized. This mutation, Hmr, maps to 1-31.84 (9D1-9E4). Hmr may be the consequence of a P element insertion. It rescues hybrid males from the cross of D. melanogaster females to males of its three sibling species, D. simulans, D. mauritiana and D. sechellia. This rescue is recessive, since hybrid males that carry both Hmr and a duplication expected to be Hmr + are not rescued. Hmr also rescues the otherwise inviable female hybrids from the cross of compound-X D. melanogaster females to males of its sibling species. This rescue is also recessive, since a compound-X heterozygous for Hmr does not rescue. Another mutation, discovered on the In(1)AB chromosome of D. melanogaster, is also found to rescue normally inviable species hybrids: unlike Hmr, however, In(1)AB rescues hybrid females from the cross of In(1)AB/Y males to sibling females, as well as hybrid males from the cross of In(1)AB females to sibling males. These data are interpreted on the basis of a model for the genetic basis of hybrid inviability of complementary genes

  20. Pheromone Production, Attraction, and Interspecific Inhibition among Four Species of Ips Bark Beetles in the Southeastern USA

    Directory of Open Access Journals (Sweden)

    Göran Birgersson

    2012-01-01

    Full Text Available Hindgut volatiles from attacking, unmated males of Ips avulsus, I. calligraphus, I. grandicollis, and I. pini were analyzed by combined gas chromatography and mass spectrometry. Based on the quantitative identifications of hindguts and subsequent individual aerations, baits were formulated and a combined species-specific subtractive field bioassay was set up for the four bark beetle species. The bioassays were subtractive for the compounds identified in the hindgut analysis of each species, and volatiles identified in sympatric species were added as potential inhibitors alone and in combination. The trap catches from this bioassay revealed strong interspecific inhibition. The subtractive assays showed that I. grandicollis and I. calligraphus share (–-(4S-cis-verbenol as one pheromone component, while their second, synergistic pheromone component, (–-(S-ipsenol in I. grandicollis and (±-ipsdienol in I. calligraphus, acts as an interspecific inhibitor to the other species. I. avulsus and I. pini were found to have very similar production of hindgut volatiles, and both use ipsdienol and lanierone as synergistic pheromone components. No beetle-produced interspecific inhibitor was identified between these two species. Lanierone was found to be an interspecific inhibitor for both I. calligraphus and I. grandicollis.

  1. Interspecific hybridisation and interaction with cultivars affect the genetic variation of Ulmus minor and U. glabra in Flanders

    NARCIS (Netherlands)

    Cox, K.; Broek, vanden A.; Mijnsbrugge, vander K.; Buiteveld, J.; Collin, R.W.J.; Heybroek, H.; Mergeay, J.

    2014-01-01

    Interspecific hybridisation and gene flow from cultivated plants may have profound effects on the evolution of wild species. Considering the cultural history and past use of Ulmus minor and Ulmus glabra trees in Flanders (northern Belgium), we investigated the extent of human impact on the genetic

  2. Population-Specific Responses to Interspecific Competition in the Gut Microbiota of Two Atlantic Salmon (Salmo salar) Populations.

    Science.gov (United States)

    He, Xiaoping; Chaganti, Subba Rao; Heath, Daniel D

    2018-01-01

    The gut microbial community in vertebrates plays a role in nutrient digestion and absorption, development of intestine and immune systems, resistance to infection, regulation of bone mass and even host behavior and can thus impact host fitness. Atlantic salmon (Salmo salar) reintroduction efforts into Lake Ontario, Canada, have been unsuccessful, likely due to competition with non-native salmonids. In this study, we explored interspecific competition effects on the gut microbiota of two Atlantic salmon populations (LaHave and Sebago) resulting from four non-native salmonids. After 10 months of rearing in semi-natural stream tanks under six interspecific competition treatments, we characterized the gut microbiota of 178 Atlantic salmon by parallel sequencing the 16S rRNA gene. We found 3978 bacterial OTUs across all samples. Microbiota alpha diversity and abundance of 27 OTUs significantly differed between the two populations. Interspecific competition reduced relative abundance of potential beneficial bacteria (six genera of lactic acid bacteria) as well as 13 OTUs, but only in the LaHave population, indicating population-specific competition effects. The pattern of gut microbiota response to interspecific competition may reflect local adaptation of the host-microbiota interactions and can be used to select candidate populations for improved species reintroduction success.

  3. Effects of intra- and interspecific competition on the sensitivity of Daphnia magna populations to the fungicide carbendazim

    NARCIS (Netherlands)

    Arco, Del Ana Isabel; Rico Artero, Andreu; Brink, van den P.J.

    2015-01-01

    The ecological risk assessment of pesticides is generally based on toxicity data obtained from single-species laboratory experiments and does not take into account ecological interactions such as competition or predation. Intraspecific and interspecific competition are expected to result in

  4. Effects of intra- and interspecific competition on diet, growth and behaviour of Labeo calbasu (Hamilton) and Cirrhinus cirrhosus (Bloch)

    NARCIS (Netherlands)

    Rahman, M.M.; Verdegem, M.C.J.

    2010-01-01

    Effects of intra- and interspecific competition on diet, growth, grazing, swimming, resting and social behaviour of two carps calbasu (Labeo calbasu) and mrigal (Cirrhinus cirrhosus) were examined in single and mixed species treatments. Three treatments (tanks with 4 L. calbasu, 4 C. cirrhosus or 2

  5. 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...

  6. [RAPD analysis of the intraspecific and interspecific variation and phylogenetic relationships of Aegilops L. species with the U genome].

    Science.gov (United States)

    Goriunova, S V; Chikida, N N; Kochieva, E Z

    2010-07-01

    RAPD analysis was used to study the genetic variation and phylogenetic relationships of polyploid Aegilops species with the U genome. In total, 115 DNA samples of eight polyploid species containing the U genome and the diploid species Ae. umbellulata (U) were examined. Substantial interspecific polymorphism was observed for the majority of the polyploid species with the U genome (interspecific differences, 0.01-0,2; proportion of polymorphic loci, 56.6-88.2%). Aegilops triuncialis was identified as the only alloploid species with low interspecific polymorphism (interspecific differences, 0-0.01, P = 50%) in the U-genome group. The U-genome Aegilops species proved to be separated from other species of the genus. The phylogenetic relationships were established for the U-genome species. The greatest separation within the U-genome group was observed for the US-genome species Ae. kotschyi and Ae. variabilis. The tetraploid species Ae. triaristata and Ae. columnaris, which had the UX genome, and the hexaploid species Ae. recta (UXN) were found to be related to each other and separate from the UM-genome species. A similarity was observed between the U M-genome species Ae. ovata and Ae. biuncialis, which had the UM genome, and the ancestral diploid U-genome species Ae. umbellulata. The UC-genome species Ae. triuncialis was rather separate and slightly similar to the UX-genome species.

  7. Genetic variation and control of chloroplast pigment concentrations in Picea rubens, Picea mariana and their hybrids. I. Ambient and elevated [CO2] environments

    International Nuclear Information System (INIS)

    Major, J.E.; Barsi, D.C.; Mosseler, A.; Campbell, M.

    2007-01-01

    A significant decline has been noted in the red spruce component of the Acadian forest region in eastern Canada and the northeastern United States as a result of excessive harvesting, acid rain, and global warming. Two experiments were performed to acquire benchmark adaptive traits for information from a red spruce (RS) (Picea rubens Sargand) and black spruce (BS) (P. mariana (Mill.) B.S.P.) genetic complex grown in ambient carbon dioxide concentration ([CO 2 ]). The first experiment involved RS-BS seed sources from across the RS geographical range, while the second experiment involved an intra- and interspecific controlled-cross experiment to determine if RS and BS have unique chloroplast pigment concentrations and traits that reflect adaptations to different ecological niches. The objective was to determine species origin and hybrid variations in chloroplast pigment concentrations; examine the effect of elevated [CO 2 ] on chloroplast pigments; determine the inheritance of chloroplast pigments and examine the relationship of chloroplast pigment concentrations of trees grown at ambient [CO 2 ] with productivity traits and nitrogen concentrations. The traits related to light-energy processing have pronounced ecological implications for plant health. Results from the species origin experiment showed that total chlorophyll concentration was about 15 per cent higher in ambient [CO 2 ] than in elevated [CO 2 ]. In ambient [CO 2 ], BS populations had 11 per cent higher total chlorophyll and carotenoid concentrations than RS populations. Results from the controlled-cross experiment showed that families with a hybrid index of 25 per cent RS had the highest total chlorophyll concentrations, and families with hybrid indices of 75 and 100 had the lowest amounts. A predominant male effect for chlorophyll concentration was noted. In ambient and elevated [CO 2 ] environments, crosses with BS males had 10.6 and 17.6 per cent higher total chlorophyll concentrations than crosses

  8. On a Variational Approach to Optimization of Hybrid Mechanical Systems

    Directory of Open Access Journals (Sweden)

    Vadim Azhmyakov

    2010-01-01

    Full Text Available This paper deals with multiobjective optimization techniques for a class of hybrid optimal control problems in mechanical systems. We deal with general nonlinear hybrid control systems described by boundary-value problems associated with hybrid-type Euler-Lagrange or Hamilton equations. The variational structure of the corresponding solutions makes it possible to reduce the original “mechanical” problem to an auxiliary multiobjective programming reformulation. This approach motivates possible applications of theoretical and computational results from multiobjective optimization related to the original dynamical optimization problem. We consider first order optimality conditions for optimal control problems governed by hybrid mechanical systems and also discuss some conceptual algorithms.

  9. Intuitionistic hybrid logic

    DEFF Research Database (Denmark)

    Braüner, Torben

    2011-01-01

    Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area.......Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area....

  10. 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.

  11. Characteristics of hybrid scenarios in KSTAR

    Science.gov (United States)

    Lee, Youngho; Byun, Cheol-Sik; Na, Yong-Su; Kstar Team

    2017-10-01

    We report the characteristics of hybrid scenarios under development in KSTAR. Firstly, detailed definition of the hybrid scenario in KSTAR is described and categorized according to the MHD activities. The discharges exhibiting H89 >1.9, betaN >2.2 sustained more than 5*tauE at q95 <6.5 without or mild sawtooth are classified into the hybrid regime. Fishbones and neoclassical tearing modes are usually observed in this regime. Improved confinement in this regime is also confirmed with comparing general H-mode in KSTAR. Secondly, several experimental approaches are presented to access the hybrid regime. Here, four different recipes are described. Thirdly, the origin of the confinement enhancement is discussed. The role of the plasma rotation is found to be small in experiments where electron cyclotron heating is applied to reduce the toroidal rotation. The pedestal enhancement is thought to be the main reason for the confinement improvement in KSTAR hybrid scenarios.

  12. 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

  13. 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.

  14. 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)

  15. Establishment and interspecific associations in two species of Ichthyocotylurus (Trematoda) parasites in perch (Perca fluviatilis)

    Science.gov (United States)

    2011-01-01

    Background Co-infections of multiple parasite species in hosts may lead to interspecific associations and subsequently shape the structure of a parasite community. However, few studies have focused on these associations in highly abundant parasite species or, in particular, investigated how the associations develop with time in hosts exposed to co-infecting parasite species for the first time. We investigated metacercarial establishment and interspecific associations in the trematodes Ichthyocotylurus variegatus and I. pileatus co-infecting three age cohorts of young perch (Perca fluviatilis). Results We found that the timing of transmission of the two Ichthyocotylurus species was very similar, but they showed differences in metacercarial development essentially so that the metacercariae of I. pileatus became encapsulated faster. Correlations between the abundances of the species were significantly positive after the first summer of host life and also within the main site of infection, the swim bladder. High or low abundances of both parasite species were also more frequent in the same host individuals than expected by chance, independently of host age or size. However, the highest abundances of the species were nevertheless observed in different host individuals and this pattern was consistent in all age cohorts. Conclusions The results suggest similar temporal patterns of transmission, non-random establishment, and facilitative rather than competitive associations between the parasite species independently of the age of the infracommunities. However, we suggest that spatial differences in exposure are most likely responsible for the segregation of the parasite species observed in the few most heavily infected hosts. Regardless of the underlying mechanism, the result suggests that between-species associations should be interpreted with caution along with detailed examination of the parasite distribution among host individuals. PMID:21599910

  16. Functional evolution of jumping in frogs: Interspecific differences in take-off and landing.

    Science.gov (United States)

    Reilly, Stephen M; Montuelle, Stephane J; Schmidt, André; Krause, Cornelia; Naylor, Emily; Essner, Richard L

    2016-03-01

    Ancestral frogs underwent anatomical shifts including elongation of the hindlimbs and pelvis and reduction of the tail and vertebral column that heralded the transition to jumping as a primary mode of locomotion. Jumping has been hypothesized to have evolved in a step-wise fashion with basal frogs taking-off with synchronous hindlimb extension and crash-landing on their bodies, and then their limbs move forward. Subsequently, frogs began to recycle the forelimbs forward earlier in the jump to control landing. Frogs with forelimb landing radiated into many forms, locomotor modes, habitats, and niches with controlled landing thought to improve escape behavior. While the biology of take-off behavior has seen considerable study, interspecific comparisons of take-off and landing behavior are limited. In order to understand the evolution of jumping and controlled landing in frogs, data are needed on the movements of the limbs and body across an array of taxa. Here, we present the first description and comparison of kinematics of the hindlimbs, forelimbs and body during take-off and landing in relation to ground reaction forces in four frog species spanning the frog phylogeny. The goal of this study is to understand what interspecific differences reveal about the evolution of take-off and controlled landing in frogs. We provide the first comparative description of the entire process of jumping in frogs. Statistical comparisons identify both homologous behaviors and significant differences among species that are used to map patterns of trait evolution and generate hypotheses regarding the functional evolution of take-off and landing in frogs. © 2015 Wiley Periodicals, Inc.

  17. 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

  18. 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.

  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 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