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Sample records for allozymes

  1. AFSC/ABL: Chum salmon allozyme baseline

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Allozymes from 46 loci were analyzed from chum salmon (Oncorhynchus keta) collected at 61 locations in southeast Alaska and northern British Columbia. Of the 42...

  2. AFSC/ABL: Chinook allozyme baseline

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Allozyme variation was used to examine population genetic structure of adult chinook salmon, Oncorhynchus tshawytscha, collected between 1988 and 1993 from 22...

  3. Genetic Diversity Based on Allozyme Alleles of Chinese Cultivated Rice

    Institute of Scientific and Technical Information of China (English)

    TANG Sheng-xiang; WEI Xing-hua; JIANG Yun-zhu; D S Brar; G S Khush

    2007-01-01

    Genetic diversity was analyzed with 6 632 core rice cultivars selected from 60 282 Chinese rice accessions on the basis of 12 allozyme loci, Pgil, Pgi2, Ampl, Amp2, Amp3, Amp4, Sdh1, Adh1, Est1, Est2, Est5 and Est9, by starch gel electrophoresis. Among the materials examined, 52 alleles at 12 polymorphic loci were identified, which occupied 96.3% of 54 alleles found in cultivated germplasm of O.sativa L. The number of alleles per locus ranged from 2 to 7 with an average of 4.33. The gene diversity (He) each locus varied considerably from 0.017 for Amp4 to 0.583 for Est2 with an average gene diversity (Ht) 0.271, and Shannon-Wiener index from 0.055 to 0.946 with an average of 0.468. The degree of polymorphism (DP) was in a range from 0.9 to 46.9% with an average of 21.4%. It was found that the genetic diversity in japonica (Keng) subspecies was lower in terms of allele's number, Ht and S-W index, being 91.8, 66.2 and 75.7% of indica (Hsien) one, respectively. Significant genetic differentiation between indica and japonica rice has been appeared in the loci Pgil, Amp2, Pgi2, and Est2, with higher average coefficient of genetic differentiation (Gst) 0.635, 0.626, 0.322 and 0.282, respectively. Except less allele number per locus (3.33) for modern cultivars, being 76.9% of landraces, the Ht and S-W index showed in similar between the modern cultivars and the landraces detected. In terms of allozyme, the rice cultivars in the Southwest Plateau and Central China have richer genetic diversity. The present study reveals again that Chinese cultivated rice germplasm has rich genetic diversity, showed by the allozyme allele variation.

  4. Diversifying selection underlies the origin of allozyme polymorphism at the phosphoglucose isomerase locus in Tigriopus californicus.

    Directory of Open Access Journals (Sweden)

    Sean D Schoville

    Full Text Available The marine copepod Tigriopus californicus lives in intertidal rock pools along the Pacific coast, where it exhibits strong, temporally stable population genetic structure. Previous allozyme surveys have found high frequency private alleles among neighboring subpopulations, indicating that there is limited genetic exchange between populations. Here we evaluate the factors responsible for the diversification and maintenance of alleles at the phosphoglucose isomerase (Pgi locus by evaluating patterns of nucleotide variation underlying previously identified allozyme polymorphism. Copepods were sampled from eleven sites throughout California and Baja California, revealing deep genetic structure among populations as well as genetic variability within populations. Evidence of recombination is limited to the sample from Pescadero and there is no support for linkage disequilibrium across the Pgi locus. Neutrality tests and codon-based models of substitution suggest the action of natural selection due to elevated non-synonymous substitutions at a small number of sites in Pgi. Two sites are identified as the charge-changing residues underlying allozyme polymorphisms in T. californicus. A reanalysis of allozyme variation at several focal populations, spanning a period of 26 years and over 200 generations, shows that Pgi alleles are maintained without notable frequency changes. Our data suggest that diversifying selection accounted for the origin of Pgi allozymes, while McDonald-Kreitman tests and the temporal stability of private allozyme alleles suggests that balancing selection may be involved in the maintenance of amino acid polymorphisms within populations.

  5. Diversifying selection underlies the origin of allozyme polymorphism at the phosphoglucose isomerase locus in Tigriopus californicus.

    Science.gov (United States)

    Schoville, Sean D; Flowers, Jonathan M; Burton, Ronald S

    2012-01-01

    The marine copepod Tigriopus californicus lives in intertidal rock pools along the Pacific coast, where it exhibits strong, temporally stable population genetic structure. Previous allozyme surveys have found high frequency private alleles among neighboring subpopulations, indicating that there is limited genetic exchange between populations. Here we evaluate the factors responsible for the diversification and maintenance of alleles at the phosphoglucose isomerase (Pgi) locus by evaluating patterns of nucleotide variation underlying previously identified allozyme polymorphism. Copepods were sampled from eleven sites throughout California and Baja California, revealing deep genetic structure among populations as well as genetic variability within populations. Evidence of recombination is limited to the sample from Pescadero and there is no support for linkage disequilibrium across the Pgi locus. Neutrality tests and codon-based models of substitution suggest the action of natural selection due to elevated non-synonymous substitutions at a small number of sites in Pgi. Two sites are identified as the charge-changing residues underlying allozyme polymorphisms in T. californicus. A reanalysis of allozyme variation at several focal populations, spanning a period of 26 years and over 200 generations, shows that Pgi alleles are maintained without notable frequency changes. Our data suggest that diversifying selection accounted for the origin of Pgi allozymes, while McDonald-Kreitman tests and the temporal stability of private allozyme alleles suggests that balancing selection may be involved in the maintenance of amino acid polymorphisms within populations.

  6. Allozyme gene diversities in some leaf beetles (Coleoptera: Chrysomelidae).

    Science.gov (United States)

    Krafsur, E S

    1999-08-01

    Gene diversity at allozyme loci was investigated in the bean leaf beetle, Ceratoma trifurcata Forster; the elm leaf beetle, Xanthogaleruca luteola (Muller); the cottonwood leaf beetle, Chrysomela scripta Fabricus; the western corn rootworm, Diabrotica virgifera virgifera LeConte; the southern corn rootworm, also called the spotted cucumber beetle, D. undecimpunctata howardi Baker; the northern corn rootworm, D. barberi Smith and Lawrence; and the Colorado potato beetle, Leptinotarsa decemlineata (Say). Six of these species are economically important pests of crops and display adaptive traits that may correlate with genetic diversity. Gene diversity H(E) in bean leaf beetles was 17.7 +/- 4.0% among 32 loci. In western corn rootworms, H(E) = 4.8 +/- 2.0% among 36 loci, and in spotted cucumber beetles, H(E) = 11.9 +/- 2.7% among 39 loci. Diversity among 27 loci was 10.5 +/- 4.3% in the Colorado potato beetle. The data were compared with gene diversity estimates from other leaf beetle species in which heterozygosities varied from 0.3 to 21% and no correlation was detected among heterozygosities, geographic ranges, or population densities. Distributions of single-locus heterozygosities were consistent with selective neutrality of alleles.

  7. Historical metal pollution in natural gudgeon populations: Inferences from allozyme, microsatellite and condition factor analysis

    Energy Technology Data Exchange (ETDEWEB)

    Knapen, Dries, E-mail: dries.knapen@ua.ac.be [University of Antwerp, Department of Biology, Ecophysiology, Biochemistry and Toxicology Research Group, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); De Wolf, Hans [University of Antwerp, Department of Biology, Ecophysiology, Biochemistry and Toxicology Research Group, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Knaepkens, Guy [University of Antwerp, Department of Biology, Ethology Research Group, Universiteitsplein 1, 2610 Wilrijk (Belgium); Bervoets, Lieven [University of Antwerp, Department of Biology, Ecophysiology, Biochemistry and Toxicology Research Group, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Eens, Marcel [University of Antwerp, Department of Biology, Ethology Research Group, Universiteitsplein 1, 2610 Wilrijk (Belgium); Blust, Ronny [University of Antwerp, Department of Biology, Ecophysiology, Biochemistry and Toxicology Research Group, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Verheyen, Erik [Royal Belgian Institute of Natural Sciences, Department of Vertebrates, Molecular Laboratory, Vautierstraat 29, 1000 Brussel (Belgium)

    2009-10-19

    This study presents the results of a microsatellite and allozyme analysis on natural populations of the gudgeon (Gobio gobio) located in a pollution gradient of cadmium and zinc. Differences among contaminated and reference populations were observed at 2 allozyme loci, as well as a relationship between the fish condition factor and glucose-6-phosphate dehydrogenase genotypes, the locus that showed the largest difference in allele frequencies. The microsatellite data partly confirmed the differentiation pattern that was revealed by the allozyme survey. Our data further suggest that at least 2 microsatellite loci may be affected by natural selection. We thus illustrate that both microsatellite and allozyme loci do not necessarily behave as selectively neutral markers in polluted populations. Estimates of population differentiation can therefore be significantly different depending on which loci are being studied. Finally, these results are discussed in the light of the conservation unit concept, because microsatellites are often used to assess genetic variation in endangered natural populations and to propose measures for conservation or management.

  8. Diversifying Selection Underlies the Origin of Allozyme Polymorphism at the Phosphoglucose Isomerase Locus in Tigriopus californicus

    OpenAIRE

    Schoville, Sean D.; Flowers, Jonathan M.; Ronald S Burton

    2012-01-01

    The marine copepod Tigriopus californicus lives in intertidal rock pools along the Pacific coast, where it exhibits strong, temporally stable population genetic structure. Previous allozyme surveys have found high frequency private alleles among neighboring subpopulations, indicating that there is limited genetic exchange between populations. Here we evaluate the factors responsible for the diversification and maintenance of alleles at the phosphoglucose isomerase (Pgi) locus by evaluating pa...

  9. Effects of metal contamination from mine tailings on allozyme distributions of populations of Great Plains fishes

    Energy Technology Data Exchange (ETDEWEB)

    Brown, K.; Roark, S. [Wichita State Univ., KS (United States). Dept. of Biological Sciences

    1995-12-31

    This study was conducted to assess the effects of zinc and lead on genetic variability of minnow populations (Gambusia affinis, Pimephales notatus, and Fundulus notatus) sampled from two creeks, one receiving mine drainage (Willow Creek) and one reference (Brush Creek), in the Tri-State Mining district in Kansas. Zinc and lead concentrations were greater in water samples taken from sites in Willow Creek compared to sites sampled in Brush Creek. While total numbers of fish captured from Willow Creek were smaller than numbers taken from Brush Creek, there were no differences in these fish communities for estimates of species diversity, richness and evenness. Genetic differentiation within creeks was rare. However, there was significant differentiation between creeks for allozymes of the enzymes glucose phosphate isomerase (GPI) in F. notatus and P. notatus, malate dehydrogenase (MDH) in G. affinis, and phosphogluconate dehydrogenase (PGDH) in F. notatus. Proportions of heterozygous genotypes of P. notatus and G. affinis were higher in Willow Creek compared to Brush Creek. In vitro experiments were conducted to assess the effects of zinc and lead on sensitivity of enzyme staining during electrophoresis. Results indicated allozyme sensitivity to zinc for GPI and PGDH loci. Other studies suggest that zinc competitively competes with magnesium as a cofactor for these enzymes. Allozymes did not exhibit differential sensitivity to lead. The significant differentiation between creek populations and the results of the in vitro tests indicate a selective effect of zinc on allozymic distributions of these fishes. These results demonstrate the potential use of genetic variability as a bioindicator of heavy metal contamination.

  10. Effects of metal contamination from mine tailings on allozyme distributions of populations of Great Plains fishes

    Energy Technology Data Exchange (ETDEWEB)

    Roark, S.; Brown, K. [Wichita State Univ., KS (United States). Dept. of Biological Sciences

    1996-06-01

    This study was conducted to assess the effects of zinc and lead on genetic variability of minnow populations (Gambusia affinis, Pimephales notatus, and Fundulus notatus) sampled from two creeks, one receiving mine drainage (Willow Creek) and one reference (Brush Creek), in the Tri-State Mining District in Kansas. Zinc and lead concentrations were greater in water samples taken from sites in Willow Creek compared to sites sampled in Brush Creek. Although total numbers of fish captured from Willow Creek were smaller than numbers taken from Brush Creek, there were no differences in these fish communities for estimates of species diversity, richness, and evenness. Genetic differentiation within creeks was rare. However, there was significant differentiation between creeks for allozymes of the enzymes glucose phosphate isomerase (Gpi) in F. notatus and P. notatus, malate dehydrogenase (Mdh) in G. affinis, and phosphogluconate dehydrogenase (Pgdh) in F. notatus. Proportions of heterozygous genotypes of P. notatus and G. affinis were higher in Willow Creek compared to Brush Creek. In vitro experiments were conducted to assess the effects of zinc and lead on sensitivity of enzyme staining during electrophoresis. Results indicated allozyme sensitivity to zinc for Gpi and Pgdh loci, but not for products of the Mdh locus. No sensitivity to lead was noted for allozymes. The significant differentiation between creek populations and the results of the in vitro tests indicate a selective effect of zinc on allozymic distributions of these fishes. These results provide additional support for the use of genetic structure and variability as a bioindicator of heavy metal contamination.

  11. Congruence between starch gel and polyacrylamide gel electrophoresis in detecting allozyme variation in pulmonate land slugs.

    Science.gov (United States)

    Geenen, Sofie; Jordaens, Kurt; Castilho, Rita; Backeljau, Thierry

    2003-02-01

    The predominantly selfing slug species Arion (Carinarion) fasciatus, A. (C.) silvaticus and A. (C.) circumscriptus are native in Europe and have been introduced into North America, where each species consists of a single, homozygous multilocus genotype (strain), as defined by starch gel electrophoresis (SGE) of allozymes. In Europe, the "one strain per species" hypothesis does not hold since polyacrylamide gel electrophoresis (PAGE) of allozymes uncovered 46 strains divided over the three species. However, electrophoretic techniques may differ in their ability to detect allozyme variation. Therefore, several Carinarion populations from both continents were screened by applying the two techniques simultaneously on the same individual slugs and enzyme loci. SGE and PAGE yielded exactly the same results, so that the different degree of variation in North American and European populations cannot be attributed to differences in resolving power between SGE and PAGE. We found four A. (C.) silvaticus strains in North America indicating that in this region the "one strain per species" hypothesis also cannot be maintained. Hence, the discrepancies between previous electrophoretic studies on Carinarion are most likely due to sampling artefacts and possible founder effects.

  12. Hybrids between olive flounder Paralichthys olivaceus and stone flounder Kareius bicoloratus: karyotype, allozyme and RAPD analyses

    Science.gov (United States)

    You, Feng; Wang, Wei; Xu, Dongdong; Zhu, Xiangping; Ni, Jing; Wu, Zhihao; Xu, Yongli; Wang, Xincheng; Zhang, Peijun

    2009-05-01

    The hybrid between olive flounder Paralichthys olivaceus and stone flounder Kareius bicoloratus was produced by artificial insemination of olive flounder eggs with stone flounder sperm. Sinistral and dextral are two types of hybrid progeny after metamorphosis. Karyotypes of both hybrid flounders are the same as those of the two parental species. Of the 22 loci examined from 12 allozymes, 12 confirmed hybridization of the paternal and maternal loci in hybrids and no difference was found in allozyme patterns of sinistral and dextral hybrid fishes. RAPD patterns of these specimens were also studied with 38 primers selected from 104 tested. Among them, the PCR products of 30 primers showed hybridization of the paternal and maternal bands. Genetic variation between hybrids and their parental stocks was analyzed by RAPD using 10 of the above 38 primers. The average heterozygosity and genetic distance were calculated. The results suggested that the filial generation could inherit a little more genetic materials from paternal fish than that from maternal fish.

  13. Genetic Variation among 11 Abies concolor Populations Based on Allozyme Analysis

    Institute of Scientific and Technical Information of China (English)

    Zhang Jin-feng; Li Hui; Dong Jian-sheng; Wang Jun-hui

    2005-01-01

    In order to obtain information on the genetic structure of Abies concolor and the genetic variation among 11 populations introduced from America to China, allozyme analysis based on starch gel electrophoresis technology was used. 24 loci of 10allozyme systems were mensurated, and the genetic structure and genetic diversity of the 11 populations of A. concolor evaluated.The results show that the genetic variation among is significant, and the genetic variation within A. concolor populations is more important. In contrast with other conifers, the variation of A. concolor is above the average level of conifers, and higher than the same level ofAbies. The percentage of polymorphic loci (P) was 62.5%, the number of alleles per locus (A) 2.08, the number of effective alleles per locus (Ae) was 1.37, the expected heterozygosity (H) 0.204, and the Shannon information index (I) 0.351 7. There is a short genetic distance (D=0.061) and a low gene flow (Nm=0.839 4) among the 11 introduced populations of A. concolor with high genetic variation. The genetic differentiation coefficient (Gst) was 0.229 5, which is higher than that of the mean in Abies or Pinus.

  14. Genetic variation of natural and cultured stocks of Paralichthys olivaceus by allozyme and RAPD

    Institute of Scientific and Technical Information of China (English)

    YOU Feng; ZHANG Peijun; WANG Keling; XIANG Jianhai

    2007-01-01

    Population genetics of the left-eyed flounder, Paralichthys olivaceus, including natural and cultured stocks distributed in the coastal waters near Qingdao of eastern maritime China, was analyzed in allozyme and RAPD. The results showed that among total 29 gene loci of 15 isozymes, 9 and 7 were polymorphic in natural and cultured stocks, respectively. The status of genetic diversity in P olivaceus is low in terms of polymorphic loci in chi-square test and genetic departure index of Hardy-Weinberg equilibrium. More alleles in IDHP, CAT, GDH and Ldh-C allozymes were found in the fish, which could be used as markers in assortive breeding and distinguishing stock, population or species evolution. Total 88 and 86 RAPD bands ranging from 200 to 2 500 bp were recognized individually in average of 7.8-8.0 bands per primer. The genetic diversity in cultured stock is lower than that in natural ones showing an obviously decreasing genetic divergence. Therefore, effective countermeasures must be taken to protect genetic resources of marine cultured fishes. The 2 markers have their own pros and cons. Combining the 2 markers to investigate the genetic variation of populations is suggested. The results provide basic data of this flounder and they are useful for studying genetic improvement and genetic resources of the fish.

  15. Hybrids between olive flounder Paralichthys olivaceus and stone flounder Kareius bicoloratus: karyotype, allozyme and RAPD analyses

    Institute of Scientific and Technical Information of China (English)

    YOU Feng; WANG Wei; XU Dongdong; ZHU Xiangping; NI Jing; WU Zhihao; XU Yongli; WANG Xincheng; ZHANG Peijun

    2009-01-01

    The hybrid between olive flounder Paralichthys olivaceus and stone flounder Kareius bicoloratus was produced by artificial insemination of olive flounder eggs with stone flounder Sperm. Sinistral and dextral are two types of hybrid progeny after metamorphosis. Karyotypes of both hybrid flounders are the same as those of the two parental species. Of the 22 loci examined from 12 allozymes,12 confirmed hybridization of the paternal and matemal loci in hybrids and no difference was found in allozyme patterns of sinistral and dextral hybrid fishes. RAPD patterns of these specimens were also studied with 38 primers selected from 104 tested. Among them, the PCR products of 30 primers showed hybridization of the paternal and maternal bands. Genetic variation between hybrids and their parental stocks was analyzed by RAPD using 10 of the above 38 primers. The average heterozygosity and genetic distance were calculated. The results suggested that the filial generation could inherit a little more genetic materials from paternal fish than that from maternal fish.

  16. Allozyme variation in Czech populations of the invasive spiny-cheek crayfish Orconectes limosus (Cambaridae

    Directory of Open Access Journals (Sweden)

    L. Filipová

    2009-01-01

    Full Text Available The North American spiny-cheek crayfish, Orconectes limosus, was most probably introduced into Europe only once, in 1890. The size of the founding population was just 90 individuals. Low genetic variability resulting from a bottleneck effect during introduction might therefore be supposed in European spiny-cheek crayfish populations. On the other hand, the fast spread of O. limosus in Europe and colonisation of various habitats suggest that this species does not suffer from inbreeding depression due to an introduction bottleneck. We analysed 14 O. limosus populations from the Czech Republic using allozyme electrophoresis to evaluate the level of intra- and among-population genetic variation. Out of eight well-scoring allozyme loci chosen for detailed analysis, six were variable in studied populations, suggesting that sufficient variability was maintained during the introduction. Genetic differentiation of Czech populations of the spiny-cheek crayfish was relatively low and did not show any clear geographic pattern, probably due to long-range translocations by humans.

  17. Evaluation of genetic variation in the clown Knifefish, Chitala chitala, using allozymes, RAPD, and microsatellites.

    Science.gov (United States)

    Mandal, Anup; Lal, Kuldeep Kumar; Mohindra, Vindhya; Singh, Rajeev Kumar; Punia, Peyush; Chauhan, U K; Lakra, Wazir Singh

    2009-04-01

    Twenty-seven enzyme systems, six random amplified polymorphic DNA (RAPD) primers, and two microsatellite loci were tested to determine intraspecific divergence in the natural population of the endangered Indian featherback fish, Chitala chitala, for the first time. The 262 samples of C. chitala were collected from six riverine locations in India: the Satluj, Ganga (Ghagra, Bhagirathi, and Brahmaputra), Mahanadi, and Narmada river systems. The analysis revealed population subdivisions, with an F(ST) value from 0.1235 (95% confidence 0.0868-0.1621) for RAPD and a combined F(ST) of 0.0344 (95% confidence 0.0340-0.0350) for microsatellite loci. An analysis of 38 allozyme loci did not reveal any polymorphism in the samples from any of the riverine localities; a possible explanation for this could be that the ancestors of Chitala could have faced a population reduction in prehistoric periods, as low allozyme variation is also reported for other species of Chitala from south Asia.

  18. VARIASI GENETIK IKAN TUNA SIRIP KUNING, Thunnus albacares DENGAN ANALISIS ELEKTROFORESIS ALLOZYME DAN Mt-DNA

    Directory of Open Access Journals (Sweden)

    Gusti Ngurah Permana

    2007-04-01

    Full Text Available Sampel ikan tuna sirip kuning, T. albacares diambil dari tiga lokasi (perairan Bali, Sulawesi Utara, dan Maluku Utara dan dilakukan analisis variasi genetik dengan metode elektroforesis allozyme menggunakan 15 enzim dan mt-DNA dengan 4 enzim restriksi. Hasil penelitian ini diperoleh 4 lokus enzim polimorfik yaitu: Idh-*2 (isocitrate dehydrogenase, Gpi-2* (glucose phoshate dehydrogenase , Mdh-1* (malat e dehydrogenase, dan Est-1* (esterase. Frekuensi alel allozyme terlihat adanya perbedaan yang nyata (Fst = 0,12; P<0,05 antar lokasi yaitu Bali (A, B, C, D, Sulawesi Utara dan Maluku Utara (A, B, C. 15 komposit haplotipe ditemukan pada populasi Bali, Sulawesi Utara, dan Maluku Utara. Haplotype diversity pada populasi Bali 0,886; Sulawesi Utara 0,790; dan Maluku Utara 0,785; dengan rata-rata dari haplotype diversity adalah 0,857. Jarak genetik dari ketiga populasi berkisar antara 0,003--0,023 (rata-rata 0,016. Populasi Maluku Utara dan Sulawesi Utara mempunyai jarak genetik terdekat yaitu 0,003. Hal ini merupakan indikator bahwa Sulawesi Utara dan Maluku Utara sering digunakan sebagai jalur migrasi dengan adanya kesamaan alel yang ditemukan pada kedua populasi tesebut, jika dibandingkan dengan populasi Bali (0,023.

  19. Nuclear and mitochondrial gene genealogies and allozyme polymorphism across a major phylogeographic break in the copepod Tigriopus californicus.

    Science.gov (United States)

    Burton, R S; Lee, B N

    1994-05-24

    The genetic structure of natural populations is frequently inferred from geographic distributions of alleles at multiple gene loci. Surveys of allozyme polymorphisms in the tidepool copepod Tigriopus californicus have revealed sharp genetic differentiation of populations, indicating that gene flow among populations is highly restricted. Analysis of population structure in this species has now been extended to include nuclear and mitochondrial gene genealogies. DNA sequences of the mtDNA-encoded cytochrome-c oxidase subunit I gene from 21 isofemale lines derived from seven populations reveal a phylogeographic break between populations north and south of Point Conception, California, with sequence divergence across the break exceeding 18%, the highest level of mtDNA divergence yet reported among conspecific populations. Divergence between populations based on 22 sequences of the nuclear histone H1 gene is geographically concordant with the mitochondrial sequences. In contrast with previously studied nuclear genes in other sexually reproducing metazoans, the H1 gene genealogy from T. californicus shows no evidence of recombination. The apparent absence of intragenic recombinants probably results from the persistent lack of gene flow among geographically separated populations, a conclusion strongly supported by allozyme data and the mitochondrial gene genealogy. Despite strong population differentiation at allozyme loci, the phylogeographic break identified by the DNA sequences was not evident in the allozyme data.

  20. Morphological and allozyme studies of midwife toads (genus Alytes), including the description of two new taxa from Spain

    NARCIS (Netherlands)

    Arntzen, J.W.; García-París, M.

    1995-01-01

    Allozyme variation in 31 to 50 presumptive loci of 12 populations of European midwife toads of the genus Alytes show appreciable genetic divergences (DiNe from 0.29 to 0.72) among four groups. These groups correspond to A. cisternasii Boscá, 1879, A. obstetricans (Laurenti, 1768), A. muletensis (San

  1. Starch gel and cellulose acetate electrophoretic analysis of allozyme frequencies in barn swallow (Hirundo rustica) populations at a dioxin contaminated site in northern Louisiana

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This study compared the genetic variability of Louisiana barn swallows at a dioxin-contaminated wetland to two reference populations. Allozyme frequencies,...

  2. Starch gel analysis of allozyme frequencies in mosquitofish (Gambusia affinis) populations on a dioxin contaminated site/drainage in north Louisiana

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This study compared the genetic variability of Louisiana mosquitofish at 15 sites in a dioxincontaminated watershed and one site outside the watershed. Allozyme...

  3. Nuclear and mitochondrial gene genealogies and allozyme polymorphism across a major phylogeographic break in the copepod Tigriopus californicus.

    OpenAIRE

    Burton, R S; Lee, B. N.

    1994-01-01

    The genetic structure of natural populations is frequently inferred from geographic distributions of alleles at multiple gene loci. Surveys of allozyme polymorphisms in the tidepool copepod Tigriopus californicus have revealed sharp genetic differentiation of populations, indicating that gene flow among populations is highly restricted. Analysis of population structure in this species has now been extended to include nuclear and mitochondrial gene genealogies. DNA sequences of the mtDNA-encod...

  4. The evolutionary history of Drosophila buzzatii. XXXII. Linkage disequilibrium between allozymes and chromosome inversions in two colonizing populations.

    Science.gov (United States)

    Betrán, E; Quezada-Díaz, J E; Ruiz, A; Santos, M; Fontdevila, A

    1995-02-01

    Chromosome polymorphism in Drosophila buzzatii is under selection but the genes responsible for the effect of the inversions of fitness are unknown. On the other hand, there is evidence for selection on several allozyme loci but the presence of paracentric inversions on the second chromosome, where most of the polymorphic loci are located, complicates the interpretation. Studies of the associations between allozymes and inversions are thus necessary to help understand the effect of selection at both the chromosomal and allozymic level. Until now this kind of information has only been available in D. buzzatii for two loci, Est-1 and Est-2, in Australian populations. Here we describe the genetic constitution of two Old World populations, Carboneras and Colera. Emphasis has been placed on the analysis of the linkage disequilibria between the second chromosome arrangements and three allozyme loci, Est-2, Pept-2 and Aldox, located on this chromosome. In addition, the recombination frequencies between the loci, and between the loci and the inversion breakpoints, have been estimated and a genetic map of the three loci has been produced. The two populations differ in allele and arrangement frequencies, as well as in the pattern of one-locus disequilibria. Est-2 and Aldox are associated with the second chromosome arrangements in both populations. On the other hand, Pept-2 is associated with the inversions in Colera but not in Carboneras. The gametic associations among the three loci are discussed taking into account the position of these loci on the chromosome map and the lack of recombination in the heterokaryotypes.

  5. Physiological effects of an allozyme polymorphism: glutamate-pyruvate transaminase and response to hyperosmotic stress in the copepod Tigriopus californicus.

    Science.gov (United States)

    Burton, R S; Feldman, M W

    1983-04-01

    In order to regulate cell volume during hyperosmotic stress, the intertidal copepod Tigriopus californicus, like other aquatic crustaceans, rapidly accumulates high levels of intracellular alanine, proline, and glycine. Glutamate-pyruvate transaminase (GPT; EC 2.6.1.2), which catalyzes the final step of alanine synthesis, is genetically polymorphic in T. californicus populations at Santa Cruz, California. Spectrophotometric studies of homogenates derived from a homozygous isofemale line of each of the two common GPT alleles indicated that the GPTF allozyme has a significantly higher specific activity than the GPTS allozyme. Under conditions of hyperosmotic stress, individual adult copepods of GPTF and GPTF/S genotypes accumulated alanine, but not glycine or proline, more rapidly than GPTS homozygotes. When young larvae were subjected to the same hyperosmotic conditions, GPTS larvae suffered a significantly higher mortality than GPTF or GPTF/S larvae. These results suggest that the biochemical differences among GPT allozymes result in specific physiological variation among GPT genotypes and that this physiological variation is manifested in differential genotypic survivorships under some naturally occurring environmental conditions.

  6. Inhibition of glucosephosphate isomerase allozymes of the mosquitofish, Gambusia holbrooki, by mercury

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, V.J.; Newman, M.C. (Univ. of Georgia, Aiken, SC (United States). Savannah River Ecology Lab.)

    1994-01-01

    Frequencies of allozyme genotypes are being used as population-level indicators of environmental heavy-metal contamination. A genotype of glucose phosphate isomerase, Gpi-2[sup 38/38], of mosquitofish (Gambusia holbrooki) has been identified as mercury-sensitive in an acute toxicity assay. Partially purified preparations of GPI-2 38/38 and GPI-2 100/100 were assayed to determine differences in maximum gluconeogenic reaction velocity at seven mercury (added as HgCl[sub 2]) concentrations, 15 to 960 nM Hg. Log-Probit analysis of the inhibition curves indicated that the log (IC50) (log[sub 10] of the Hg concentration causing a 50% reduction in reaction velocity) for GPI-2 100/100 initial uninhibited reaction velocity was greater than that of GPI-2 38/38. Although the mechanism of inhibition was not experimentally determined, under the assumption of noncompetitive interaction between Hg and GPI-2, the inhibitor dissociation constants (95% asymptotic C.I.) for GPI-2 100/100 and GPI-2 38/38 were estimated from the log (IC50) as 204 nM Hg (155---269 nM Hg) and 479 nM Hg (363-617 nM Hg), respectively. These results suggested that Hg susceptibility related to the Gpi-2[sup 38/38] genotype in acute toxicity assays was likely not due to enhanced Hg inhibition of GPI-2 38/38.

  7. Allozyme variation of oleaster populations (wild olive tree) (Olea europaea L.) in the Mediterranean Basin.

    Science.gov (United States)

    Lumaret, R; Ouazzani, N; Michaud, H; Vivier, G; Deguilloux, M-F; Di Giusto, F

    2004-04-01

    As a result of the early domestication and extensive cultivation of the olive tree throughout the Mediterranean Basin, the wild-looking forms of olive (oleasters) presently observed constitute a complex, potentially ranging from wild to feral forms. Allozyme variation was analysed at 10 loci in 31 large and 44 small oleaster populations distributed in various habitats of the Mediterranean Basin and in two populations of the wild subspecies Olea europaea subsp (ssp) guanchica, endemic to the Canary islands and closely related to oleasters. At eight polymorphic loci, 25 alleles were identified. Genetic evidence that nondomesticated oleasters still survive locally was provided by the occurrence of four and one alleles shared exclusively by the eight western and two eastern oleaster populations, respectively, which were collected in forests potentially containing genuinely wild forms according to environmental, historical and demographic criteria. As reported previously from cytoplasmic and RAPDs analysis, substantial genetic differentiation was observed between the eastern oleaster populations genetically close to most olive clones cultivated in the Mediterranean Basin, and the western populations that are related to the wild Canarian populations. In addition, the occurrence of significantly lower heterozygosity in cultivated olive than in oleasters, whatever their origin, suggests that intensive selection involving inbreeding has taken place under cultivation to obtain particular characteristics in the olive cultivars.

  8. Allozyme variation and structure of the Canarian endemic palm tree Phoenix canariensis (Arecaceae): implications for conservation.

    Science.gov (United States)

    González-Pérez, M A; Caujapé-Castells, J; Sosa, P A

    2004-09-01

    Electrophoretic analysis of 18 allozyme loci was used to estimate the levels and structuring of genetic variation within and among natural populations of the protected endemic palm species from the Canary Islands (Phoenix canariensis) to evaluate its genetic relationship with the widespread congener P. dactylifera, and to assess comparatively the genetic variation in the populations where the two species coexist with morphologically intermediate plants (mixed populations). Our survey revealed that the within-population component explains roughly 75% of the genetic variation levels detected in P. canariensis (A=1.59; P=41.8; He=0.158), which rank higher than those reported for other species of the Arecaceae. A Principal Component analysis (PCA) based on allele frequencies consistently separates populations of P. canariensis and P. dactylifera, and reveals a close genetic relationship between P. canariensis and the mixed populations. Reduced levels of genetic variation in P. canariensis with respect to P. dactylifera, the fact that the genetic makeup of the Canarian endemic (with no unique alleles) is a subset of that found in P. dactylifera, and the high genetic identity between both species strongly suggest that P. canariensis is recently derived from a common ancestor closely related to P. dactylifera.

  9. Isozyme and allozyme markers distinguishing two morphologically similar, medically important Mastomys species (Rodentia: Muridae

    Directory of Open Access Journals (Sweden)

    Van der Bank Herman FH

    2001-09-01

    Full Text Available Abstract Background Two common southern African mice species, Mastomys coucha and M. natalensis, are widely distributed throughout the subregion and overlap in many areas. They also share a high degree of morphological similarity, making them impossible to distinguish in the field at present. These multimammate mice are documented carriers of serious disease vectors causing Lassa fever, plague and encephalomyocarditis, which coupled to their cohabitation with humans in many areas, could pose a significant health risk. A preliminary study reported the presence of isozyme markers at three loci (GPI-2, PT-2, -3 in one population each of M. coucha and M. natalensis. Two additional populations (from the Vaal Dam and Richards Bay were sampled to determine the reliability of these markers, and to seek additional genetic markers. Results Fifteen proteins or enzymes provided interpretable results at a total of 39 loci. Additional fixed allele differences between the species were detected at AAT-1, ADH, EST-1, PGD-1, Hb-1 and -2. Average heterozygosities for M. coucha and M. natalensis were calculated as 0.018 and 0.032 respectively, with a mean genetic distance between the species of 0.26. Conclusions The confirmation of the isozyme and the detection of the additional allozyme markers are important contributions to the identification of these two medical and agricultural pest species.

  10. Allozyme relationships in hypostomines (Teleostei: Loricariidae) from the Itaipu Reservoir, Upper Rio Paraná basin, Brazil.

    Science.gov (United States)

    Zawadzki, Cláudio Henrique; Renesto, Erasmo; dos Reis, Roberto Esser; Moura, Maurício Osvaldo; Mateus, Rogério Pincela

    2005-03-01

    In an allozyme electrophoresis survey of 15 hypostomine species from the Itaipu Hydroelectric Reservoir, 25 loci from 14 enzyme systems were scored. Allozyme data allowed recording diagnostic genetic markers for all species analyzed and for some species groups within Hypostomus, a taxon which is taxonomically still unresolved in the Upper Rio Paraná basin. The mean expected heterozygosity of the species was considerably variable and hypotheses to tentatively explain this variation are discussed. A cladogram based upon the allelic frequencies of the species analyzed was produced by the continuous maximum likelihood method: Rhinelepis aspera and M. parananus were separated from the species of Hypostominae by a long branch length. Pterygoplichthys anisitsi was the sister of all the representatives of the genus Hypostomus. Within Hypostomus, two main clades were produced: in the first, H. cochliodon was the sister of the species comprising the H. plecostomus group, and in the second, the tree showed the following relationships: (H. albopunctatus (H. regani + Hypostomus sp. 3) + (H. margaritifer (H. microstomus (Hypostomus sp. 1 (H. ternetzi + Hypostomus sp. 2)). Hypostomus ternetzi and Hypostomus sp. 2 are referred to here as representatives of the H. ternetzi group.

  11. Start of reproduction and allozyme heterozygosity in Pinus sibirica under different techniques of artificial forest stand establishment

    Directory of Open Access Journals (Sweden)

    S.N. Velisevich

    2013-12-01

    Full Text Available Siberian stone pine (Pinus sibirica Du Tour is one of the main forest-forming tree species in boreal forests of Eurasia. Large edibleseeds of this species have an important resource value because of their high nutritious properties. Development of approaches toestablishment of early cone producing Siberian stone pine stands including utilization of corresponding genetic background is one of the priorities of forest resource management. The goal of our study was to evaluate the effect of stand density on the differentiation of trees bythe age of first reproduction and the relationship of allozyme heterozygosity and morphological traits variability in Siberian stone pine.Morphological and allozyme variability in artificial Pinus sibirica stands with high and low density was investigated. In the high-densitystand the distance between trees was 0.7 and 3 meters (4080 trees per ha while in the lowdensity stand it was 8 and 8 meters (144 treesper ha. Age of formation of first male and female cones was evaluated by retrospective method based on analysis of tracks of cones ona shoot bark. Tree height, diameter and number of male, female and vegetative shoots in a crown of model trees were measured.Genotypes of the trees were determined by 29 isozyme loci coding for 16 enzymes (ADH, FDH, FEST, GDH, GOT, IDH, LAP, MDH, MNR, PEPCA, 6-PGD, PGI, PGM, SDH, SKDH, SOD. In the low-density stand, the portion of generative trees was higher and differentiation of trees by age of reproduction starting was lower in spite of the smaller age of trees as compared to the high-density stand. Inboth samples, the age of formation of first generative organs was related negatively with stem height, stem diameter and number offemale shoots. In the high-density stand, positive relation of age of first reproduction with total number of shoots and number ofmale shoots was found. In both samples nonreproductive trees were less heterozygous at

  12. Genome-wide SNPs resolve a key conflict between sequence and allozyme data to confirm another threatened candidate species of river blackfishes (Teleostei: Percichthyidae: Gadopsis).

    Science.gov (United States)

    Unmack, Peter J; Sandoval-Castillo, Jonathan; Hammer, Michael P; Adams, Mark; Raadik, Tarmo A; Beheregaray, Luciano B

    2017-02-22

    Conflicting results from different molecular datasets have long confounded our ability to characterise species boundaries. Here we use genome-wide SNP data and an expanded allozyme dataset to resolve conflicting systematic hypotheses on an enigmatic group of fishes (Gadopsis, river blackfishes, Percichthyidae) restricted to southeastern Australia. Previous work based on three sets of molecular markers: mtDNA, nuclear intron DNA and 51 allozyme loci was unable to clearly resolve the status of a putative fifth candidate species (SWV) within Gadopsis marmoratus. Resolving the taxonomic status of candidate species SWV is particularly critical as based on IUCN criteria this taxon would be considered Critically Endangered. After all filtering steps we retained a subset of 10,862 putatively unlinked SNP loci for population genetic and phylogenomic analyses. Analyses of SNP loci based on maximum likelihood, fastSTRUCTURE and DAPC were all consistent with the previous and updated allozyme results supporting the validity of the candidate Gadopsis species SWV. Immediate conservation actions should focus on preventing take by anglers, protection of water resources to sustain perennial reaches and drought refuge pools, and aquatic and riparian habitat protection and improvement. In addition, a formal morphological taxonomic review of the genus Gadopsis is urgently required.

  13. Morphological and allozyme variation in a collection of Lagenaria siceraria (Molina Standl. from Côte d'Ivoire

    Directory of Open Access Journals (Sweden)

    Koffi KK.

    2009-01-01

    Full Text Available This study describes the intraspecific variation of 30 edible-seed Lagenaria siceraria germplasm accessions from the University of Abobo-Adjamé. These accessions were collected from three (Centre, East and South geographical zones of Côte d’Ivoire. Selection based on seed size by the farmers has resulted in subdividing the species into two cultivars: large-seeded and smallseeded. The morphological diversity study of the collection included 18 accessions and 24 traits. The multivariate analysis of variance (MANOVA showed a significant difference between the two groups of cultivars. Principal component analysis on 13 traits pointed out variations among individuals, mainly on the basis of flower, fruit, and seed size. Dendrogram with UPGMA method allowed clustering of the cultivars. The genetic structure analysis among accessions using allozyme markers showed the following values: 18.95% for the proportion of polymorphic loci (P, 1.21 for the number of alleles (A and 0.053 for observed heterozygosity (Ho. The level of the within accessions genetic diversity (HS = 0.188 was higher than the genetic variation among accessions (DST = 0.082. The estimates of F-statistics indicated a low level of genetic differentiation between accessions (FST = 0.298. Such a value suggested that L. siceraria maintains about 30% of its genetic variation among accessions. Nei genetic distances between the two cultivars were also low (0.002, indicating that cultivars were genetically similar enough to belong to the same genetic group.

  14. Microgeographic allozyme differentiation in the hybrid zone of Mytilus galloprovincialis Lmk. and M. edulis L. on the continental European coast

    Science.gov (United States)

    Comesaña, A. S.; Sanjuan, A.

    1997-03-01

    The European Mytilus galloprovincialis Lmk. and M. edulis L. coexist and hybridize in different proportions in extended areas of the British and Atlantic French coasts. M. galloprovincialis typical allozymes seem to predominate in wave exposed areas, at high levels of attachment and in larger mussels in the British hybrid zone. Mussel samples from exposed and sheltered areas, 200 m apart, and from high and low levels of attachment were collected from a location of the French hybrid zone in 1988 92. Pure M. galloprovincialis and M. edulis populations were also taken as controls. Diagnostic enzyme loci for both Mytilus (EST-D *, LAP-1*, MPI*, ODH*) and AP-1 *, LAP-2* and PGM * loci were studied. The frequencies of the M. galloprovincialis typical alleles were significantly greater in exposed populations than in sheltered samples (e.g. 0.729 to 0.803 vs 0.192 to 0.581 for EST-D *90), and at high level of attachment than at low level for the sheltered area (e.g. 0.581 vs 0.192 for EST-D *90). Putative M. galloprovincialis was more abundant on the exposed coast (0.591 and 0.702) than on the sheltered shore, where it predominated at the high shore but not at the low shore location (0.371 vs 0.045). Significantly positive correlations between shell length and typical M. galloprovincialis compound allele frequencies were found only for populations from exposed areas. Relationships between the Mytilus genetic differentiation and ecological factors are discussed.

  15. Latitudinal clines in Drosophila melanogaster: body size, allozyme frequencies, inversion frequencies, and the insulin-signalling pathway

    Indian Academy of Sciences (India)

    Gerdien De Jong; Zoltán Bochdanovits

    2003-12-01

    Many latitudinal clines exist in Drosophila melanogaster: in adult body size, in allele frequency at allozyme loci, and in frequencies of common cosmopolitan inversions. The question is raised whether these latitudinal clines are causally related. This review aims to connect data from two very different fields of study, evolutionary biology and cell biology, in explaining such natural genetic variation in D. melanogaster body size and development time. It is argued that adult body size clines, inversion frequency clines, and clines in allele frequency at loci involved in glycolysis and glycogen storage are part of the same adaptive strategy. Selection pressure is expected to differ at opposite ends of the clines. At high latitudes, selection on D. melanogaster would favour high larval growth rate at low temperatures, and resource storage in adults to survive winter. At low latitudes selection would favour lower larval critical size to survive crowding, and increased male activity leading to high male reproductive success. Studies of the insulin-signalling pathway in D. melanogaster point to the involvement of this pathway in metabolism and adult body size. The genes involved in the insulin-signalling pathway are associated with common cosmopolitan inversions that show latitudinal clines. Each chromosome region connected with a large common cosmopolitan inversion possesses a gene of the insulin transmembrane complex, a gene of the intermediate pathway and a gene of the TOR branch. The hypothesis is presented that temperate D. melanogaster populations have a higher frequency of a ‘thrifty’ genotype corresponding to high insulin level or high signal level, while tropical populations possess a more ‘spendthrift’ genotype corresponding to low insulin or low signal level.

  16. [Genetic diversity and subdivision parameters of Colias crocea Fourc. and C. erate Esp. (Lepidoptera, Pieridae) in Crimea according to allozyme and RAPD-PCR analyses].

    Science.gov (United States)

    Milovanov, A E; Simchuk, A P

    2008-01-01

    Some parameters of genetic diversity and subdivision were tested in syntopic Crimean populations of two species of the sulfur butterllies, Colias crocea Fourc. and C. erate Esp. by allozyme and RAPD-PCR analyses. Genetic diversity in each of the species compared appeared to be approximately equal: the portion of polimorphic loci P95 (99) is 67% for C. crocea and is 61% for C. erate. Paratypic forms of both species do not differ from nominative ones by parameters of genetic diversity. The mean expected heterozygosities (H'(e)) in the C. crocea, C. erate and their paratypic forms by the RAPD-PCD data are 24.3 +/- 4.4%, 21.7 +/- 4.2%, 26.4 +/- 4.1%, respectively. The observed heterozygosities by the allozyme data in other samples are considerably less than theoretically expected ones (H(o) = 15.6 +/- 3.3%, H(e) = 50.5 +/- 4.5% for C. crocea; H(o) = 17.95 +/- 6.15%, H(e) = 50.8 +/- 8% for C. erate, and H(o) = 24.2 +/- 7.5%, H(e) = 50.9 +/- 8.7% for paratypic forms, respectively). The mean observed heterozygosity in the paratypic forms of C. erate (f. androconiata, f. chrysodona, f. edusoides) is almost two times higher than that of the f. chlorodona and f. eratoides. Paratypic forms of both species differ from nominative ones (particularly from that of C. crocea) by the level of intrapopulation inbreeding and by the degree of gene flow (F = 0.691 for C. crocea, 0.646 for C. erate, and 0.524 for paratypic forms). One can suppose a significant gene exchange among adjacent populations of C. crocea and C. erate (Wright's F(ST) = 0.155 for 6 allozyme and 18 RAPD loci, Nm = 1.363). Nei's similarity coefficients (S) varies from 0.7554 among nominative C. crocea and C. erate (D(N) = 0.28) to 0.8092 among C. crocea and paratypic forms (D = 0.21) and to 0.8936 among C. erate and paratypic forms of both species (D(N) = 0.11). Paratypic forms with rounded valve margin preliminarily identified as C. crocea revealed a considerable degree of similarity to the paratypic forms of C

  17. [Allozyme variation of seed embryos and mating system in relict populations of Scots pine (Pinus sylvestris L.) from the Kremenets Hill Ridge and Maloe Poles'e].

    Science.gov (United States)

    Korshikov, I I; Kalafat, L A; Lisnichuk, A N; Velikorid'ko, T I; Mudrik, E A

    2011-07-01

    Allozyme variation at ten polymorphic loci and mating system was studied in three small isolated relict populations (4.4 to 22 ha) and in three artificial stands of Pinus sylvestris from the Kremenets Hill Ridge and Maloe Poles'e. It was established that the mean heterozygosity of 130 to 140 year-old trees from natural populations (H(O) = 0.288; H(E) = 0.277) was substantially lower, compared to 30 to 40 year-old trees from artificial stands (H(O) = 0.358; H(E) = 0.330). The observed heterozygosity of seed embryos (H(O) = 0.169 and 0.180) was substantially lower than of the mature trees from populations and artificial stands, respectively. In the embryo samples, irrespectively of the forest stand origin, substantial hetedrozygote deficiency was observed (at six to eight loci), compared to the Hardy-Weinberg expectations. The proportion of cross pollination in the populations and artificial stands was low, t(m) = 0.588 to 0.721; and t(m) = 0.455 to 0.837, respectively.

  18. Allozyme comparison of two populations of Rineloricaria (Siluriformes, Loricariidae from the Ivaí River, upper Paraná River basin, Brazil

    Directory of Open Access Journals (Sweden)

    Daniel M. Limeira

    2009-01-01

    Full Text Available Two allopatric morphotypes of the genus Rinelocaria were compared through the allozyme electrophoresis technique: one morphotype, R. pentamaculata, from the Keller River in the middle stretch of the Ivaí River basin and the other, R. aff. pentamaculata, from the São João River in the upper portion of the Ivaí River basin. The morphotype from the São João River was collected upstream from the São João waterfall, which is about 80 m deep. Twelve enzymatic systems (AAT, ADH, EST, GCDH, G3PDH, GPI, IDH, LDH, MDH, ME, PGM and SOD were analyzed, which allowed to score 22 loci. Only loci Aat-2, Est-3 and Mdh-C showed polymorphism. The two samples differed in allele frequencies at the three polymorphic loci. The average expected heterozygosity for all loci was 0.0806 ± 0.0447 in the Keller River sample. For the São João River morphotype, this value was 0.0489 ± 0.0350. Nei' s genetic identity and distance between the two populations were respectively 0.9789 and 0.0213. Wright's F IS, F IT and F STover all loci were estimated as 0.3121, 0.4021 and 0.1309, respectively. We consider that the two morphotypes represent species in statu nascendi.

  19. Allozyme analysis of the four species of Hypostomus (Teleostei: Loricariidae from the Ivaí river, upper Paraná river basin, Brazil - doi: 10.4025/actascibiolsci.v35i4.16355

    Directory of Open Access Journals (Sweden)

    Suzana de Paiva

    2013-07-01

    Full Text Available Allozyme electrophoresis analysis were performed in four species of Hypostomus (Loricariidae, H. albopunctatus, H. hermanni, H. regani, e Hypostomus sp. 1/NUP 5612 from the Ivaí river, a tributary of the upper Paraná river. The study of 14 loci revealed diagnostic characters and exclusive alleles in a low frequency. The heterozygosity ranged from 0.000 in H. albopunctatus to 0.199 in H. hermanni, which was higher than the heterozygosity in other samples of Hypostomus in literature, as well as in other fish groups. Hypostomus albopunctatus and H. regani revealed higher similarity (I = 0.804, while H. hermanni and Hypostomus sp. 1/NUP 5612 showed the least genetic identity (I = 0.569. All samples were genetically distinguished, despite there were several shared alleles. The FST value was 0.671, showing a high genetic differentiation among the samples. Hypostomus sp. 1/NUP 5612 was genetically distinguished from the three congeners by the loci Adh-A and G3pdh-B and by present rare exclusive alleles in other six enzymatic systems.

  20. Allozymic variation in the clam genus Eurhomalea (Bivalvia: Veneriidae along southern South American coast Variación alozímica en el género de almejas Eurhomalea (Bivalvia: Veneriidae a lo largo de la costa sur de Sudamérica

    Directory of Open Access Journals (Sweden)

    M.H GALLARDO

    2003-09-01

    Full Text Available The correspondence between allozymic variation and specific differentiation was studied in four populations corresponding to the three nominal, allopatric species of clam genus Eurhomalea (E. rufa, E. lenticularis, E. exalbida described for southern South America. Allozyme variation scored in 12 loci was high as indicated by heterozygosity levels (15.8-20.7 % and by the presence of only three monomorphic loci (Hk-2, Icd-2, and Xdh-1. These high estimates of allelic variability were influenced by the low levels of interspecific genetic similarity (I = 0.64 and for the high conspecific values of genetic identity observed. The high estimates of substructuring found at the species level (F ST = 0.39 contrasted with the low differentiation (F ST = 0.027 and high migration rate (Nm = 9 existing among conspecific samples. Diagnostic allele fixation coinciding with specific recognition was recorded at locus Hk-1 whereas nearly-fixed differences at loci (Adh, alpha-Gpd, Icd-1, Ldh, Odh, Pgm-3 differed sharply in frequency among species. The Wagner procedure and the neighbor-joining algorithm produced a similar tree topology highly related to the geographic distance and to their taxonomic recognition. The lack of coincidence between patterns of allozymic variation and the two distinctive shell morphs (flat and globoid occurring in E. exalbida from Ushuaia bay do not support their taxonomic recognition.Se estudió la correspondencia entre la variación bioquímica y la diferenciación específica en cuatro poblaciones correspondientes a las tres especies nominales y alopátricas en las almejas del género Eurhomalea (E. rufa, E. lenticularis, E. exalbida descritas para la zona sur de Sudamérica. La variación alozímica registrada en 12 loci fue alta como lo indican los altos niveles de heterocigosidad (15,8-20,7 % y por la presencia de solo tres loci monomórficos (Hk-2, Icd-2 y Xdh-1. Esta alta estimación de variabilidad alélica influyó en los bajos

  1. Toxicity of neem seed extract to Tessaratoma papillosa (Drury) relative to its allozyme genotypes%印楝种子提取物对荔枝蝽的毒性及与其等位酶基因型之间的关系

    Institute of Scientific and Technical Information of China (English)

    卢芙萍; 赵冬香; 刘业平; 王爱萍; 陈青

    2006-01-01

    The relationships between the susceptibility to neem seed extract and the allozyme genotypes were examined in the first instar nymphs of Tessaratoma papillosa (Drury) for two polymorphic enzyme loci of Pgi and Mdh using allozyme analysis. Acute exposures of the insect to 5.2 mg/mL (LC50 value) neem seed extract resulted in 51.8% mortality in 24 h. Under the given experimental conditions, insect mortalities were significantly different among certain genotypes and alleles. At locus Pgi, the insects with the Pgi-bb genotype displayed the highest mortality (84%), whereas those with Pgi-aa and Pgi-cc showed the lowest mortalities (0 and 7% , respectively), which were significantly different from that of Pgi-bb. At locus Mdh, the insects with the genotype Mdh-cc and Mdh-aa exhibited the highest mortality (93 % ), but no mortality was observed in the insects with the genotype Mdh-cc. These results clearly indicated that the insects with genotype Mdh-aa and Mdh-cc were significantly different from those with other three genotypes Mdh-ab, Mdh-bb and Mdh-bc in response to neem seed extract. In contrast, the mortalities of the insects with the Pgi-a and Mdh-c allele were the lowest, and were significantly different from those with other alleles. Our studies showed that individuals of T. papillosa with different genotypes had significantly different responses to neem seed extract. Such distinct relationships between the insect susceptibility to neem seed extract and its allozyme genotypes may allow us to use certain genotypes and alleles as genetic markers to assess the susceptibility of T. papillosa to neem seed extract.%用5.2 mg/mL(LC50)的印楝种子提取物对荔枝蝽1龄若虫进行急性毒性处理,24 h死亡率为51.8%.通过等位酶分析检测了死亡与存活试虫两种酶(PGI和MDH),两个基因座(Pgi和Mdh)上各基因型及等位基因与印楝种子提取物毒性之间的关系,进行致死性差异比较研究.结果表明,印楝种子提取物对具

  2. 应用同工酶技术研究我国湖北钉螺(腹足纲:麂眼螺超科:圆口螺科)不稳定螺群体内的遗传变异%ALLOZYME-BASED GENETIC VARIATION WITHIN AN UNSTABLE"POPULATION" OF CHINESE ONCOMELANIA HUPENSIS(GASTROPODA: RISSOACEA: POMATIOPSIDAE)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    [Objective] To answer the following questions:① For Oncomelania snails collected two years apart from the same locality,has there been genetic divergence?②How much experimental error has there been in studying subsets of these populations? ③As this is an unstable population,what has the net effect been on Hardy-Weinberg equilibrium(Hwe)?[Methods] Allozymes were studied using horizontal starch gel electrophoresis.Data collected from numbers of experiments were conapiled.Data from each collection were divided into two equal subsets based on chronology of the experiments.Thirty-four loci were studied using 72 to 180 snails per subset.[Results] The mean number of alleles per locus ranged frcra 1.5~1.9.With each consecutive subset,the 96 polymorphic loci dropped from 38.2 to 17.6.The mean heterozygosity was very low:0.033 to 0.049 and not significantly different from Hardy-Weinberg expectations.Ten loci and 11 alleles exclusive to the first group were eliminated from the overall study reducing the number of polymorphic loci from 19 to 10.There were significant departures from Hwe at five loci having a substantial number of individuals for each allele.Nei's and Wright's D were 0.003±0.001 and 0.054±0.006 respectively.[Conclusion] ①There were significant errors seen primarily in the results scored' in the earliest experiments.②These earlier errors involving scoring difficult to resolve loci,and interpretation of rare alleles that were not found in later experiment had no significant effect on overall genetic distance.③The use of Wright's D for closely related populations is explained.Results with Nei's D indicated no significant difference among the four subunits; Wright's D yielded significant difference between the collections made two years apart,attributed to the annual flooding of the Yangtze River mixing snails from different localities.④ Major polymorphic loci were not in Hwe as predicted using the unstable population model.⑤One must study 25 or

  3. Allozymes Genetic Diversity of Quercus mongolica Fisch in China

    Institute of Scientific and Technical Information of China (English)

    LI Wenying; GU Wanchun

    2006-01-01

    A gel electrophoresis method was used to study the genetic diversity of 8 Quercus mongolica populations throughout its range in China.Eleven of 21 loci from 13 enzymes assayed were polymorphic.Q.mongolica maintained low level of genetic variation compared with the average Quercus species.At the species level,: the mean number of alleles per locus (A) was 1.905, the percentage of polymorphic loci (P) was 52.38%, the observed heterozygosity (He) was 0.092 and the expected heterozygosity (He) was 0.099.At the population level, the estimates were A =1.421, P =28.976%, Ho= 0.088, He =0.085.Genetic differentiation (Gst was high among populations, it was 0.107.According to the UPGMA cluster analysis based on the genetic distance, 4 populations located in northeast and 2 populations in southwest of the geographical distribution are classified into 2 subgroups, but there was no clear relationship between genetic distance and geographic distance among populations.The low level of genetic diversity of Q.mongolica might be related to the long-term exploitation as economic tree species in history are comparatively seriously disturbed and damaged by human beings, and most of the existing stands are secondary forests.

  4. AFSC/ABL: Sockeye salmon allozyme baseline - 1982-1990

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Genetic data were collected and prepared with the use of protein electrophoresis from 52 spawning locations in southeastern Alaska and northern British Columbia....

  5. Genetic relationships among five nemipterid fish species from the Indian coast using allozyme analysis

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.; Arolkar, U.; Rathod, V.

    Based on Nei's genetic distance Nemipterus peronii and N. japonicus showed a greater affinity to Parascolopsis aspinosa than to the other Nemipterus species studied. Significant differences between the Indian west and east coast samples of N...

  6. Concordance between life history traits, invasion history, and allozyme diversity of the Everglades invader Melaleuca quinquenervia

    Science.gov (United States)

    During the century following its initial introduction in 1886, the Australian tree Melaleuca quinquenervia(Myrtaceae) dispersed from a few introduction points to occupy over 200,000 ha, primarily in historic Everglades wetlands of southern Florida. Cellulose acetate gel electrophoresis (CAGE) was us...

  7. AFSC/ABL: Juvenile chum salmon allozyme stock identification, Gulf of Alaska 2000-2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Summer surveys (Julyb??August) of juvenile salmon ecology along the continental shelf of the Gulf of Alaska are conducted annually by scientists from the Ocean...

  8. AFSC/ABL: Juvenile chum salmon allozyme stock identification, Bering Sea 2002

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Genetic stock identification techniques were used to identify the origin and provide stock-specific migration and distribution patterns of juvenile chum...

  9. AFSC/ABL: Rockfish allozyme species identification (Sebastes aleutianus and borealis)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Rougheye rockfish (Sebastes aleutianus) and shortraker rockfish (Sebastes borealis) were collected from the Washington coast, the Gulf of Alaska, the southern Bering...

  10. AFSC/ABL: Immature chum salmon allozyme ID of mixed stocks

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Immature chum salmon were collected by the F/V Northwest Explorer between September 5 and October 8, during the 2002 BASIS survey across the eastern Bering Sea shelf...

  11. Allozyme Genetic Diversity and Conservation Strategy of Ten Natural Populations of Pinus bungeana Zuuc. ex Endl

    Institute of Scientific and Technical Information of China (English)

    Li Bin; Gu Wanchun; Chen Xiaoyang

    2003-01-01

    Pinus bungeana is a three-needle pine with typical fragmented distribution in central and northwestern China. Its natural resources are gradually decreasing and need to be conserved. For conserving genetic diversity of P. bungeana, the authors sampled 10 natural populations in its distribution areas and conducted the analysis of isozymes. Thirty one loci with 53 alleles on the basis of 16 enzyme systems were assayed. The parameters of genetic diversity at species and population level are respectively as follows: As= 1.742, Ae[s] = 1.49, Ps= 54.8%, He[s] = 0.162, Ap= 1.39, Ae[p]= 1.30, Pp= 34.85, He[p] = 0.0986. In comparison with other pines, P. bungeana possesses a slightly low amount of genetic variation especially at the population level. By contrast, the level of population genetic differentiation (GST = 0.135) is higher compared to other pines. All ten populations are divided into three groups according to Nei's genetic identity (I). There is a slight relation (r = 0.31) between genetic distance and geographical distance.Some populations are obviously deviate from Hardy-Weinberg equilibrium but the total population is basically accordant with Hardy-Weinberg equilibrium. The correlation analysis between allele frequencies and ecological factors showed that the alleles at loci of Idh and Pgi-2 had gradient variation trends of their frequencies. The sample capturing curves' analysis indicated that the captured alleles increased when the number of sampled populations increased and 99% out of whole allele pool of ten populations would be captured when five populations were randomly selected. At last,. the population genetic structure of P. bungeana and its conservation strategy were discussed.

  12. Variation in genetic traits of the lugworm Arenicola marina: temperature related expression of mitochondrial allozymes?

    NARCIS (Netherlands)

    Hummel, H.; Sommer, A.; Bogaards, R.H.; Portner, H.O.

    1997-01-01

    Genetic traits of the lugworm Arenicola marina were determined for 4 Atlantic populations from France to Norway and compared with a population from the sub-arctic White Sea in Russia. Seven loci were analysed using horizontal starch gel electrophoresis. A low heterozygosity (0.09 to 0.17) and a non-

  13. [Allozyme diversity and genetic divergence of the dolly varden Salvelinus malma Walbaum from the Kuril islands].

    Science.gov (United States)

    Omel'chenko, V T; Salmenkova, E A; Shed'ko, S V

    2002-09-01

    Genetic variation was studied in the southern subspecies of the Asian Dolly Varden Salvelinus malma krascheninnikovi from the Kuril Islands. Thirty-six genetic loci controlling 19 enzyme systems were analyzed in 13 Dolly Varden populations from the Shumshu, Paramushir, Onekotan, Rasshua, Simushir, Urup, Iturup, and Kunashir islands. In the studied populations, the proportion of polymorphic loci was 35 to 85% and the mean heterozygosity was 0.104 to 0.173; populations from the Kunashir Island were characterized by maximum heterozygosity. In the island populations examined, significant inter-population heterogeneity of allele frequencies was found for all studied population pairs. For the total population of all islands, the inter-population diversity (GST = 0.188) was comparable to this parameter for the total population from the Kunashir Island (GST = 0.170). Genetic distances between populations did not correlate with the corresponding geographical distances, which indicates the lack of a pronounced gene exchange between the island populations. Cluster analysis and multidimensional scaling based on genetic distances did not reveal clear groups among the studied populations but indicated greater similarity within the Iturup-Simushir-Urup-Paramushir group and a greater genetic divergence of the Kunashir, Onekotan, Rasshua, and especially Shumshu populations. In the Shumshu population, allele frequencies indicate the admixture of genes of the northern Dolly Varden. The observed pattern of genetic differentiation was probably caused largely by genetic drift under the conditions of a limited gene flow because of homing (which is typical of the Dolly Varden) and the presence of isolated nonanadromous populations. The population-genetic analysis of the Dolly Varden from the Kuril Islands does not give grounds to distinguish any other isolated Dolly Varden species in this region than S. malma, which is represented by the southern form S. m. krascheninnikovi with an admixture of the northern form S. m. malma in the Shumshu Island.

  14. Genetic Variation of Three Populations of Indian Frog (Hoplobatrachus tigerinus Revealed by Allozyme Marker

    Directory of Open Access Journals (Sweden)

    M. Belal Hossain

    2012-01-01

    Full Text Available The Indian bullfrog, Hoplobatrachus tigerinus plays a significant role in maintaining the natural balance in the ecosystems. It plays an important role in controlling the various agricultural pests because of its omnivorous feeding habit. The aim of the present study is to know the genetic variation of H. tigerinus in three natural habitats. Samples collected from three districts of Bangladesh were analyzed with five enzymes (MDH, LDH, GPI, PGM and EST in CA 6.1 buffer system for their genetic variation. Four polymorphic loci (Mdh-1, Est-1, Gpi-1 and Pgm were interpretable in muscle with starch gel electrophoresis. Among the 5 presumptive loci, the mean proportion of polymorphic loci was observed 80, 80 and 60% in Rangpur, Khulna and Mymensingh populations, respectively. The highest mean number of allele per locus and mean proportion of heterozygous loci per individual were observed in the Rangpur population. The average observed heterozygosity (Ho was 0.163 and expected heterozygosity (He was 0.469. In pair-wise analysis, comparatively higher Nm value (5.507 was estimated between the Rangpur and Khulna populations corresponding lower level of FST value (0.043. The UPGMA dendrogram showed two clusters among the three Indian bullfrog populations. Rangpur and Khulna populations formed one cluster while Mymensingh population formed another cluster. The Mymensingh population separated from Rangpur and Khulna by a genetic distance of 0.177 whereas, the Khulna population is different from the Rangpur population by the genetic distance of 0.052. The results suggested that the considerable genetic variation is maintained among the natural H. tigerinus populations.

  15. [Genetical control of the allozymes in juniper (Juniperus excelsa Bieb.) of the Crimea].

    Science.gov (United States)

    Korshikov, I I; Nikolaeva, A V

    2007-01-01

    Genetical control of nine enzyme systems has been studied in preserved juniper species (Juniperus excelsa Bieb.) of the natural population of the mountain Crimea. Isozymes were extracted from the haploid seed endosperms and separated elecrophoretically. As a result 16 loci have been identified. Fourteen of them were polymorphic (14--Gdh, Got-1, Mdh-1, Mdh-2, Mdh-3, Acp-1, Acp-2, Acp-3, Lap-1, Dia-1, Fdh, Sod-1, Sod-2, Sod-3). Analysis of the allele segragation of the heterozygous trees confirmed their monogenic inheritance.

  16. Fin whale MDH-1 and MPI allozyme variation is not reflected in the corresponding DNA sequences

    NARCIS (Netherlands)

    Olsen, Morten Tange; Pampoulie, Christophe; Danielsdottir, Anna K.; Lidh, Emmelie; Berube, Martine; Vikingsson, Gisli A.; Palsboll, Per J.

    2014-01-01

    The appeal of genetic inference methods to assess population genetic structure and guide management efforts is grounded in the correlation between the genetic similarity and gene flow among populations. Effects of such gene flow are typically genomewide; however, some loci may appear as outliers, di

  17. Species-richness of the Anopheles annulipes Complex (Diptera: Culicidae) Revealed by Tree and Model-Based Allozyme Clustering Analyses

    Science.gov (United States)

    2007-01-01

    and systematics ofAnopheles: insights from a molecular phy· logeny of Australasian mosquitoes. Molecular Phylogenetics and Evolution 9: 262-275. Foley... systematics and pop- ulation studies. Sydney: Academic Press. Roscnberg NA, Burke T, Elo K, Feldman MW, Freidlin PJ, Groenen MAM, Hillel J, Maki·Taniia...of molecular-functional variation patterns among butterfly species complexes IColias: Lepidoptera , Pieridae). Molecular Ecology 12: 1265-1275. © 2007

  18. [Comparative study of allozyme polymorphism in groups of pine trees (Pinus sylvestris L.) with different seed productivity].

    Science.gov (United States)

    Korshikov, I I; Kalafat, L A

    2004-01-01

    Genotypes of 196 Pinus sylvestris L. plants from 10 natural populations of five Ukrainian regions have been determined using 19 polymorphic isozyme loci. Variability of quantity of full-grained, empty-grained and underdeveloped seeds in the cones of these plants has been studied. The basic indexes of genetic polymorphism were determined for 6 samples presented by 18-19 trees with high and low productivity of the full-grained, empty-grained and underdeveloped seeds. The maximum amount of rare alleles and genotypes as well as the highest heterozygosity (Ho = 0.285) were typical for the sample of plants with the maximum quantity of empty-grained seeds in the cones.

  19. Wildlife genetics and disease: allozyme evolution in the wild boar (Sus scrofa caused by a swine fever epidemy

    Directory of Open Access Journals (Sweden)

    Schreiber Arnd

    2000-05-01

    Full Text Available Abstract Enzyme polymorphism at 42 loci was compared before and after a major epidemy of swine fever in wild boars from northern Vosges (France. No change was observed in the 38 monomorphic loci, but allele frequencies at the phosphoglucomutase locus PGM-2* changed significantly. Possible causes for this observation are discussed, and it appears that PGM-2 locus could be a genetic marker of resistance to this viral disease.

  20. Allozyme-specific modification of a maize seed chitinase by a protein secreted by the fungal pathogen Stenocarpella maydis.

    Science.gov (United States)

    Naumann, Todd A; Wicklow, Donald T

    2010-07-01

    Stenocarpella maydis causes both dry-ear rot and stalk rot of maize. Maize inbred lines have varying levels of resistance to ear rot caused by S. maydis. The genetic basis of resistance appears to rely on multiple genetic factors, none of which are known. The commonly used stiff-stalk inbred line B73 has been shown to be strongly susceptible to ear rot caused by S. maydis. Here, we report that the ChitA protein alloform from B73, ChitA-F, encoded by a known allele of the chiA gene, is susceptible to modification by a protein (Stm-cmp) secreted by S. maydis. We also identify a new allele of chiA (from inbred line LH82) which encodes ChitA-S, an alloform of ChitA that is resistant to Stm-cmp modification. Chitinase zymogram analysis of seed from a commercial field showed the presence of both ChitA alloforms in healthy ears, and showed that ChitA-F but not ChitA-S was modified in ears rotted by S. maydis. The ChitA-F protein was purified from inbred line B73 and ChitA-S from LH82. ChitA-F was modified more efficiently than ChitA-S by S. maydis protein extracts in vitro. The chiA gene from LH82 was cloned and sequenced. It is a novel allele that encodes six polymorphisms relative to the known allele from B73. This is the first demonstration that the susceptibility to modification of a fungal targeted plant chitinase differs among inbred lines. These findings suggest that the LH82 chiA allele may be a specific genetic determinant that contributes to resistance to ear rot caused by S. maydis whereas the B73 allele may contribute to susceptibility.

  1. Allozyme variability in sexual and parthenogenetic freshwater planarians : Evidence for polyphyletic origin of parthenogenetic lineages through hybridization with coexisting sexuals

    NARCIS (Netherlands)

    Pongratz, Norbert; Sharbel, Timothy F.; Beukeboom, Leo W.; Michiels, Nico K.

    1998-01-01

    In Dugesia polychroa, a hermaphroditic planarian, diploid sexual and polyploid pseudogamous parthenogenetic forms exist in separate populations and in sympatry. Parthenogens produce viable, haploid sperm that are exchanged between two individuals during copulation and trigger sperm-dependent parthen

  2. 卤虫等位酶的遗传控制%GENETIC CONTROL OF ALLOZYMES IN THE BRINE SHRIMP (ARTEMIA)

    Institute of Scientific and Technical Information of China (English)

    董树刚; 付成秋; 程继军; 高明君

    2000-01-01

    应用聚丙烯酰胺凝胶电泳技术分析了孤雌生殖卤虫产生的罕见雄体、两性卤虫及其杂交后代(F1)的酯酶(EST)、超氧物歧化酶(SOD)、过氧化物酶(PRX)、碱性磷酸酶( ALP)、四唑氧化酶(TO)和乳酸脱氢酶(LDH)的同工酶酶谱表型.对编码五种酶的19个位点、35个等位基因的表达进行了遗传分析.结果表明,在EST、PRX和TO酶谱中既有共显性等位基因,又有沉默等位基因的表达;卤虫PRX、ALP和SOD为单体酶,在EST和TO酶谱中还存在着二聚体同工酶;除LDH为单态外,其余五种同工酶为多态酶.

  3. Genetic evidence for population expansion in Hydrotaea irritans (Fallèn) (Diptera: Muscidae)

    DEFF Research Database (Denmark)

    Loeschcke, V.; Nielsen, B. O.; Pedersen, A. Aa.;

    2004-01-01

    geographic variation, F-statistics, allozyme electrophoresis, skewed allele frequencies, bottleneck, population expansion......geographic variation, F-statistics, allozyme electrophoresis, skewed allele frequencies, bottleneck, population expansion...

  4. ALLOZYME DIVERSITY IN NATURAL POPULATIONS OF BETULA ALNOIDES FROM GUANGXI, CHINA%广西区西南桦天然居群遗传多样性的研究

    Institute of Scientific and Technical Information of China (English)

    曾杰; 王中仁; 周世良; 郑海水; 白嘉雨

    2003-01-01

    以采自广西区11个西南桦(Betula alnoides)天然居群的种子培育出的幼苗为材料,取其嫩叶开展21种酶系统的水平切片淀粉凝胶电泳实验,运用作者改进的Tris-马来酸提取缓冲液 (含30%PVP 40 000和1%2-巯基乙醇),筛选出AMP(氨基肽酶Aminopeptidase)、FBA(果糖二磷酸酶Fructose-bisphosphate aldolase)、GDH(谷氨酸脱氢酶Glutamate dehydrogenase)、G6PD(6-磷酸葡萄糖脱氢酶Glucose-6-phosphate dehydrogenase)、IDH(异柠檬酸脱氢酶Isocitrate dehydrogenase)、MDH(苹果酸脱氢酶Malate dehydrogenase)、PGD(6-磷酸葡萄糖酸脱氢酶Phosphogluconate dehydrogenase)、PGI(磷酸葡萄糖异构酶Phosphoglucoisomerase)、PGM(磷酸葡萄糖变位酶Phosphoglucomutase)和SKD(莽草酸脱氢酶Shikimate dehydrogenase)等10种酶,获得了清晰且可重复的酶谱.通过谱带遗传分析确定了15个位点,其中有6个单态位点,9个多态位点 (0.95标准),具40个等位基因.在居群水平上,西南桦的多态位点百分数 (P) 为55.2%,平均每个位点的等位基因数 (A) 为2.00,平均预期杂合度 (He) 为0.204.均超过Hamrick (1992)等提出的远交风媒木本植物的平均值(53.0%,1.84%和0.154),表明西南桦的遗传变异水平高.在11个西南桦居群内,实际杂合度 (Ho)均高于预期杂合度,出现杂合子过量,可能存在利于杂合子的自然选择.西南桦遗传多样性与地理位置相关不显著.居群2 (靖西地州)、5 (平果海城)、9 (田林者苗) 包含绝大部分的等位基因,而且具较高的遗传多样性,应加以保护和管理,作为其基因资源就地保存的基地.本研究解决了以西南桦嫩叶为材料进行等位酶分析的关键技术,为进一步开展西南桦乃至桦木属树种的遗传结构和遗传多样性等提供了技术基础;同时掌握了西南桦天然居群的遗传多样性现状,为其有效保护和合理经营以及西南桦的遗传改良提供了理论依据.

  5. Clonal Structure of Phragmites australis in Wetland Downstream the Yellow River Marked by Allozymes%黄河下游湿地芦苇种群克隆结构的等位酶分析

    Institute of Scientific and Technical Information of China (English)

    郭卫华; 张淑萍; 宋百敏; 王仁卿

    2003-01-01

    以等位酶为标记, 采用水平切片淀粉凝胶电泳技术, 对黄河下游湿地15个芦苇(Phragmites australis (Cav.) Trin. ex Steud)种群的克隆结构进行了初步研究. 8个酶系统17个等位酶位点的检测表明, 芦苇种群克隆多样性很高, 基因型比率PD=0.53 (0.10~0.85), 不同克隆在规模上相差很大. 克隆结构分析表明, 芦苇种群内克隆之间的镶嵌明显.

  6. Allozyme Polymorphism and Genetic Differentiation Among Populations of Jaculus jaculus and J.orientalis (Rodentia:Dipodidae)in Tunisia%突尼斯非洲跳鼠(Jaculus jaculus)和埃及跳鼠(J.orientalis)群体的等位酶多态及遗传分化

    Institute of Scientific and Technical Information of China (English)

    Abderraouf Ben Faleh; Adel AB Shahin; Khaled Sai

    2009-01-01

    Genetic variability and divergence among natural populations of Jaculus jaculus and J.orientalis in Tunisia were examined by electrophoretic analysis of 16 enzymatic proteins encoded by 23 genetic loci.Low levels of genetic variability were found among populations Of both species in comparison to those of other rodent and mammal species of which data are available.In J.jaculus populations,the mean level of observed heterozygosity(Hobs)ranged from 0.08 to 0.19,while the mean percenmge of polymorphic loci(P)ranged from 26.2%to 45.2%and the mean number of alleles per locus(A)ranged from 1.1 to 1.4.Nevertheless,the mean values were 0.10 to 0.15,29.3%to 44.1%and 1.1 to 1.7.respectively,for J.onentalls.In addition,populations of the two species have revealed a lower degree of genetic differentiation (Fst=0.0017 fot J.jaculus and 0.0019 for J.orientalis).Moreover,Fst was 0.607,P<0.05 between populations of the two species,indicating that tbey were highly genetically diverged from each other.The present data assures the previous results on the validity of the present taxonomic situation of the two species and emphasis on the effect of geographic factors(environments type and bioclimatic stages)on the genetic structure of both species.%运用16种酶蛋白编码的23个遗传座位对突尼斯非洲跳鼠(Jaculus jaculus)和埃及跳鼠(J.orientalis)自然群体的遗传变异和分化进行了电泳分析.结果表明,与其他啮齿动物等哺乳动物的相关数据比较,发现这两个种群体的遗传变异水平较低.非洲跳鼠群体的观测杂合度(Hobs)为0.08-0.19,多态座位百分比(P)为26.2%-45.2%,每个座何的平均等位基因数(A)为1.1-1.4;埃及跳鼠的Hobs为0.10-0.15,P为29.3%-44.1%,A为1.1-1.7.两个种群体各自的遗传分化程度较低(非洲跳鼠和埃及跳鼠的Fst分别为0.0017和0.0019).而两个种群体间的Fst为0.607(P<0.05),表明两个种之间高度的遗传分化.本研究支持这两个种分类地位的合法性,并强调了地理因素(环境类犁和生物气候阶段)对两个种遗传结构的影响.

  7. Mating system and genetic diversity of a rare desert legume Ammopiptanthus nanus (Leguminosae)

    Institute of Scientific and Technical Information of China (English)

    Guo-Qing CHEN; Hong-Wen HUANG; Daniel J CRAWFORD; Bo-Rong PAN; Xue-Jun GE

    2009-01-01

    Ammopiptanthus nanus is an endangered evergreen shrub endemic to the deserts of central Asia and plays an important role in delaying further desertification. We examined allozyme variation and AFLP diversity in A. Nanus populations and investigated the mating system of this species using progeny arrays assayed for poly-morphic allozyme loci. Mating system analysis in the Keyi'eryongke'er population showed low levels of out-crossing, and strong inbreeding depression. Low levels of genetic variation were detected at both population (allozyme, Pp=14.0%,A=1.14, He=0.031; AFLP, Pp=14.5%, Shannon's information index I=0.063) and species (allozyme, Pp=21.1%,A=1.21, He=0.040; AFLP, Pp=20.9%, I=0.083) levels; while moderate genetic differentia-tion existed among populations, as indicated by allozymes (GST=0.081) and AFLP (GST=0.151-0.193). Founder effect, bottlenecks in evolutionary history, the mixed mating system and co-ancestry may have influenced the level of genetic diversity in A. Nanus. Markers of both types provide new insights for conservation management, indicating that the Biao'ertuokuoyi and Keyi'eryongke'er populations should be given priority for in situ conser-vation and regarded as seed sources for ex situ conservation.

  8. Balancing a cline by influx of migrants: a genetic transition in water frogs of eastern Greece.

    Science.gov (United States)

    Hotz, Hansjürg; Beerli, Peter; Uzzell, Thomas; Guex, Gaston-Denis; Pruvost, Nicolas B M; Schreiber, Robert; Plötner, Jörg

    2013-01-01

    Variation patterns of allozymes and of ND3 haplotypes of mitochondrial DNA reveal a zone of genetic transition among western Palearctic water frogs extending across northeastern Greece and European Turkey. At the western end of the zone, allozymes characteristic of Central European frogs known as Pelophylax ridibundus predominate, whereas at the eastern end, alleles characteristic of western Anatolian water frogs (P. cf. bedriagae) prevail. The ND3 haplotypes reveal 2 major clades, 1 characteristic of Anatolian frogs, the other of European; the European clade itself has distinct eastern and western subclades. Both the 2 major clades and the 2 subclades overlap within the transition zone. Using Bayesian model selection methods, allozyme data suggest considerable immigration into the Nestos River area from eastern and western populations. In contrast, the ND3 data suggest that migration rates are so high among all locations that they form a single panmictic unit; the best model for allozymes is second best for mitochondrial DNA (mtDNA). Nuclear markers (allozymes), which have roughly 4 times as deep a coalescent history as mtDNA data and thus may reflect patterns over a longer time, indicate that eastern and western refugial populations have expanded since deglaciation (in the last 10,000 years) and have met near the Nestos River, whereas the mtDNA with its smaller effective population size has already lost the signal of partitioning into refugia.

  9. [Variability of enzyme systems in the coenopopulation of Taraxacum officinale s.l. from the zone of East-Ural- radioactive trace].

    Science.gov (United States)

    Ul'ianova, E V; Pozolotina, V N

    2004-01-01

    Levels of soil contamination with 90Sr and 137Cs radionuclides on the plots within the zone of Eastern-Ural radioactive trace exceed values of the global level 4-240 times. We have carried out allozyme analysis of apomict species Taraxacum officinale s.l. from this zone. Zimogrammes were interpreted as allozyme phenotypes. In condition of chronic irradiation the plants had increased phenogenetic variability of majority enzymes systems and high frequency of rare morphs. Thus, in plant coenopopoulations situated in radioactive-polluted zone, genomic recombination processes show higher intensity. High enzymatic variability provides the material for natural selection and increase the adaptive potential of coenopopulations.

  10. STARVATION RESISTANCE IN DROSOPHILA-MELANOGASTER IN RELATION TO THE POLYMORPHISMS AT THE ADH AND ALPHA-GPDH LOCI

    NARCIS (Netherlands)

    OUDMAN, L; VANDELDEN, W; KAMPING, A; BIJLSMA, R

    1994-01-01

    In view of the world-wide latitudinal cline of the Adh and alpha Gpdh allozyme frequencies of Drosophila melanogaster and the interactions between these loci, experiments were performed to study the phenotypic effects of these loci. Starvation resistance, oxygen consumption, body weight, protein con

  11. Phytophthora ipomoeae, a new homothallic species causing leaf blight on Ipomoea longipedunculata in the Toluca Valley of central Mexico

    NARCIS (Netherlands)

    Flier, W.G.; Grunwald, N.J.; Kroon, L.P.N.M.; Bosch, van den G.B.M.; Garay-Serrano, E.; Lozoya-Saldan, H.; Bonants, P.J.M.; Turkensteen, L.J.

    2002-01-01

    A Phytophthora species was found on blighted foliage of Ipomoea longipedunculata, a morning glory native to the highlands of central Mexico. Based on host range, morphology, allozymes, mitochondrial DNA haplotype and rDNA sequences it is concluded that a new Phytophthora species, P. ipomoeae sp. nov

  12. Hidden diversity in marine algae : Some examples of genetic variation below the species

    NARCIS (Netherlands)

    vanOppen, MJH; Klerk, H; Olsen, JL; Stam, WT

    1996-01-01

    An important aspect of marine biodiversity studies is identification of species and subspecies complexes. Here we present a number of examples from marine algae in which allozymes, DNA sequences and RAPDs are used to identify cryptic species and explore phylogenetic-population level relationships ov

  13. Microgeographic Edaphic Differentiation in Hordein Polymorphisms of Wild Barley

    DEFF Research Database (Denmark)

    Nevo, E.; Beiles, A.; Storch, N.

    1983-01-01

    and topography. Likewise, significant correlations were found between hordein phenotypes and allozyme types detected in a previous study. Our results suggest that at least part of the hordein polymorphisms in wild barley is adaptive and selected by soil and topographic differences over very short distances....

  14. A Multivariate Study on Genetic Variation in Teak (Tectona grandis (L.))

    DEFF Research Database (Denmark)

    Kjær, Erik Dahl; Siegismund, Hans Redlef; Suangtho, V.

    1996-01-01

    Genetic differentiation between populations of teak (Tectona grandis (L.)) was examined in 9 quantitative characters and 10 allozyme loci. Large differences between populations were revealed in the quantitative traits. Regional patterns were revealed by multivariate analysis of the data, but ther...

  15. Variation in Fitness-Related Characters among Small and Large Populations of Salvia-Pratensis

    NARCIS (Netherlands)

    Ouborg, N.J.; Van Treuren, R.

    1995-01-01

    1 The threatened perennial Salvia pratensis is restricted to a few isolated populations in the Netherlands, which vary in size from 10 to 1500 flowering individuals. Small populations are known to have significantly lower allozyme diversity than the large populations, probably as a consequence of ge

  16. VARIATION IN FITNESS-RELATED CHARACTERS AMONG SMALL AND LARGE POPULATIONS OF SALVIA-PRATENSIS

    NARCIS (Netherlands)

    OUBORG, NJ; VANTREUREN, R

    1995-01-01

    1 The threatened perennial Salvia pratensis is restricted to a few isolated populations in the Netherlands, which vary in size from 10 to 1500 flowering individuals. Small populations are known to have significantly lower allozyme diversity than the large populations, probably as a consequence of ge

  17. The genetic origin of honey bee colonies used in the COLOSS Genotype-Environment Interactions Experiment: a comparison of methods

    DEFF Research Database (Denmark)

    Francis, Roy M; Kryger, Per; Meixner, Marina;

    2014-01-01

    to describe the genetic background and population allocation of the bees used in this experiment. Two wing morphometric and two genetic methods were employed to discriminate bee populations. Classical morphometry of 11 angles on the wings were carried out on 350 bees. Geometric morphometry on 19 wing...... landmarks was carried out on 381 individuals. DNA microsatellite analysis was carried out on 315 individuals using 24 loci. Allozyme analysis was performed on 90 individuals using six enzyme systems. DNA microsatellite markers produced the best discrimination between the subspecies (Apis mellifera carnica......, A. m. ligustica, A. m. macedonica, A. m. mellifera and A. m. siciliana) used in the experiment. Morphometric methods generally showed an intermediate level of discrimination, usually best separating A. m. siciliana and A. m. ligustica from the remaining populations. Allozyme markers lack power...

  18. Genetic diversity in European red deer (Cervus elaphus L.): anthropogenic influences on natural populations.

    Science.gov (United States)

    Hartl, Günther B; Zachos, Frank; Nadlinger, Karl

    2003-08-01

    Allozyme, microsatellite and mtDNA (RFLP and sequence) data of European red deer populations were examined as to their capability of indicating anthropogenic influences such as the keeping of animals in enclosures, selective hunting for trophies translocation of specimens to improve trophy quality and habitat fragmentation. Deer in enclosures revealed considerable deviations of allele frequencies from isolation-by-distance expectations but no remarkable loss of genetic diversity. Particular allozyme genotypes were associated with antler morphology, and selective hunting was shown to alter allele frequencies in the expected direction. Habitat fragmentation is reflected by various kinds of genetic markers but due to the lack of information on population histories no unequivocal evidence on particular human activities could be obtained.

  19. Differential fitness of allelic isozymes in the marine gastropods Littorina punctata and Littorina neritoides, exposed to the environmental stress of the combined effects of cadmium and mercury pollution

    Science.gov (United States)

    Lavie, Batia; Nevo, Eviatar

    1987-07-01

    The present study tested the separate and the interactive pollution effects of cadmium and mercury on the electrophoretically detected allelic isozyme frequencies of the enzyme phosphoglucose isomerase for two species of littoral marine gastropods — Littorina punctata and L. neritoides — and the enzyme amino peptidase for L. neritoides. Our results indicate differential survivorship of allelic isozyme genotypes specific for each type of pollutant and for their interaction, as well as trends common to all pollutants. Theoretically the results reflect the adaptive nature of at least some allozymic genotypes in these marine gastropods and seem inconsistent with the neutral theory of allozyme polymorphisms. Practically, the results reinforce earlier conclusions that changes in the frequency of allelic isozymes may be used as a genetic monitor of pollution.

  20. Population genetic structure in Myrtus communis L. in a chronically fragmented landscape in the Mediterranean: can gene flow counteract habitat perturbation?

    Science.gov (United States)

    Albaladejo, R G; Carrillo, L F; Aparicio, A; Fernández-Manjarrés, J F; González-Varo, J P

    2009-05-01

    Ancient managed landscapes provide ideal opportunities to assess the consequences of habitat fragmentation on the patterns of genetic diversity and gene flow in long-lived plant species. Using amplified fragment length polymorphism (AFLP) and allozyme markers, we quantified seed-mediated gene flow and population genetic diversity and structure in 14 populations of Myrtus communis (myrtle), a common endozoochorous shrub species of forest patches in lowland agricultural Mediterranean areas. Overall, allozyme diversity for myrtle was low (P(95) = 25%; A = 1.411; H(e) = 0.085) compared to other known populations, and a significant portion of populations (57%) had lower levels of allelic diversity and/or heterozygosity than expected at random, as shown by simulated resampling of the whole diversity of the landscape. We found significant correlations between allozyme variability and population size and patch isolation, but no significant inbreeding in any population. Genetic differentiation among populations for both allozyme and AFLP markers was significant (Phi(ST) = 0.144 and Phi(ST) = 0.142, respectively) but an isolation-by-distance pattern was not detected. Assignment tests on AFLP data indicated a high immigration rate in the populations (ca. 20-22%), likely through effective seed dispersal across the landscape by birds and mammals. Our results suggest that genetic isolation is not the automatic outcome of habitat destruction since substantial levels of seed-mediated gene flow are currently detectable. However, even moderate rates of gene flow seem insufficient in this long-lived species to counteract the genetic erosion and differentiation imposed by chronic habitat destruction.

  1. Degree of intraspecific genetic divergence and variability in three Sciaenid species

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.; Taniguchi, N.; Seki, S.

    variation exists in natural populations of many species (Allen dorf and Utter, 1979). Phenotypes of allozyme can be scored during most stages of their life cycle and their genetics more easily interpreted than the pro portional and meristic characters... on sciaenid taxonomy ofJapan and its adjacent regions have been based mainly on morphological characters. Comprehensive and phylogenetical studies of this particular group of fishes based on the anatomical characters and alla zymes were performed (Taniguchi...

  2. Genetic variation among agamid lizards of the trapelus agiliscomplex in the caspian-aral basin

    Energy Technology Data Exchange (ETDEWEB)

    Macey, J. Robert; Ananjeva, Natalia B.

    2004-05-19

    Allozyme variation is examined in eight populations of Trapelus from the Caspian-Aral Basin of the former USSR. Thirty-one loci (15 variable) exhibit remarkably low levels of genetic variation with only a Nei's genetic distance of 0.117 across 2500 km. An isolated population on the European side of the Caspian Sea is found to phenetically cluster inside the Asian populations examined, suggesting that it should not be considered taxonomically distinct.

  3. Asexual reproduction and molecular systematics of the sea anemone Anthopleura krebsi (Actiniaria: Actiniidae)

    OpenAIRE

    Braga Gomes, Paula; Zamponi, Mauricio Oscar; Solé-Cava, Antonio Mateo

    2014-01-01

    In this paper we use allozyme analyses to demonstrate that individuals in Anthopleura krebsi aggregates are monoclonal. Additionally, sympatric samples of the red and the green colour-morphs of A. krebsi from Pernambuco, Brazil were genetically compared and no significant differences were observed between them (gene identity= 0.992), indicating that they do not belong to different biological species. All individuals within aggregates of the green colour-morph were found to be identical over t...

  4. Concordance of nuclear and mitochondrial DNA markers in detecting a founder event in Lake Clark sockeye salmon

    Science.gov (United States)

    Ramstad, Kristina M.; Woody, Carol Ann; Habicht, Chris; Sage, G. Kevin; Seeb, James E.; Allendorf, Fred W.

    2007-01-01

    Genetic bottleneck effects can reduce genetic variation, persistence probability, and evolutionary potential of populations. Previous microsatellite analysis suggested a bottleneck associated with a common founding of sock-eye salmon Oncorhynchus nerka populations of Lake Clark, Alaska, about 100 to 400 generations ago. The common foundingevent occurred after the last glacial recession and resulted in reduced allelic diversity and strong divergence of Lake Clarksockeye salmon relative to neighboring Six Mile Lake and LakeIliamna populations. Here we used two additional genetic marker types (allozymes and mtDNA) to examine these patterns further. Allozyme and mtDNA results were congruent with the microsatellite data in suggesting a common founder event in LakeClark sockeye salmon and confirmed the divergence of Lake Clarkpopulations from neighboring Six Mile Lake and Lake Iliamna populations. The use of multiple marker types provided better understanding of the bottleneck in Lake Clark. For example, the Sucker Bay Lake population had an exceptionally severe reduction in allelic diversity at microsatellite loci, but not at mtDNA. This suggests that the reduced microsatellite variation in Sucker Bay Lake fish is due to consistently smaller effective population size than other Lake Clark populations, rather than a more acute or additional bottleneck since founding. Caution is urged in using reduced heterozygosity as a measure of genetic bottleneck effects because stochastic variance among loci resulted in an overall increase in allozyme heterozygosity within bottlenecked Lake Clark populations. However, heterozygosity excess, which assesses heterozygosity relative to allelic variation, detected genetic bottleneck effects in both allozyme and microsatellite loci. 

  5. Desert springs: deep phylogeographic structure in an ancient endemic crustacean (Phreatomerus latipes.

    Directory of Open Access Journals (Sweden)

    Michelle T Guzik

    Full Text Available Desert mound springs of the Great Artesian Basin in central Australia maintain an endemic fauna that have historically been considered ubiquitous throughout all of the springs. Recent studies, however, have shown that several endemic invertebrate species are genetically highly structured and contain previously unrecognised species, suggesting that individuals may be geographically 'stranded in desert islands'. Here we further tested the generality of this hypothesis by conducting genetic analyses of the obligate aquatic phreatoicid isopod Phreatomerus latipes. Phylogenetic and phylogeographic relationships amongst P. latipes individuals were examined using a multilocus approach comprising allozymes and mtDNA sequence data. From the Lake Eyre region in South Australia we collected data for 476 individuals from 69 springs for the mtDNA gene COI; in addition, allozyme electrophoresis was conducted on 331 individuals from 19 sites for 25 putative loci. Phylogenetic and population genetic analyses showed three major clades in both allozyme and mtDNA data, with a further nine mtDNA sub-clades, largely supported by the allozymes. Generally, each of these sub-clades was concordant with a traditional geographic grouping known as spring complexes. We observed a coalescent time between ∼2-15 million years ago for haplotypes within each of the nine mtDNA sub-clades, whilst an older total time to coalescence (>15 mya was observed for the three major clades. Overall we observed that multiple layers of phylogeographic history are exemplified by Phreatomerus, suggesting that major climate events and their impact on the landscape have shaped the observed high levels of diversity and endemism. Our results show that this genus reflects a diverse fauna that existed during the early Miocene and appears to have been regionally restricted. Subsequent aridification events have led to substantial contraction of the original habitat, possibly over repeated Pleistocene

  6. A FORTRAN program for the calculation and analysis of two-locus linkage disequilibrium coefficients.

    Science.gov (United States)

    Black, W C; Krafsur, E S

    1985-08-01

    A FORTRAN program was written that calculates composite linkage disequilibrium coefficients from genotypic data. Chi-square tests determine whether coefficients calculated for allele and locus pairs are significantly greater than zero. A subroutine is provided that partitions the variance in linkage disequilibrium into within- and between-subpopulation components. Output obtained from analysis of allozyme data collected from natural subpopulations of the house fly (Musca domestica L.) are included to illustrate features of the program.

  7. Identification of a whitefly species by genomic and behavioral studies

    Science.gov (United States)

    Perring, T.M.; Cooper, A.D.; Rodriguez, R.J.; Farrar, C.A.; Bellows, T.S.

    1993-01-01

    An introduced whitefly species, responsible for over a half billion dollars in damage to U.S. agricultural production in 1991, is morphologically indistinguishable from Bemisia tabaci (Gennadius). However, with the use of polymerase chain reaction-based DNA differentiation tests, allozymic frequency analyses, crossing experiments, and mating behavior studies, the introduced whitefly is found to be a distinct species. Recognition of this new species, the silverleaf whitefly, is critical in the search for management options.

  8. Population Structure of Phytophthora infestans in the Toluca Valley Region of Central Mexico.

    Science.gov (United States)

    Grünwald, N J; Flier, W G; Sturbaum, A K; Garay-Serrano, E; van den Bosch, T B; Smart, C D; Matuszak, J M; Lozoya-Saldaña, H; Turkensteen, L J; Fry, W E

    2001-09-01

    ABSTRACT We tested the hypothesis that the population of Phytophthora infestans in the Toluca valley region is genetically differentiated according to habitat. Isolates were sampled in three habitats from (i) wild Solanum spp. (WILD), (ii) land-race varieties in low-input production systems (RURAL), and (iii) modern cultivars in high-input agriculture (VALLEY). Isolates were sampled in 1988-89 (n= 179) and in 1997-98 (n= 389). In both sampling periods, the greatest genetic diversity was observed in RURAL and VALLEY habitats. Based on the Glucose-6-phosphate isomerase and Peptidase allozymes, the subpopulations from the three habitats were significantly differentiated in both sampling periods. In contrast to allozyme data for 1997-98, no differences were found among the three subpopulations for sensitivity to metalaxyl. Two groups of isolates identical for allozyme and mating type were further investigated by restriction fragment length polymorphism fingerprinting; 65% of one group and 85% of another group were demonstrated to be unique. The genetic diversity data and the chronology of disease occurrence during the season are consistent with the hypothesis that populations of P. infestans on wild Solanum populations are derived from populations on cultivated potatoes in the central highlands of Mexico near Toluca.

  9. Genetic Differentiations among the Populations of Salvia japonica (Lamiaceae and Its Related Species

    Directory of Open Access Journals (Sweden)

    SUDARMONO

    2008-03-01

    Full Text Available Morphological and genetic variations within Salvia japonica (Lamiaceae and its related species in Japan were analyzed for clarifying their taxonomic significance. The genetic variations were explored through chloroplast and nuclear ribosomal DNA sequences and allozyme polymorphisms. Since chromosome numbers characterized the genus of Salvia, we also examined whether the karyotypes were different. We examined 58 populations of S. japonica and 14 populations of others species of Salvia. Among the populations of S. japonica represented four forms (f. japonica, f. longipes, f. lanuginosa and f. albiflora. The size of chromosomes were various among Salvia spp. Based on the allozyme as well as the DNA sequence, the populations of S. japonica separated from the others Salvia species. The populations of S. japonica exhibited four combinations of the morphological characters. However, these combinations did not correlate to the four forms of S. japonica. In addition, the morphological variations did not correlate to the allozyme and DNA sequences. It is suggested that the four morphological variations as well as the four form of S. japonica should not considered to be a taxonomic unit; accordingly, S. japonica were considered to be still at the early stage of speciation process.

  10. Genetic analysis of ecological relevant morphological variability in Plantago lanceolata L. : 2. Localisation and organisation of quantitative trait loci.

    Science.gov (United States)

    Wolff, K

    1987-04-01

    Morphological variability was analysed in an F2-generation derived from crosses between two ecotypes of Plantago lanceolata L. Six allozyme loci, localised in five linkage groups, were used as markers. For two marker loci, Got-2 and Gpi-1, segregations did not fit monogenic ratios. In the linkage groups to which these two loci belonged, male sterility genes appeared to be present. In these crosses, male sterility (type 3, as described by Van Damme 1983) may be determined by two recessive loci located in the linkage groups of Got-2 and of Gpi-1. Many correlations of morphological and life history characters with allozyme markers were observed. The quantitative trait loci did not appear to be concentrated in major gene complexes. Often many loci were involved, sometimes with effects opposite to those expected from the population values. Main effects of the linkage groups appeared to be more important than interaction effects in determining variability. It also appeared that there is a positive correlation between the number of heterozygous allozyme loci and generative growth.

  11. Duplication of Locus Coding of Malate Dehydrogenase in Populus tomentosa Carr.

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Horizontal starch-gel electrophoresis was used to study crude enzyme extraction from young leaves of 234 clones of Populus tomentosa Carr. selected from nine provenances in North China. Ten enzyme systems were resolved. One hundred and fifty-six clones showing unusual allozyme band patterns at locus Mdh-1 were found. Three allozyme bands at locus Mdh-1 were 9:6:1 in concentration. Further studies on the electrophoretic patterns of ground mixed pollen extraction of 30 male clones selected at random from the 156 clones were conducted and it was found that allozyme bands at locus Mdh-1 were composed of two dark-stained bands and a weak band. Only one group of the malate dehydrogenase (MDH) zymogram composed of two bands was obtained from the electrophoretic segregation of pollen leachate of the same clones. A comparison of the electrophoretic patterns one another suggested that the locus Mdh-1 coding malate dehydrogenase in diploid species of P. tomentosa was duplicated. The duplicate gene locus possessed three same alleles and was located in mitochondria. The locus duplication of alleles coding malate dehydrogenase in P. tomentosa was discovered and reported for the first time.

  12. Farmed cod escapees and net-pen spawning left no clear genetic footprint in the local wild cod population

    Directory of Open Access Journals (Sweden)

    Rebekka Varne

    2015-11-01

    Full Text Available This study investigated a potential genetic introgression from farmed to wild cod Gadus morhua L. in the Trondheimsfjord, Norway. During the first 2 yr of operation of a cod farm in the inner part of the fjord, 2 large escape events and extensive pen spawning were reported. Analyses of 4 allozyme markers revealed no significant changes in allele frequencies between samples of wild cod before and after cod farming, although prominent allele frequency differences were demonstrated between wild and farmed samples. Analyses of 10 DNA markers showed a significant change between pre- and post-farming samples, due to contradictory allele frequency differences at Tch11, Pan I and Gmo132. Excluding those 3 markers due to null alleles (Tch11 and selection (Gmo132 and Pan I, the DNA markers paralleled the non-changed allele frequency signal from the allozymes. The topographies of the allozyme- and DNA-based dendrogram of the samples were congruent. Recaptures of tagged and released farmed cod indicated a seemingly random diffusion throughout the fjord and ended after approx. 6 mo. During an ongoing pen spawning, plankton net surveys sampling for cod eggs in the surroundings of the cod farm suggested the eggs originated from the farm. No larvae were present in the plankton samples. The apparent absence of introgression is explained relative to fitness and survival of pen-spawned larvae and adult escapees, and to a purging effect of the estuarine circulation of the Trondheimsfjord.

  13. Panax ginseng natural populations: their past, current state and perspec-tives

    Institute of Scientific and Technical Information of China (English)

    Yuri N ZHURAVLEV; Olga G KOREN; Galina D REUNOVA; Tamara I MUZAROK; Tatiyana Yu GORPENCHENKO; Irina L KATS; Yuliya A KHROLENKO

    2008-01-01

    Aim:The mating system of Panax ginseng, genetics and ontogenetic structure of its natural populations of Primorye (Russia) were investigated. Methods: Genetic diversity was assessed using allozyme and the fluorescently based au-tomated amplified fragment length polymorphism (AFLP) and simple sequence repeats (SSR) markers. Results: Total genetic diversity at species level is low with allozyme assay (0.023), and high with AFLP (0.255) and SSR (0.259) meth-ods. It is observed within populations according to allozyme (>99%), AFLP (>85%), and SSR (>73%) assays. The indices of genetic variability distribution point out the re-colonization of the Sikhote-Alin by ginseng plants from southern refuges during the warming period in the early Holocene. The capability of gin-seng plants to cross- and self-pollinate was shown and the assumption that Panax ginseng is a facultative apomictic plant was confirmed. The reproductive system of ginseng possesses high plasticity and stability of the fertilization process that help the species to survive in stress conditions. Disturbances caused by external or internal factors can be reduced due to the morphogenetic potential of ginseng ovule or apomictic embryo development. Analysis of life stages structure of gin-seng populations demonstrates that all of them are not full-constituents because some life stages are absent or occur rarely. Conclusion: In all 3 populations, virgin and young generative individuals are predominant. This means that popu-lations studied are viable and the reintroduction of natural ginseng population is possible yet.

  14. Genetic structure and indirect estimates of gene flow in three taxa of Cucurbita (Cucurbitaceae) in western Mexico.

    Science.gov (United States)

    Montes-Hernandez, Salvador; Eguiarte, Luis E

    2002-07-01

    Cultivated squash (Cucurbita argyrosperma ssp. argyrosperma and C. moschata) are important in the Mexican traditional agroecosystem. They are typically cultivated within maize fields where adjacent populations of a wild, close relative, C. argyrosperma ssp. sororia, occur. Consequently, there are ample opportunities for gene flow between domesticated and free-living Cucurbita populations. We used allozymes to examine genetic variation and gene flow among these three Cucurbita taxa in the state of Jalisco in Western Mexico. Twelve polymorphic allozyme loci were used to calculate genetic diversity for 16 populations of Cucurbita. We found high levels of genetic variation: polymorphism of 0.96, mean allelic diversity of 2.08, average expected heterozygosity 0.407, and little differentiation among conspecific populations (D = 0.081; F(ST) = 0.087; N(e)m = 5.22). These findings indicate that Cucurbita possess a high pollen dispersal potential, a somewhat surprising result considering they have specialist pollinators. Unweighted pair group method with arithmetic means (UPGMA) analysis of allozymes suggests the existence of at least two distinct groups of populations, one consisting of both subspecies of C. argyrosperma and another consisting of C. moschata.

  15. Genetic relationships and reproductive-isolation mechanisms among the Fejervarya limnocharis complex from Indonesia (Java) and other Asian countries.

    Science.gov (United States)

    Djong, Tjong Hon; Islam, Mohammed Mafizul; Nishioka, Midori; Matsui, Masafumi; Ota, Hidetoshi; Kuramoto, Mitsuru; Khan, Md Mukhlesur Rahman; Alam, Mohammad Shafiqul; Anslem, De Silva; Khonsue, Wichase; Sumida, Masayuki

    2007-04-01

    In order to elucidate the genetic relationships and reproductive-isolation mechanisms among the Fejervarya limnocharis complex from Indonesia and other Asian countries, allozyme analyses and crossing experiments were carried out using 208 individuals from 21 localities in eight Asian countries. The allozyme analyses revealed that 17 enzymes examined were controlled by genes at 27 loci, and that 7.9 phenotypes were produced by 5.2 alleles on average. The two species recognized in F. limnocharis sensu lato from Southeast Asia (i.e., F. limnocharis sensu stricto and F. iskandari) were found to occur sympatrically at three localities (Bogor, Cianjur and Malingping), all on Java, Indonesia. Fejervaya iskandari was dominant at each of these localities and showed substantial geographic genetic variation. Laboratory-produced hybrids between F. limnocharis and F. iskandari from Java became underdeveloped and died at the tadpole stage, suggesting that these species are completely isolated by hybrid inviability. Hybrids between topotypic F. limnocharis and the Malaysian and Japanese conspecific populations developed normally to metamorphosis. Likewise, hybrids between topotypic F. iskandari and the Thailand and Bangladesh conspecific populations also showed normal viability throughout larval development. The present allozyme analyses and crossing experiments strongly suggested the presence of two distinct forms, the large type and the small type, in the F. limnocharis complex from Asia, and further subdivision of the large type into the F. limnocharis assemblage and the F. iskandari assemblage. The small type was found in samples from India, Thailand, Bangladesh and Sri Lanka, and included at least three different species. The sample from Pilok, Thailand, was considered to represent an undescribed species.

  16. The Atlantic-Mediterranean transition: discordant genetic patterns in two seabream species, Diplodus puntazzo (Cetti) and Diplodus sargus (L.).

    Science.gov (United States)

    Bargelloni, L; Alarcon, J A; Alvarez, M C; Penzo, E; Magoulas, A; Palma, J; Patarnello, T

    2005-09-01

    Sparids are a group of demersal perciform fish of high commercial value, which have experienced an extensive radiation, particularly in the Mediterranean, where they occupy a variety of different niches. The present study focuses on two species: Diplodus sargus and D. puntazzo, presenting a wide distribution from the Mediterranean to the eastern Atlantic coasts. They display similar ecological behaviour and are evolutionary closely related. Both are highly appreciated in fisheries and D. puntazzo is currently under domestication process. However, little is know on their population structure and it is an open question whether any genetic differentiation exists at the geographic level. To address this issue we examined sequence variation of a portion of the mitochondrial DNA (mtDNA) control region in population samples of each of the two species collected over a wide geographic range. In addition to the mtDNA, analysis of nuclear loci (allozymes) was included in the study to compare patterns revealed by nuclear and mitochondrial markers. The studied samples covered an area from the eastern Mediterranean to the Portuguese coasts immediately outside the Gibraltar Strait. The two species revealed a level of sequence polymorphism remarkably different for the control region with the D. puntazzo and D. sargus showing 111 and 28 haplotypes, respectively. Such a difference was not detected with allozyme markers. The two species also showed large differences in their population structure. While D. puntazzo presented a marked genetic divergence between the Atlantic and Mediterranean samples, D. sargus showed little intraspecific differentiation. These results were supported using both mtDNA and allozyme markers, and were interpreted as the consequence of differences in the history of the two species such as fluctuations in the effective population size due to bottlenecks and expansions, possibly combined with present-day differences in levels of gene flow.

  17. Paternity and gene dispersal in limber pine (Pinus flexilis James).

    Science.gov (United States)

    Schuster, W S; Mitton, J B

    2000-03-01

    This study provides empirical information on intrapopulation gene dispersal via pollen, the size of genetic 'neighbourhoods', and interpopulation gene flow in a long-lived conifer, limber pine (Pinus flexilis). We used allozyme loci for a paternity analysis of 518 seeds produced in an isolated population of limber pine located in north-eastern Colorado, U.S.A., separated by 2 km from the nearest conspecific trees and nearly 100 km from populations in the Rocky Mountains. We also used indirect techniques (FST analyses) to estimate gene flow rates among subdivisions of the study population and among five widely separated populations. Within the main study population limber pine exhibited a polymorphism level of 50%, observed heterozygosity of 0.159, and 2.36 alleles per polymorphic locus. Mountain populations were slightly more variable. The main study population showed significant differentiation in allozymes among neighbouring subpopulations. The mean FST was 0.031 and the gene flow rate among subpopulations was estimated as 7.8 migrants per generation. Among widely separated populations the mean FST was 0.035 and the gene flow rate was estimated as 6.9 migrants per generation. The paternity analysis indicated a best estimate of 6.5% pollen immigration (minimum 1.1%) from populations 2 km to 100+ km away. For 4% of the seeds examined, paternity could be ascribed to a single tree in the study population. Fractional paternity and likelihood methods were used to estimate pollen dispersal distances for the remainder of the seeds. Mean pollen dispersal distance was estimated at 140 m using the fractional method, similar to results from the other techniques. This compares with a mean distance of 172 m between potential mates. These results suggest near-panmictic pollen dispersal over this population, which covers about 15 ha. The observed allozyme differences and surprisingly low estimates of among-subpopulation gene flow are ascribed to a probable restriction of gene

  18. [Detection of the mitochondrial DNA haplotype characteristic of the least cisco (Coregonus sardinella, Valenciennes, 1848) in the vendace (C. albula, Linnaeus, 1758) population of Vodlozero (the Baltic Sea basin)].

    Science.gov (United States)

    Borovikova, E A; Makhrov, A A

    2009-01-01

    Analysis of the nucleotide sequence of the mitochondrial ND-1 gene in the vendace population in lake Vodlozero (the eastern part of the Baltic Sea basin) revealed a sequence variant that is closely related to that of the least cisco of Siberia (the Indigirka River). Thus, together with the results of morphological and allozyme analysis of this population performed earlier, the results obtained in this study are suggestive of the immigration of the least cisco to the Baltic Sea basin during the last glaciation.

  19. Epigenetics of dominance for enzyme activity

    Indian Academy of Sciences (India)

    Kuldip S Trehan; Kulbir S Gill

    2002-03-01

    We have isolated and purified two parental homodimers and a unique heterodimer of acid phosphatase [coded by Acph-11.05() and Acph-10.95()] from isogenic homozygotes and heterozygotes of Drosophila malerkotliana. and produce qualitatively different allozymes and the two alleles are expressed equally within and across all three genotypes and and play an equal role in the epigenetics of dominance. Subunit interaction in the heterodimer over a wide range of H+ concentrations accounts for the epigenetics of dominance for enzyme activity.

  20. Intrageneric phylogeny of Acomys (rodentia, muridae) using mitochondrial gene cytochrome b.

    Science.gov (United States)

    Barome, P O; Monnerot, M; Gautun, J C

    1998-06-01

    This paper investigates interspecies relationships within the genus Acomys (spiny mice) by analyzing entire mitochondrial cytochrome b gene (1141 bp). This gene provides strong phylogenetic signal, as shown by high support of the topology obtained (bootstrap value and RNA support number). The phylogeny is congruent with inferences from allozymes for the species considered. Controversial taxonomy of Acomys cahirinus, dimidiatus, airensis, and ignitus is clarified, with their specific ranks confirmed on the basis of tree topology and nucleotide distances. Phylogenetic relationship between the undescribed species Acomys sp. from west Africa and A. airensis argue in favor of two distinct colonization events in this zone.

  1. Asexual reproduction and molecular systematics of the sea anemone Anthopleura krebsi (Actiniaria: Actiniidae).

    Science.gov (United States)

    Gomes, Paula Braga; Zamponi, Mauricio Oscar; Solé-Cava, Antonio Mateo

    2003-03-01

    In this paper we use allozyme analyses to demonstrate that individuals in Anthopleura krebsi aggregates are monoclonal. Additionally, sympatric samples of the red and the green colour-morphs of A. krebsi from Pernambuco, Brazil were genetically compared and no significant differences were observed between them (gene identity = 0.992), indicating that they do not belong to different biological species. All individuals within aggregates of the green colour-morph were found to be identical over the five polymorphic loci analysed. Such results would be extremely unlikely (P asexual reproduction in this species.

  2. Three new species of the salamander genus Hynobius (Amphibia, Urodela, Hynobiidae) from Kyushu, Japan.

    Science.gov (United States)

    Nishikawa, Kanto; Matsui, Masafumi

    2014-08-14

    Three new species of lotic breeding Hynobius, formerly assigned to H. boulengeri, are described from the Kyushu region, southwestern Japan. They differ from all the known congeners by a unique combination of body size, character ratios, coloration, mtDNA, and allozymic characteristics. Together with H. stejnegeri they form a clade, which is not a sister group of H. boulengeri, and their speciation in Kyushu is surmised to have occurred at the end of Miocene, accompanied by differentiations in larval period and metamorphosing size. Measures of conservation of these new species are discussed briefly. 

  3. [Ploidy and genetic structure of hybrid populations of water frogs Pelophylax esculentus (L., 1758) complex (Amphibia, Ranidae) of Ukraine].

    Science.gov (United States)

    Mezhzherin, S V; Morozov-Leonov, S Iu; Rostovskaia, O V; Shabanov, D A; Sobolenko, L Iu

    2010-01-01

    The present study of green frog hybrid populations of Ukraine, including analysis of allozyme variability and planimetric analysis oferythrocytes size has confirmed that the unique region in this area is the Severski Donets basin The allopolyploid individuals there are met very frequently (5.7% of all investigated frogs). In other areas of Ukraine only two polyploid hybrids have been recorded. Beside that, one frog was defined as triploid Rana ridibundus. According to our investigations, all triploid hybrids from the Severski Donets basin are identified as P. esculentu (=lessonae)--2 ridibundus males.

  4. Population genetic structure and mating system in the hybrid zone between Pinus sibirica Du Tour and P. pumila (Pall.) Regel at the Eastern Baikal Lake shore

    OpenAIRE

    E. A. Petrova; S. N. Goroshkevich; Y.S. Belokon; D.V. Politov

    2013-01-01

    Genetic structure of sympatric Pinus sibirica Du Tour and P. pumila (Pall.) Regel populations and putative interspecific hybrids between them was analyzed in the Baikal Lake region (Barguzin Biosphere Natural Reserve, Davsha River basin) by means of 31 allozyme loci controlling 18 enzyme systems. Several alleles at loci Adh-1, Fest-2, Lap-3, Pgi-1, Sod-3 and Skdh-1 were diagnostic for P. sibirica, while alleles typical for P. pumila were detected at loci Gdh, Got-3, Lap-3, Mdh-2, Mdh-4, Pepca...

  5. A FORTRAN program for analysis of genotypic frequencies and description of the breeding structure of populations.

    Science.gov (United States)

    Black, W C; Krafsur, E S

    1985-08-01

    A FORTRAN program, "Genestats" was designed to analyse genotypic and allelic frequencies in subpopulations. The genotypes of individuals gathered from electrophoretic analysis at one or more loci are submitted. The program subsequently calculates allele frequencies, determines if significant heterogeneity exists among subpopulations, tests for departures from random mating in subpopulations and calculates F-statistics. A description of the statistical methods is provided. Printout from analysis of allozyme data collected from field subpopulations of the house fly (Musca domestica L.) is provided to illustrate and evaluate the computational methods.

  6. A tiger mouse and relatives. Variants caused by an activated transposable element?

    Science.gov (United States)

    Wallace, M E; Nash, H R

    1984-01-01

    In a laboratory-bred population of wild Peruvian house mice, one male had an excessive rate of non-pairing of the X and Y chromosomes. After crossing him with laboratory stock mice, a mouse of very unusual phenotype appeared from a yellow (AyA) mother. He was yellow with black dorsal stripes; hence Tiger. He was mated to many females, and inbred F2 and F3 generations were raised. There were no more tiger phenotypes, but his F1 contained an excess of black-and-tans over yellows, showing him to be a gonosomic mosaic Ayat/atat; the homozygous cell line probably arose from the heterozygous one. The mitotic karyotype was normal. Some of Tiger's mates were of known allozyme types and their progeny were scored. The allozyme segregations were normal, except at the Es-3 locus (esterase-3), for which Tiger was typed as homozygous. Several unusual events among Tiger's close relatives included a mutation to an unstable pattern mutant, three probable translocations, and several cases of somatic defect. All unusual mice derived from Tiger's yellow mother, whose genome was one-quarter Peruvian. Yellow is associated with an ecotropic murine leukemia virus. The Peru genome is characterized by a high occurrence of mutation and aberrant karyotypes. It is suggested that something from the Peru genome in Tiger's mother caused instability of the DNA sequence associated with yellow, with related disturbance at different locations thereafter. The nature of this instability, and of the Peru genome, is discussed.

  7. Speciation process of Salvia isensis (Lamiaceae), a species endemic to serpentine areas in the Ise-Tokai district, Japan, from the viewpoint of the contradictory phylogenetic trees generated from chloroplast and nuclear DNA.

    Science.gov (United States)

    Sudarmono; Okada, Hiroshi

    2007-07-01

    To understand the speciation process of Salvia isensis (Lamiaceae), a species endemic to a special environment (serpentine areas in the Ise-Tokai district, central Honshu, Japan), chloroplast DNA (cpDNA) and nuclear ribosomal DNA (nrDNA) were employed to analyze the phylogenetic relationships of S. isensis with related species in Japan. Allozymic polymorphisms were also used to analyze genetic relationships among Salvia species. A contradiction in the phylogenetic positions of species studied was detected when phylogenetic trees were constructed using cpDNA or nrDNA, i.e., S. isensis was a sister to the other species in phylogenetic trees generated from cpDNA, while S. japonica was a sister to the other species in the case of nrDNA. Genetic relationships between Salvia species estimated from allozymic polymorphisms did not contradict to the topology for nrDNA. Using the present results, the speciation process of S. isensis is discussed with regard to introgressive gene exchanges between related species.

  8. [Variation in mitochondrial DNA in Far Eastern mullet pilengas, Liza haematocheilus Temminck and Schlegel, acclimatized in the Azov-Black Sea basin].

    Science.gov (United States)

    Salmenkova, E A; Gordeeva, N V; Omel'chenko, V T; Makhotkin, M A; Dudkin, S I

    2007-09-01

    This study continues the investigation of genetic variation in the populations of native and acclimatized in the Azov-Black Sea basin pilengas from the Sea of Japan. The previous comparison based on allozyme analysis was supplemented by analysis of restriction polymorphism of a mitochondrial DNA fragment containing the cytochrome b gene and the D-loop. Five out of fifteen endonucleases tested detected polymorphic sites. In the samples of native and acclimatized pilengas, five common haplotypes were found; ten and three "population-specific" haplotypes were detected in the Far Eastern and the Azov populations, respectively. The differences in haplotype distributions between these populations were highly significant (P < 0.001). The mtDNA variation was lower in the Azov than in the Far Eastern population (haplotype diversity mu respectively 6.35 +/- 0.27 and 9.14 +/- 0.55), which is in good agreement with the decrease in the number of polymorphic loci and the mean number of alleles per locus, found earlier for allozyme markers in this population. The reasons for these differences in the acclimatized population are discussed.

  9. DNA variation of the mammalian major histocompatibility complex reflects genomic diversity and population history

    Energy Technology Data Exchange (ETDEWEB)

    Yuhki, Naoya; O' Brien, S.J. (National Cancer Institute, Frederick, MD (USA))

    1990-01-01

    The major histocompatibility complex (MHC) is a multigene complex of tightly linked homologous genes that encode cell surface antigens that play a key role in immune regulation and response to foreign antigens. In most species, MHC gene products display extreme antigenic polymorphism, and their variability has been interpreted to reflect an adaptive strategy for accommodating rapidly evolving infectious agents that periodically afflict natural populations. Determination of the extent of MHC variation has been limited to populations in which skin grafting is feasible or for which serological reagents have been developed. The authors present here a quantitative analysis of restriction fragment length polymorphism of MHC class I genes in several mammalian species (cats, rodents, humans) known to have very different levels of genetic diversity based on functional MHC assays and on allozyme surveys. When homologous class I probes were employed, a notable concordance was observed between the extent of MHC restriction fragment variation and functional MHC variation detected by skin grafts or genome-wide diversity estimated by allozyme screens. These results confirm the genetically depauperate character of the African cheetah, Acinonyx jubatus, and the Asiatic lion, Panthera leo persica; further, they support the use of class I MHC molecular reagents in estimating the extent and character of genetic diversity in natural populations.

  10. Genetic diversity in the Homosporous Fern Ophioglossum vulgatum (Ophioglossaceae) from South Korea: inference of mating system and population history.

    Science.gov (United States)

    Chung, Mi Yoon; López-Pujol, Jordi; Chung, Jae Min; Moon, Myung-Ok; Chung, Myong Gi

    2013-03-01

    It is generally believed that the members of Ophioglossaceae have subterranean, potentially bisexual gametophytes, which favor intragametophytic selfing. In Ophioglossaceae, previous allozyme studies revealed substantial inbreeding within Botrychium species and Mankyua chejuense. However, little is known about the mating system in species of the genus Ophioglossum. Molecular marker analyses can provide insights into the relative occurrence of selfing versus cross-fertilization in the species of Ophioglossum. We investigated allozyme variation in 8 Korean populations of the homosporous fern Ophioglossum vulgatum to infer its mating system and to get some insight into the population-establishment history in South Korea. We detected homozygous genotypes for alternative alleles at several loci, which suggest the occurrence of intragametophytic self-fertilization. Populations harbor low within-population variation (% P = 7.2, A = 1.08, and H (e) = 0.026) and a high among-population differentiation (F (ST) = 0.733). This, together with the finding that alternative alleles were fixed at several loci, suggests that the number and size of populations of O. vulgatum might have been severely reduced during the last glaciation (i.e., due to its in situ persistence in small, isolated refugia). The combined effects of severe random genetic drift and high rates of intragametophytic selfing are likely responsible for the genetic structure displayed by this homosporous fern. Its low levels of genetic diversity in South Korea justify the implementation of some conservation measures to ensure its long-term preservation.

  11. The influence of space in genetic-environmental relationships when environmental heterogeneity and seed dispersal occur at similar scale.

    Science.gov (United States)

    Volis, S; Anikster, Y; Olsvig-Whittaker, L; Mendlinger, S

    2004-02-01

    We tested the importance of microenvironmental topographic parameters as predictors of emmer wheat genetic variation using three classes of single-locus (or at most several-loci) genetic markers (allozymes, glutenins, and qualitative traits) and two classes of markers of polygenic inheritance (phenological and morphological traits). Canonical correspondence analysis (CCA) and redundancy analysis (RDA) detected a significant effect of spatially structured environmental variation on genetic differences between plants for allozymes, glutenins, and quantitative morphological and phenological traits. However, after removing a spatial component of variation in partial CCA and partial RDA, the relationship of the remaining environmental variation with these genetic markers could be explained by chance alone, allowing us to rule out microniche topographic specialization in emmer wheat. Topographic autocorrelation exhibited a certain degree of similarity with genetic marker autocorrelation, indicating similar scales of environmental heterogeneity and seed flow. The detected population genetic structure agrees with one expected under isolation by distance as a result of limited gene flow. A negative relationship of genetic similarity with the logarithm of distance between plants was detected for both molecular markers and quantitative traits, which differed in the strength but not the pattern of association.

  12. Population genetic structure and mating system in the hybrid zone between Pinus sibirica Du Tour and P. pumila (Pall. Regel at the Eastern Baikal Lake shore

    Directory of Open Access Journals (Sweden)

    E.A. Petrova

    2013-12-01

    Full Text Available Genetic structure of sympatric Pinus sibirica Du Tour and P. pumila (Pall. Regel populations and putative interspecific hybrids between them was analyzed in the Baikal Lake region (Barguzin Biosphere Natural Reserve, Davsha River basin by means of 31 allozyme loci controlling 18 enzyme systems. Several alleles at loci Adh-1, Fest-2, Lap-3, Pgi-1, Sod-3 and Skdh-1 were diagnostic for P. sibirica, while alleles typical for P. pumila were detected at loci Gdh, Got-3, Lap-3, Mdh-2, Mdh-4, Pepca, Pgi-1, Pgd-2, Pgd-3, Pgm-1 and Pgm-2. All hybrids were heterozygous for the diagnostic Skdh-2 locus. Classification into hybrids and parental species using PCA analysis of multilocus allozyme genotypes had good correspondence with diagnoses made by morphological and anatomical analyses. Approximately 27% of embryos in P. pumila seeds had P. sibirica paternal contribution, and 8% of haplotypes in effective pollen pool combined alleles typical for P. pumila and P. sibirica, and therefore were classified as pollinated by the hybrids. About 83% of embryos in seeds from the hybrids most likely originated from fertilization by P. sibirica pollen, 14% from P. pumila and 3% from hybrid trees. This result favours the view that hybrids make both male and female contributions to the reproductive output of the population and confirm the presence of backcrosses and F2 hybrids.

  13. [Genetic Differentiation of the Three Species of Genus Astragalus L. of Section Cenantrum Bunge (Fabaceae)].

    Science.gov (United States)

    Dymshakova, O S; Krivenko, D A; Belyaev, A Yu; Verkhozina, A V

    2015-08-01

    Genetic differentiation based on allozyme data was detected between species of the genus Astragalus L., section Cenantrum Bunge (Fabaceae): A.frigidus (L.) A. Gray s.l., A. mongholicus Bunge s. l, and A. sericeocanus Gontsch, which is endemic to the Northeast coast of Lake Baikal. The results of allozyme analysis confirm the natural division of the section into subsections based on morphological features. Differences between A. frigidus (subsection Elliptica Gontsch.) and A. mongholicus and A. sericeocanus (subsection Semilunaria Gontsch.) were observed. These differences were caused by the presence of species-specific alleles and the allele frequencies of the primary alleles, DN = 1.24. The genetic distance obtained for A. mongholicus and A. sericeocanus (0.10) corresponds to the status of closely related species of one subsection. Between populations of A. frigidus and between populations of A. mongholicus from the central part of areal, DN = 0.02 and 0.03 respectively. This genetic distance corresponds to the interpopulation level and was determined by the allele frequencies. The peripheral population of A. mongholicus is separated (DN = 0.36), which is probably due to the long isolation and the "founder effect."

  14. Structure of Allozymatic Diversity of Ten Temperate and Adapted Exotic Breeding Populations of Maize (Zea mays L.)

    Institute of Scientific and Technical Information of China (English)

    ZHENG Da-hao; YU Yang; WANG Zhen-ping; LI Yan-ru

    2009-01-01

    Ten temperate and adapted exotic breeding populations of maize were studied with electrophoretic techniques. Three isozyme systems coded by nine allozyme loci were used for evaluating the genetic variability within and among populations.The results revealed that 78.57% of allozyme loci were polymorphic. Low allelic variation with a mean number of 1.84 alleles per locus per population was detected. But, these populations still maintained higher level of heterozygosity;moreover, the exotic populations had greater gene diversity than the temperate populations. All the populations were non-panmictic with negative Wright's fixation indexes (-0.091- -0.424). The tropical BS16 was typified by maximum allelic richness, percent of polymorphic loci and heterozygosity. More than 93% of the gene diversity maintained within populations, and the genetic differentiation among populations was low (0.002-0.191). Multivariate analysis demonstrated that the tropical BS29 diverged from other populations in the reverse direction. The temperate BS9 and tropical BS 16 were divergent each other, and highly differentiated from other temperate and tropical populations, consequently, these two populations would be analogically postulated as potential germplasms to establish new heterotic groups for temperate maize breeding programs.

  15. 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.

  16. The role of stress proteins in responses of a montane willow leaf beetle to environmental temperature variation

    Indian Academy of Sciences (India)

    Elizabeth P Dahlhoff; Nathan E Rank

    2007-04-01

    The heat shock response is a critical mechanism by which organisms buffer effects of variable and unpredictable environmental temperatures. Upregulation of heat shock proteins (Hsps) increases survival after exposure to stressful conditions in nature, although benefits of Hsp expression are often balanced by costs to growth and reproductive success. Hsp-assisted folding of variant polypeptides may prevent development of unfit phenotypes; thus, some differences in Hsp expression among natural populations of ectotherms may be due to interactions between enzyme variants (allozymes) and Hsps. In the Sierra willow leaf beetle Chrysomela aeneicollis, which lives in highly variable thermal habitats at the southern edge of their range in the Eastern Sierra Nevada, California, allele frequencies at the enzyme locus phosphoglucose isomerase (PGI) vary across a climatic latitudinal gradient. PGI allozymes differ in kinetic properties, and expression of a 70 kDa Hsp differs between populations, along elevation gradients, and among PGI genotypes. Differences in Hsp70 expression among PGI genotypes correspond to differences in thermal tolerance and traits important for reproductive success, such as running speed, survival and fecundity. Thus, differential Hsp expression among genotypes may allow functionally important genetic variation to persist, allowing populations to respond effectively to environmental change.

  17. River basin-related genetic structuring in an endangered fish species, Chondrostoma lusitanicum, based on mtDNA sequencing and RFLP analysis.

    Science.gov (United States)

    Mesquita, N; Carvalho, G; Shaw, P; Crespo, E; Coelho, M M

    2001-03-01

    Chondrostoma lusitanicum is a Portuguese endemic cyprinid with a restricted distribution and reduced numbers in some basins, justifying its status as a threatened species. We examined genetic population structure using samples from throughout its geographical range in Portugal, using sequencing of b cytochrome and restriction fragment length polymorphism analysis of the NADH subunits 5 and 6. There was reduced within-population genetic variability but considerable among-population differentiation, particularly marked between both the Mira and Arade basins in the extreme south and other populations. These results confirm phylogeographic relationships suggested by previous fragmentary allozyme studies for C. lusitanicum, and are in accordance with allozyme and mitochondrial DNA data on phylogeography of coexisting cyprinid species of the genus Leuciscus. The levels of genetic divergence revealed by sequence and RFLP data showed strongly concordant patterns: geographical genetic structuring, with the definition of three distinct groups, was observed. The high values of nucleotide divergence and pairwise sequence divergence of the Mira and Arade groups, when compared with all other samples, support a distinct taxonomic status probably at the species level. Results are also discussed in relation to conservation of this highly fragmented species, in terms of Evolutionary Significant Units and Management Units.

  18. On gene pool divergence of the brown hare (Lepus europaeus, Pallas in Vojvodina

    Directory of Open Access Journals (Sweden)

    Đan Mihajla R.

    2004-01-01

    Full Text Available Today it is widely accepted that a conservation of genetic diversity increases chances of animal survival. The aim of this study was investigation of gene pool divergence of the brown hare (Lepus europaeus in Vojvodina. Allozymic diversity of 60 brown hares from different localities in Vojvodina was studied by polyacrylamide and starch gel electrophoresis at 31 putative structural gene loci. Only five loci: Idh-2, Pgd, Pgm, Es-1 and Es-D were polymorphic, possessing 2 to 6 different alleles. The value of average heterozygosity (Ho was 0.0427, while polymorphism (P99% was 8.4%. Nei's values of genetic distance (ranged from 0.000 to 0.029 and modified Roger's distance (ranged from 0.030 to 0.181 were calculated among hare populations. Apart from the relatively high values of heterozygosity and polymorphism, the nuclear gene pool diversity of brown hare population in Vojvodina based on allozyme variation is low and corresponds to the data obtained for the populations in Austria and Central Europe.

  19. Herança genética e desequilíbrio de ligação em locos de isoenzimas em Esenbeckia leiocarpa. Genetic inheritance and linkage disequilibrium in isozymes loci of Esenbeckia leiocarpa.

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Sícole SEOANE

    2004-06-01

    Full Text Available Oito sistemas enzimáticos (EST, IDH, PGM, PGI, MDH, PER, 6PGDH e SKDH codificando nove locos foram investigados em Esenbeckia leiocarpa. Quatro sistemas isoenzimáticos foram monomórficos (IDH, PGM, 6PGDH e SKDH e quatro polimórficos (EST, PGI, MDH e PER. A herança mendeliana foi confirmada para quatro locos, pelo teste de ajuste dos padrões de segregação observados em relação à razão de segregação esperada 1:1, em progênies de árvores heterozigotas. O desequilíbrio de ligação foi examinado para dez pares de locos. Apenas um simples par de locos parece estar em desequilíbrio de ligação, Est-1:Prx-1.Eight enzymes systems (EST, IDH, PGM, PGI, MDH, PER, 6PGDH and SKDH coding for nine loci were investigate in Esenbeckia leiocarpa. Four allozyme systems were monomorphic (IDH, PGM, 6PGDH and SKDH and four polymorphic (EST, PGI, MDH and PER. Mendelian inheritance was confirmed for four loci by testing the fit of band-pattern to 1:1 expected segregation ratio in progeny from heterozygous trees. Linkage disequilibrium was examined for ten pair of allozymes loci. A simple pair of loci appears to be in linkage disequilibrium, Est-1:Prx-1.

  20. Identificação de parentais e híbridos entre Vitis vinifera e Vitis rotundifolia utilizando polimorfismo enzimático e marcador RAPD Identification of parents and hybrids among Vitis vinifera and Vitis rotundifolia using isozyme polymorphism and rapd marker

    Directory of Open Access Journals (Sweden)

    Haiko Enok Sawazaki

    1996-01-01

    Full Text Available Identificaram-se parentais e híbridos entre Vitis vinifera (videiras comuns e V. rotundifolia (muscadínias, utilizando-se o polimorfismo enzimático e marcador RAPD (Random Amplified Polymorphic DNA. Os sistemas GOT (glutamato-oxalo-acetato-transaminase, IDH (isocitrato desidrogenase e PGI (fosfoglucose isomerase diferenciaram a muscadínia, sendo observadas cinco aloenzimas para o GOT, duas para o LAP (leucina aminopeptidase e quatro para o EST (esterase. Os sistemas PGI e IDH apresentaram-se como diméricos com o fenótipo de quatro aloenzimas em duas regiões e três em uma região respectivamente. O marcador RAPD apresentou polimorfismo que permitiu a diferenciação entre todos os cultivares. Os dendrogramas UPGMA (unweighted pair-group method with aritmetic mean obtidos pelas isoenzimas e pelo marcador RAPD foram semelhantes, sendo a aproximação mais forte entre 'Itália' e 'Rubi' que se ligaram aos cultivares Patrícia e A Dona. Os cultivares Piratininga e Eugênio, também bastante próximos, foram os seguintes a se ligarem às demais viníferas. Pelo polimorfismo enzimático e marcador RAPD, a muscadínia ficou bastante isolada dos outros grupos. Pelo método RAPD, aplicado às muscadínias, ao híbrido da Carolina do Norte NC66 C203-9, a um possível híbrido e seu parental feminino, observou-se o seguinte: os híbridos foram intermediários às muscadínias e viníferas, porém o possível híbrido se assemelhou ao parental feminino, enquanto o NC66203-9 apresentou bandas provenientes das muscadínias e viníferas, comprovando sua origem híbrida.Aiming to identify parents and hybrids among Vitis vinifera (bunch grapes and Vitis rotundifolia (muscadine grapes isozyme polymorphism and RAPD marker were used. GOT (glutamate oxaloacetate transaminase, IDH (isocitrate dehydrogenase and PGI (phosphoglucoisomerase systems could differentiate the muscadine, being identified five allozymes for GOT, two allozymes for LAP (leucine

  1. Inhibition of human alcohol and aldehyde dehydrogenases by acetaminophen: Assessment of the effects on first-pass metabolism of ethanol.

    Science.gov (United States)

    Lee, Yung-Pin; Liao, Jian-Tong; Cheng, Ya-Wen; Wu, Ting-Lun; Lee, Shou-Lun; Liu, Jong-Kang; Yin, Shih-Jiun

    2013-11-01

    Acetaminophen is one of the most widely used over-the-counter analgesic, antipyretic medications. Use of acetaminophen and alcohol are commonly associated. Previous studies showed that acetaminophen might affect bioavailability of ethanol by inhibiting gastric alcohol dehydrogenase (ADH). However, potential inhibitions by acetaminophen of first-pass metabolism (FPM) of ethanol, catalyzed by the human ADH family and by relevant aldehyde dehydrogenase (ALDH) isozymes, remain undefined. ADH and ALDH both exhibit racially distinct allozymes and tissue-specific distribution of isozymes, and are principal enzymes responsible for ethanol metabolism in humans. In this study, we investigated acetaminophen inhibition of ethanol oxidation with recombinant human ADH1A, ADH1B1, ADH1B2, ADH1B3, ADH1C1, ADH1C2, ADH2, and ADH4, and inhibition of acetaldehyde oxidation with recombinant human ALDH1A1 and ALDH2. The investigations were done at near physiological pH 7.5 and with a cytoplasmic coenzyme concentration of 0.5 mM NAD(+). Acetaminophen acted as a noncompetitive inhibitor for ADH enzymes, with the slope inhibition constants (Kis) ranging from 0.90 mM (ADH2) to 20 mM (ADH1A), and the intercept inhibition constants (Kii) ranging from 1.4 mM (ADH1C allozymes) to 19 mM (ADH1A). Acetaminophen exhibited noncompetitive inhibition for ALDH2 (Kis = 3.0 mM and Kii = 2.2 mM), but competitive inhibition for ALDH1A1 (Kis = 0.96 mM). The metabolic interactions between acetaminophen and ethanol/acetaldehyde were assessed by computer simulation using inhibition equations and the determined kinetic constants. At therapeutic to subtoxic plasma levels of acetaminophen (i.e., 0.2-0.5 mM) and physiologically relevant concentrations of ethanol (10 mM) and acetaldehyde (10 μm) in target tissues, acetaminophen could inhibit ADH1C allozymes (12-26%) and ADH2 (14-28%) in the liver and small intestine, ADH4 (15-31%) in the stomach, and ALDH1A1 (16-33%) and ALDH2 (8.3-19%) in all 3 tissues. The

  2. Mating system and seed variation of Acacia hybrid (A. mangium × A. auriculiformis)

    Indian Academy of Sciences (India)

    Chin-Hong Ng; Soon-Leong Lee; Kevin Kit-Siong Ng; Norwati Muhammad; Wickneswari Ratnam

    2009-04-01

    The mating system and seed variation of Acacia hybrid (A. mangium × A. auriculiformis) were studied using allozymes and random amplified polymorphic DNA (RAPD) markers, respectively. Multi-locus outcrossing rate estimations indicated that the hybrid was predominantly outcrossed (mean±s.e. $t_{m} = 0.86\\pm 0.01$). Seed variation was investigated using 35 polymorphic RAPD fragments. An analysis of molecular variance (AMOVA) revealed the highest genetic variation among seeds within a pod (66%–70%), followed by among pods within inflorescence (29%–37%), and the least variation among inflorescences within tree (< 1%). In addition, two to four RAPD profiles could be detected among seeds within pod. Therefore, the results suggest that a maximum of four seeds per pod could be sampled for the establishment of a mapping population for further studies.

  3. Synchronous polyandry and multiple paternity in the frog Crinia georgiana (Anura: Myobatrachidae).

    Science.gov (United States)

    Roberts; Standish; Byrne; Doughty

    1999-03-01

    Multiple paternity has rarely been reported in anuran amphibians, with only three previous documented examples. For the Australian frog Crinia georgiana, we observed synchronous polyandry in an average of 44% of matings observed at four field sites. This suggests matings involving more than one male are common in this species. One to eight males were observed in amplectant groups with second males amplexed ventrally. Genetic analyses, using allozyme electrophoresis, of offspring from two matings indicated that at least two of three possible males fathered offspring. Third males were unlikely to have shared paternity, explained by their inappropriate position during amplexus. Multiple paternity may be more common in frogs than has been reported. Copyright 1999 The Association for the Study of Animal Behaviour.

  4. Challenging the knowledge bio-based fisheries of tropical tuna stocks: assessing genomic population structure in yellowfin (Thunnus albacares

    Directory of Open Access Journals (Sweden)

    Carlo Pecoraro

    2014-06-01

    The YFT genetic population structure will be investigated at global scale (between- and within-ocean, using next-generation sequencing (2b-RAD method for genotyping by sequencing through examination of Single Nucleotide Polymorphisms (SNPs. This approach can represent a major advancement over classical techniques used until now (i.e. based on allozymes, DNA microsatellites and mitochondrial DNA in order to reveal the YFT stock structure between and within each ocean. The novel genomic data that will be generated can potentially reveal YFT population structure at a level not possible through classical latter approaches with significant implication for YFT stock assessment and management. In fact a carelessness of the proper genetic structure might lead to the over-exploitation and depletion of some populations with dramatic consequences for the long-term conservation and sustainable use of YFT stocks.

  5. Ploidy differences represent an impassable barrier for hybridization. Is there an exception among botiid loaches (Cypriniformes: Botiidae?

    Directory of Open Access Journals (Sweden)

    Joerg Bohlen

    2015-12-01

    Full Text Available One of the most efficient mechanisms to keep animal lineages separate is a difference in ploidy level, since hybrid offspring from parents with different ploidy level are generally sterile. In the freshwater fish family Botiidae, ploidy difference has been held responsible for the separation of its two subfamilies, the tetraploid Botiinae and the diploid Leptobotiinae. However, the species ‘Botia’ zebra combines a number of morphological characters of a genus of Leptobotiinae with morphological characters of a genus of Botiinae, giving rise to the idea that it is the result of a hybridisation event between two species from different subfamilies. We here present a closer morphological examination, an allozyme comparison between ‘Botia’ zebra and the two potential parental species, a cytogenetic analyses as well as phylogenetic reconstructions basing on the complete mitochondrial cytochrome b gene and on the nuclear RAG-1 gene. The results are discussed in a phylogenetic, geographic and ecologic context.

  6. Detecting population structure in a high gene-flow species, Atlantic herring (Clupea harengus): direct, simultaneous evaluation of neutral vs putatively selected loci

    DEFF Research Database (Denmark)

    André, C.; Larsson, L. C.; Laikre, L.;

    2010-01-01

    DNA, with one microsatellite locus, Cpa112, previously shown to be influenced by divergent selection associated with salinity, and one locus located in the major histocompatibility complex class IIA (MHC-IIA) gene, using the same individuals across analyses. Samples were collected in 2002 and 2003...... at two locations in the North Sea, one location in the Skagerrak and one location in the low-saline Baltic Sea. Levels of divergence for putatively neutral markers were generally low, with the exception of single outlier locus/sample combinations; microsatellites were the most statistically powerful...... to detect population structure in Atlantic herring (Clupea harengus), a migratory pelagic species with large effective population sizes. We compared the spatial and temporal patterns of divergence and statistical power of three traditional genetic marker types, microsatellites, allozymes and mitochondrial...

  7. Population genetic structuring in Opisthorchis viverrini over various spatial scales in Thailand and Lao PDR.

    Science.gov (United States)

    Laoprom, Nonglak; Sithithaworn, Paiboon; Andrews, Ross H; Ando, Katsuhiko; Laha, Thewarach; Klinbunga, Sirawut; Webster, Joanne P; Petney, Trevor N

    2012-01-01

    Khon Kaen Province in northeast Thailand is known as a hot spot for opisthorchiasis in Southeast Asia. Preliminary allozyme and mitochondrial DNA haplotype data from within one endemic district in this Province (Ban Phai), indicated substantial genetic variability within Opisthorchis viverrini. Here, we used microsatellite DNA analyses to examine the genetic diversity and population structure of O. viverrini from four geographically close localities in Khon Kaen Province. Genotyping based on 12 microsatellite loci yielded a mean number of alleles per locus that ranged from 2.83 to 3.7 with an expected heterozygosity in Hardy-Weinberg equilibrium of 0.44-0.56. Assessment of population structure by pairwise F(ST) analysis showed inter-population differentiation (Pviverrini over a small spatial scale which is similar to that found at a larger scale. This provides the basis for the investigation of the role of parasite genetic diversity and differentiation in transmission dynamics and control of O. viverrini.

  8. [GENETIC VARIABILITY OF MATERNAL PLANTS AND SEED EMBRYOS OF KOCH PINE POPULATIONS (PINUS KOCHIANA KLOTZSCH EX KOCH) IN CRIMEA].

    Science.gov (United States)

    Korshykov, I I; Kalafat, L O; Vynogradova, O M; Podgornyi, D Y

    2016-01-01

    Comparative studies of genetic variability were undertaken for 12 allozyme loci selections of trees and embryos of seed, and also for the crossing systems in five populations of Koch pine of (Pinus kochiana Klotzsch ex Koch) in Crimea. It was shown that in seed embryos the allelic variety peculiar to the maternal plants was restored, however the level of the available (H₀) heterozygosity was considerably lower, 0.286 and 0.189 respectively. For the embryos unlike the trees, in the majority of the analyzed loci the considerable divergence was specific in the actual distribution of genotypes from the theoretically expected according to Hardy- Weinberg law. The proportion of cross pollination at the unilocal (t(s)) estimation varied from 0.384 to 0.673 in the populations, while at the multilocal ones (t(m)) it was 0.639-0.841.

  9. [Genetic polymorphism of clones and their seed progeny in the scotch pine clone plantation].

    Science.gov (United States)

    Korshikov, I I; Demkovich, A E

    2010-01-01

    Genetic variation at 12 allozyme loci (10 of them being polymorphic ones) has been studied in the archive-clone plantation of 23 Pinus sylvestris plus-trees and their seed progeny in the south-east of Ukraine. More than a half of clones had 4-8 heterozygous loci, whereas their seed progeny was marked by a lower variation than maternal trees. Seed progeny was obtained at a high outcrossing rate (t(m) = 95%). The clone progeny was characterized by a high percentage of abnormal allele segregation in megagametophytes. There was also a high frequency of significant deviation in distribution of seed embryo genotypes from the theoretically expected one according to the Hardy-Weinberg law.

  10. Description of a new brown frog from Tsushima Island, Japan (Anura: Ranidae: Rana).

    Science.gov (United States)

    Matsui, Masafumi

    2014-09-01

    Because all available evidence from allozymes, mtDNA sequences, and artificial hybridization suggests presence of high genetic differentiation between populations of East Asian brown frogs currently assigned to Rana dybowskii Günther, 1876, I compared morphological characters between specimens from Tsushima Island of Japan and Maritime territory of Russia. The population from Tsushima is slightly, but significantly different from R. dybowskii from Russia, including the holotype. I therefore consider the Tsushima population to be specifically distinct, and describe it as a new species R. uenoi. The new species also occurs in the Korean Peninsula and adjacent islands, but the distributional relationships with R. dybowskii are unclear, as detailed distribution in northern Korea is lacking.

  11. Dichotomous electrophoretic taxonomic key for identification of sibling species A, B, and C of the Anopheles quadrimaculatus complex (Diptera: Culicidae).

    Science.gov (United States)

    Narang, S K; Kaiser, P E; Seawright, J A

    1989-03-01

    Samples of 17 populations of Anopheles quadrimaculatus Say from Florida, Alabama, Arkansas, Louisiana, Mississippi, Tennessee, New York, and New Jersey were analyzed for genetic variability at 33 enzyme loci. Statistical analysis of electromorph frequency distributions indicated that sympatric sibling (morphologically indistinguishable) species occurred in about 59% of the populations tested. The association of polytene chromosome and electrophoretic patterns of individual field-collected females confirmed species-specific diagnostic allozymes, which were useful in identifying sibling species A, B, and C and in estimating the proportions of each species at the 17 collection sites. A dichotomous electrophoretic key is presented for the identification of sibling species of the An. quadrimaculatus complex. The electrophoretic method is better than the ovarian polytene chromosome method, because mosquitoes of both sexes and females irrespective of their gonotrophic condition can be identified.

  12. [Macrogeographic genetic variability in the gastropod mollusk Littorina sitkana from the northwest Pacific].

    Science.gov (United States)

    Zaslavskaya, N I; Pudovkin, A I

    2005-03-01

    Variation at four highly polymorphic allozyme loci (inorganic pyrophosphatase, peptidase, and two esterase loci) was examined in 25 settlements of the marine snail Littorina sitkana (Mollusca, Gastropoda). The sampling localities covered a wide part of the species range: from the Peter the Great Bay (the Sea of Japan) at the southwest to the Mednyi Island (Commander Islands) at the northeast. Like other littorines lacking the pelagic stage, L. sitkana was characterized by significant genetic differentiation (G(ST) for the pooled sample was 0.310). Cluster analysis and nonmetric multidimensional scaling conducted on a matrix of pairwise genetic distances between all of the settlements studied revealed four genetically different groups: southern Primorye, northern Prymorye, Sakhalin, and Kuril-Commanders. The population-genetic structure of the L. sitkana settlements is close to that described by the isolation-by-distance and stepping-stone models: the geographic and the genetic distances between the most settlements examined are distinctly correlated.

  13. Genetic diversity and gene flow in the morphologically variable, rare endemics Begonia dregei and Begonia homonyma (Begoniaceae).

    Science.gov (United States)

    Matolweni, L O; Balkwill, K; McLellan, T

    2000-03-01

    Begonia dregei and B. homonyma (Begoniaceae), rare plants endemic to coastal forests of eastern South Africa, are two closely related species with high levels of variation among populations in the shape of leaves. Distribution of genetic variation and genetic relatedness were investigated in 12 populations of B. dregei and seven of B. homonyma using polyacrylamide gel electrophoresis. Twelve of the 15 enzyme loci examined were polymorphic, but only seven loci were polymorphic within at least one population. Genetic diversity measures indicated that the among-population gene differentiation represents >90% of the total genetic component in both species considered individually or combined. This indicated restricted gene flow, consistent with the limited dispersal abilities of Begonia generally and the ancient separation of isolated forest patches. Genetic distances among populations are much higher than usually found within species. Allozyme data provide no support for the recognition of B. dregei and B. homonyma as distinct species.

  14. Population differences in self-fertility in the "self-incompatible" milkweed Asclepias exaltata (Asclepiadaceae).

    Science.gov (United States)

    Lipow, S R; Broyles, S B; Wyatt, R

    1999-08-01

    Individual plants of Asclepias exaltata (Asclepiadaceae) typically express an unusual self-incompatibility system under single-gene control. Hand-pollinations performed in six natural populations detected occasional self-fertile plants. The frequency of self-fertile individuals ranged from 0 to 34.0% and differed significantly among populations. Self-fertility appears to be under genetic control, as the ability of most plants (80.0 %) to set fruit following self-pollinations was identical under natural and greenhouse conditions. Seed- and fruit-set, however, were significantly lower from self- vs. cross-pollinations. Allozyme analysis of the population with the highest frequency of self-fertility revealed that adult plants were not significantly inbred. Finally, fruit-set following within-population cross-pollinations did not differ from that following wide, between-population cross-pollinations.

  15. An expanded genetic linkage map of an intervarietal Agaricus bisporus var. bisporusxA. bisporus var. burnettii hybrid based on AFLP, SSR and CAPS markers sheds light on the recombination behaviour of the species.

    Science.gov (United States)

    Foulongne-Oriol, Marie; Spataro, Cathy; Cathalot, Vincent; Monllor, Sarah; Savoie, Jean-Michel

    2010-03-01

    A genetic linkage map for the edible basidiomycete Agaricus bisporus was constructed from 118 haploid homokaryons derived from an intervarietal A. bisporus var. bisporus x A. bisporus var. burnettii hybrid. Two hundred and thirty-one AFLP, 21 SSR, 68 CAPS markers together with the MAT, BSN, PPC1 loci and one allozyme locus (ADH) were evenly spread over 13 linkage groups corresponding to the chromosomes of A. bisporus. The map covers 1156cM, with an average marker spacing of 3.9cM and encompasses nearly the whole genome. The average number of crossovers per chromosome per individual is 0.86. Normal recombination over the entire genome occurs in the heterothallic variety, burnettii, contrary to the homothallic variety, bisporus, which showed adaptive genome-wide suppressed recombination. This first comprehensive genetic linkage map for A. bisporus provides foundations for quantitative trait analyses and breeding programme monitoring, as well as genome organisation studies.

  16. [Genetic structure of the populations of Pallas pine (Pinus pallasiana D. Don) reforested in extreme conditions].

    Science.gov (United States)

    Korshikov, I I; Krasnoshtan, O V

    2010-01-01

    The paper reports on an intensive reforestation of Pallas pine (Pinus pallasiana D. Don) in post-fire sites in the native Mountainous Crimean populations and around the previously planted seed-producing trees in ore-mining dumps of the Krivoy Rog region. Self-sown progeny growing in the dump is characterized by a better growth and comes to the reproductive development phase earlier compared to that one growing in post-fire forest. Allele variability at 20 allozyme loci is less in self-sown progeny than in the native populations whereas its heterozygosity level is similar. Genetic distance (D(N)) among self-sown progenies in post-fire sites and ore-mining dump is comparable to that of the natural populations.

  17. Genetic variability in the Florida manatee (Trichechus manatus)

    Science.gov (United States)

    McClenaghan, Leroy R.; O'Shea, Thomas J.

    1988-01-01

    Tissue was obtained from 59 manatee (Trichechus manatus) carcasses salvaged from 20 counties in Florida. Allozyme phenotypes at 24 structural loci were determined by gel electrophoresis. Averages for the proportion of polymorphic loci and mean heterozygosity were 0.300 (range, 0.167-0.417) and 0.050 (range, 0.028-0.063), respectively. These estimates are equivalent to or higher than those generally reported for other species of marine mammals and do not support the hypothesis that body size and heterozygosity in mammals are related inversely. Among-region gene diversity accounted for only 4% of the total diversity. High rates of gene flow probably account for genetic homogeneity across regions. An F-statistic analysis revealed a general tendency toward excess homozygosity within regions. Management efforts to prevent future reductions in population size that would erode existing genic diversity should continue.

  18. Genetic markers for the identification of two tick species, Amblyomma dissimile and Amblyomma rotundatum.

    Science.gov (United States)

    Lampo, M; Rangel, Y; Mata, A

    1997-06-01

    Genetic markers are described for 2 species of reptile and amphibian ticks, Amblyomma dissimile and Amblyomma rotundatum, by allozyme electrophoresis. Fixed allelic differences in 4 out of the 8 examined loci allowed the unequivocal separation of both of these species. A strong correlation was found between these genetic markers and the relative size of the spurs in coxae IV but not with the punctuation pattern of the scutum. Moreover, no overlap was found in the distribution of relative spur sizes between samples of both species. The percent polymorphic loci and the mean percent heterozygosity per locus for A. rotundatum was considerably lower than that for A. dissimile. Differences in the amount of genetic variability may be related to their modes of reproduction.

  19. Mitochondrial DNA variation of Triatoma infestans populations and its implication on the specific status of T. melanosoma

    Directory of Open Access Journals (Sweden)

    Fernando A Monteiro

    1999-09-01

    Full Text Available DNA sequence comparison of 412 base-pairs fragments of the mitochondrial cytochrome B gene was used to infer the genetic structure of nine geographical Triatoma infestans populations and their phylogenetic relationship with T. melanosoma and T. brasiliensis. T. infestans and T. melanosoma were compared by morphometry, allozyme and cytogenetic analyses, as well as subjected to reciprocal crosses, in order to clarify the taxonomic status of the latter. No differences were found to distinguish the two species and the crosses between them yielded progeny. T. infestans populations presented four haplotypes that could be separated in two clusters: one formed by the samples from Bolivia (Andes and Chaco and the other formed by samples from Argentina and Brazil. Silvatic and domestic T. infestans populations from Bolivia (Andes were genetically identical.

  20. [Age dynamics of population gene pool of the Crimean pine (Pinus pallasiana D. Don) in Crimea].

    Science.gov (United States)

    Korshikov, I I; Mudrik, E A; Krasnoshtan, O V; Velikorid'ko, T I; Kalafat, L A; Podgornyĭ, D Iu

    2011-01-01

    Polymorphism of young (14-16 years), middle-aged (70-80 years) and old (120-150 years) plants and their seed embryos has been studied using 20 and 10 allozyme loci correspondingly in the population of Pinus pallasiana D. Don from Mountain Crimea. It was revealed that the old-aged trees had significantly lower level of expected heterozygosity than the young plants. The level of observed heterozygosity of embryos of the uneven-aged plants was slightly different among the embryo samples and significantly lower than in the samples of maternal trees. Supernumerary homozygotation of the embryos is caused by low level of cross-pollination in three studied samples of plants (t(m) = 0,537-0,637).

  1. Contrasting patterns of spatial genetic differentiation in two east asian five-needle pine species, Pinus koraiensis and P. armandii

    Directory of Open Access Journals (Sweden)

    Belokon M.-M.

    2008-09-01

    Full Text Available Two species of East Asian five-needle pines of the section Strobus, Korean pine, Pinus koraiensis Sieb. et Zucc. and Armand's pine, Pinus armandii Franch are traditionally placed in two different subsections, Cembrae and Strobi, respectively.However, data on similarity of these pines in needle anatomy and pollen structure are reported. By means of starch gel electrophoresis we studied allozyme variation within populations of these species and between the two species. Among 30 studied loci we selected 17 polymorphic loci with reliable interpretation of allele correspondencebetween species. Allozyme patterns were similar in both species with respect to number of loci and predominant alleles at most loci. Intra-specific differentiation among 12 populations of Pinus koraiensis from Russia, Northeast China and South Korea was low, FST (proportion of among population variation in total variation was as low as 0.019, DN (Nei's genetic distance varied between 0.001 and 0.006. This genetic uniformity can be explained by a common gene pool of this species within virtually continuous range under similar ecological conditions. Common vectors of selection, natural gene flow through pollen and seed dispersal as well as mixing of genetic material between regions by humans (at least in Russian forestry practice are putative factors responsible for low differentiation in Korean stone pine. We estimated the same parameters in Pinus armandii from continental China (Guizhou, Shaanxi, Shenyan where its range is highly fragmented, and found differentiation in this species to be much more pronounced (FST = 0.067, DN = 0.011-0.029. By adding a sample from Taiwan both FST (0.338 and DN (up to 0.232 were substantially higher indicating high level of differences between continental and Taiwanese P. armandii, putatively due to longer isolation time. Maximal contribution was fromloci Adh-1, Got-3, Mdh-1, 6-Pgd-3, Pgm-2 and Skdh-2. Differences were mainly caused by allelic

  2. Contrasting patterns of spatial genetic differentiation in two east asian five-needle pine species, Pinus koraiensis and P. armandii

    Directory of Open Access Journals (Sweden)

    M.M. Belokon

    2013-12-01

    Full Text Available Two species of East Asian five-needle pines of the section Strobus, Korean pine, Pinus koraiensis Sieb. et Zucc. and Armand's pine, Pinus armandii Franch are traditionally placed in two different subsections, Cembrae and Strobi, respectively. However, data on similarity of these pines in needle anatomy and pollen structure are reported. By means of starch gel electrophoresis we studied allozyme variation within populations of these species and between the two species. Among 30 studied loci we selected 17 polymorphic loci with reliable interpretation of allele correspondence between species. Allozyme patterns were similar in both species with respect to number of loci and predominant alleles at most loci. Intra-specific differentiation among 12 populations of Pinus koraiensis from Russia, Northeast China and South Korea was low, FST (proportion of among population variation in total variation was as low as 0.019, DN (Nei's genetic distance varied between 0.001 and 0.006. This genetic uniformity can be explained by a common gene pool of this species within virtually continuous range under similar ecological conditions. Common vectors of selection, natural gene flow through pollen and seed dispersal as well as mixing of genetic material between regions by humans (at least in Russian forestry practice are putative factors responsible for low differentiation in Korean stone pine. We estimated the same parameters in Pinus armandii from continental China (Guizhou, Shaanxi, Shenyan where its range is highly fragmented, and found differentiation in this species to be much more pronounced (FST = 0.067, DN = 0.011-0.029. By adding a sample from Taiwan both FST (0.338 and DN (up to 0.232 were substantially higher indicating high level of differences between continental and Taiwanese P. armandii, putatively due to longer isolation time. Maximal contribution was from loci Adh-1, Got-3, Mdh-1, 6-Pgd-3, Pgm-2 and Skdh-2. Differences were mainly caused by

  3. A new species of the ghost shrimp genus Lepidophthalmus (Crustacea: Decapoda: Axiidea) from the southwestern Gulf of Mexico.

    Science.gov (United States)

    Felder, Darryl L

    2015-07-13

    A new species of Lepidophthalmus lacking a ventral median sclerite on the second abdominal somite is described from coastal waters of the southwestern Gulf of Mexico. Lepidophthalmus statoni sp. nov., originally recognized only as a unique population in allozyme studies, is sympatric with the ventrally plated species Lepidophthalmus manningi Felder & Staton, 2000, but more closely resembles Lepidophthalmus louisianensis (Schmitt, 1935) from the northern and northwestern Gulf of Mexico. Apparently restricted to intertidal and shallow subtidal tropical waters, the new species is known to range from western Campeche to middle-upper reaches of Veracruz, Mexico. As many members of the genus, it commonly inhabits euryhaline inlets, estuaries, and protected shorelines, including richly organic muddy to clayey sands and sandy muds adjacent to shoreline vegetation. Coloration is documented and discussed as a tool to facilitate field identifications, as are morphological characters.

  4. Biomphalaria prona (Gastropoda: Planorbidae: a morphological and biochemical study

    Directory of Open Access Journals (Sweden)

    W. Lobato Paraense

    1992-06-01

    Full Text Available Two samples of Biomphalaria prona (Martens, 1873 from Lake Valencia (type locality and seven from other Venezuelan localities were studied morphologically (shell and reproductive system and biochemically (allozyme electrophoresis. In spite of marked differences in shell characters, all of them proved indistinguishable under the anatomic and biochemical criteria. So far B. prona has been considered an endemic species, restricted to Lake Valencia. It is now demonstrated that the extralacustrine populations refered to Biomphalaria havanensis (Pfeiffer, 1839 by several authors correspond in shell characters to an extreme variant of B. prona from the Lake and really belong to the last*mentioned species. They may be regarded as the result of a process of directional selection favoring a shell phenotype other than those making up the modal class in the Lake.

  5. Genetic structure of the sea-bob shrimp (Xiphopenaeus kroyeri Heller, 1862; Decapoda, Penaeidae along the Brazilian southeastern coast

    Directory of Open Access Journals (Sweden)

    Carolina Moreira Voloch

    2005-01-01

    Full Text Available The sea-bob shrimp, Xiphopenaeus kroyeri, is one of the most important economic marine resources along the entire Brazilian coast. Nevertheless, despite its economic importance, no studies have examined the population genetics of this species. In this paper, we used ten allozyme loci to study the pattern of genetic structuring in X. kroyeri along the southeastern Brazilian coast. Seven of the ten analyzed loci were polymorphic, yielding observed heterozygosity values higher than those reported for other penaeid shrimps. The population from São Paulo was significantly different from the other two populations (Rio de Janeiro and Espírito Santo, which, in turn, seem to form a single panmitic unit. Therefore, our results clearly indicate that conservation policies for this species should consider the São Paulo population as an independent stock from those of Rio de Janeiro and Espírito Santo.

  6. Haploid Origin of Cork Oak Anther Embryos Detected by Enzyme and RAPD Gene Markers.

    Science.gov (United States)

    Bueno; Agundez; Gomez; Carrascosa; Manzanera

    2000-05-01

    In vitro-induced cork oak (Quercus suber L.) embryos from anther cultures proved to be of haploid origin both by enzyme and RAPD gene marker analysis. The problem considered was to ascertain if embryo cultures originated either from a single haploid cell, from a microspore, or from multiple haploid cells. Therefore, a heterozygotic gene was searched for in the parent tree. The gene coding for shikimate dehydrogenase (SKDH1) proved to be heterozygous in the parental tree, and subsequently, these allozymes were screened for the embryos induced in anther cultures from the same tree. Only haploid embryos were found, confirming the microspore origin. Different genotypes were not identified inside each anther by isozyme analysis, probably because of selective pressure for one embryo early in development, but both parental SKDH1 alleles were found in the embryos of different anthers. The banding patterns detected by RAPD markers permitted the identification of multiple microspore origins inside each anther.

  7. Reconciling patterns of inter-ocean molecular variance from four classes of molecular markers in blue marlin (Makaira nigricans).

    Science.gov (United States)

    Buonaccorsi, V P; McDowell, J R; Graves, J E

    2001-05-01

    Different classes of molecular markers occasionally yield discordant views of population structure within a species. Here, we examine the distribution of molecular variance from 14 polymorphic loci comprising four classes of molecular markers within approximately 400 blue marlin individuals (Makaira nigricans). Samples were collected from the Atlantic and Pacific Oceans over 5 years. Data from five hypervariable tetranucleotide microsatellite loci and restriction fragment length polymorphism (RFLP) analysis of whole molecule mitochondrial DNA (mtDNA) were reported and compared with previous analyses of allozyme and single-copy nuclear DNA (scnDNA) loci. Temporal variance in allele frequencies was nonsignificant in nearly all cases. Mitochondrial and microsatellite loci revealed striking phylogeographic partitioning among Atlantic and Pacific Ocean samples. A large cluster of alleles was present almost exclusively in Atlantic individuals at one microsatellite locus and for mtDNA, suggesting that, if gene flow occurs, it is likely to be unidirectional from Pacific to Atlantic oceans. Mitochondrial DNA inter-ocean divergence (FST) was almost four times greater than microsatellite or combined nuclear divergences including allozyme and scnDNA markers. Estimates of Neu varied by five orders of magnitude among marker classes. Using mathematical and computer simulation approaches, we show that substantially different distributions of FST are expected from marker classes that differ in mode of inheritance and rate of mutation, without influence of natural selection or sex-biased dispersal. Furthermore, divergent FST values can be reconciled by quantifying the balance between genetic drift, mutation and migration. These results illustrate the usefulness of a mitochondrial analysis of population history, and relative precision of nuclear estimates of gene flow based on a mean of several loci.

  8. From Africa to Europe and back: refugia and range shifts cause high genetic differentiation in the Marbled White butterfly Melanargia galathea

    Directory of Open Access Journals (Sweden)

    Rödder Dennis

    2011-07-01

    Full Text Available Abstract Background The glacial-interglacial oscillations caused severe range modifications of biota. Thermophilic species became extinct in the North and survived in southern retreats, e.g. the Mediterranean Basin. These repeated extinction and (recolonisation events led to long-term isolation and intermixing of populations and thus resulted in strong genetic imprints in many European species therefore being composed of several genetic lineages. To better understand these cycles of repeated expansion and retraction, we selected the Marbled White butterfly Melanargia galathea. Fourty-one populations scattered over Europe and the Maghreb and one population of the sibling taxon M. lachesis were analysed using allozyme electrophoresis. Results We obtained seven distinct lineages applying neighbour joining and STRUCTURE analyses: (i Morocco, (ii Tunisia, (iii Sicily, (iv Italy and southern France, (v eastern Balkans extending to Central Europe, (vi western Balkans with western Carpathian Basin as well as (vii south-western Alps. The hierarchy of these splits is well matching the chronology of glacial and interglacial cycles since the Günz ice age starting with an initial split between the galathea group in North Africa and the lachesis group in Iberia. These genetic structures were compared with past distribution patterns during the last glacial stage calculated with distribution models. Conclusions Both methods suggest climatically suitable areas in the Maghreb and the southern European peninsulas with distinct refugia during the last glacial period and underpin strong range expansions to the North during the Postglacial. However, the allozyme patterns reveal biogeographical structures not detected by distribution modelling as two distinct refugia in the Maghreb, two or more distinct refugia at the Balkans and a close link between the eastern Maghreb and Sicily. Furthermore, the genetically highly diverse western Maghreb might have acted as source

  9. 微卫星DNA多态性分析在常用近交系小鼠遗传监测中的应用研究%Microsatellite DNA Polymorphisms in Inbred Strain Mice and Selection as Genetic Monitoring Markers

    Institute of Scientific and Technical Information of China (English)

    欧阳兆和; 陈振文; 李瑞生; 战大伟

    2003-01-01

    The aim of genetic monitoring is to checking the genetic contamination within inbred starains, which insures that the strains according with the require of colony . At present the methods based on allozyme biochemistry are the National Standard instructed. methods that using microsatellite DNA would be more useful for genetic monitoring than methods based on allozyme biochemistry because the genome itself is being tested rather than a protein product and a larger portion of the genome can be sampled, and easy to distinguish. methods that using microsatellite DNA had abundant microsatellite loci(over 7300, before 1999) can be identified. Applying enough microsatellite loci will present abundant straps and well polymorphism, which can reflection inherit and variation of roundly genene. In addition, this novel approach allows the rapid, sensitive, convenientand accuracy, even individual identificaton. So we should select microsatellite DNA which is polymorphisms as genetic monitoring markers to determining the strains' origin and genetic background of inbred mice.Untill now Only feasibility has been reported, and in which microsatellite DNA loci have not enough polymorphisms to distinguish genetic differences. Articles on standards and practicality have not been founded in our country. With the optimization of components of reaction buffer and amplificaton parameter, PCR for amplification microsatellite DNA was finally set up. Using the techniques microsatellite DNA can amplified efficaciously. The final concentrations of Mg2+ was 1 . 5-3.0 mmol/L, annealing temperature was 50 ℃-65 ℃. The condition for the PCR amplify were , 94 ℃ for 3min, 30cycles of 94℃ for 30s, 50℃-65℃ for 30s,72℃ for 1min,finally at 72℃ for 1min,then store at 4℃.

  10. Genetic analysis of Apis mellifera macedonica (type rodopica populations selectively reared for purposive production of honey bee queens in Bulgaria

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    VIDA H. GEORGIEVA

    2016-04-01

    Full Text Available The genetic polymorphism in selectively reared in Bulgaria, local honey bee populations of Apis mellifera macedonica subspecies (type rodopica, has been studied, using analysis of six enzyme systems (MDH-1, ME, EST-3, ALP, PGM and HK corresponding to 6 loci. Totally 458 worker bees from 12 bee breeding bases for artificially inseminated queens were used for this study. All these stations are part of the National Bee Breeding Association which officially implements a National Program for sustainable beekeeping in Bulgaria. All of the six loci were found to be polymorphic. Only EST-3 locus was established as fixed in one of the investigated populations. Polymorphism with three alleles was ascertained for MDH, ME, ALP, PGM and HK loci and with five alleles for EST-3 locus. The most common alleles in almost all of the populations were MDH-1 100, ME 100, EST-3 100, PGM 100 and HK 100. Two private alleles (frequency < 0.05 were found for two of the populations. The calculated level of polymorphism was 88.33% in only one of the populations and 100% - in all others. The observed and expected heterozygosities (Ho and He ranged from 0.157 to 0.250 and from 0.206 to 0.272, respectively. The estimated mean FST value from allozyme data was 0.035. On the bases of the allele frequencies of the studied allozyme loci the Nei's (1972 genetic distance was estimated. It ranged between 0.002 and 0.060 among the populations studied.

  11. Population genetic structure of Venezuelan chiropterophilous columnar cacti (Cactaceae).

    Science.gov (United States)

    Nassar, Jafet M; Hamrick, J L; Fleming, Theodore H

    2003-11-01

    We conducted allozyme surveys of three Venezuelan self-incompatible chiropterophilous columnar cacti: two diploid species, Stenocereus griseus and Cereus repandus, and one tetraploid, Pilosocereus lanuginosus. The three cacti are pollinated by bats, and both bats and birds disperse seeds. Population sampling comprised two spatial scales: all Venezuelan arid zones (macrogeographic) and two arid regions in northwestern Venezuela (regional). Ten to 15 populations and 17-23 loci were analyzed per species. Estimates of genetic diversity were compared with those of other allozyme surveys in the Cactaceae to examine how bat-mediated gene dispersal affects the population genetic attributes of the three cacti. Genetic diversity was high for both diploid (P(s) = 94.1-100, P(p) = 56.7-72.3, H(s) = 0.182-0.242, H(p) = 0.161-0.205) and tetraploid (P(s) = 93.1, P(p) = 76.1, H(s) = 0.274, H(p) = 0.253) species. Within-population heterozygote deficit was detected in the three cacti at macrogeographic (F(IS) = 0.145-0.182) and regional (F(IS) = 0.057-0.174) levels. Low genetic differentiation was detected at both macrogeographic (G(ST) = 0.043-0.126) and regional (G(ST) = 0.009-0.061) levels for the three species, suggesting substantial gene flow among populations. Gene exchange among populations seems to be regulated by distance among populations. Our results support the hypothesis that bat-mediated gene dispersal confers high levels of genetic exchange among populations of the three columnar cacti, a process that enhances levels of genetic diversity within their populations.

  12. No more time to stay 'single' in the detection of Anisakis pegreffii, A. simplex (s. s.) and hybridization events between them: a multi-marker nuclear genotyping approach.

    Science.gov (United States)

    Mattiucci, S; Acerra, V; Paoletti, M; Cipriani, P; Levsen, A; Webb, S C; Canestrelli, D; Nascetti, G

    2016-07-01

    A multi-marker nuclear genotyping approach was performed on larval and adult specimens of Anisakis spp. (N = 689) collected from fish and cetaceans in allopatric and sympatric areas of the two species Anisakis pegreffii and Anisakis simplex (s. s.), in order to: (1) identify specimens belonging to the parental taxa by using nuclear markers (allozymes loci) and sequence analysis of a new diagnostic nuclear DNA locus (i.e. partial sequence of the EF1 α-1 nDNA region) and (2) recognize hybrid categories. According to the Bayesian clustering algorithms, based on those markers, most of the individuals (N = 678) were identified as the parental species [i.e. A. pegreffii or A. simplex (s. s.)], whereas a smaller portion (N = 11) were recognized as F1 hybrids. Discordant results were obtained when using the polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLPs) of the internal transcribed spacer (ITS) ribosomal DNA (rDNA) on the same specimens, which indicated the occurrence of a large number of 'hybrids' both in sympatry and allopatry. These findings raise the question of possible misidentification of specimens belonging to the two parental Anisakis and their hybrid categories derived from the application of that single marker (i.e. PCR-RFLPs analysis of the ITS of rDNA). Finally, Bayesian clustering, using allozymes and EF1 α-1 nDNA markers, has demonstrated that hybridization between A. pegreffii and A. simplex (s. s.) is a contemporary phenomenon in sympatric areas, while no introgressive hybridization takes place between the two species.

  13. Analysis of mating system in two Pinus cembra L. populations of the Ukrainian Carpathians

    Directory of Open Access Journals (Sweden)

    Dmitri V. Politov

    2008-09-01

    Full Text Available In natural pine populations, a mixed mating system is typical,characterized by the proportions of selfed and outcrossed seeds. Swiss stone pine(Pinus cembra L. is one of the least studied European conifers in this respect. The mating system of six polymorphic allozyme loci were studied in haploid megagametophytes and diploid open-pollinated embryos in two stands located in theEast Carpathians. In the 'Gorgany' population (24 trees, 198 seeds the mean singlelocus estimated outcrossing rate (ts was 0.731, and the multilocus estimate (tm was 0.773. In the 'Yayko' population the outcrossing rate was lower (27 trees, 213 seeds, ts=0.645, tm=0.700, suggesting 23-30% of seeds are self-pollinated. Correlation ofoutcrossing rate estimates among loci was less than 1, (0.300 in 'Gorgany' and 0.469 in 'Yayko' indicating biparental inbreeding occurred. Differences between tm and ts (0.042 in 'Gorgany' and 0.056 in 'Yayko' can also be influenced by consanguineous mating, indicated by the presence of spatial and genetic family structure. In small isolated populations of Pinus cembra, which are typical for the Carpathian part of the species' range, inbreeding depression may negatively affect seed quality. The high proportion of selfed seeds observed here can be expected in any seedlot of this species and should be taken into account while planning gene conservation orreforestation measures. Maternal trees in these populations showed no heterozygote deficiency at these allozyme loci, and instead showed increased proportions of heterozygotes (inbreeding coefficient FIS = -0.200 in 'Gorgany' and -0.142 in 'Yayko'. Balancing selection may explain heterozygosity levels up to and above equilibrium proportions.

  14. High genetic diversity and population structure in the endangered Canarian endemic Ruta oreojasme (Rutaceae).

    Science.gov (United States)

    Meloni, Marilena; Reid, Andrea; Caujapé-Castells, Juli; Soto, Moisés; Fernández-Palacios, José María; Conti, Elena

    2015-10-01

    Insular species are expected to have low genetic diversity, for their populations are often small and isolated, and characterized by restricted gene flow and increased incidence of inbreeding. However, empirical results do not always match this expectation. For example, population genetic analyses of several Canarian endemics, based mainly on allozymes, show levels of genetic diversity exceptionally high for insular species. To investigate whether genetic variation in rare species endemic to Canary Islands is low, as predicted by theoretical expectations, or high, as documented in some previous studies, we analysed genetic diversity of the endangered Ruta oreojasme, a rare endemic of the island of Gran Canaria, using microsatellite markers, which are more variable than allozymes. Our analyses identified very high levels of genetic diversity (A = 7.625, P = 0.984, H o = 0.558, H e = 0.687) for R. oreojasme. Even though the distribution of the species is restricted to the South of Gran Canaria, only one population shows low genetic diversity, isolation and signs of a recent bottleneck/founder event. Some intrinsic characteristics of R. oreojasme (hermaphroditism, proterandry and polyploidy), the relative climatic stability of the Canarian archipelago during Quaternary glacials/interglacials, the size of most populations (thousands of individuals), its age, and the relative proximity of the archipelago to the mainland might have contributed to the high diversity that characterises this endemic. As expected, given the marked topographic complexity of Gran Canaria, we found marked genetic structure in R. oreojasme populations. Our results support the observation that Canarian endemics are characterised by unexpectedly high genetic diversity and provides important insights for potential applications to the conservation of R. oreojasme.

  15. Phylogenetic relationships within the Alcidae (Charadriiformes: Aves) inferred from total molecular evidence

    Science.gov (United States)

    Friesen, V.L.; Baker, A.J.; Piatt, John F.

    1996-01-01

    The Alcidae is a unique assemblage of Northern Hemisphere seabirds that forage by "flying" underwater. Despite obvious affinities among the species, their evolutionary relationships are unclear. We analyzed nucleotide sequences of 1,045 base pairs of the mitochondrial cytochrome b gene and allelic profiles for 37 allozyme loci in all 22 extant species. Trees were constructed on independent and combined data sets using maximum parsimony and distance methods that correct for superimposed changes. Alternative methods of analysis produced only minor differences in relationships that were supported strongly by bootstrapping or standard error tests. Combining sequence and allozyme data into a single analysis provided the greatest number of relationships receiving strong support. Addition of published morphological and ecological data did not improve support for any additional relationship. All analyses grouped species into six distinct lineages: (1) the dovekie (Alle alle) and auks, (2) guillemots, (3) brachyramphine murrelets, (4) synthliboramphine murrelets, (5) true auklets, and (6) the rhinoceros auklet (Cerorhinca monocerata) and puffins. The two murres (genus Uria) were sister taxa, and the black guillemot (Cepphus grylle) was basal to the other guillemots. The Asian subspecies of the marbled murrelet (Brachyramphus marmoratus perdix) was the most divergent brachyramphine murrelet, and two distinct lineages occurred within the synthliboramphine murrelets. Cassin's auklet (Ptychoramphus aleuticus) and the rhinoceros auklet were basal to the other auklets and puffins, respectively, and the Atlantic (Fratercula arctica) and horned (Fratercula corniculata) puffins were sister taxa. Several relationships among tribes, among the dovekie and auks, and among the auklets could not be resolved but resembled "star" phylogenies indicative of adaptive radiations at different depths within the trees.

  16. Impacts of forest fragmentation on the mating system and genetic diversity of white spruce (Picea glauca) at the landscape level.

    Science.gov (United States)

    O'Connell, L M; Mosseler, A; Rajora, O P

    2006-12-01

    We studied the mating system of white spruce (Picea glauca) in a landscape fragmented by agriculture in northern Ontario, Canada. We sampled 23 stands that ranged in size from 1 to >500 trees isolated by 250-3000 m from the nearest other stand. Six polymorphic allozyme loci from four enzyme systems were used to genotype approximately 10 000 embryos from 104 families. We detected no allele frequency heterogeneity in the pollen pool among stands or families (Phi(FT)=-0.025). Overall, estimates of outcrossing were high (t(m)=94% and mean t(s)=91%) but significantly different from unity. Bi-parental inbreeding (t(m)-t(s)=3.2%) was low but significantly different from zero. Allozyme-based outcrossing estimates did not differ significantly among three stand-size classes (SSCs): small (large (> or =100 trees). The number of effective pollen donors was high in all SSCs, but was significantly lower in small stands (N(ep)=62.5) than in medium-sized and large stands (both N(ep)=143). The primary selfing rate was significantly higher in medium stands than in large stands. We found no significant difference in genetic diversity measures in the filial (seed) population among SSCs. Overall, these results indicate that white spruce stands in this fragmented landscape are resistant to genetic diversity losses, primarily through high pollen-mediated gene-flow and early selection against inbred embryos. We discuss the importance of using seed data, in conjunction with genetic data, to evaluate the impacts of fragmentation on natural populations.

  17. Non-equilibrium estimates of gene flow inferred from nuclear genealogies suggest that Iberian and North African wall lizards (Podarcis spp. are an assemblage of incipient species

    Directory of Open Access Journals (Sweden)

    Harris D James

    2008-02-01

    Full Text Available Abstract Background The study of recently-diverged species offers significant challenges both in the definition of evolutionary entities and in the estimation of gene flow among them. Iberian and North African wall lizards (Podarcis constitute a cryptic species complex for which previous assessments of mitochondrial DNA (mtDNA and allozyme variation are concordant in describing the existence of several highly differentiated evolutionary units. However, these studies report important differences suggesting the occurrence of gene flow among forms. Here we study sequence variation in two nuclear introns, β-fibint7 and 6-Pgdint7, to further investigate overall evolutionary dynamics and test hypotheses related to species delimitation within this complex. Results Both nuclear gene genealogies fail to define species as monophyletic. To discriminate between the effects of incomplete lineage sorting and gene flow in setting this pattern, we estimated migration rates among species using both FST-based estimators of gene flow, which assume migration-drift equilibrium, and a coalescent approach based on a model of divergence with gene flow. Equilibrium estimates of gene flow suggest widespread introgression between species, but coalescent estimates describe virtually zero admixture between most (but not all species pairs. This suggests that although gene flow among forms may have occurred the main cause for species polyphyly is incomplete lineage sorting, implying that most forms have been isolated since their divergence. This observation is therefore in accordance with previous reports of strong differentiation based on mtDNA and allozyme data. Conclusion These results corroborate most forms of Iberian and North African Podarcis as differentiated, although incipient, species, supporting a gradual view of speciation, according to which species may persist as distinct despite some permeability to genetic exchange and without having clearly definable genetic

  18. Population structure of the peridomestic mosquito Ochlerotatus notoscriptus in Australia.

    Science.gov (United States)

    Foley, D H; Russell, R C; Bryan, J H

    2004-06-01

    Ochlerotatus notoscriptus (Skuse) (Diptera: Culicidae) is the predominant peridomestic mosquito in Australia where it is the primary vector of dog heartworm, Dirofilaria immitis (Leidy), and a potentially important vector of arboviruses (Barmah Forest, Ross River) with geographical variation of vector competence. Although widespread, Oc. notoscriptus has low dispersal ability, so it may have isolated subpopulations. The identification of gene flow barriers may assist in understanding arbovirus epidemiology and disease risk, and for developing control strategies for this species. We investigated the population structure of Oc. notoscriptus from 17 sites around Australia, using up to 31 putative allozyme loci, 11 of which were polymorphic. We investigated the effect of larval environment and adult morphology on genetic variation. At least five subpopulations were found, four in New South Wales (NSW) and one unique to Darwin. Perth samples appear to be a product of recent colonization from the Australian east coast. For NSW sites, a Mantel test revealed an isolation by distance effect and spatial autocorrelation analysis revealed an area of effective gene flow of 67 km, which is high given the limited dispersal ability of this species. No consistent difference was observed between 'urban' and 'sylvan' habitats, which suggests frequent movement between these sites. However, a finer-scaled habitat study at Darwin revealed small but significant allele frequency differences, including for Gpi. No fixed allozyme differences were detected for sex, size, integument colour or the colour of species-diagnostic pale scales on the scutum. The domestic habit of Oc. notoscriptus and assisted dispersal have helped to homogenize this species geographically but population structure is still detectable on several levels associated with geographical variation of vector competence.

  19. Phylogenetic relationships within the Alcidae (Charadriiformes: Aves) inferred from total molecular evidence.

    Science.gov (United States)

    Friesen, V L; Baker, A J; Piatt, J F

    1996-02-01

    The Alcidae is a unique assemblage of Northern Hemisphere seabirds that forage by "flying" underwater. Despite obvious affinities among the species, their evolutionary relationships are unclear. We analyzed nucleotide sequences of 1,045 base pairs of the mitochondrial cytochrome b gene and allelic profiles for 37 allozyme loci in all 22 extant species. Trees were constructed on independent and combined data sets using maximum parsimony and distance methods that correct for superimposed changes. Alternative methods of analysis produced only minor differences in relationships that were supported strongly by bootstrapping or standard error tests. Combining sequence and allozyme data into a single analysis provided the greatest number of relationships receiving strong support. Addition of published morphological and ecological data did not improve support for any additional relationship. All analyses grouped species into six distinct lineages: (1) the dovekie (Alle alle) and auks, (2) guillemots, (3) brachyramphine murrelets, (4) synthliboramphine murrelets, (5) true auklets, and (6) the rhinoceros auklet (Cerorhinca monocerata) and puffins. The two murres (genus Uria) were sister taxa, and the black guillemot (Cepphus grylle) was basal to the other guillemots. The Asian subspecies of the marbled murrelet (Brachyramphus marmoratus perdix) was the most divergent brachyramphine murrelet, and two distinct lineages occurred within the synthliboramphine murrelets. Cassin's auklet (Ptychoramphus aleuticus) and the rhinoceros auklet were basal to the other auklets and puffins, respectively, and the Atlantic (Fratercula arctica) and horned (Fratercula corniculata) puffins were sister taxa. Several relationships among tribes, among the dovekie and auks, and among the auklets could not be resolved but resembled "star" phylogenies indicative of adaptive radiations at different depths within the trees.

  20. 利用等位酶对油松无性系种子进行父本分析%A PATERNITY ANALYSIS OF SEEDS FROM DIFFERENT CLONES IN A PINUS TABULAEFORMIS CARR. SEED ORCHARD

    Institute of Scientific and Technical Information of China (English)

    张冬梅; 沈熙环; 何田华

    2001-01-01

    Paternity analysis of a clonal seed orchard of Pinustabulaeformis Carr. was conducted by means of allozyme markers. Multilocus allozyme genotypes at 10 loc i of 17 clones were inferred from a sample of at least eight megagametophytes pe r clone, while the genotypes of the other 32 parental clones were from buds. A t otal of 200 embryos and endosperms were analyzed, of which the paternity could be accurately identified for just 89 samples. A low degree of selfing was found w ithin the seed orchard, while higher male strobili production did not indicate a higher degree of fertilization success. Half of the allozyme loci were found to deviate from Hardy-Weinberg equilibrium. At the same time, the effective dispe rsal distance of pollen and spatial genetic structure of the seed orchard popula tion were analyzed by means of spatial autocorrelation. A few Moran's I valu es f or this test in short distance classes were significantly positive. The results indicated that the pattern of spatial genetic structure is very weak in the prog eny population.%利用水平淀粉凝胶电泳8种酶10个位点34个等位基因,对辽宁兴城油松无性系种子园中17个无性系20个单株的200粒种子作了父本分析。无性系雄花量的多少与授粉座果率并不成正比;不同无性系对花粉的接受存在一定的选择性,分析试样单株与周围的无性系并没有构成固定的授粉组合,说明授粉期风向等气象因子,无性系的雌雄花器的构造,受精机理等对受粉的成败都有作用;种子园结实初期自交现象并不明显,在分析试样中只有16#,17#,19#无性系存在自交现象;种子园内花粉的有效传播一般在半径30m范围内。同时,分析了种子园子代的等位酶变异和空间遗传结构,从另一侧面反映出采种母树周围花粉分布比较均匀,并说明散粉期间风向等气象因子对授粉成败影响较大。

  1. Advances in genetics and breeding in abalone:a review%鲍遗传育种研究进展

    Institute of Scientific and Technical Information of China (English)

    蔡明夷; 柯才焕; 周时强; 王桂忠

    2004-01-01

    Abalones are important farming species with a high economic value. They have already been farmed for more than 50 years. As problems and new requirements rose continuously in culture industry of abalone, studies on genetic and breeding techniques are needed to improve characteristics and to gain new traits. This review concentrates on advances in genetics and breeding techniques in abalone. As for genetic studies, karyological analyses, allozyme, DNA markers and genetic diversity were reviewed. So far, karyological analyses in abalone have been performed in 12 species that can be divided into three groups according to the chromosome number. In some economically important species, loci of allozymes and. microsatellites have been isolated and applied to investigate the genetic structure of natural and hatchery populations and to identify the result of chromosome set manipulation, but the related reports are only a few yet. The resultsof investigation with DNA markers and allozymes showed that the genetic structure of natural populations presents two characteristics: excessive homozygosity and subdivision. Advances of various breeding techniques, including introduction, selection,hybridization, polyploidy, gynogenesis and gene manipulation, were reviewed in the other part. Although Haliotis discus discus, introduced from Japan, has become one of the most important culture species in China, the economic, social and environmental effects of introduction have been rarely studied. Selection is one of the most important and basic breeding techniques, but the studies on selection are only a few and preliminary, referring to the relations between genetic characteristics and the traits of growth and resistance, genetic diversity and heritability of quantitative traits, and the effect of selection. Interspecific hybridization was the first breeding program carded out in abalone. Experimental hybridization have been carded out for about 20 crosses. Heterosis,such as faster

  2. Molecular phylogenetics of the avian genus Pipilo and a biogeographic argument for taxonomic uncertainty.

    Science.gov (United States)

    Zink, R M; Weller, S J; Blackwell, R C

    1998-10-01

    We sequenced 1709 base pairs (bp) of mitochondrial DNA including parts of cytochrome b, ND 2, and the control region (CR I, II) for seven members of the avian genus Pipilo (towhees), Melozone kieneri (rusty-crowned ground-sparrow), and Arremonops rufivirgatus (olive sparrow). A total of 457 bp was variable and 257 bp were potentially phylogenetically informative. All gene regions were similarly variable (20.2 to 28.4%) except for CR II (38.4%); third position transitions were as common as substitutions in the CR. Tree topology was sensitive to choice of outgroup(s) and individual sequences used as exemplars. Six trees were considered viable phylogenetic hypotheses based on maximum parsimony and maximum likelihood analyses. These trees generally supported two groups of towhees (rufous-sided group, brown towhee group), a sister taxon relationship for P. aberti and P. crissalis, and a sister taxon relationship for P. ocai and P. maculatus. The occurrence of M. kiernei within Pipilo in three trees challenges the monophyly of the latter; the other species of Melozone and other outgroups require study to resolve Pipilo monophyly. The relationships of P. albicollis and P. fuscus were ambiguous, as they were with previous data sets (allozymes, mtDNA restriction sites); they could be sister species or either one could be the basal species in the brown towhee group. We suggest that this taxonomic uncertainty obtains from the contemporaneous origin of P. fuscus, P. albicollis, and the ancestor of P. aberti/P. crissalis. We favor a "star" phylogeny because species in unrelated lineages found in the same region as P. albicollis are similarly difficult to resolve phylogenetically. Synapomorphies from coding genes and the CR did not preferentially support basal and terminal nodes, and hence did not provide different windows of taxonomic resolution, which might be expected from the apparent rapid rate of CR evolution. Phylogenetic trees inferred from allozymes, restriction sites

  3. Population genetic structure and differentiation of Anthoxanthum a lpinum in the subalpine-alpine ecocline of Swiss Alps%阿尔卑斯山高山-亚高山过渡区高山黄花茅的群体遗传结构和分化研究

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Allozyme variation in 6 enzyme systems coding 10 loci was estimated for 18 subpopulations of Anthoxanthum alpinum from three altitudinal transects in two localities of the Swiss Alps. Mean proportions of polymorphic loci (95% criterion), average number of alleles perlocus, and mean expected heterozygosity were 64.9%, 2.3 7 and 0.252, respectively. Mean genetic distance among populations was 0.011, and 79% of the genetic variation resided within populations. Based on allozyme analysis, marginal subpopulations appeared to have similar level of genetic variability to central subpopulations. Relatively high genetic differentiation, low gene flow values and small neighbourhood sizes suggested that inbreeding followed by genetic drift was possible causes of low genetic variability in Arp ette A. alpinum populations.%应用等位酶分析,在瑞士阿尔卑斯山的阿尔拜特(Arpette)和拜阿尔普(Belalp),沿三 个不同的海拔梯度,研究了高山黄花茅3个自然居群的遗传变异和分化。研究结果表明,平 均的多态性位点比例为64.9%,每个位点平均等位基因数为2.37,平均期望杂合性为0.252。 亚居群间平均的遗传距离为0.011,发现79%的遗传变异存在于居群内。基于等位酶分析,边缘亚居群与中心亚居群似乎有类似的遗传变异性。相对比较高的遗传分化、低的亚居群间 基因流和小的邻居大小值暗示,近交和随后的遗传漂变可能是导致阿尔拜特黄花茅居群遗传变异性较低的主要原因。

  4. Determining gene flow and the influence of selection across the equatorial barrier of the East Pacific Rise in the tube-dwelling polychaete Alvinella pompejana

    Directory of Open Access Journals (Sweden)

    Plouviez Sophie

    2010-07-01

    Full Text Available Abstract Background Comparative phylogeography recently performed on the mitochondrial cytochrome oxidase I (mtCOI gene from seven deep-sea vent species suggested that the East Pacific Rise fauna has undergone a vicariant event with the emergence of a north/south physical barrier at the Equator 1-2 Mya. Within this specialised fauna, the tube-dwelling polychaete Alvinella pompejana showed reciprocal monophyly at mtCOI on each side of the Equator (9°50'N/7°25'S, suggesting potential, ongoing allopatric speciation. However, the development of a barrier to gene flow is a long and complex process. Secondary contact between previously isolated populations can occur when physical isolation has not persisted long enough to result in reproductive isolation between genetically divergent lineages, potentially leading to hybridisation and subsequent allelic introgression. The present study evaluates the strength of the equatorial barrier to gene flow and tests for potential secondary contact zones between A. pompejana populations by comparing the mtCOI gene with nuclear genes. Results Allozyme frequencies and the analysis of nucleotide polymorphisms at three nuclear loci confirmed the north/south genetic differentiation of Alvinella pompejana populations along the East Pacific Rise. Migration was oriented north-to-south with a moderate allelic introgression between the two geographic groups over a narrow geographic range just south of the barrier. Multilocus analysis also indicated that southern populations have undergone demographic expansion as previously suggested by a multispecies approach. A strong shift in allozyme frequencies together with a high level of divergence between alleles and a low number of 'hybrid' individuals were observed between the northern and southern groups using the phosphoglucomutase gene. In contrast, the S-adenosylhomocysteine hydrolase gene exhibited reduced diversity and a lack of population differentiation possibly due to

  5. Genotype and toxicity relationships among Hyalella azteca: I. Acute exposure to metals or low pH

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Y.; Guttman, S.I.; Oris, J.T.; Bailer, A.J.

    2000-05-01

    Comparative genotype and toxin interactions at three polymorphic enzyme loci were examined in a laboratory population of amphipods (Hyalella azteca) during acute exposure to cadmium, zinc, copper, lead, or low pH. Significant toxin-genotype interactions were observed using logistic regression to model mortality in ten of 15 analyses. Both stressor-specific and nonspecific modes of selection were observed. In general, low pH selected for different genotypes than those selected by metals, especially zinc. Different modes of selection were also observed when amphipods were exposed to different metals. These results suggest that exposure to low pH would significantly reduce the ability of H. azteca to survive subsequent contamination by metals; exposure to stressors in the reverse order would also compromise a population's chance of survival. A genetic distance analysis showed that the magnitude of genetic differentiation consistently increased among survivors compared with that of the initial populations. These increases in genetic divergence estimates suggest that acute exposure to metals or low pH may have an evolutionarily significant impact on the species. They also suggest that both genotype frequency and genetic distance measures (based on allozyme data) may be used as bioindicators for environmental monitoring programs. Validation of such bioindicators requires an understanding of the population's genetic background, genetic structure, and history.

  6. Genotype and toxicity relationships among Hyalella azteca: II. Acute exposure to fluoranthene-contaminated sediment

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Y.; Guttman, S.I.; Oris, J.T.; Huang, X.; Burton, G.A.

    2000-05-01

    This study examined the genotypic responses of Hyalella azteca to the toxicity of sediment contaminated by the polycyclic aromatic hydrocarbon (PAH) fluoranthene. The authors monitored the time to death for 696 H. azteca exposed to ultraviolet light and sediment spiked with fluoranthene. The survival distribution functions within the genotypes at each of these variable allozyme loci (acid phosphatase [ACP*], glucose-6-phosphate isomerase [GPI*], and phosphoglucomutase [PGM*]) were compared using a long-rank test. Results showed significant differences among SDFs at all three loci. No association of heterozygosity with time to death was observed. The homozygote ACP*-CC was associated with decreased survivorship compared with ACP*-AA, ACP*-BB, and ACP*-AB. However, GPI*-AA was associated with increased survivorship compared with GPI*-BB, GPI*-CC, and GPI*-BC. Significant differences in resistance also were observed for PGM*-BB versus either PGM*-AC or PGM*-BC. These results indicate that differential resistance to PAH phototoxicity was genetically related, producing significant alteration in the frequencies of several genotypes in the population.

  7. Molecular Variation of Adh and P6 Genes in an African Population of Drosophila Melanogaster and Its Relation to Chromosomal Inversions

    Science.gov (United States)

    Benassi, V.; Aulard, S.; Mazeau, S.; Veuille, M.

    1993-01-01

    Four-cutter molecular polymorphism of Adh and P6, and chromosome inversion polymorphism of chromosome II were investigated in 95 isogenic lines of an Ivory Coast population of Drosophila melanogaster, a species assumed to have recently spread throughout the world from a West African origin. The P6 gene showed little linkage disequilibrium with the In(2L)t inversion, although it is located within this inversion. This suggests that the inversion and the P6 locus have extensively exchanged genetic information through either double crossover or gene conversion. Allozymic variation in ADH was in linkage disequilibrium with In(2L)t and In(2R)NS inversions. Evidence suggests either that inversion linkage with the Fast allele is selectively maintained, or that this allele only recently appeared. Molecular polymorphism at the Adh locus in the Ivory Coast is not higher than in North American populations. New haplotypes specific to the African population were found, some of them connect the ``Wa(s)-like'' haplotypes found at high frequencies in the United States to the other slow haplotypes. Their relation with In(2L)t supports the hypothesis that Wa(s) recently recombined away from an In(2L)t chromosome which may be the cause of its divergence from the other haplotypes. PMID:8349110

  8. Eco-logo-genetical characteristic of seed progeny of the Taraxacum officinale S.L. from the zone of east-ural radioactive trace

    Energy Technology Data Exchange (ETDEWEB)

    Pozolotina, V.; Ulyanova, E. [Russian Academy of Sciences, Institute of Plant and Animal Ecology, Ural Division, Ekaterinburg (Russian Federation)

    2004-07-01

    Levels of soil contamination with {sup 90}Sr and {sup 137}Cs radionuclides within the zone of Eastern-Ural radioactive trace, at the plots differently distant from the place of Kyshtym accident of 1957, exceed values of the global level 4-40 times. It was shown that the same coeno-population from EURT in the different years revealed the whole variety of previously described low-level irradiation effects. They are: stimulating one (vitality indexes in seed progeny exceed significantly those registered in the background samples); the depressing one, marked for high mortality level; and an indifferent effect showing neither significant differences from the background plants. Variation scope exceeding the normal one in regard to plants growth and development rates, as well as high frequencies of chromosome and morphological aberrations indicate to the plant genome non-stability caused by chronic low-level irradiation loads. Seed progeny also demonstrated the similar ambiguous response to additional irradiation, which is confirmed by allozyme analysis results. Standard electrophoretic methods are applicable to the dandelion studies. Some enzyme systems (Got, Dia) seem to be more suitable for seedlings, whereas the others provided satisfactory results being used for the seed material. In plant coeno-populations situated in radionuclides-polluted zone, genomic recombination processes show higher intensity. High enzymatic variability provides the material for natural selection and increase the adaptive potential of coeno-populations. (author)

  9. Comparison of remote consequences in Taraxacum officinale seed progeny collected in radioactively or chemically contaminated areas.

    Science.gov (United States)

    Pozolotina, Vera N; Antonova, Elena V; Bezel, Victor S

    2012-10-01

    We carried out a comparative study of seed progeny taken from the dandelion (Taraxacum officinale s.l.) coenopopulations exposed for a long time to radioactive or chemical contamination originated from the East-Ural radioactive trace zone (EURT) or Nizhniy Tagil metallurgical combine impact zone (NTMC), respectively. Coenopopulations from EURT, NTMC and background areas significantly differ from each other with respect to the qualitative and quantitative composition of allozyme phenes. An analysis of clonal diversity showed the uniqueness of all coenopopulations in terms of their phenogenetics. P-generation seed viability was found to decrease in a similar manner as all types of the industrial stress increased. Studies of F (1)-generation variability in radio- and metal resistance by family analysis showed that seed progeny from EURT impact zone possessed high viability that, however, was accompanied by development of latent injuries resulting in low resistance to additional man-caused impacts. In F (1)-generation originated from NTMC zone, high seed viability was combined with increased resistance to provocative heavy metal and radiation exposure. No significant differences in responses to 'habitual' and 'new' factors, i.e. pre-adaptation effect, were found in samples from the contaminated areas.

  10. Population genetic structuring in Opisthorchis viverrini over various spatial scales in Thailand and Lao PDR.

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    Nonglak Laoprom

    Full Text Available Khon Kaen Province in northeast Thailand is known as a hot spot for opisthorchiasis in Southeast Asia. Preliminary allozyme and mitochondrial DNA haplotype data from within one endemic district in this Province (Ban Phai, indicated substantial genetic variability within Opisthorchis viverrini. Here, we used microsatellite DNA analyses to examine the genetic diversity and population structure of O. viverrini from four geographically close localities in Khon Kaen Province. Genotyping based on 12 microsatellite loci yielded a mean number of alleles per locus that ranged from 2.83 to 3.7 with an expected heterozygosity in Hardy-Weinberg equilibrium of 0.44-0.56. Assessment of population structure by pairwise F(ST analysis showed inter-population differentiation (P<0.05 which indicates population substructuring between these localities. Unique alleles were found in three of four localities with the highest number observed per locality being three. Our results highlight the existence of genetic diversity and population substructuring in O. viverrini over a small spatial scale which is similar to that found at a larger scale. This provides the basis for the investigation of the role of parasite genetic diversity and differentiation in transmission dynamics and control of O. viverrini.

  11. Chikungunya virus susceptibility & variation in populations of Aedes aegypti (Diptera: Culicidae mosquito from India

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    Mangesh D Gokhale

    2015-01-01

    Full Text Available Background & objectives: Although having immense clinical relevance, yet only a few studies have been targeted to understand the chikungunya virus (CHIKV susceptibility and growth in Aedes aegypti populations from India. This study was undertaken to investigate CHIKV susceptibility and growth kinetics in Ae. aegypti along with genetic heterogeneity of Ae. aegypti populations. Methods: Dose dependent CHIKV susceptibility and growth kinetic studies for three CHIKV strains reported from India were carried out in Ae. aegypti mosquito populations. The phenotypic variation and genetic heterogeneity in five Ae. aegypti populations were investigated using multivariate morphometrics and allozyme variation studies. Results: The dissemination and growth kinetics studies of the three CHIKV strains showed no selective advantage for a particular strain of CHIKV in Ae. aegypti. At 100 per cent infection rate, five geographic Ae. aegypti populations showed differences in dissemination to three CHIKV strains. Morphometric studies revealed phenotypic variation in all the studied populations. The allelic frequencies, F statistics, and Nei′s genetic identity values showed that genetic differences between the populations were small, but significant. Interpretation & conclusions: The results obtained in this study suggest that genetic background of the vector strongly influences the CHIKV susceptibility in Ae. aegypti.

  12. Genetic and morphometric differences between yellowtail snapper (Ocyurus chrysurus, Lutjanidae populations of the tropical West Atlantic

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    Anderson V. Vasconcellos

    2008-01-01

    Full Text Available Populations of Ocyurus chrysurus were compared genetically and morphometrically along the West Atlantic coast to test the null hypothesis of population homogeneity in the area. Brazilian populations were found to be differentiated in shape (canonical variates analysis; F[48,515] = 10.84, p < 0.0001. Analyses of mitochondrial DNA sequences (663 bp of the control region did not show any differences between Brazilian populations but could detect differences between Brazilian and Caribbean (Belize populations. The samples from Pernambuco differed significantly from the other Brazilian populations in allozyme frequencies (11 loci; F ST = 0.167; p < 0.05, but this may have resulted from the small number of samples analysed for that population. Sequence variation of Belize samples departed from neutral expectations (Fu's FS = -8.88; p < 0.001. A mismatch distribution analysis points to an ancient population expansion in that area. We conclude that the genetic data do not allow the rejection of the null hypothesis of panmixia for Brazilian yellowtail snapper populations which should be treated as a single genetic stock, with a latitudinal gradient on their morphology which probably results from phenotypic plasticity. On the other hand, there is a severe restriction to gene flow between O. chrysurus populations from the Caribbean and from the southwestern Atlantic.

  13. Extended parental care in communal social groups

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    Stephen H. Forbes

    2002-11-01

    Full Text Available Recent developments in social insect research have challenged the need for close kinship as a prerequisite for the evolution of stable group living. In a model communal bee species, Lasioglossum (Chilalictus hemichalceum, previous allozyme work indicated that groups of cooperating adult females are not relatives. Yet at any given time, not all group members perform the risky task of foraging. We previously hypothesized that tolerance for non-foragers was a component of extended parental care, previously known only for kin based social systems. DNA microsatellites were used to study colony genetic structure in order to test this hypothesis. Microsatellite polymorphism was substantial (He = 0.775. Overall intracolony relatedness, mainly of immatures, was low but significant in nine, late season nests (r = 0.136 plus or minus0.023, indicating that broods contain five to six unrelated sib ships. Detailed analyses of kinship between pairs of individuals revealed that most pairs were unrelated and most related pairs were siblings. Mothers are absent for 89-91% of the developing immature females, and 97% of developing males. Alternatively, 46% of adult females had neither sibs nor offspring in their nests. These findings indicate that the extended parental care model applies broadly to both kin based and nonkin based social systems in the Hymenoptera.

  14. Genetic diversity and differentiation of mud crab Scylla serrata populations from southeastern China

    Institute of Scientific and Technical Information of China (English)

    LI Zhongbao; LI Shaojing; WANG Guizhong

    2004-01-01

    The genetic diversity and differentiation of 6 mud crab Scylla serrata populations from southeastern China are investigated using allozyme electrophoresis. The mean number of alleles per locus population is 1.3 ± 0.1; the percentage of polymorphic loci per population is 27.3; the observed heterozygosity ranges from ( 0.195 ± 0.083)to ( 0.241 ± 0.090) and the expected heterozygosity ranges from ( 0.105 ± 0.043 ) to ( 0.131 ± 0.047 ). The coefficient of gene differentiation among populations is low (Fst =0.032), indicating that only 3.2 % of the total genetic diversity comes from inter-population, while the remaining 96.8 % comes from intra-population differences.The genetic distance among populations is 0.000~0.008 (the average is 0.002). Gene flow among the populations is large (Nm= 7.56).Genetic structure is very similar among 6 Scylla serrata populations.

  15. Barriers to gene flow in the marine environment: insights from two common intertidal limpet species of the Atlantic and Mediterranean.

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    Alexandra Sá-Pinto

    Full Text Available Knowledge of the scale of dispersal and the mechanisms governing gene flow in marine environments remains fragmentary despite being essential for understanding evolution of marine biota and to design management plans. We use the limpets Patella ulyssiponensis and Patella rustica as models for identifying factors affecting gene flow in marine organisms across the North-East Atlantic and the Mediterranean Sea. A set of allozyme loci and a fragment of the mitochondrial gene cytochrome C oxidase subunit I were screened for genetic variation through starch gel electrophoresis and DNA sequencing, respectively. An approach combining clustering algorithms with clinal analyses was used to test for the existence of barriers to gene flow and estimate their geographic location and abruptness. Sharp breaks in the genetic composition of individuals were observed in the transitions between the Atlantic and the Mediterranean and across southern Italian shores. An additional break within the Atlantic cluster separates samples from the Alboran Sea and Atlantic African shores from those of the Iberian Atlantic shores. The geographic congruence of the genetic breaks detected in these two limpet species strongly supports the existence of transpecific barriers to gene flow in the Mediterranean Sea and Northeastern Atlantic. This leads to testable hypotheses regarding factors restricting gene flow across the study area.

  16. Metabolic adjustments in Satanoperca aff. jurupari (Perciformes: Cichlidae

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    Chippari-Gomes Adriana R.

    2003-01-01

    Full Text Available In this paper, we describe the enzyme levels and isozyme distribution in skeletal and heart muscle of Satanoperca aff. jurupari, (Cichlidae, subgroup Geophaginae. LDH and CS were measured in skeletal and heart muscle. Starch gel electrophoresis was used to determine the isozyme/allozyme patterns in different tissues; LDH, MDHs, PGM, PGI, ADH, G-6-PDH and SOD were screened for the numbers of loci, presence of alleles, and tissue specificity. The LDH/CS ratio in heart and skeletal muscle were 173.36 and 6.1, respectively, indicating anaerobic metabolism in the former and aerobic metabolism in the latter muscle. No inhibition by pyruvate (based on the ratios of LDH activity with 1 mM and 10 mM pyruvate was detected in heart and skeletal muscle, indicating the presence of physiological plasticity in heart muscle. The heart can cope with anaerobic metabolism for short periods of hypoxia such as occurs in nature. Isozyme patterns for most of the enzymes analyzed were similar to the general patterns for advanced teleosts. S. aff. jurupari had no reduced LDH-B* expression in heart muscle, but the, MDHs-B* locus was duplicated, as reported for most Amazon cichlids species. Only three out of the 13 loci analyzed (PGM, PGI and SOD were variable. These results are consistent with the metabolic profile and life style of the most cichlids. A low genetic variability may be a counterpart for plasticity, and may be guaranteed by the regulation of invariable structural genes.

  17. Introgression and susceptibility to disease in a wild population of rainbow trout

    Science.gov (United States)

    Currens, K.P.; Hemmingsen, A.R.; French, R.A.; Buchanan, D.V.; Schreck, C.B.; Li, H.W.

    1997-01-01

    We examined susceptibility of wild rainbow trout Oncorhynchus mykiss from the Metolius River, a tributary of the Deschutes River, Oregon, to genetic introgression and ceratomyxosis as a result of stocking nonnative hatchery rainbow trout. Ceratomyxa shasta, an enzootic myxosporean parasite that can be lethal to nonnative hatchery rainbow trout, might have been limiting the interbreeding of hatchery and wild rainbow trout in the river. However, rainbow trout from the Metolius River had allozyme frequencies intermediate between those of wild and hatchery fish at LDH-B2* and sSOD-1*, two diagnostic genetic loci that allow the inland subspecies of rainbow trout to be distinguished from hatchery strains of coastal origin. They also had notable frequencies of ADA-1*85, an allele documented in hatchery rainbow trout but rarely seen in wild populations. We also found that rainbow trout in the Metolius River averaged 138.9 scales in the lateral series, intermediate between the counts for 9 coastal or nonnative hatchery populations, which always had fewer than 140 scales, and 10 inland populations, which always had more than 140 scales. Disease challenges revealed that rainbow trout from the Metolius River had much greater susceptibility to C. shasta than rainbow trout from the Deschutes River, which have genetic resistance to the lethal disease. Based on these data, we concluded that introgression with nonnative hatchery rainbow trout has reduced the abilities of wild rainbow trout in the Metolius River to survive when conditions for ceratomyxosis infection occur.

  18. Genetic structure and phylogeography of European catfish (Silurus glanis) populations.

    Science.gov (United States)

    Triantafyllidis, A; Krieg, F; Cottin, C; Abatzopoulos, T J; Triantaphyllidis, C; Guyomard, R

    2002-06-01

    The genetic structure of Silurus glanis (Europe's largest freshwater fish species) across most of its natural distribution was investigated using 10 microsatellite loci. The revealed levels of genetic diversity were much higher than previous allozyme and restriction fragment length polymorphism mitochondrial DNA analyses had shown; relative levels of variability among populations were however, in good agreement with the previous studies. Populations from large basins (Volga and Danube rivers) were the most polymorphic, while samples from the smaller Greek rivers, which are more prone to genetic bottleneck, exhibited the lowest levels of genetic diversity. Microsatellite multilocus genotyping permitted the assignment of individual fish to their population of origin with a score as high as 98.3%. Despite the great genetic differentiation of S. glanis populations, no consistent pattern of geographical structuring was revealed, in contrast to previous studies of European freshwater fish species. A model of isolation by distance seems more probable and a hypothesis of recent dispersion from only one glacial refugium is proposed. The discovery of the highest levels of microsatellite and mitochondrial diversity in the Volga sample and the presence of river connections, during the Pleistocene, between this area and all major areas of the present catfish distribution, place this refugium around the Ponto-Caspian region. Combining these data with those from previous studies, a number of markers are now available to monitor wild and hatchery populations even at the individual level.

  19. Hybrid male sterility between the fresh- and brackish-water types of ninespine stickleback Pungitius pungitius (Pisces, Gasterosteidae).

    Science.gov (United States)

    Takahashi, Hiroshi; Nagai, Terumi; Goto, Akira

    2005-01-01

    Two ecologically distinct forms, fresh- and brackish-water types, of ninespine stickleback co-exist in several freshwater systems on the coast of eastern Hokkaido. Recent genetic analyses of 13 allozyme loci revealed genetic separation between the two types even though their spawning grounds were in close proximity. On the other hand, there is only a small difference in mitochondrial DNA (mtDNA) sequence between the two types suggesting that they diverged quite recently or that mtDNA introgression occurred between them. To test for postzygotic reproductive isolating mechanisms and hybrid mediated gene flow, we examined the viability and reproductive performance of reciprocal F1 hybrids. The hybrids grew to the adult size normally and both sexes expressed secondary sexual characters in the reciprocal crosses. The female hybrids were reciprocally fertile, while the male hybrids were reciprocally sterile. Histological and flow-cytometric analyses of the hybrid testis revealed that the sterility pattern was classified as 'gametic sterility,' with gonads of normal size but abnormal spermatogenesis. To our knowledge, the present finding is a novel example of one sex hybrid sterility in the stickleback family (Gasterosteidae).

  20. Genetic diversity analysis by RAPD in Cathaya argyrophylla Chun et Kuang

    Institute of Scientific and Technical Information of China (English)

    汪小全; 邹喻苹; 张大明; 洪德元; 刘正宇

    1997-01-01

    Genetic diversity level of Cathaya argyrophylla was confirmed by random amplified polymorphic DNA (RAPD) markers. Seventy five samples (individuals), collected from Hunan and Sichuan provinces of China were used in the study. 21 10-mer oligonucleotide primers detected 106 sites, and 34 (32% ) of them were polymor-phic. The level of genetic variation in C. argyrophylla was lower than those of other conifers, and was considered to be associated with the complexity of habitats. The percentages of polymorphic sites (PPS) in the Hunan and Sichuan pop-ulations were 18% and 25% respectively. 7.99% of genetic variation existed between the two populations; this value was higher than the mean value (6.8%) among populations in conifers displayed by allozyme. Some subpopulations of C. argyrophylla were greatly differentiated because of site mutation and genetic drift. The highest value of genetic dif-ference between subpopulations amounted to 16. 23% . In addition, a concept of diversity coefficient(DC), a value us

  1. Chromosomal similarity between the Scaly-headed parrot (Pionus maximiliani, the Short-tailed parrot (Graydidascalus brachyurus and the Yellow-faced parrot (Salvatoria xanthops (Psittaciformes: Aves: a cytotaxonomic analysis

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    Renato Caparroz

    2004-01-01

    Full Text Available Behavior, morphology, allozyme studies and DNA hybridization and sequencing data all suggest the independent evolution of the Old and New World parrots and support tribe status for the American species, although the phylogenetic relationships within this tribe are still poorly understood. A previous study has shown that the Yellow-faced parrot (Amazona xanthops Spix 1824 exhibits large karyotypic differences compared to the other Amazona species and suggested that this species should be renamed Salvatoria xanthops, although the relationships between S. xanthops and the other New World parrots remain unclear. In the present work, we describe the karyotype of the Scaly-headed parrot (Pionus maximiliani, Kuhl 1820 and the karyotype and C-banding pattern of the Short-tailed parrot (Graydidascalus brachyurus, Kuhl 1820 and compare them to the karyotype and C-banding pattern of S. xanthops, as well as to the karyotypes of other New World parrots. The chromosomal similarity between these three species and the karyotypic differences between them and other New World parrots suggest that G. brachyurus and S. xanthops are sister species and are most closely related to members of the genus Pionus.

  2. Effects of crossing distance and genetic relatedness on pollen performance in Alstroemeria aurea (Alstroemeriaceae).

    Science.gov (United States)

    Souto, Cintia P; Aizen, Marcelo A; Premoli, Andrea C

    2002-03-01

    Prezygotic barriers may represent effective mechanisms to avoid the deleterious effects of inbreeding. This study reports the existence of distance-dependent prezygotic barriers in self-compatible Alstroemeria aurea, a clonal herb native to temperate forests of the southern Andes. We analyzed pollen germination and tube growth as indicators of donor-recipient affinity using crossing distances of 1, 10, and 100 m. We used allozyme electrophoresis to determine the actual genetic relatedness between donor and recipient ramets. Pollen germination was not affected by distance between mates, but the number of pollen tubes reaching the base of the style increased strongly with distance between donor and recipient. This pattern was related to an increase in genetic dissimilarity with distance between mates. In contrast, pollen tube-style interactions did not change with distance when we restricted analysis to individuals at different distances that appeared to be genetically identical. This test implied genetic dissimilarity as the critical factor affecting pollen performance. We propose that the existence of prezygotic barriers might contribute to the high degree of genetic mixing exhibited by some clonal species.

  3. Temporal change in the genetic structure between and within cohorts of a marine fish, Diplodus sargus, induced by a large variance in individual reproductive success.

    Science.gov (United States)

    Planes, S; Lenfant, P

    2002-08-01

    Temporal changes at 16 allozyme loci in the Diplodus sargus population of Banyuls-sur-Mer (Mediterranean Sea, France) were monitored. Temporal genetic variation within a single population was examined over two temporal scales: (i) among three year-classes sampled at the same age, and (ii) within a single year-class sampled three times over a two-year period. We observed a significant change in the genotypic structure within the same cohort during the first two years following settlement and before recruitment into the adult population. In addition, comparison of year-classes showed that cohorts differed significantly one year after settlement, whereas they became similar later on before recruitment into the adult population. The observed changes in the genetic structure within and between year-classes may be the result of complex selective processes or genetic drift. Linkage disequilibrium and genetic relatedness data suggest that these changes are due to large variation in reproductive success, followed by homogenization through adult movement. Overall, these results demonstrated a rapid genetic change within a population.

  4. Hybrid dynamics in a species group of swallowtail butterflies.

    Science.gov (United States)

    Dupuis, J R; Sperling, F A H

    2016-10-01

    Hybrid zones provide unique natural laboratories for studying mechanisms of evolution. But identification and classification of hybrid individuals (F1, F2, backcross, etc.) can be complicated by real population changes over time as well as by use of different marker types, both of which challenge documentation of hybrid dynamics. Here, we use multiple genetic markers (mitochondrial DNA, microsatellites and genomewide single nucleotide polymorphisms) to re-examine population structure in a hybrid zone between two species of swallowtail butterflies in western Canada, Papilio machaon and P. zelicaon. Our aim was to test whether their hybrid dynamics remain the same as found 30 years ago using morphology and allozymes, and we compared different genetic data sets as well as alternative hybrid identification and classification methods. Overall, we found high differentiation between the two parental species, corroborating previous research from the 1980s. We identified fewer hybrid individuals in the main zone of hybridization in recent years, but this finding depended on the genetic markers considered. Comparison of methods with simulated data sets generated from our data showed that single nucleotide polymorphisms were more powerful than microsatellites for both hybrid identification and classification. Moreover, substantial variation among comparisons underlined the value of multiple markers and methods for documenting evolutionarily dynamic systems.

  5. Assessment of Genetic Diversity in Seed Plants Based on a Uniform π Criterion

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    Bin Ai

    2014-12-01

    Full Text Available Despite substantial advances in genotyping techniques and massively accumulated data over the past half century, a uniform measurement of neutral genetic diversity derived by different molecular markers across a wide taxonomical range has not yet been formulated. We collected genetic diversity data on seed plants derived by AFLP, allozyme, ISSR, RAPD, SSR and nucleotide sequences, converted expected heterozygosity (He to nucleotide diversity (π, and reassessed the relationship between plant genetic diversity and life history traits or extinction risk. We successfully established a uniform π criterion and developed a comprehensive plant genetic diversity database. The mean population-level and species-level π values across seed plants were 0.00374 (966 taxa, 155 families, 47 orders and 0.00569 (728 taxa, 130 families, 46 orders, respectively. Significant differences were recovered for breeding system (p < 0.001 at the population level and geographic range (p = 0.023 at the species level. Selfing taxa had significantly lower π values than outcrossing and mixed-mating taxa, whereas narrowly distributed taxa had significantly lower π values than widely distributed taxa. Despite significant differences between the two extreme threat categories (critically endangered and least concern, the genetic diversity reduction on the way to extinction was difficult to detect in early stages.

  6. Experimental and genetic analyses reveal that inbreeding depression declines with increased self-fertilization among populations of a coastal dune plant.

    Science.gov (United States)

    Dart, S; Eckert, C G

    2013-03-01

    Theory predicts that inbreeding depression (ID) should decline via purging in self-fertilizing populations. Yet, intraspecific comparisons between selfing and outcrossing populations are few and provide only mixed support for this key evolutionary process. We estimated ID for large-flowered (LF), predominantly outcrossing vs. small-flowered (SF), predominantly selfing populations of the dune endemic Camissoniopsis cheiranthifolia by comparing selfed and crossed progeny in glasshouse environments differing in soil moisture, and by comparing allozyme-based estimates of the proportion of seeds selfed and inbreeding coefficient of mature plants. Based on lifetime measures of dry mass and flower production, ID was stronger in nine LF populations [mean δ = 1-(fitness of selfed seed/fitness of outcrossed seed) = 0.39] than 16 SF populations (mean δ = 0.03). However, predispersal ID during seed maturation was not stronger for LF populations, and ID was not more pronounced under simulated drought, a pervasive stress in sand dune habitat. Genetic estimates of δ were also higher for four LF (δ = 1.23) than five SF (δ = 0.66) populations; however, broad confidence intervals around these estimates overlapped. These results are consistent with purging, but selective interference among loci may be required to maintain strong ID in partially selfing LF populations, and trade-offs between selfed and outcrossed fitness are likely required to maintain outcrossing in SF populations.

  7. Opisthorchis viverrini: Implications of the systematics of first intermediate hosts, Bithynia snail species in Thailand and Lao PDR.

    Science.gov (United States)

    Kiatsopit, Nadda; Sithithaworn, Paiboon; Saijuntha, Weerachai; Petney, Trevor N; Andrews, Ross H

    2013-03-01

    Bithynia snails are important hosts of the human liver fluke, Opisthorchis viverrini. Allozyme markers were used to examine genetic variation and the systematics of Bithynia snails from different geographical localities in Thailand and Lao PDR. Our results show that Bithynia siamensis goniomphalos contains two major evolutionary clades with at least nine morphologically similar but genetically distinct "cryptic" species (taxa). Clade A consists of snails from the Chi and the Mun River wetlands, Thailand and clade B consists of snails from the Nam Ngum River wetland, Lao PDR, as well as snails from some localities in the Songkram River wetland, Thailand. There is an association between O. viverrini cryptic taxa with B. s. goniomphalos cryptic taxa within the defined wetlands. Bithynia species are the critical amplifying component of O. viverrini and they control transmission from humans to fish second intermediate hosts. These findings are particularly important for understanding the transmission dynamics of O. viverrini. They are, in addition, a link in the life cycle of O. viverrini which can be used for developing and implementing programs to eliminate and control opisthorchiasis and its associated cholangiocarcinoma.

  8. Extra-Mediterranean glacial refugia in a Mediterranean faunal element: the phylogeography of the chalk-hill blue Polyommatus coridon (Lepidoptera, Lycaenidae)

    Science.gov (United States)

    Kühne, Gero; Kosuch, Joachim; Hochkirch, Axel; Schmitt, Thomas

    2017-01-01

    Most warm-adapted Central European species are thought to have survived ice ages exclusively in Mediterranean refugia. During recent years, this point of view has been questioned. Therefore, we tested the hypothesis that extra-Mediterranean refugia also played a role in warm-adapted insect species and selected the chalk-hill blue, Polyommatus coridon. We sequenced two mitochondrial loci (COI, CR) in 150 individuals from 30 populations covering nearly the complete range. Minimum spanning networks and other statistical analyses concordantly revealed four genetic lineages with strong phylogeographic signal: a western group in Italy, France and western/central Germany, an eastern lineage in the Balkan Peninsula, the Carpathian Basin and eastern Central Europe, an Alpine group with populations in the Alps and southern Germany and a Pyrenean group. Our results are generally consistent with previous analyses for P. coridon based on allozymes and DNA sequences, but provide additional insights. We propose that these four lineages have evolved during allopatry in different glacial refugia, two in typical Mediterranean refugia (Apennines and Balkan Peninsulas), but two in extra-Mediterranean areas south of the Alps and Pyrenees. This supports survival of warm-adapted organisms in these regions in close geographic proximity to the refugia of high mountain species.

  9. Molecular Population Genetics

    Science.gov (United States)

    Casillas, Sònia; Barbadilla, Antonio

    2017-01-01

    Molecular population genetics aims to explain genetic variation and molecular evolution from population genetics principles. The field was born 50 years ago with the first measures of genetic variation in allozyme loci, continued with the nucleotide sequencing era, and is currently in the era of population genomics. During this period, molecular population genetics has been revolutionized by progress in data acquisition and theoretical developments. The conceptual elegance of the neutral theory of molecular evolution or the footprint carved by natural selection on the patterns of genetic variation are two examples of the vast number of inspiring findings of population genetics research. Since the inception of the field, Drosophila has been the prominent model species: molecular variation in populations was first described in Drosophila and most of the population genetics hypotheses were tested in Drosophila species. In this review, we describe the main concepts, methods, and landmarks of molecular population genetics, using the Drosophila model as a reference. We describe the different genetic data sets made available by advances in molecular technologies, and the theoretical developments fostered by these data. Finally, we review the results and new insights provided by the population genomics approach, and conclude by enumerating challenges and new lines of inquiry posed by increasingly large population scale sequence data. PMID:28270526

  10. Spatial Analysis of Phytophthora infestans Genotypes and Late Blight Severity on Tomato and Potato in the Del Fuerte Valley Using Geostatistics and Geographic Information Systems.

    Science.gov (United States)

    Jaime-Garcia, R; Orum, T V; Felix-Gastelum, R; Trinidad-Correa, R; Vanetten, H D; Nelson, M R

    2001-12-01

    ABSTRACT Genetic structure of Phytophthora infestans, the causal agent of potato and tomato late blight, was analyzed spatially in a mixed potato and tomato production area in the Del Fuerte Valley, Sinaloa, Mexico. Isolates of P. infestans were characterized by mating type, allozyme analysis at the glucose-6-phosphate isomerase and peptidase loci, restriction fragment length polymorphism with probe RG57, metalaxyl sensitivity, and aggressiveness to tomato and potato. Spatial patterns of P. infestans genotypes were analyzed by geographical information systems and geo-statistics during the seasons of 1994-95, 1995-96, and 1996-97. Spatial analysis of the genetic structure of P. infestans indicates that geographic substructuring of this pathogen occurs in this area. Maps displaying the probabilities of occurrence of mating types and genotypes of P. infestans, and of disease severity at a regional scale, were presented. Some genotypes that exhibited differences in epidemiologically important features such as metalaxyl sensitivity and aggressiveness to tomato and potato had a restricted spread and were localized in isolated areas. Analysis of late blight severity showed recurring patterns, such as the earliest onset of the disease in the area where both potato and tomato were growing, strengthening the hypothesis that infected potato tubers are the main source of primary inoculum. The information that geostatistical analysis provides might help improve management programs for late blight in the Del Fuerte Valley.

  11. Heterozygote excess through life history stages in Cestrum miradorense Francey (Solanaceae), an endemic shrub in a fragmented cloud forest habitat.

    Science.gov (United States)

    Reyes-Zepeda, F; González-Astorga, J; Montaña, C

    2013-01-01

    Comparisons of genetic diversity and population genetic structure among different life history stages provide important information on the effect of the different forces and micro-evolutionary processes that mould diversity and genetic structure after fragmentation. Here we assessed genetic diversity and population genetic structure using 32 allozymic loci in adults, seeds, seedlings and juveniles of eight populations of the micro-endemic shrub Cestrum miradorense in a highly fragmented cloud forest in central-eastern Mexico. We expected that due to its long history or rarity, this species may have endured the negative effects of fragmentation and would show moderate to high levels of genetic diversity. High genetic diversity (H(e) = 0.445 ± 0.03), heterozygote excess (F(IT) = -0.478 ± 0.034, F(IS) = -0.578 ± 0.023) and low population differentiation (F(ST) = 0.064 ± 0.011) were found. Seeds had higher genetic diversity (H(e) = 0.467 ± 0.05) than the later stages (overall mean for adults, seedlings and juveniles H(e) = 0.438 ± 0.08). High gene flow was observed despite the fact that the fragmentation process began more than 100 years ago. We conclude that the high genetic diversity was the result of natural selection, which favours heterozygote excess in all stages, coupled with a combination of a reproductive system and seed/pollen dispersal mechanisms that favour gene flow.

  12. Genetic structure and phyletic relationships of eastern Mediterranean Bacillus atticus brunner (Insecta Phasmatodea): a biochemical study.

    Science.gov (United States)

    Mantovani, B; Scali, V

    1993-10-01

    The allozymic characterization of several new Croatian, Greek, and Turkish samples thought to belong to different subspecies of Bacillus atticus or to atticus-like taxa is given. Several allelic combinations (zymotypes) were observed among both diploid and triploid samples; the occurrence of highly different levels of heterozygosity for the same locus among populations is also common. The biochemical-genetic features of the numerous zymotypes are interpreted on the basis of the recently assessed cytology of their parthenogenetic reproduction. Biochemical and meiotic features also allow one to suggest that both diploid and triploid cytotypes of B. atticus are more likely interracial hybrids in origin. The new triploid Greek samples show only small genetic distances from the Turkish triploid and diploid ones; also, they do not show clear-cut morphological differences, so that all triploids and Turkish diploid samples are together referred to as B. a. carius. On the other hand, all Croatian, Greek, and Italian diploids appear to belong to the same electrophoretic cluster, biochemically differentiated at a subspecific level from B. a. carious. This newly defined comprehensive group of diploid samples, which also morphologically show gradual patterns of variation, is referred to as B. a. atticus.

  13. [Molecular variability in the commom shrew Sorex araneus L. from European Russia and Siberia inferred from the length polymorphism of DNA regions flanked by short interspersed elements (Inter-SINE PCR) and the relationships between the Moscow and Seliger chromosome races].

    Science.gov (United States)

    Bannikova, A A; Bulatova, N Sh; Kramerov, D A

    2006-06-01

    Genetic exchange among chromosomal races of the common shrew Sorex araneus and the problem of reproductive barriers have been extensively studied by means of such molecular markers as mtDNA, microsatellites, and allozymes. In the present study, the interpopulation and interracial polymorphism in the common shrew was derived, using fingerprints generated by amplified DNA regions flanked by short interspersed repeats (SINEs)-interSINE PCR (IS-PCR). We used primers, complementary to consensus sequences of two short retroposons: mammalian element MIR and the SOR element from the genome of Sorex araneus. Genetic differentiation among eleven populations of the common shrew from eight chromosome races was estimated. The NP and MJ analyses, as well as multidimensional scaling showed that all samples examined grouped into two main clusters, corresponding to European Russia and Siberia. The bootstrap support of the European Russia cluster in the NJ and MP analyses was respectively 76 and 61%. The bootstrap index for the Siberian cluster was 100% in both analyses; the Tomsk race, included into this cluster, was separated with the bootstrap support of NJ/MP 92/95%.

  14. Ecological and genetic data indicate recovery of the endangered coral Acropora palmata in Los Roques, Southern Caribbean

    Science.gov (United States)

    Zubillaga, A. L.; Márquez, L. M.; Cróquer, A.; Bastidas, C.

    2008-03-01

    The rapid decline of Acropora cervicornis and Acropora palmata has often been linked with coral reef deterioration in the Caribbean; yet, it remains controversial whether these species are currently recovering or still declining. In this study, the status of ten populations of A. palmata in Los Roques National Park (LRNP), Venezuela is presented. Six of these populations showed signs of recovery. Ten 80 m2 belt-transects were surveyed at each of the ten reef sites. Within belt-transects, each colony was measured (maximum diameter and height) and its status (healthy, diseased or injured) was recorded. Populations in recovery were defined by a dominance of small to medium-sized colonies in densities >1 colony per 10 m2, together with 75% undamaged colonies, a low prevalence of diseases (<10%), and a low density of predators (0.25 snails per colony). Based on allozyme analysis of seven polymorphic loci in four populations ( N = 30), a moderate to high-genetic connectivity among these populations ( F ST = 0.048) was found with a predominance of sexual over asexual reproduction ( N* : N = 1; N go : N = 0.93-1). Both ecological and molecular data support a good prognosis for the recovery of this species in Los Roques.

  15. Temporal patterns of genetic and phenotypic variation in the epidemiologically important drone fly, Eristalis tenax.

    Science.gov (United States)

    Francuski, Lj; Matić, I; Ludoški, J; Milankov, V

    2011-06-01

    Eristalis tenax L. (Diptera: Syrphidae) is commonly known as the drone fly (adult) or rat-tailed maggot (immature). Both adults and immature stages are identified as potential mechanical vectors of mycobacterial pathogens, and early-stage maggots cause accidental myiasis. We compared four samples from Mount Fruška Gora, Serbia, with the aim of obtaining insights into the temporal variations and sexual dimorphism in the species. This integrative approach was based on allozyme loci, morphometric wing parameters (shape and size) and abdominal colour patterns. Consistent sexual dimorphism was observed, indicating that male specimens had lighter abdomens and smaller and narrower wings than females. The distribution of genetic diversity at polymorphic loci indicated genetic divergence among collection dates. Landmark-based geometric morphometrics revealed, contrary to the lack of divergence in wing size, significant wing shape variation throughout the year. In addition, temporal changes in the frequencies of the abdominal patterns observed are likely to relate to the biology of the species and ecological factors in the locality. Hence, the present study expands our knowledge of the genetic diversity and phenotypic plasticity of E. tenax. The quantification of such variability represents a step towards the evaluation of the adaptive potential of this species of medical and epidemiological importance.

  16. Postglacial colonisation of western Central Europe by Polyommatus coridon (Poda 1761) (Lepidoptera: Lycaenidae): evidence from population genetics.

    Science.gov (United States)

    Schmitt, T; Giessl, A; Seitz, A

    2002-01-01

    The genetic population structure of Polyommatus coridon (Poda 1761) over large regions of France, Italy and Germany was studied by allozyme electrophoresis. The genetic diversity within populations was high for all parameters analysed (number of alleles 2.72; observed and expected heterozygosity 19.6% and 20.3%, respectively; percentage of polymorphic loci: total: 76.4% and, with polymorphism if the frequency of the commonest allele is below 95%: 53.1%), whereas genetic differentiation between populations was comparatively low (FST = 0.021 +/- 0.002). The mean number of alleles declined significantly from southern to northern populations (r = -0.53, P = 0.0005). Similar effects were found also for other parameters of genetic diversity. This is interpreted as a loss of genetic diversity during postglacial expansion. However, samples from France and Italy had similar patterns of genetic diversity indicating no significant loss in this region. Populations from southern Germany were genetically uniform, well differentiated from French populations and showed a significant loss of genetic diversity. Probably, this is due to a bottleneck during passing through the Burgundian Gap, which is a migration corridor from north-eastern France to southern Germany. In contrast to southern German populations, western German populations were not well differentiated from French populations. Nevertheless, they were genetically impoverished, probably as a result from local bottlenecks and post-expansion phenomena.

  17. The gynogenetic reproduction of diploid and triploid hybrid spined loaches (Cobitis: Teleostei), and their ability to establish successful clonal lineages--on the evolution of polyploidy in asexual vertebrates.

    Science.gov (United States)

    Janko, Karel; Bohlen, Jörg; Lamatsch, Dunja; Flajshans, Martin; Epplen, Jörg T; Ráb, Petr; Kotlík, Petr; Slechtová, Vera

    2007-10-01

    Polyploidisation is assumed to have played a significant role in the evolution of hybrid asexual lineages. The virtual absence of natural asexual systems in which more than a single ploidy level successfully establishes successful independent clonal lineages is generally explained by the strong effects of polyploidisation on fitness. Experimental crosses were made between diploid and triploid asexual Cobitis elongatoides x C. taenia hybrids (female) and both parental spined loach species (male). Genotyping of the progeny using allozymes and multilocus DNA fingerprinting, along with flow cytometric measurement of ploidy level, demonstrated the occurrence of gynogenetic reproduction in both female biotypes. The incorporation of the sperm genome occurred in some progeny, giving rise to a higher ploidy level, but the rate of polyploidisation differed significantly between the diploid and triploid females. These outcomes are consistent with the existence of developmental constraints on tetraploidy, which determine the rarity of tetraploids in natural populations. No cases of ploidy level reduction were observed. Since diploid and triploid hybrid populations occur where the lack of potential progenitor excludes the possibility of de novo origin, it is probable that both diploid and triploid females can establish successful clonal lineages. Spined loaches represent a unique example, among asexual vertebrates, where more than one ploidy level can establish persistent clonal lineages, which are reproductively independent of one another.

  18. Clonal diversity and clone formation in the parthenogenetic Caucasian rock Lizard Darevskia dahli [corrected].

    Science.gov (United States)

    Vergun, Andrey A; Martirosyan, Irena A; Semyenova, Seraphima K; Omelchenko, Andrey V; Petrosyan, Varos G; Lazebny, Oleg E; Tokarskaya, Olga N; Korchagin, Vitaly I; Ryskov, Alexey P

    2014-01-01

    The all-female Caucasian rock lizard species Darevskia dahli and other parthenogenetic species of this genus reproduce normally via true parthenogenesis. Previously, the genetic diversity of this species was analyzed using allozymes, mitochondrial DNA, and DNA fingerprint markers. In the present study, variation at three microsatellite loci was studied in 111 specimens of D. dahli from five populations from Armenia, and new information regarding clonal diversity and clone formation in D. dahli was obtained that suggests a multiple hybridization origin. All individuals but one were heterozygous at the loci studied. Based on specific allele combinations, 11 genotypes were identified among the individuals studied. Individuals with the same genotypes formed distinct clonal lineages: one major clone was represented by 72 individuals, an intermediate clone was represented by 21 individuals, and nine other clones were rare and represented by one or several individuals. A new approach based on the detection and comparison of genotype-specific markers formed by combinations of parental-specific markers was developed and used to identify at least three hybridization founder events that resulted in the initial formation of one major and two rare clones. All other clones, including the intermediate and seven rare clones, probably arose through postformation microsatellite mutations of the major clone. This approach can be used to identify hybridization founder events and to study clone formation in other unisexual taxa.

  19. Delimiting species by reproductive isolation: the genetic structure of epigean and hypogean Trichomycterus spp. (Teleostei, Siluriformes) in the restricted area of Torotoro (Upper Amazon, Bolivia).

    Science.gov (United States)

    Renno, Jean-François; Gazel, Claude; Miranda, Guido; Pouilly, Marc; Berrebi, Patrick

    2007-11-01

    Genetic variability of Trichomycterus from the region of Torotoro (Bolivia, Upper Amazon), distributed in the same watershed where the habitat is structured by waterfalls, canyons and a cave, was studied by allozyme (twelve putative loci) and RFLP-mtDNA (DLoop and cytochrome b) analyses. Alloenzymatic variation studied by Correspondence Analysis and Maximum Likelihood Analysis revealed a four-group structure, which was largely congruent with the distribution of the 14 mtDNA haplotypes. Two of these four clusters (I and II) were differentiated by two diagnostic loci (IDH and G3PDH), two semi-diagnostic loci (PGM and 6PGDH) and consequently a very high F(st )value (estimator theta = 0.77). Therefore, clusters I and II are reproductively isolated. The distribution limit of these two (sibling) species does not correspond to those of the morphological species of Trichomycterus identified in this region: the epigean T. cf. barbouri and the hypogean T. chaberti. However, hypogean fish exhibited two mtDNA haplotypes, a private one and another shared with the epigean Trichomycterus from upstream reaches.

  20. Genetic heterogeneity among intertidal habitats in the flat periwinkle, Littorina obtusata.

    Science.gov (United States)

    Schmidt, Paul S; Phifer-Rixey, Megan; Taylor, Graeme M; Christner, John

    2007-06-01

    Comparisons among patterns exhibited by functionally distinct genetic markers have been widely used to infer the impacts of demography and selection in structuring genetic variation in natural populations. However, such multilocus comparisons remain an indirect evaluation of selection at particular candidate loci; ideally, the identification of a candidate gene by comparative genetic methodologies should be complemented by functional analyses and experimental manipulations of genotypes in the laboratory or field. We examined genotype frequency variation among replicated intertidal habitats at two spatial scales in the grazing snail Littorina obtusata. Both of the candidate allozyme markers varied predictably with environment, and these patterns were consistent at both spatial scales. Three of four reference loci were spatially homogeneous, but one microsatellite exhibited significant structure at both geographical and mesoscales. To initiate a direct examination of whether the observed genotype frequency variation at one of the candidate markers, mannose-6-phosphate isomerase (MPI), was impacted by differential survivorship of genotypes, we conducted a series of laboratory-based thermal stress assays using snails from two geographically disparate source populations. When snails were exposed to bouts of thermal/desiccation stress, patterns of mortality were nonrandom with respect to MPI genotype. Furthermore, patterns of mortality in the laboratory manipulation coincided with the observed distribution of genotypes in the field. The data suggest the operation of selection at the Mpi or a linked locus, but functional studies and further experimentation are required to establish the relationship between MPI genotype and fitness across heterogeneous intertidal environments.

  1. Genetic differentiation and estimation of effective population size and migration rates in two sympatric ecotypes of the marine snail Littorina saxatilis.

    Science.gov (United States)

    Fernández, J; Galindo, J; Fernández, B; Pérez-Figueroa, A; Caballero, A; Rolán-Alvarez, E

    2005-01-01

    On exposed rocky shores in Galicia (northwest Spain), a striking polymorphism exists between two ecotypes (RB and SU) of Littorina saxatilis that occupy different levels of the intertidal zone and exhibit an incomplete reproductive isolation. The setting has been suggested to represent ongoing sympatric speciation by ecological adaptation of the two ecotypes to their respective habitats. In this article we address whether or not the ecotypes have developed their own population structures in response to the rigors of their corresponding environments and life histories. We analyzed four to five allozymic loci from three surveys of the same sites, spanning a 14-year period. An experimental design including three localities with two transects per locality and three shore levels allowed studying temporal and spatial population structure and estimation of effective population sizes (N(e)), neighborhood sizes (N(n)), and migration rates (m). Genetic differentiation was significantly lower in RB populations (theta(ST) = 0.067) than in SU ones (theta(ST) = 0.124). Mean estimates of N(e), N(n), and m did not differ significantly between ecotypes, but local ecotype differences in migration between the two closest localities (larger migration rates in RB than in SU populations) could explain the pattern in population differentiation.

  2. The genetic dynamics of the rapid and recent colonization of Denmark by Arion lusitanicus (Mollusca, Pulmonata, Arionidae).

    Science.gov (United States)

    Engelke, S; Kömpf, J; Jordaens, K; Tomiuk, J; Parker, E D

    2011-06-01

    We describe the genetic dynamics of the recent establishment of the 'Iberian slug', Arion lusitanicus J. Mabille 1868, in Denmark and compare its population structure to two other members of the 'large Arion complex', Arion ater ater, native to Denmark, and Arion ater rufus, introduced into Denmark in the early 1900s. Assaying allozyme polymorphism at seven enzyme loci, we found that: (1) None of the three taxa reproduce primarily by self-fertilization. Differences among loci and colonies in the pattern of deviation from Hardy-Weinberg equilibrium are most consistent with isolate mixing and perhaps with low amounts of selfing. (2) For both A. lusitanicus and A. a. rufus, gene diversity is lower in Danish colonies than in southern German colonies, implying population bottlenecks in the establishment of Danish colonies. (3) Significant linkage disequilibrium values usually involve the same three loci, viz. PGI, MDH-1 and MDH-2, suggesting physical linkage among these loci. (4) For both A. a. rufus and A. lusitanicus, the overall gene frequencies from Denmark and southern Germany are homogeneous, while variation among colonies within these regions ranges from around 15 to 28% for the three taxa. This indicates strong, local population genetic subdivision but with little restriction to gene flow from possible source areas. The heterogeneity in measures of diversity and differentiation indicates that population structure for all three taxa is dominated by ongoing founder effects, local extinction/colonisation dynamics, and genetic drift processes.

  3. Cryptic species of deep-sea clams (Mollusca: Bivalvia: Vesicomyidae) from hydrothermal vent and cold-water seep environments

    Science.gov (United States)

    Vrijenhoek, Robert C.; Schutz, Steven J.; Gustafson, Richard G.; Lutz, Richard A.

    1994-08-01

    A protein-electrophoretic analysis of six putative morphospecies in the bivalve family Vesicomyidae from eight deep-sea hydrothermal vent sites in the eastern Pacific, three cold-water seep sites in the eastern Pacific and the Gulf of Mexico, and one whale-carcass site off Southern California revealed electromorph patterns diagnostic of 10 vesicomyid species. Electrophoretic patterns for 14 enzymes encoded by 17 presumptive gene loci were scored in all 10 species. The pairwise genetic distances (Nei's D) for these 10 species ranged from 0.857 to 2.792, values within the range expected for distinct species and genera. However, the degree of genetic divergence among these taxa could not be used for phylogenetic inferences because allozyme differences had in many cases reached evolutionary saturation. Notwithstanding, the present results revealed a significant problem with current morphospecies identifications of these clams and with applications of the current generic names Calyptogena and Vesicomya. Given the cryptic nature of these taxa, we suggest that subsequent studies simply refer to these clams as "vesicomyids" until careful morphological analyses and molecular studies are completed and systematic relationships are clarified.

  4. Genetic diversity in Chilean populations of rainbow trout, Oncorhynchus mykiss

    Directory of Open Access Journals (Sweden)

    Claudia B Cárcamo

    2015-03-01

    Full Text Available The rainbow trout Oncorhynchus mykiss, was first introduced in Chile between 1905 and 1920 and is currently widely distributed in Chile from Antofagasta (23°S to Patagonia (55°S. The broad range of the geographic and climatic distributions of this species in Chile offers a unique opportunity to study the effect of naturalization of an introduced species on its genetic variability. It is of particular importance to observe the genetic variability of populations in the northern range of this species distribution, in a transition zone where a Mediterranean-type climate changes to an arid climate. The present study analyzed allozymic variability and distribution within and between populations of O. mykiss from the river basins of Elqui and Limari rivers, and six culture strains, using starch-gel protein electrophoresis. Populations were found to be in Hardy-Weinberg equilibrium and the average values of He (0.045, polymorphism (13.9% and allele per locus (1.19 are similar to rainbow trout in its native distributional range. About 77.8% of the genetic variability was within population, similar to the variability reported for wild populations in the northern hemisphere. However, a marked genetic differentiation between wild populations was also found. This is likely to be the consequence of initial founder effects followed by subsequent introgression of resident populations caused by reseeding with trout of different origins in both basins.

  5. Genetic ecotoxicology of radionuclides in mosquitofish: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Theodorakis, C.W. [Oak Ridge Associated Universities, TN (United States); Blaylock, B.G. [SENES, Oak Ridge, TN (United States); Shugart, L.R. [Oak Ridge National Lab., TN (United States)

    1995-12-31

    This paper summarizes several experiments conducted at Oak Ridge National Laboratory over the last several years. In 1977, approximately 250 western mosquitofish (Gambusia affinis) were transplanted from a non-contaminated pond into a radionuclide-contaminated settling basin. These, two populations, along with an additional contaminated and non-contaminated population, are the focus of these studies. Parameters measured were DNA strand breaks, fecundity, embryonic abnormalities, and RAPD and allozyme genotypes. The results are as follows: (1) the fish from the contaminated sites had more strand breaks than reference fish; (2) the number of strand breaks were negatively correlated with fecundity and positively correlated with abnormalities; (3) the contaminated populations had higher genetic diversity, and displayed a higher frequency of certain RAPD markers (contaminant-indicative markers) as well as nucleoside phosphorylase (NP) heterozygotes; (4) fish which displayed the contaminant-indicative markers or were NP heterozygotes had higher fecundity and fewer strand breaks than other fish when exposed to radiation. These types of studies are significant because they integrate responses from the molecular, organismal and population levels of biological organization. These results are discussed in relation to needs for future study and relevancy of RAPD research, as well as genetic ecotoxicology in general, to environmental monitoring programs.

  6. Shift in phenotypic variation coupled with rapid loss of genetic diversity in captive populations of Eristalis tenax (Diptera: Syrphidae): consequences for rearing and potential commercial use.

    Science.gov (United States)

    Francuski, Ljubinka; Djurakic, Marko; Ludoski, Jasmina; Hurtado, Pilar; Pérez-Bañón, Celeste; Ståhls, Gunilla; Rojo, Santos; Milankov, Vesna

    2014-04-01

    Because of its importance as a pollinator and its potential economic usefulness for the biodegradation of organic animal waste, the genetic and phenotypic diversity of the drone fly, Eristalis tenax L. (Diptera: Syrphidae), was studied in both wild and captive populations from southeastern Europe. Wild specimens from a natural protected habitat (with low human impact), field crop habitat (semisynanthropic condition), and intensive pig farming habitat (synanthropic condition) were compared with a laboratory colony reared on artificial media An integrative approach was applied based on allozyme loci, cytochrome c oxidase I mitochondrial DNA, wing traits (size and shape), and abdominal color patterns. Our results indicate that the fourth and eighth generations of the laboratory colony show a severe lack of genetic diversity compared with natural populations. Reduced genetic diversity in subsequent generations (F4 and F8) of the laboratory colony was found to be linked with phenotypic divergence. Loss of genetic variability associated with phenotypic differentiation in laboratory samples suggests a founder effect, followed by stochastic genetic processes and inbreeding. Hence, our results have implications for captive bred Eristalis flies, which have been used in crop pollination and biodegradation of organic waste under synanthropic conditions.

  7. Barriers to gene flow in the marine environment: insights from two common intertidal limpet species of the Atlantic and Mediterranean.

    Science.gov (United States)

    Sá-Pinto, Alexandra; Branco, Madalena S; Alexandrino, Paulo B; Fontaine, Michaël C; Baird, Stuart J E

    2012-01-01

    Knowledge of the scale of dispersal and the mechanisms governing gene flow in marine environments remains fragmentary despite being essential for understanding evolution of marine biota and to design management plans. We use the limpets Patella ulyssiponensis and Patella rustica as models for identifying factors affecting gene flow in marine organisms across the North-East Atlantic and the Mediterranean Sea. A set of allozyme loci and a fragment of the mitochondrial gene cytochrome C oxidase subunit I were screened for genetic variation through starch gel electrophoresis and DNA sequencing, respectively. An approach combining clustering algorithms with clinal analyses was used to test for the existence of barriers to gene flow and estimate their geographic location and abruptness. Sharp breaks in the genetic composition of individuals were observed in the transitions between the Atlantic and the Mediterranean and across southern Italian shores. An additional break within the Atlantic cluster separates samples from the Alboran Sea and Atlantic African shores from those of the Iberian Atlantic shores. The geographic congruence of the genetic breaks detected in these two limpet species strongly supports the existence of transpecific barriers to gene flow in the Mediterranean Sea and Northeastern Atlantic. This leads to testable hypotheses regarding factors restricting gene flow across the study area.

  8. Towards multilocus sequence typing of the Leishmania donovani complex: resolving genotypes and haplotypes for five polymorphic metabolic enzymes (ASAT, GPI, NH1, NH2, PGD).

    Science.gov (United States)

    Mauricio, Isabel L; Yeo, Matthew; Baghaei, Mehdi; Doto, Daniela; Pratlong, Francine; Zemanova, Eva; Dedet, Jean-Pierre; Lukes, Julius; Miles, Michael A

    2006-06-01

    Multilocus enzyme electrophoresis is the gold standard for identification of Leishmania species and strains. Drawbacks include: only amino acid polymorphisms affecting electrophoretic mobility are detected; distinct allozymes can have coincident mobilities; few characters are available; and parasites must be cultured in bulk. So far, thousands of Leishmania strains have been phenotyped by multilocus enzyme electrophoresis. Here, we sequence enzyme-coding genes to provide a PCR-based higher resolution equivalent of multilocus enzyme electrophoresis, particularly for Leishmania infantum. Of 15 enzymes used for multilocus enzyme electrophoresis (MON typing) we have sequenced aspartate aminotransferase, glucose-6-phosphate isomerase, nucleoside hydrolase 1, nucleoside hydrolase 2 and 6-phosphogluconate dehydrogenase. Heterozygous alleles were common, with multiple heterozygous sites within a single locus for several of the genes. Haplotypes were resolved by allele-specific PCR and allele-specific sequencing. Heterozygous haplotypes conformed to the haplotypes of putative parents. One strain appeared to be hybrid across two genetic groups of the Leishmania donovani complex. In most cases, a single amino acid polymorphism was responsible for change in enzyme mobility. Some indistinguishable phenotypes were produced by distinct genotypes. Silent genetic polymorphisms provided enhanced discrimination over multilocus enzyme electrophoresis, for example, by subdividing the zymodeme MON-1. The PCR-based genotyping that we describe could be applied directly to clinical samples or to small volume cultures and in a multilocus sequence typing format. Furthermore, it can be used to detect recombination indirectly and for population genetics studies.

  9. Genetic variability in spotted seatrout (Cynoscion nebulosus), determined with microsatellite DNA markers

    Science.gov (United States)

    Ward, R.; Bowers, K.; Hensley, R.; Mobley, B.; Belouski, E.

    2007-01-01

    Variation in the allele frequencies of five microsatellite loci was surveyed in 1256 individual spotted seatrout (Cynoscion nebulosus) obtained from 12 bays and estuaries from Laguna Madre, Texas, to Charlotte Harbor, Florida, to St. John's River on the Florida Atlantic Coast. Texas and Louisiana collection sites were resampled each year for two to four years (1998-2001). Genetic differentiation was observed. Spotted seatrout from Florida waters were strongly differentiated from spotted seatrout collected in Louisiana and Texas. The greatest genetic discontinuity was observed between Tampa Bay and Charlotte Harbor, and Charlotte Harbor seatrout were most similar to Atlantic Coast spotted seatrout. Texas and Louisiana samples were not strongly structured within the northwestern Gulf of Mexico and there was little evidence of temporal differentiation within bays. These findings are contrary to those of earlier analyses with allozymes and mitochondrial DNA (mtDNA) where evidence of spatial differentiation was found for spotted seatrout resident on the Texas coast. The differences in genetic structure observed among these markers may reflect differences in response to selective pressure, or may be due to differences in underlying genetic processes.

  10. Genetic diversity and the genetic structure of natural populations of Chamaecyparis obtusa: implications for management and conservation.

    Science.gov (United States)

    Tsumura, Y; Matsumoto, A; Tani, N; Ujino-Ihara, T; Kado, T; Iwata, H; Uchida, K

    2007-08-01

    We investigated 25 natural populations of Chamaecyparis obtusa using 51 cleaved amplified polymorphic sequence (CAPS) markers, which were developed using information on sequence-tagged sites (STS) in Cryptomeria japonica. Most CAPS markers have codominant expression patterns, and are suitable for population studies because of their robustness and convenience. We estimated various genetic diversity parameters, including average heterozygosity (H(e)) and allelic richness and found that the more peripheral populations tended to have lower genetic diversity than central populations, in agreement with a previous theoretical study. The overall genetic differentiation between populations was low, but statistically significant (G(ST)=0.039), and similar to the level reported in a previous allozyme study. We attempted to detect non-neutral loci associated with local adaptation to clarify the relationship between the fixation index (F(ST)) and H(e) values for each locus and found seven candidates non-neutral loci. Phylogenetic tree analysis of the populations and Bayesian clustering analysis revealed a pattern of gradually increasing isolation of populations with increasing geographical distance. Three populations had a high degree of linkage disequilibrium, which we attribute to severe bottlenecks due to human disturbance or competition with other species during their migration from refugia after the most recent glaciation. We concluded that the small populations in western Japan and in Kanto district are more important, from a conservation perspective, than the populations in central Japan, due to their genetic divergence, relatively small sizes and restricted areas.

  11. Phylogenetic Relationships of Palaearctic Formica Species (Hymenoptera, Formicidae) Based on Mitochondrial Cytochrome b Sequences

    Science.gov (United States)

    Goropashnaya, Anna V.; Fedorov, Vadim B.; Seifert, Bernhard; Pamilo, Pekka

    2012-01-01

    Ants of genus Formica demonstrate variation in social organization and represent model species for ecological, behavioral, evolutionary studies and testing theoretical implications of the kin selection theory. Subgeneric division of the Formica ants based on morphology has been questioned and remained unclear after an allozyme study on genetic differentiation between 13 species representing all subgenera was conducted. In the present study, the phylogenetic relationships within the genus were examined using mitochondrial DNA sequences of the cytochrome b and a part of the NADH dehydrogenase subunit 6. All 23 Formica species sampled in the Palaearctic clustered according to the subgeneric affiliation except F. uralensis that formed a separate phylogenetic group. Unlike Coptoformica and Formica s. str., the subgenus Serviformica did not form a tight cluster but more likely consisted of a few small clades. The genetic distances between the subgenera were around 10%, implying approximate divergence time of 5 Myr if we used the conventional insect divergence rate of 2% per Myr. Within-subgenus divergence estimates were 6.69% in Serviformica, 3.61% in Coptoformica, 1.18% in Formica s. str., which supported our previous results on relatively rapid speciation in the latter subgenus. The phylogeny inferred from DNA sequences provides a necessary framework against which the evolution of social traits can be compared. We discuss implications of inferred phylogeny for the evolution of social traits. PMID:22911845

  12. Endemic North African Quercus afares Pomel originates from hybridisation between two genetically very distant oak species (Q. suber L. and Q. canariensis Willd.): evidence from nuclear and cytoplasmic markers.

    Science.gov (United States)

    Mir, C; Toumi, L; Jarne, P; Sarda, V; Di Giusto, F; Lumaret, R

    2006-02-01

    Hybridisation is a potent force in plant evolution, although there are few reported examples of stabilised species that have been created through homoploid hybridisation. We focus here on Quercus afares, an endemic North African species that combines morphological, physiological and ecological traits of both Q. suber and Q. canariensis, two phylogenetically distant species. These two species are sympatric with Q. afares over most of its distribution. We studied two Q. afares populations (one from Algeria and one from Tunisia), as well as several populations of both Q. suber and Q. canariensis sampled both within and outside areas where these species overlap with Q. afares. A genetic analysis was conducted using both nuclear (allozymes) and chloroplastic markers, which shows that Q. afares originates from a Q. suber x Q. canariensis hybridisation. At most loci, Q. afares predominantly possesses alleles from Q. suber, suggesting that the initial cross between Q. suber and Q. canariensis was followed by backcrossing with Q. suber. Other hypotheses that can account for this result, including genetic drift, gene silencing, gene conversion and selection, are discussed. A single Q. suber chlorotype was detected, and all Q. afares individuals displayed this chlorotype, indicating that Q. suber was the maternal parent. Q. afares is genetically, morphologically and ecologically differentiated from its parental species, and can therefore be considered as a stabilised hybrid species.

  13. Contrasting nuclear and cytoplasmic exchanges between phylogenetically distant oak species (Quercus suber L. and Q. ilex L.) in Southern France: inferring crosses and dynamics.

    Science.gov (United States)

    Mir, C; Jarne, P; Sarda, V; Bonin, A; Lumaret, R

    2009-03-01

    Gene flow is particularly frequent in the genus Quercus (oaks), especially between closely related species. We focus here on Quercus ilex and the cork-producing Quercus suber, which occasionally hybridize although they are phylogenetically markedly separated. Morphological observations were combined with both allozymic and chloroplastic diagnostic markers to characterize hybridization and introgression and to infer their dynamics in two French regions (French Catalonia and Provence), which are separated by several hundred kilometres. Some hybrids were found in both regions, indicating recent hybridization events. As expected from previous studies, most hybrids resulted from female symbol Q. ilex x male symbol Q. suber crosses, but our data showed that the reciprocal cross is also possible. Partial independence between nuclear and chloroplastic introgression was observed in the two species. Nuclear introgression was limited in both species and both regions, with no preferred direction. In Provence, chloroplastic introgression was very rare in both species. Conversely, all Q. suber individuals from French Catalonia were introgressed by Q. ilex chlorotypes. This might be explained by introgression in the Iberian Peninsula antedating the first occurrence of the two species in French Catalonia. We also observed a new chlorotype that was created locally, and was exchanged between the two species. However, the two species still remain genetically differentiated. The dynamics and complexity of exchanges and the factors determining them (including human management of Q. suber) are discussed.

  14. Hierarchical patterns of paternity within crowns of Albizia julibrissin (Fabaceae).

    Science.gov (United States)

    Pardini, Eleanor A; Hamrick, J L

    2007-01-01

    The floral architecture and phenology of the tree species Albizia julibrissin (Fabaceae) offer the potential for flowers within inflorescences to share common pollen donors. Patterns of paternity within individual tree crowns may differ among isolated individuals and those in populations due to differences in pollinator foraging behavior. To determine how genetic diversity is partitioned within individual seed pools and whether these patterns differ among isolated and population trees, we obtained all fruits from three inflorescences from four clusters from three isolated trees and from three population trees in Athens, Georgia. We assayed 14 polymorphic allozymes to genotype all progeny within singly sired fruits to determine the multilocus genotype of each fruit's pollen donor. Inflorescences had multiple pollen donors, but simulation analyses revealed that redundancy of pollen donors tended to be more likely within inflorescences than randomly across the crown. Analysis of genetic and genotypic diversity indicated that individual maternal trees received pollen from many donors in uneven frequencies. Results suggest that isolated trees receive pollen from slightly fewer pollen donors and experience more within-plant pollinator movement than trees in populations. However, isolated trees receive qualitatively similar pollen from many sources, suggesting that these trees are not effectively isolated and that pollen moves long distances in this species.

  15. Morphological variation in a secondary contact between divergent lineages of brown trout (Salmo trutta from the Iberian Peninsula

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    Miguel Hermida

    2009-01-01

    Full Text Available The aim of this study was to analyze the morphological variation of brown trout (Salmo trutta in the Duero basin, an Atlantic river basin in the Iberian Peninsula, where a spatial segregation of two divergent lineages was previously reported, based on isozyme, microsatellite and mtDNA data. In these studies, two divergent pure regions (Pisuerga and Lower-course and several hybrid populations between them were identified. Morphological variation was evaluated in 11 populations representative of the genetic differentiation previously observed in the Duero basin, using multivariate analysis on 12 morphometric and 4 meristic traits. A large differentiation between populations was observed (interpopulation component of variance: 41.8%, similar to that previously detected with allozymes and microsatellites. Morphometric differentiation was also reflected by the high classification success of pure and hybrid individuals to their respective populations, using multivariate discriminant functions (94.1% and 79.0%, respectively. All multivariate and clustering analyses performed demonstrated a strong differentiation between the pure regions. The hybrid populations, though showing large differentiation among them, evidenced an intermediate position between the pure samples. Head and body shape traits were the most discriminant among the morphometric characters, while pectoral rays and gillrakers were the most discriminant among the meristic traits. These results confirmed the high divergence of the brown trout from the Duero basin and suggest some traits on which selection could be acting to explain the spatial segregation observed.

  16. Morphological variation in a secondary contact between divergent lineages of brown trout (Salmo trutta) from the Iberian Peninsula.

    Science.gov (United States)

    Hermida, Miguel; San Miguel, Eduardo; Bouza, Carmen; Castro, Jaime; Martínez, Paulino

    2009-01-01

    The aim of this study was to analyze the morphological variation of brown trout (Salmo trutta) in the Duero basin, an Atlantic river basin in the Iberian Peninsula, where a spatial segregation of two divergent lineages was previously reported, based on isozyme, microsatellite and mtDNA data. In these studies, two divergent pure regions (Pisuerga and Lower-course) and several hybrid populations between them were identified. Morphological variation was evaluated in 11 populations representative of the genetic differentiation previously observed in the Duero basin, using multivariate analysis on 12 morphometric and 4 meristic traits. A large differentiation between populations was observed (interpopulation component of variance: 41.8%), similar to that previously detected with allozymes and microsatellites. Morphometric differentiation was also reflected by the high classification success of pure and hybrid individuals to their respective populations, using multivariate discriminant functions (94.1% and 79.0%, respectively). All multivariate and clustering analyses performed demonstrated a strong differentiation between the pure regions. The hybrid populations, though showing large differentiation among them, evidenced an intermediate position between the pure samples. Head and body shape traits were the most discriminant among the morphometric characters, while pectoral rays and gillrakers were the most discriminant among the meristic traits. These results confirmed the high divergence of the brown trout from the Duero basin and suggest some traits on which selection could be acting to explain the spatial segregation observed.

  17. Genetic differentiation between conspecific populations of Merodon avidus A (Diptera, Syrphidae

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    Milankov Vesna R.

    2004-01-01

    Full Text Available Allozyme variability of populations of Merodon avidus A (M i l a n - k o v et al., 2001 from Dubašnica Mountain (Serbia, Morinj Bay (Montenegro and Pindos Mountain (Greece was analysed. The influence of gene flow on genetic differentiation among populations from the three biogeographical regions was also investigated. Genetic differentiaiton quantified by the Fst value, which is an inverse function of gene flow between populations, seemed to be correlated to both geographic and genetic distance (D, N e i, 1978, Namely in the population pairs Morinj - Dubašnica (253 km air distance, Morinj - Pindos (390km air distance genetic differentiation and genetic distance increased with the geographic distance (Fst = 0.133, D = 0.022 and Fst = 0.309, D = 0.052, respectively. The exception was the population pair Dubašnica - Pindos (500 km air distance, where a lower degree of genetic differentiation was observed (Fst = 0.266; D = 0.047 than was expected based solely on the geographic distance. Results of this study suggest that that genetic differentiation among conspecific populations depends not only on the number of migrants (i. e. gene flow, but also on different selection pressure in different habits.

  18. Phytophthora infestans population structure: a worldwide scale

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    Cárdenas Toquica Martha

    2012-08-01

    Full Text Available Phytophthora infestans, the causal agent of late blight disease in potato and other members of the Solanaceae family, is responsible for causing the Irish potato famine and, even today, it causes enormous economic losses all over the world. For the establishment of an adequate pest management strategy, the determination of population structure is required. To characterize P. infestans populations worldwide two allozymes, Gpi (Glucose-6-phospate isomerase and Pep (Peptidase, the RG57 DNA RFLP fingerprinting probe, as well as resistance to the fungicide metalaxyl and the mating type, have been used as markers. P. infestans populations in Mexico have been one of the main focuses of research in the population biology of this pathogen because this country has been considered as one of the possible centers of origin of this oomycete. In this review we present the population structure of P. infestans in Mexico, Europe, Africa, Asia, North America, and South America expanding on the present situation of P. infestans in Colombia. Finally, we will discuss different lines of research that are being carried out today with respect to P. infestans in Colombia, which have shown the importance of continuing the study of this devastating plant pathogen in our country.

  19. PHYTOPHTHORA INFESTANS POPULATION STRUCTURE: A WORLDWIDE SCALE

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    MARTHA CÁRDENAS

    2012-01-01

    Full Text Available Phytophthora infestans, the causal agent of late blight disease in potato and other members of the Solanaceae family, is responsible for causing the Irish potato famine and, even today, it causes enormous economic losses all over the world. For the establishment of an adequate pest management strategy, the determination of the pathogen’s population structure is required. To characterize P. infestans populations worldwide two allozymes, Gpi (Glucose-6-phospate isomerase and Pep (Peptidase, the RG57 DNA RFLP fingerprinting probe, as well as resistance to the fungicide metalaxyl and mating type, have been used as markers. P. infestans populations in Mexico have been one of the main focuses of research in the population biology of this pathogen because this country has been considered as one of the possible centers of origin of this oomycete. In this review we present the population structure of P. infestans in Mexico, Europe, Africa, Asia, North America, and South America, expanding it on the present situation of P. infestans in Colombia. Finally, we will discuss different lines of research that are being carried out today with respect to P. infestans in Colombia, which have shown the importance of continuing the study of this devastating plant pathogen in our country.

  20. Genetic diversity through life history of Dioon edule Lindley (Zamiaceae, Cycadales).

    Science.gov (United States)

    Octavio-Aguilar, P; González-Astorga, J; Vovides, A P

    2009-07-01

    The distribution of genetic diversity and structure for three populations of Dioon edule Lindley (Zamiaceae) at Monte Oscuro (MO), El Farallón (EF) and Rancho del Niño (RN) in Veracruz, Mexico was studied using 20 allozyme loci, considering four life history classes: seeds, seedlings, juveniles and adults. The MO population is genetically less diverse than the EF and RN populations. Total and local inbreeding differ significantly between life history classes. An increment of inbreeding among all classes was observed, and genetic differentiation among populations was higher in seeds and seedlings than in juveniles and adults. In terms of percentage of polymorphic loci, the MO seeds showed least (80%), followed by RN (95%) and EF had the highest values (100%), probably because of a reduction in effective population size and habitat fragmentation processes. In this context, the mean effective population size was 23.2 +/- 11.3 for all populations. We conclude that seed cohorts in EF and RN represent a reservoir of genetic diversity within these two populations. Also, preservation of adult plants is an essential aspect to consider in management and conservation efforts for populations of Dioon edule in natural conditions.

  1. Lack of taxonomic differentiation in an apparently widespread freshwater isopod morphotype (Phreatoicidea: Mesamphisopidae: Mesamphisopus) from South Africa.

    Science.gov (United States)

    Gouws, Gavin; Stewart, Barbara A; Matthee, Conrad A

    2005-10-01

    The unambiguous identification of phreatoicidean isopods occurring in the mountainous southwestern region of South Africa is problematic, as the most recent key is based on morphological characters showing continuous variation among two species: Mesamphisopus abbreviatus and M. depressus. This study uses variation at 12 allozyme loci, phylogenetic analyses of 600 bp of a COI (cytochrome c oxidase subunit I) mtDNA fragment and morphometric comparisons to determine whether 15 populations are conspecific, and, if not, to elucidate their evolutionary relationships. Molecular evidence suggested that the most easterly population, collected from the Tsitsikamma Forest, was representative of a yet undescribed species. Patterns of differentiation and evolutionary relationships among the remaining populations were unrelated to geographic proximity or drainage system. Patterns of isolation by distance were also absent. An apparent disparity among the extent of genetic differentiation was also revealed by the two molecular marker sets. Mitochondrial sequence divergences among individuals were comparable to currently recognized intraspecific divergences. Surprisingly, nuclear markers revealed more extensive differentiation, more characteristic of interspecific divergences. This disparity and the mosaic pattern of differentiation may be driven by stochastic population crashes and genetic bottlenecks (caused by seasonal habitat fluctuations), coupled with genetic drift.

  2. Biochemical comparison of two Hypostomus populations (Siluriformes, Loricariidae) from the Atlântico Stream of the upper Paraná River basin, Brazil

    Science.gov (United States)

    2009-01-01

    Two syntopic morphotypes of the genus Hypostomus - H. nigromaculatus and H. cf. nigromaculatus (Atlântico Stream, Paraná State) - were compared through the allozyme electrophoresis technique. Twelve enzymatic systems (AAT, ADH, EST, GCDH, G3PDH, GPI, IDH, LDH, MDH, ME, PGM and SOD) were analyzed, attributing the score of 20 loci, with a total of 30 alleles. Six loci were diagnostic (Aat-2, Gcdh-1, Gpi-A, Idh-1, Ldh-A and Mdh-A), indicating the presence of interjacent reproductive isolation. The occurrence of few polymorphic loci acknowledge two morphotypes, with heterozygosity values He = 0.0291 for H. nigromaculatus and He = 0.0346 for H. cf. nigromaculatus. FIS statistics demonstrated fixation of the alleles in the two morphotypes. Genetic identity (I) and distance (D) of Nei (1978) values were I = 0.6515 and D = 0.4285. The data indicate that these two morphotypes from the Atlântico Stream belong to different species. PMID:21637646

  3. Biochemical comparison of two Hypostomus populations (Siluriformes, Loricariidae from the Atlântico Stream of the upper Paraná River basin, Brazil

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    Kennya F. Ito

    2009-01-01

    Full Text Available Two syntopic morphotypes of the genus Hypostomus - H. nigromaculatus and H. cf. nigromaculatus (Atlântico Stream, Paraná State - were compared through the allozyme electrophoresis technique. Twelve enzymatic systems (AAT, ADH, EST, GCDH, G3PDH, GPI, IDH, LDH, MDH, ME, PGM and SOD were analyzed, attributing the score of 20 loci, with a total of 30 alleles. Six loci were diagnostic (Aat-2, Gcdh-1, Gpi-A, Idh-1, Ldh-A and Mdh-A, indicating the presence of interjacent reproductive isolation. The occurrence of few polymorphic loci acknowledge two morphotypes, with heterozygosity values He = 0.0291 for H. nigromaculatus and He = 0.0346 for H. cf. nigromaculatus. F IS statistics demonstrated fixation of the alleles in the two morphotypes. Genetic identity (I and distance (D of Nei (1978 values were I = 0.6515 and D = 0.4285. The data indicate that these two morphotypes from the Atlântico Stream belong to different species.

  4. Population genetic structure of Brazilian shrimp species (Farfantepenaeus sp., F. brasiliensis, F. paulensis and Litopenaeus schmitti: Decapoda: Penaeidae

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    Jaqueline Gusmão

    2005-03-01

    Full Text Available Penaeid shrimps are important resources for worldwide fisheries and aquaculture. In the Southwest Atlantic, Farfantepenaeus brasiliensis, F. paulensis, F. subtilis, Farfantepenaeus sp. and Litopenaeus schmitti are among the most important commercially exploited species. Despite their high commercial value, there is little information available on the different aspects of their biology or genetics and almost no data on their stock structure. We used allozymes to estimate variability levels and population genetic structure of F. brasiliensis, F. paulensis, L. schmitti and the recently detected species Farfantepenaeus sp. along as much as 4,000 km of Brazilian coastline. No population heterogeneity was detected in F. brasiliensis or L. schmitti along the studied area. In contrast, F ST values found for Farfantepenaeus sp. and F. paulensis indicate that the populations of those two species are genetically structured, comprising different fishery stocks. The largest genetic differences in F. paulensis were found between Lagoa dos Patos (South and the two populations from Southeast Brazil. In Farfantepenaeus sp., significant differences were detected between the population from Recife and those from Fortaleza and Ilhéus.

  5. Biology of tiny animals: three new species of minute salamanders (Plethodontidae: Thorius) from Oaxaca, Mexico

    Science.gov (United States)

    Rovito, Sean M.; García-París, Mario; Maisano, Jessica A.; Wake, David B.

    2016-01-01

    We describe three new species of minute salamanders, genus Thorius, from the Sierra Madre del Sur of Oaxaca, Mexico. Until now only a single species, T. minutissimus, has been reported from this region, although molecular data have long shown extensive genetic differentiation among geographically disjunct populations. Adult Thorius pinicola sp. nov., T. longicaudus sp. nov., and T. tlaxiacus sp. nov. are larger than T. minutissimus and possess elliptical rather than oval nostrils; T. pinicola and T. longicaudus also have longer tails. All three new species occur west of the range of T. minutissimus, which has the easternmost distribution of any member of the genus. The new species are distinguished from each other and from other named Thorius in Oaxaca by a combination of adult body size, external morphology and osteology, and by protein characters (allozymes) and differences in DNA sequences. In addition, we redescribe T. minutissimus and a related species, T. narisovalis, to further clarify the taxonomic status of Oaxacan populations and to facilitate future studies of the remaining genetically differentiated Thorius that cannot be satisfactorily assigned to any named species. Populations of all five species considered here appear to have declined dramatically over the last one or two decades and live specimens are difficult to find in nature. Thorius may be the most endangered genus of amphibians in the world. All species may go extinct before the end of this century. PMID:27896029

  6. Biology of tiny animals: three new species of minute salamanders (Plethodontidae: Thorius from Oaxaca, Mexico

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    Gabriela Parra-Olea

    2016-11-01

    Full Text Available We describe three new species of minute salamanders, genus Thorius, from the Sierra Madre del Sur of Oaxaca, Mexico. Until now only a single species, T. minutissimus, has been reported from this region, although molecular data have long shown extensive genetic differentiation among geographically disjunct populations. Adult Thorius pinicola sp. nov., T. longicaudus sp. nov., and T. tlaxiacus sp. nov. are larger than T. minutissimus and possess elliptical rather than oval nostrils; T. pinicola and T. longicaudus also have longer tails. All three new species occur west of the range of T. minutissimus, which has the easternmost distribution of any member of the genus. The new species are distinguished from each other and from other named Thorius in Oaxaca by a combination of adult body size, external morphology and osteology, and by protein characters (allozymes and differences in DNA sequences. In addition, we redescribe T. minutissimus and a related species, T. narisovalis, to further clarify the taxonomic status of Oaxacan populations and to facilitate future studies of the remaining genetically differentiated Thorius that cannot be satisfactorily assigned to any named species. Populations of all five species considered here appear to have declined dramatically over the last one or two decades and live specimens are difficult to find in nature. Thorius may be the most endangered genus of amphibians in the world. All species may go extinct before the end of this century.

  7. Comparative molecular analysis of evolutionarily distant glyceraldehyde-3-phosphate dehydrogenase from Sardina pilchardus and Octopus vulgaris.

    Science.gov (United States)

    Baibai, Tarik; Oukhattar, Laila; Mountassif, Driss; Assobhei, Omar; Serrano, Aurelio; Soukri, Abdelaziz

    2010-12-01

    The NAD(+)-dependent cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12), which is recognized as a key to central carbon metabolism in glycolysis and gluconeogenesis and as an important allozymic polymorphic biomarker, was purified from muscles of two marine species: the skeletal muscle of Sardina pilchardus Walbaum (Teleost, Clupeida) and the incompressible arm muscle of Octopus vulgaris (Mollusca, Cephalopoda). Comparative biochemical studies have revealed that they differ in their subunit molecular masses and in pI values. Partial cDNA sequences corresponding to an internal region of the GapC genes from Sardina and Octopus were obtained by polymerase chain reaction using degenerate primers designed from highly conserved protein motifs. Alignments of the deduced amino acid sequences were used to establish the 3D structures of the active site of two enzymes as well as the phylogenetic relationships of the sardine and octopus enzymes. These two enzymes are the first two GAPDHs characterized so far from teleost fish and cephalopod, respectively. Interestingly, phylogenetic analyses indicated that the sardina GAPDH is in a cluster with the archetypical enzymes from other vertebrates, while the octopus GAPDH comes together with other molluscan sequences in a distant basal assembly closer to bacterial and fungal orthologs, thus suggesting their different evolutionary scenarios.

  8. Distribution of pathogenic Naegleria spp in Thailand.

    Science.gov (United States)

    Tiewcharoen, S; Junnu, V

    2001-01-01

    Research concerning the distribution, isolation, viability, ultrastructure, morphology and immunogenicity of Naegleria fowleri has been increasing in Thailand during 1988-2000. The distribution of the organism was carried out from 1985 to 1987 in Si Sa Ket and Ubon Rachathani Provinces, after the first fatal case was reported in Si Sa Ket. Since then in a 1998 survey of N. fowleri in stagnant water around industrial areas was carried out in Pathum Thani, Samut Prakan and Lopburi provinces. The results showed that 10% of pathogenic Naegleria belonged to species fowleri as characterized by morphology and the occurrence of pathogenesis in mice after nasal inoculation. In the same year, Nacapunchai et al (1999) determined the prevalence of amebae in aquatic habitat of human environments in five parts of Thailand during the summer. Fourteen percent of free living Naegleria spp were found in both soil and water resources. Recent studies of the ultrastructure, factors affecting the viability and SDS-PAGE electrophoretic patterns of 3 Thai strains of pathogenic Naegleria spp indicated their similarities in morphological characteristics of pathogenic reference control, Naegleria fowleri CDC VO 3081. Additional study using a genetic approach to species criteria using allozyme electrophoresis had been conducted.

  9. Fine-scale genetic structure in Pinus clausa (Pinaceae) populations: effects of disturbance history.

    Science.gov (United States)

    Parker, K C; Hamrick, J L; Parker, A J; Nason, J D

    2001-07-01

    Spatial autocorrelation analyses of 12 allozyme loci were used to compare genetic structure within populations of two varieties of Pinus clausa. P. clausa var. immuginata populations tend to be uneven-aged, with continuous recruitment in small gaps created by wind damage, whereas P. clausa var. clausa populations are more even-aged, with recruitment postdating periodic canopy fires. Three var. immuginata populations and three matched pairs of var. clausa populations, including both a mature and a nearby recently burned population, were examined. Aggregation of multilocus genotypes at small distances was evident in all young var. clausa populations. Little inbreeding was apparent among juveniles or adults in these populations; their genetic structure is likely to have resulted from limited seed dispersal. Genotypes were not significantly spatially structured in nearby matched mature populations. Genetic structure was less evident in var. immuginata populations. Aggregated genotypes were only apparent in the population where patches included juveniles of similar ages; dense juvenile clumps in the other two var. immuginata populations comprised a variety of ages. Interannual variability in allele frequencies of surviving seedlings may account for the absence of genetic structure in these populations.

  10. Historical ecology meets conservation and evolutionary genetics: a secondary contact zone between Carabus violaceus (Coleoptera, Carabidae populations inhabiting ancient and recent woodlands in north-western Germany

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    Andrea Matern

    2011-05-01

    Full Text Available Only very few cases have documented that an increase in connectivity after a period of fragmentation in ecological time has had an effect on the distribution, genetic structure and morphology of stenotopic species. In this study we present an example of clinal variability in a woodland ground beetle as a result of changes in the connectivity of a landscape during the last two centuries. The study area hosts both the nominate form C. violaceus s. str. and the subspecies C. v. purpurascens, which is ranked as a distinct species by some authors. We studied 12 Carabus violaceus populations from a 30 km transect of ancient and recent forests in north-western Germany. We analyzed three polymorphic enzyme loci, classified the elytron sculpture and measured the shape of the aedeagus tip of the specimens. C. violaceus showed secondary gradients both in allozyme markers and morphometric characters in our study area. A genetic differentiation of 16% between the populations is high but lies within the range of intraspecific variability in habitat specialists of the genus Carabus. Populations had no significant deficit of heterozygotes. We found many hybrid populations in terms of morphological properties. This study highlights the conservation value of ancient woodland and the consequences of landscape connectivity and defragmentation on the genetic setting of a ground beetle. Moreover, it shows that differences in the external shape of male genitalia do not prevent gene flow within the genus Carabus. Thus, the establishment of species status should not exclusively be based on this property.

  11. Molecular systematics, phylogeny and ecology of anisakid nematodes of the genus Anisakis Dujardin, 1845: an update

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    Mattiucci S.

    2006-06-01

    Full Text Available Advances in the taxonomy and ecological aspects concerning geographical distribution and hosts of the so far genetically recognised nine taxa of the nematodes belonging to genus Anisakis (i.e. A. pegreffii, A. simplex s.s., A. simplex C, A. typica, A. ziphidarum, Anisakis sp., A. physeteris, A. brevispiculata and A. paggiae are here summarized. Genetic differentiation and phylogenetic relationships inferred from allozyme (20 enzyme-loci and mitochondrial (sequences of cox-2 gene markers, are revised and compared. The two genetic analyses are congruent in depicting their phylogenetic relationships. Two main clusters are showed to exist in the obtained trees, one encompassing the species A. pegreffii, A. simplex s.s., A. simplex C, A. typica, A. ziphidarum and Anisakis sp.; while, the second including A. physeteris, A. brevispiculata and A. paggiae. The existence of two clades is also supported by their morphological differentiation in adult and larval morphology. Comparison of phylogenetic relationships among Anisakis spp. with those currently available for their cetacean definitive hosts suggests parallelism between host and parasite phylogenetic tree topologies. Preliminary data for reconstruction of a possible co-evolutionary scenario between cetacean hosts and their Anisakis endoparasites suggests that cospeciation and host-switching events may have accompanied the evolution of this group of parasites. Finally, genetic/molecular markers for the identification of the so far genetically recognized taxa of Anisakis at any life-stage and both sexes were given also in relation to human anisakiosis is discussed.

  12. Adaptive evolution of rbcL in Conocephalum (Hepaticae, bryophytes).

    Science.gov (United States)

    Miwa, Hidetsugu; Odrzykoski, Ireneusz J; Matsui, Atsushi; Hasegawa, Masami; Akiyama, Hiroyuki; Jia, Yu; Sabirov, Renat; Takahashi, Hideki; Boufford, David E; Murakami, Noriaki

    2009-07-15

    An excess of nonsynonymous substitutions over synonymous ones has been regarded as an important indicator of adaptive evolution or positive selection at the molecular level. We now report such a case for rbcL sequences among cryptic species in Conocephalum (Hepaticae, Bryophytes). This finding can be regarded as evidence of adaptive evolution in several cryptic species (especially in F and JN types) within the genus. Bryophytes are small land plants with simple morphology. We can therefore expect the existence of several biologically distinct units or cryptic species within each morphological species. In our previous study, we found three rbcL types in Asian Conocephalum japonicum (Thunb.) Grolle and also found evidence strongly suggesting that the three types are reproductively isolated cryptic species. Additionally, we examined rbcL sequence variation in six cryptic species of C. conicum (L.) Dumort. previously recognized by allozyme analyses. As a result, we were able to discriminate the six cryptic species based only on their rbcL sequences. We were able to show that rbcL sequence variation is also useful in finding cryptic species of C. conicum.

  13. Molecular genetic evidence for the place of origin of the Pacific rat, Rattus exulans.

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    Vicki Thomson

    Full Text Available Commensal plants and animals have long been used to track human migrations, with Rattus exulans (the Pacific rat a common organism for reconstructing Polynesian dispersal in the Pacific. However, with no knowledge of the homeland of R. exulans, the place of origin of this human-commensal relationship is unknown. We conducted a mitochondrial DNA phylogeographic survey of R. exulans diversity across the potential natural range in mainland and Island Southeast Asia in order to establish the origin of this human-commensal dyad. We also conducted allozyme electrophoresis on samples from ISEA to obtain a perspective on patterns of genetic diversity in this critical region. Finally, we compared molecular genetic evidence with knowledge of prehistoric rodent faunas in mainland and ISEA. We find that ISEA populations of R. exulans contain the highest mtDNA lineage diversity including significant haplotype diversity not represented elsewhere in the species range. Within ISEA, the island of Flores in the Lesser Sunda group contains the highest diversity in ISEA (across all loci and also has a deep fossil record of small mammals that appears to include R. exulans. Therefore, in addition to Flores harboring unusual diversity in the form of Homo floresiensis, dwarfed stegodons and giant rats, this island appears to be the homeland of R. exulans.

  14. Reproductive strategies and genetic variability in tropical freshwater fish

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    Maria Dolores Peres Lassala

    2007-01-01

    Full Text Available We estimated the genetic variability of nine fish species from the Brazilian upper Paraná River floodplain (Astyanax altiparanae, Hoplias malabaricus, Leporinus lacustris, Loricariichthys platymetopon, Parauchenipterus galeatus, Pimelodus maculatus, Rhaphiodon vulpinus, Roeboides paranensis and Serrasalmus marginatus based on data for 36 putative allozyme loci obtained using corn starch gel electrophoresis of 13 enzymatic systems: aspartate aminotransferase (EC 2.6.1.1, acid phosphatase (EC 3.1.3.2, esterase (EC 3.1.1.1, glycerol-3-phosphate dehydrogenase (EC 1.1.1.8, glucose-6-phosphate dehydrogenase (EC 1.1.1.49, glucose-6-phosphate isomerase (EC 5.3.1.9, Iditol dehydrogenase (EC 1.1.1.14, isocitrate dehydrogenase - NADP+ (EC 1.1.1.42, L-lactate dehydrogenase (EC 1.1.1.27, malate dehydrogenase (EC 1.1.1.37, malate dehydrogenase-NADP+ (EC 1.1.1.40, phosphoglucomutase (EC 5.4.2.2 and superoxide dismutase, (EC 1.15.1.1. The mean expected heterozygosity varied from zero to 0.147. When data from the literature for 75 species of tropical fish were added to the nine species of this study, the heterozygosity values differed significantly among the groups of different reproductive strategies. The highest mean heterozygosity was for the non-migratory without parental care, followed by the long-distance migratory, and the lowest mean was for the non-migratory with parental care or internal fecundation.

  15. GENETIC AND MORPHOLOGICAL VARIATION OF POPULATIONS BELONGING TO THE BULINUS TRUNCATUS/TROPICUS COMPLEX (GASTROPODA; PLANORBIDAE) IN SOUTH WESTERN ZIMBABWE

    DEFF Research Database (Denmark)

    Mukaratirwa, S.; Kristensen, Thomas K.; Siegismund, Hans Redlef

    1998-01-01

    Aquatic snails from south western Zimbabwe belonging to the Bulinus trunscatus/tropicus complex vary widely in shell form suggesting that more than one taxon could be present. This possibility was investigated by making observations on snail samples from 13 populations from the Plumtree area......, in respect of allozyme variation (5 polymorphic loci), shell morphology (9 variables), copulatory organ and chromosome number. Comparative data were obtained from snails from north western Zimbabwe identified definitely as B. tropicus. Analysis of the genetic structure revealed a high degree of polymorphism...... among populations. Snails analyzed for chromosome number were all diploid (2n = 36). Snails exposed to Schistosoma haematobium mira-cidia were all refractory. This information supports the view of a single species, B. tropicus, which is differentiated due to migration barriers and where...

  16. Isozyme and RAPD studies in Prosopis glandulosa and P. Velutina (Leguminosae, Mimosoideae

    Directory of Open Access Journals (Sweden)

    Bessega Cecilia

    2000-01-01

    Full Text Available Allozyme and random amplified polymorphic DNA (RAPD techniques have been compared for their usefulness for genetic and taxonomic studies in Prosopis glandulosa and P. velutina populations. Isozymes and RAPDs yielded similarly high estimates of genetic variability. Genetic structure and differentiation were analyzed through non-hierarchical Wright's F DT. For all populations considered, both markers produced low gene flow (Nm 1, in agreement with that expected for conspecific populations. However, in RAPD data the expected reduction in F DT and the increase in Nm were not observed. Correlation between F DT and geographical distance matrices (Mantel test for all populations was significant (P = 0.02 when based on isozymes, but not so (P = 0.33 when based on RAPDs. No significant associations among genetic and geographical or climatic variables were observed. Two isoenzyme systems (GOT and PRX enabled us to distinguish between P. glandulosa and P. velutina, but no diagnostic band for recognition of populations or species studied here were detected by RAPD. However, RAPD markers showed higher values for genetic differentiation among conspecific populations of P. glandulosa and a lower coefficient of variation than those obtained from isozymes.

  17. Biology of tiny animals: three new species of minute salamanders (Plethodontidae: Thorius) from Oaxaca, Mexico.

    Science.gov (United States)

    Parra-Olea, Gabriela; Rovito, Sean M; García-París, Mario; Maisano, Jessica A; Wake, David B; Hanken, James

    2016-01-01

    We describe three new species of minute salamanders, genus Thorius, from the Sierra Madre del Sur of Oaxaca, Mexico. Until now only a single species, T. minutissimus, has been reported from this region, although molecular data have long shown extensive genetic differentiation among geographically disjunct populations. Adult Thorius pinicola sp. nov., T. longicaudus sp. nov., and T. tlaxiacus sp. nov. are larger than T. minutissimus and possess elliptical rather than oval nostrils; T. pinicola and T. longicaudus also have longer tails. All three new species occur west of the range of T. minutissimus, which has the easternmost distribution of any member of the genus. The new species are distinguished from each other and from other named Thorius in Oaxaca by a combination of adult body size, external morphology and osteology, and by protein characters (allozymes) and differences in DNA sequences. In addition, we redescribe T. minutissimus and a related species, T. narisovalis, to further clarify the taxonomic status of Oaxacan populations and to facilitate future studies of the remaining genetically differentiated Thorius that cannot be satisfactorily assigned to any named species. Populations of all five species considered here appear to have declined dramatically over the last one or two decades and live specimens are difficult to find in nature. Thorius may be the most endangered genus of amphibians in the world. All species may go extinct before the end of this century.

  18. Comparative genetic structure in pines: evolutionary and conservation consequences Estructura genética comparada en pinos: consecuencias evolutivas y para la conservación

    Directory of Open Access Journals (Sweden)

    PATRICIA DELGADO

    2002-03-01

    Full Text Available Pines have been the focus of several studies that estimate population genetic parameters using both allozymes and chloroplast single sequence repeats (SSRs. Also, the genus has also been recently studied using molecular systematics so that we now have a more clear understanding of their evolutionary history. With this background we studied comparatively the genetic structure in pines. Expected heterozygosity is particularly constant with a 99 % confidence interval between 0.19 and 0.23 in species that have been studied until now using allozymes. There is a significant proportion of species (9/41 that show high population differentiation estimates (Fst = or larger than 0.15 and five of these have large and wingless seeds probably associated with low densities, bird dispersal mechanisms and resistance to water stress. These species include the North American pinyon pines. Outcrossing rates are also constant among species from both subgenus Pinus and subgenus Strobus, which probably reflects a selective limit to the amount of deleterious alleles that can be maintained in pine species and this also affects inbreeding levels. We also explored the data published using microsatellites in pines and conclude that these markers uncover a higher proportion of variation and genetic differentiation as expected and that the evolutionary models that are used to derive the population genetic structure estimators should take into account other sources of mutation (point mutations, larger insertions and or deletions and duplications to better understand the comparative applications of these molecular markersLos pinos han sido el objeto de varios estudios para estimar los parámetros genéticos de la población utilizando tanto aloenzimas como fragmentos repetidos de secuencia sencilla (RSSs de cloroplasto. Este género también ha sido estudiado recientemente utilizando sistemática molecular de tal manera que ahora tenemos un entendimiento más claro de su

  19. Identificação de espécies de citros mediante polimorfismo enzimático Identification of citrus species by means of enzymatic polymorphism

    Directory of Open Access Journals (Sweden)

    Haiko Enok Sawazaki

    1992-01-01

    isocitrate dehydrogenase (IDH. Interespecific differences were observed; but, none between intraespecific C. sinensis cultivars. Some allozymes were observed in addition to those reffered in the literature on starch gel; e.g., allozymes located next to the known Pgm-1 loci. The PGM system revealed the best differentiation between the cultivars. It showed monomeric proteins and 9 alleles. The MDH system had two loci with 7 alleles; the ME system one locus with 3 alleles; the LAP system one possible locus next to the known Lap-1 and 4 alleles; the GOT two loci for dimeric proteins with 7 alleles; the PGI one locus with 3 alleles; and, the IDH one locus with 4 alleles.

  20. Herança e ligação em locos isoenzimáticos de Caesalpinia echinata L. (pau-brasil. Inheritance and linkage in isozyme loci of Caesalpinia echinata L. (pau-brasil.

    Directory of Open Access Journals (Sweden)

    João del GIUDICE-NETO

    2004-12-01

    Full Text Available Este artigo apresenta o estudo davariação isoenzimática em Caesalpinia echinata L.(pau-brasil. Onze sistemas enzimáticos (ACP,DIA, EST, G6PDH, GOT, LAP, MDH, PGI, PRX,SKDH e 6PGDH codificando dezoito locos (Acp-1,Est-3, Dia-1, G6pdh-1, Got-1, Lap-1, Mdh-1,Mdh-2, Mdh-3, Pgi-1, Pgi-2, Prx-1, Prx-2, Prx-3,Prx-4, Skdh-1, 6pgdh-1 e 6pgdh-2 foraminvestigados. Entre esses locos, Pgi-1 e Got-1foram detectados como monomórficos. Três locos(Mdh-2, G6pdh-1 e 6pgdh-1 não tiveram suaherança analisada devido à ausência de progênies deárvores heterozigotas na amostra. A herançamendeliana simples foi confirmada para dez locos(Acp-1, Dia-1, Est-3, Lap-1, Mdh-1, Mdh-3, Prx-1,Prx-3, Skdh-1 e 6pgdh-2. Três locos (Pgi-2, Prx-2e Prx-4 apresentaram desvios altamentesignificativos (P < 0,01 para a hipótese desegregação regular 1:1. As relações dedesequilíbrios de ligações foram avaliadas em 120pares de locos isoenzimáticos. Seis pares de locosapresentaram ligação: Mdh-3:Dia-1, Mdh-3:Prx-3,6pgdh-1:Pgi-2, 6pgdh-1:Prx-1, 6pgdh-2:Prx-3 ePgi-2:Prx-4.This article presents a study of isozymevariation in Caesalpinia echinata L. (brazilwood.Eleven isozyme systems (ACP, DIA, EST,G6PDH, GOT, LAP, MDH, PGI, PRX, SKDH and6PGDH codifying eighteen loci (Acp-1, Est-3,Dia-1, G6pdh-1, Got-1, Lap-1, Mdh-1, Mdh-2,Mdh-3, Pgi-1, Pgi-2, Prx-1, Prx-2, Prx-3, Prx-4,Skdh-1, 6pgdh-1 and 6pgdh-2 were investigated.Among these loci, Pgi-1 and Got-1 weremonomorphic. Three loci (Mdh-2, G6pdh-1 and6pgdh-1 were not evaluated for inheritance duethe lack of families from heterozygous mothertrees in the sampling. Mendelian inheritance wasconfirmed for ten allozyme loci (Acp-1, Dia-1,Est-3, Lap-1, Mdh-1, Mdh-3, Prx-1, Prx-3, Skdh-1,and 6pgdh-2. Three loci (Pgi-2, Prx-2 and Prx-4showed significant deviations (P < 0.01 from expectedsegregation 1:1 hypothesis. Linkage relationshipswere examined for 120 pairs of allozyme loci.Six pairs of loci showed linked: Mdh-3:Dia-1,Mdh-3:Prx-3, 6

  1. Systematics and biogeography of the jellyfish Aurelia labiata (Cnidaria: Scyphozoa).

    Science.gov (United States)

    Gershwin, L A

    2001-08-01

    The hypothesis that the common eastern North Pacific Aurelia is A. aurita is falsified with morphological analysis. The name Aurelia labiata is resurrected, and the species is redescribed, to refer to medusae differing from A. aurita by a suite of characters related to a broad and elongated manubrium. Specifically, the oral arms are short, separated by and arising from the base of the fleshy manubrium, and the planulae are brooded upon the manubrium itself, rather than on the oral arms. Aurelia aurita possesses no corresponding enlarged structure. Furthermore, the number of radial canals is typically much greater in A. labiata, and thus the canals often appear more anastomosed than in A. aurita. Finally, most A. labiata medusae possess a 16-scalloped bell margin, whereas the margin is 8-scalloped in most A. aurita. Separation of the two forms has previously been noted on the basis of allozyme and isozyme analyses and on the histology of the neuromuscular system. Partial 18S rDNA sequencing corroborates these findings. Three distinct morphotypes of A. labiata, corresponding to separate marine bioprovinces, have been identified among 17 populations from San Diego, California, to Prince William Sound, Alaska. The long-undisputed species A. limbata may be simply a color morph of A. labiata, or a species within a yet-unelaborated A. labiata species complex. The first known introduction of Aurelia cf. aurita into southern California waters is documented. Although traditional jellyfish taxonomy tends to recognize many species as cosmopolitan or nearly so, these results indicate that coastal species, such as A. labiata, may experience rapid divergence among isolated populations, and that the taxonomy of such species should therefore be scrutinized with special care.

  2. Multiple SNP markers reveal fine-scale population and deep phylogeographic structure in European anchovy (Engraulis encrasicolus L.).

    KAUST Repository

    Zarraonaindia, Iratxe

    2012-07-30

    Geographic surveys of allozymes, microsatellites, nuclear DNA (nDNA) and mitochondrial DNA (mtDNA) have detected several genetic subdivisions among European anchovy populations. However, these studies have been limited in their power to detect some aspects of population structure by the use of a single or a few molecular markers, or by limited geographic sampling. We use a multi-marker approach, 47 nDNA and 15 mtDNA single nucleotide polymorphisms (SNPs), to analyze 626 European anchovies from the whole range of the species to resolve shallow and deep levels of population structure. Nuclear SNPs define 10 genetic entities within two larger genetically distinctive groups associated with oceanic variables and different life-history traits. MtDNA SNPs define two deep phylogroups that reflect ancient dispersals and colonizations. These markers define two ecological groups. One major group of Iberian-Atlantic populations is associated with upwelling areas on narrow continental shelves and includes populations spawning and overwintering in coastal areas. A second major group includes northern populations in the North East (NE) Atlantic (including the Bay of Biscay) and the Mediterranean and is associated with wide continental shelves with local larval retention currents. This group tends to spawn and overwinter in oceanic areas. These two groups encompass ten populations that differ from previously defined management stocks in the Alboran Sea, Iberian-Atlantic and Bay of Biscay regions. In addition, a new North Sea-English Channel stock is defined. SNPs indicate that some populations in the Bay of Biscay are genetically closer to North Western (NW) Mediterranean populations than to other populations in the NE Atlantic, likely due to colonizations of the Bay of Biscay and NW Mediterranean by migrants from a common ancestral population. Northern NE Atlantic populations were subsequently established by migrants from the Bay of Biscay. Populations along the Iberian

  3. Population and subspecific genetic differentiation in the foxtail pine (Pinus balfouriana).

    Science.gov (United States)

    Oline, D K; Mitton, J B; Grant, M C

    2000-10-01

    We performed an allozyme survey of genetic differentiation in Pinus balfouriana, a subalpine conifer endemic to California that is comprised of two allopatric subspecies, one in the Klamath Mountains and the other in the southern Sierra Nevada. Although the two subspecies are morphologically distinct and gene flow between them is virtually nonexistent, we observed much higher levels of differentiation among populations within a subspecies than between the two subspecies. Differentiation is particularly strong in the Klamath populations (multilocus FST = 0.242), which are small, isolated, and ecologically marginal. We attribute this strong differentiation to the mountain island effect, in which populations restricted to high elevations become isolated from each other on different mountains separated by unsuitable intervening habitat, with consequent reduced gene flow allowing populations to evolve independently. Populations of P. balfouriana in the Klamath region only exist scattered on the few highest ridges and peaks that rise above 2,000 m, which defines the lower limit of the species elevational distribution. This pattern of distribution has allowed genetic drift and allelic sorting through historical events to produce strong population-level differentiation, which was likely in place before the two subspecies were geographically separated. Because P. balfouriana occurs on both serpentine soils and nonserpentine soils in the Klamath Mountains, we tested for genetic differentiation between populations growing on serpentine versus nonserpentine soils and our results were equivocal. Our data, combined with several other studies of conifers, show that the mountain island effect can produce significant genetic differentiation in conifers whose life-history traits of widely dispersed pollen, long generation times, and high outcrossing rates would lead us to predict a more homogenous population genetic structure.

  4. Genetic diversity of Norway spruce [Picea abies (L. Karst.] in Romanian Carpathians

    Directory of Open Access Journals (Sweden)

    Raul Gheorghe Radu

    2014-07-01

    Full Text Available The genetic diversity of Romanian most important coniferous tree species, the Norway spruce, was estimated by means of allozyme markers. A total of 695 adult trees sampled from eleven populations grouped in six mountainous areas in the Romanian Carpathians were analyzed. In three metapopulations (Maramureş, Postăvar and Parâng, to evaluate the influence of altitudinal gradient on genetic diversity, samples were collected from populations located at high and low altitude. At other location (ApuseniMountains we compared the narrow-crown biotype (Picea abies var. columnaris and the pyramidal crown biotype (Picea abies var. pyramidalis and explored the genetic structure of peat bog ecotype. By analyzing 7 enzyme systems and 12 enzyme coding loci, a total of 38 allelic variants have been detected. The mean value of polymorphic loci for the six sites was 86.1%, ranging between 83.3% and 91.7% and the mean expected heterozygosity was 0.115, resulting in a moderate level of genetic diversity. The highest genetic diversity (He = 0.134 was found in the narrow-crown spruce population. Apuseni metapopulation showed the highest genetic diversity (He = 0.125, being the most valuable for conservation of genetic resources. The small value of fixation index (FST = 0.009 indicates a low genetic differentiation between the six sites and AMOVA test revealed a very high level of genetic diversity within population (99%. Comparative analysis of genetic parameters showed small differences between high and low altitude populations at each site, probably due to the neutral character of the markers analyzed and the effect of gene flow between gradiental populations.

  5. Transformer-4 version 2.0.1, a free multi-platform software to quickly reformat genotype matrices of any marker type, and archive them in the Demiurge information system.

    Science.gov (United States)

    Caujapé-Castells, Juli; Sabbagh, Izzat; Castellano, José J; Ramos, Rafael; Henríquez, Víctor; Quintana, Francisco M; Medina, Dailos A; Toledo, Javier; Ramírez, Fernando; Rodríguez, Juan F

    2013-05-01

    Transformer-4 version 2.0.1 (T4) is a multi-platform freeware programmed in java that can transform a genotype matrix in Excel or XML format into the input formats of one or several of the most commonly used population genetic software, for any possible combination of the populations that the matrix contains. T4 also allows the users to (i) draw allozyme gel interpretations for any number of diploid individuals, and then generate a genotype matrix ready to be used by T4; and (ii) produce basic reports about the data in the matrices. Furthermore, T4 is the only way to optionally submit 'genetic diversity digests' for publication in the Demiurge online information system (http://www.demiurge-project.org). Each such digest undergoes peer-review, and it consists of a geo-referenced data matrix in the tfm4 format plus any ancillary document or hyperlink that the digest authors see fit to include. The complementarity between T4 and Demiurge facilitates a free, safe, permanent, and standardized data archival and analysis system for researchers, and may also be a convenient resource for scientific journals, public administrations, or higher educators. T4 and its converters are freely available (at, respectively, http://www.demiurge-project.org/download_t4 and http://www.demiurge-project.org/converterstore) upon registration in the Demiurge information system (http://demiurge-project.org/register). Users have to click on the link provided on an account validation email, and accept Demiurge's terms of use (see http://www.demiurge-project.org/termsofuse). A thorough user's guide is available within T4. A 3-min promotional video about T4 and Demiurge can be seen at http://vimeo.com/29828406.

  6. Conservation genetics of the endangered Iberian steppe plant Ferula loscosii (Apiaceae).

    Science.gov (United States)

    Pérez-Collazos, E; Catalán, P

    2008-07-01

    Ferula loscosii (Lange) Willk (Apiaceae) is a threatened endemic species native to the Iberian Peninsula. The plant has a narrow and disjunct distribution in three regions, NE, C and SE Spain. Genetic variability within and among 11 populations from its natural distribution was assessed using allozymes. Intermediate levels of genetic diversity were detected in F. loscosii (P(99%) = 36.83; H(E) = 0.125; H(T) = 0.152). However, the highest genetic diversity (58%) corresponded to the threatened populations from SE and C Spain (H(T) = 0.169) rather than the more abundant and larger populations from NE Spain (Ebro valley) (H(T) = 0.122). Low to moderate levels of genetic structure were found among regional ranges (G(ST) = 0.134), and several statistical spatial correlation analyses corroborated substantial genetic differentiation among the three main regional ranges. However, no significant genetic differentiation was found among the NE Spain populations, except for a northernmost population that is geographically isolated. Outcrossing mating and other biological traits of the species could account for the maintenance of the present values of genetic diversity within populations. The existence of an ancestral late Tertiary wider distribution of the species in SE and C Spain, followed by the maintenance of different Quaternary refugia in these warmer areas, together with a more recent and rapid post-glacial expansion towards NE Spain, are arguments that could explain the low genetic variability and structure found in the Ebro valley and the higher levels of diversity in the southern Iberian populations.

  7. Rice domestication: histories and mysteries.

    Science.gov (United States)

    Gross, Briana L

    2012-09-01

    Domesticated rice (Oryza sativa) is one of the world's most important food crops, culturally, nutritionally and economically (Khush 1997). Thus, it is no surprise that there is intense curiosity about its genetic and geographical origins, its response to selection under domestication, and the genetic structure of its wild relative, Oryza rufipogon. Studies of Oryza attempting to answer these questions have accompanied each stage of the development of molecular markers, starting with allozymes and continuing to genome sequencing. While many of these studies have been restricted to small sample sizes, in terms of either the number of markers used or the number and distribution of the accessions, costs are now low enough that researchers are including large numbers of molecular markers and accessions. How will these studies relate to previous findings and long-held assumptions about rice domestication and evolution? If the paper in this issue of Molecular Ecology (Huang et al. 2012) is any indication, there will be some considerable surprises in store. In this study, a geographically and genomically thorough sampling of O. rufipogon and O. sativa revealed two genetically distinct groups of wild rice and also indicated that only one of these groups appears to be related to domesticated rice. While this fits well with previous studies indicating that there are genetic subdivisions within O. rufipogon, it stands in contrast to previous findings that the two major varieties of O. sativa (indica and japonica) were domesticated from two (or more) subpopulations of wild rice.

  8. Evolutionary factors affecting Lactate dehydrogenase A and B variation in the Daphnia pulex species complex

    Directory of Open Access Journals (Sweden)

    Cristescu Melania E

    2011-07-01

    Full Text Available Abstract Background Evidence for historical, demographic and selective factors affecting enzyme evolution can be obtained by examining nucleotide sequence variation in candidate genes such as Lactate dehydrogenase (Ldh. Two closely related Daphnia species can be distinguished by their electrophoretic Ldh genotype and habitat. Daphnia pulex populations are fixed for the S allele and inhabit temporary ponds, while D. pulicaria populations are fixed for the F allele and inhabit large stratified lakes. One locus is detected in most allozyme surveys, but genome sequencing has revealed two genes, LdhA and LdhB. Results We sequenced both Ldh genes from 70 isolates of these two species from North America to determine if the association between Ldh genotype and habitat shows evidence for selection, and to elucidate the evolutionary history of the two genes. We found that alleles in the pond-dwelling D. pulex and in the lake-dwelling D. pulicaria form distinct groups at both loci, and the substitution of Glutamine (S for Glutamic acid (F at amino acid 229 likely causes the electrophoretic mobility shift in the LDHA protein. Nucleotide diversity in both Ldh genes is much lower in D. pulicaria than in D. pulex. Moreover, the lack of spatial structuring of the variation in both genes over a wide geographic area is consistent with a recent demographic expansion of lake populations. Neutrality tests indicate that both genes are under purifying selection, but the intensity is much stronger on LdhA. Conclusions Although lake-dwelling D. pulicaria hybridizes with the other lineages in the pulex species complex, it remains distinct ecologically and genetically. This ecological divergence, coupled with the intensity of purifying selection on LdhA and the strong association between its genotype and habitat, suggests that experimental studies would be useful to determine if variation in molecular function provides evidence that LDHA variants are adaptive.

  9. Evidence of genetic selection for growth in new recruits of a marine fish.

    Science.gov (United States)

    Planes, S; Romans, P

    2004-07-01

    Abstract A cohort of Diplodus sargus, a coastal marine fish abundant in the Mediterranean Sea, has been surveyed from its settlement following the pelagic larval stage up to 4 months of age, when the juveniles are moving to adult habitats in order to assess selective processes. We followed the mortality by looking at the decrease in population abundance and, simultaneously, the genetic structure using allozymes and the growth associated with each genotype to test for a relationship between genotype and phenotype. The recruitment survey demonstrated that 80% of individuals arrived within a single night and that they show very similar age providing a discrete pulse of new recruits that we followed for changes in survival and allele frequencies. After 4 months, there was a total mortality of 80.8%, with the disappearance of 181 of 224 fish that initially colonized the rocky barrier. The decrease in number followed a logarithmic model with a maximum decrease in the early period (first 30 days). The model derived from the 4 months of data demonstrates that most of the mortality in the cohort occurs over the first 120 days following settlement and the model predicted a final abundance of 10 individuals after 1 year. Within the same period of 4 months, we observed significant decrease in multilocus heterozygosity. Such a decrease in heterozygosity partly resulted from a purge of the Pgm-80* allele. Together with this major change in a natural population, an aquarium experiment demonstrated that individuals with Pgm-80* alleles show significantly lower growth than other new recruits. We propose that the decrease in frequency of Pgm-80* in the natural environment is the result of targeted predation that eliminates smaller individuals and therefore individuals bearing Pgm-80*. The potential metabolic effect as well as a scenario that could lead to the maintenance of polymorphism is discussed.

  10. Molecular identification key based on PCR/RFLP for three polychaete sibling species of the genus Marenzelleria, and the species' current distribution in the Baltic Sea

    Science.gov (United States)

    Blank, M.; Laine, A. O.; Jürss, K.; Bastrop, R.

    2008-06-01

    Studies of Marenzelleria species were often hampered by identification uncertainties when using morphological characters only. A newly developed PCR/RFLP protocol allows a more efficient discrimination of the three species Marenzelleria viridis, Marenzelleria neglecta and Marenzelleria arctia currently known for the Baltic Sea. The protocol is based on PCR amplification of two mitochondrial DNA gene segments (16S, COI) followed by digestion with restriction enzymes. As it is faster and cheaper than PCR/sequencing protocols used so far, the protocol is recommended for large-scale analyses. The markers allow an undoubted determination of species irrespective of life stage or condition of the worms in the samples. The protocol was validated on about 950 specimens sampled at more than 30 sites of the Baltic and the North Sea, and on specimens from populations of the North American east coast. Besides this test we used mitochondrial DNA sequences (16S, COI, Cytb) and starch gel electrophoresis to further investigate the distribution of the three Marenzelleria species in the Baltic Sea. The results show that M. viridis (formerly genetic type I or M. cf. wireni) occurred in the Öresund area, in the south western as well as in the eastern Baltic Sea, where it is found sympatric with M. neglecta. Allozyme electrophoresis indicated an introduction by range expansion from the North Sea. The second species, M. arctia, was only found in the northern Baltic Sea, where it sometimes occurred sympatric with M. neglecta or M. viridis. For Baltic M. arctia, the most probable way of introduction is by ship ballast water from the European Arctic. There is an urgent need for a new genetic analysis of all Marenzelleria populations of the Baltic Sea to unravel the current distribution of the three species.

  11. Phylogeography of the fire-bellied toads Bombina: independent Pleistocene histories inferred from mitochondrial genomes.

    Science.gov (United States)

    Hofman, Sebastian; Spolsky, Christina; Uzzell, Thomas; Cogălniceanu, Dan; Babik, Wiesław; Szymura, Jacek M

    2007-06-01

    The fire-bellied toads Bombina bombina and Bombina variegata, interbreed in a long, narrow zone maintained by a balance between selection and dispersal. Hybridization takes place between local, genetically differentiated groups. To quantify divergence between these groups and reconstruct their history and demography, we analysed nucleotide variation at the mitochondrial cytochrome b gene (1096 bp) in 364 individuals from 156 sites representing the entire range of both species. Three distinct clades with high sequence divergence (K2P = 8-11%) were distinguished. One clade grouped B. bombina haplotypes; the two other clades grouped B. variegata haplotypes. One B. variegata clade included only Carpathian individuals; the other represented B. variegata from the southwestern parts of its distribution: Southern and Western Europe (Balkano-Western lineage), Apennines, and the Rhodope Mountains. Differentiation between the Carpathian and Balkano-Western lineages, K2P approximately 8%, approached interspecific divergence. Deep divergence among European Bombina lineages suggests their preglacial origin, and implies long and largely independent evolutionary histories of the species. Multiple glacial refugia were identified in the lowlands adjoining the Black Sea, in the Carpathians, in the Balkans, and in the Apennines. The results of the nested clade and demographic analyses suggest drastic reductions of population sizes during the last glacial period, and significant demographic growth related to postglacial colonization. Inferred history, supported by fossil evidence, demonstrates that Bombina ranges underwent repeated contractions and expansions. Geographical concordance between morphology, allozymes, and mtDNA shows that previous episodes of interspecific hybridization have left no detectable mtDNA introgression. Either the admixed populations went extinct, or selection against hybrids hindered mtDNA gene flow in ancient hybrid zones.

  12. Population genetics of Agave cocui: evidence for low genetic diversity at the southern geographic limit of genus Agave.

    Science.gov (United States)

    Figueredo, Carmen J; Nassar, Jafet M

    2011-01-01

    The Agave genus embraces many species with outstanding ecological and economic importance in the arid regions of the Americas. Even though this genus covers a broad geographic distribution, our knowledge on the population genetics of species is concentrated in taxa located in North America. Recently, it has been demonstrated that plant domestication decreases levels of genetic diversity in managed populations and increases population structure with respect to wild populations. We examined levels of allozyme diversity (N = 17 loci) and population structure of Agave cocui, the species at the southern limit of distribution of the genus. We sampled 7 wild populations (N = 30-35 individuals per population) representative of the geographic distribution of the species in Venezuela. Among the agaves studied, A. cocui has some of the lowest estimates of genetic diversity (H(e)[species] = 0.059, H(e)[population] = 0.054) reported until present. We propose that this condition is probably linked to the recent origin of this species in arid and semiarid regions of Colombia and Venezuela, probably through one or a few founder events. The lowest estimates of genetic diversity were associated with small populations in very restricted arid patches; but also with overexploitation of rosettes for production of fermented drinks and fibers. Santa Cruz de Pecaya, one of the 2 centers of economic use of agaves in northwestern Venezuela presented one of the lowest values of genetic variability, a sign suggesting that human impact represents a significant threat to the available genetic pool that this species possesses in the region.

  13. The effect of HDL-bound and free PON1 on copper-induced LDL oxidation.

    Science.gov (United States)

    Bayrak, Ahmet; Bayrak, Tülin; Bodur, Ebru; Kılınç, Kamer; Demirpençe, Ediz

    2016-09-25

    Oxidative modification of LDL plays an important role in the development of atherosclerosis. High-density lipoprotein (HDL) confers protection against atherosclerosis and the antioxidative properties of paraoxonase 1 (PON1) has been suggested to contribute to this effect of HDL. The PON1 exist in two major polymorphic forms (Q and R), which regulate the concentration and activity of the enzyme and alter its ability to prevent lipid oxidation. However, the association of Q192R polymorphism with PON1's capacity to protect against LDL lipoperoxidation is controversial. The aim of this study was to evaluate the effects of the purified PON1 Q192R and the partially purified HDL-bound PON1 Q192R isoenzymes (HDL-PON1 Q192R) on LDL oxidation, with respect to their arylesterase/homocysteine thiolactonase (HTLase) activities. Cupric ion-induced LDL oxidation was reduced up to 48% by purified PON1 Q192, but only 33% by an equivalent activity of PON1 R192. HDL-PON1 Q192 isoenzyme caused a 65% reduction, whereas HDL-PON1 R192 isoenzyme caused only 46% reduction in copper ion-induced LDL oxidation. These findings reflect the fact that PON1 Q and PON1 R allozymes may have different protective characteristics against LDL oxidation. The protection against LDL oxidation provided by HDL-PON1 Q192R isoenzymes is more prominent than the purified soluble enzymes. Inhibition of the Ca(+2)-dependent PON1 Q192R arylesterase/HTLase by the metal chelator EDTA, did not alter PON1's ability to inhibit LDL oxidation. These studies indicate that the active site involvement of the purified enzyme is not similar to the HDL-bound one, in terms of both PON1 arylesterase/HTLase activity and the protection of LDL from copper ion-induced oxidation. Moreover, PON1's ability to protect LDL from oxidation does not seem to require calcium.

  14. Genetic ecotoxicology of radionuclides in mosquitofish: The relationship between DNA strand breaks and genotype

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    Theodorakis, C.W.; Shugart, L.R. [Oak Ridge National Lab., TN (United States)

    1995-12-31

    DNA polymorphisms revealed by RAPD (Randomly Amplified Polymorphic DNA) and allozyme analysis were compared to relative amounts of DNA strand breakage, determined by gel electrophoresis, in mosquitofish (Gambusia affinis). The fish examined were from three different experiments, as follows : (1) fish collected from a radioactively contaminated pond; (2) fish collected from a non-radioactively contaminated pond and exposed to X-rays in the laboratory; and (3) fish collected from a non-radioactively contaminated pond and caged in a radioactive or non-radioactive pond. The types of RAPD metrics used were number of bands per individual and frequency of certain bands. It was found in a previous study that in some instances the number of bands and the frequency of certain bands in the population were elevated in radionuclide-contaminated sites relative to reference sites. In several cases, the median molecular length (MML) of the DNA (which is inversely proportional to the amount of strand breakage) was correlated to the number of bands per individual. Also, for bands which had a higher population frequency in contaminated sites, the MML in many cases was higher for fish with than without these bands. Results from laboratory X-ray exposures paralleled those from the field. In the caging study, 9 out of the original 30 caged fish survived in the radioactive pond, whereas 27 fish survived in the non-radioactive cage. In the radioactive cage the genotypic distribution of the survivors was more similar to the indigenous radioactive population than to the population of origin. When the relative amount of DNA strand breakage was compared to the genotype of each survivor, the patterns were similar to those found in the field collection and laboratory studies.

  15. Genetic diversity of Siberian stone pine under introduction in the South Urals and Bashkir Cis-Urals

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    Z. Kh. Shigapov

    2016-10-01

    Full Text Available Allozyme polymorphism of Siberian stone pine Pinus sibirica Du Tour has been studied in 14 artificial stands in the South Urals and Bashkir Cis-Urals on the base of 7 gene-enzyme system analysis. The following values of genetic diversity are determined: mean number of alleles per locus (A constitutes 1.69±0.08; portion of polymorphic loci (P95 – 50.0 %; the average expected heterozygosity (He – 0.121±0.015; the average observed heterozygosity (Ho – 0.127±0.017.The level of genetic variability in artificial stands of Siberian stone pine in the region is somewhat inferior to that in natural populations of the species. The highest genotype heterozygosity is determined in high-productive 110 year-old artificial stand in the South Urals (Beloretsky-2 site, and also in Ufimsky and Mishkinsky sites in Bashkir Cis-Urals. The lowest heterozygosity values are revealed in Birsky and Tuimazinsky sites characterized by the weakened vital state of individuals. In total we can speak about the maintenance of essential part of the species’ genetic polymorphism under introduction, especially in some stands. Genetic similarity of the studied stands is shown: inter-sample component of the total genetic diversity (FST constitutes 2.2 %, the average Nei’s genetic distance (D – 0.0033±0.00023, that is also typical of natural populations of Siberian stone pine in the species range. The obtained data about the genetic variability level of artificial stands in a complex with forestry characteristics give evidence of the successful species introduction in the region and the necessity of resumption of works on Siberian stone pine culture establishment in an industrial scale.

  16. Can soil seed banks serve as genetic memory? A study of three species with contrasting life history strategies.

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    Bohumil Mandák

    Full Text Available We attempted to confirm that seed banks can be viewed as an important genetic reservoir by testing the hypothesis that standing (aboveground plants represent a nonrandom sample of the seed bank. We sampled multilocus allozyme genotypes from three species with different life history strategies: Amaranthus retroflexus, Carduus acanthoides, Pastinaca sativa. In four populations of each species we analysed the extent to which allele and genotype frequencies vary in consecutive life history stages including the summer seed bank, which has been overlooked up to now. We compared the winter seed bank (i.e., seeds collected before the spring germination peak, seedlings, rosettes, the summer seed bank (i.e., seeds collected after the spring germination peak and fruiting plants. We found that: (1 All three species partitioned most of their genetic diversity within life history stages and less among stages within populations and among populations. (2 All genetic diversity parameters, except for allele frequencies, were similar among all life history stages across all populations in different species. (3 There were differences in allele frequencies among life history stages at all localities in Amaranthus retroflexus and at three localities in both Carduus acanthoides and Pastinaca sativa. (4 Allele frequencies did not differ between the winter and summer seed bank in most Carduus acanthoides and Pastinaca sativa populations, but there was a marked difference in Amaranthus retroflexus. In conclusion, we have shown that the summer seed bank is not genetically depleted by spring germination and that a majority of genetic diversity remains in the soil through summer. We suggest that seed banks in the species investigated play an important role by maintaining genetic diversity sufficient for recovery rather than by accumulating new genetic diversity at each locality.

  17. Genetic evaluation of seeds of highly endangered Pinus uliginosa Neumann from Węgliniec reserve for ex-situ conservation program

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    Andrzej Lewandowski

    2011-01-01

    Full Text Available Peat-bog pine Pinus uliginosa Neumann has become extinct or rare in many parts of Europe. We have investigated the levels of genetic variation and inbreeding in seeds collected from a highly endangered reserve of this species in Poland, using allozymes as genetic markers. Generally, a high level of genetic variation was observed. The mean expected heterozygosity was 0.376, while average (Na and effective (Ne numbers of alleles per locus were 2.45 and 1.67, respectively. Nevertheless, we have detected relatively low levels of outcrossing, and potential biparental inbreeding. The population-wide multilocus outcrossing rate was estimated to be 0.706 (±0.091, while the minimum variance mean of single-locus estimates was distinctly lower (ts=0.611. The estimates of outcrossing calculated for individual trees ranged widely from 0.051 to 1.017, indicating the complexity of outcrossing patterns. The investigated population of P. uliginasa from Węgliniec is small and surrounded by extensive forest stands of P. sylvestris. Our three-year records of phenological observations demonstrated that flowering periods for P. uliginosa and P. sylvestris overlap, allowing for cross-pollination. The possibility of P. uliginosa pollination by P. sylvestris creates a potential danger of genetic erosion of the P. uliginosa gene pool. Nonetheless, based on a species specific cpDNA marker we have found that among 533 seedlings of P. uliginosa there were only six seedlings carrying cpDNA marker specific for P. sylvestris, indicating that such hybridization seems to be rare.

  18. Genetic variability in Astyanax altiparanae Garutti & Britski, 2000 (Teleostei, Characidae from the Upper Paraná River basin, Brazil

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    Maria Dolores Peres

    2005-12-01

    Full Text Available Allozyme data was used to assess the genetic diversity Astyanax altiparanae populations from the floodplain of the Upper Paraná River (PR. Specimens were collected in the southern Brazilian state of Paraná from PR in Porto Rico municipality and Ribeirão Ficha (RF in Ubiratã municipality. The authors used 15% (w/v corn starch gel electrophoresis to identify 21 putative loci for 13 enzymatic systems: Aspartate aminotransferase, 2.6.1.1 (AAT, Acid phosphatase, 3.1.3.2 (ACP, Esterase, 3.1.1.1 (EST, Glycerol-3-phosphate dehydrogenase, 1.1.1.8 (G3PDH, Glucose-6-phosphate dehydrogenase, 1.1.1.49 (G6PDH, Glucose-6-phosphate isomerase, 5.3.1.9 (GPI, Iditol dehydrogenase, 1.1.1.14 (IDDH, Isocitrate dehydrogenase - NADP+, 1.1.1.42 (IDH, L-Lactate dehydrogenase, 1.1.1.27 (LDH, Malate dehydrogenase, 1.1.1.37 (MDH, Malate dehydrogenase - NADP+, 1.1.1.40 (MDHP, Phosphoglucomutase, 5.4.2.2 (PGM, and Superoxide dismutase, 1.15.1.1 (SOD. The proportion of polymorphic loci were estimated as 52.38% in the PR population and 38.10% in the RF population. Expected estimated heterozygosities were 0.1518 ± 0.0493 for the PR population and 0.0905 ± 0.0464 for the RF population. The A. altiparanae heterozygosity data were similar to previous estimates for other PR basin characid species. Allele frequencies were significantly different between the PR and RF populations in respect to some loci (Acp-1, G3pdh-1, Gpi-A, Iddh-1, Mdhp-1 and Mdhp-2. Wright’s statistics for all loci were estimated as Fis = 0.3919, Fit = 0.4804 and Fst = 0.1455. Our results show that the A. altiparanae populations studied are genetically different and have a high degree of genetic variability.

  19. Inferring recruitment history from spatial genetic structure within populations of the colonizing tree Albizia julibrissin (Fabaceae).

    Science.gov (United States)

    Pardini, E A; Hamrick, J L

    2008-06-01

    Comparative analyses of spatial genetic structure (SGS) among species, populations, or cohorts give insight into the genetic consequences of seed dispersal in plants. We analysed SGS of a weedy tree in populations with known and unknown recruitment histories to first establish patterns in populations with single vs. multiple founders, and then to infer possible recruitment scenarios in populations with unknown histories. We analysed SGS in six populations of the colonizing tree Albizia julibrissin Durazz. (Fabaceae) in Athens, Georgia. Study sites included two large populations with multiple, known founders, two small populations with a single, known founder, and two large populations with unknown recruitment histories. Eleven allozyme loci were used to genotype 1385 individuals. Insights about the effects of colonization history from the SGS analyses were obtained from correlograms and Sp statistics. Distinct differences in patterns of SGS were identified between populations with multiple founders vs. a single founder. We observed significant, positive SGS, which decayed with increasing distance in the populations with multiple colonists, but little to no SGS in populations founded by one colonist. Because relatedness among individuals is estimated relative to a local reference population, which usually consists of those individuals sampled in the study population, SGS in populations with high background relatedness, such as those with a single founder, may be obscured. We performed additional analyses using a regional reference population and, in populations with a single founder, detected significant, positive SGS at all distances, indicating that these populations consist of highly related descendants and receive little seed immigration. Subsequent analyses of SGS in size cohorts in the four large study populations showed significant SGS in both juveniles and adults, probably because of a relative lack of intraspecific demographic thinning. SGS in populations

  20. Variation of partial transferrin sequences and phylogenetic relationships among hares (Lepus capensis, Lagomorpha) from Tunisia.

    Science.gov (United States)

    Awadi, Asma; Suchentrunk, Franz; Makni, Mohamed; Ben Slimen, Hichem

    2016-10-01

    North African hares are currently included in cape hares, Lepus capensis sensu lato, a taxon that may be considered a superspecies or a complex of closely related species. The existing molecular data, however, are not unequivocal, with mtDNA control region sequences suggesting a separate species status and nuclear loci (allozymes, microsatellites) revealing conspecificity of L. capensis and L. europaeus. Here, we study sequence variation in the intron 6 (468 bp) of the transferrin nuclear gene, of 105 hares with different coat colour from different regions in Tunisia with respect to genetic diversity and differentiation, as well as their phylogenetic status. Forty-six haplotypes (alleles) were revealed and compared phylogenetically to all available TF haplotypes of various Lepus species retrieved from GenBank. Maximum Likelihood, neighbor joining and median joining network analyses concordantly grouped all currently obtained haplotypes together with haplotypes belonging to six different Chinese hare species and the African scrub hare L. saxatilis. Moreover, two Tunisian haploypes were shared with L. capensis, L timidus, L. sinensis, L. yarkandensis, and L. hainanus from China. These results indicated the evolutionary complexity of the genus Lepus with the mixing of nuclear gene haplotypes resulting from introgressive hybridization or/and shared ancestral polymorphism. We report the presence of shared ancestral polymorphism between North African and Chinese hares. This has not been detected earlier in the mtDNA sequences of the same individuals. Genetic diversity of the TF sequences from the Tunisian populations was relatively high compared to other hare populations. However, genetic differentiation and gene flow analyses (AMOVA, FST, Nm) indicated little divergence with the absence of geographically meaningful phylogroups and lack of clustering with coat colour types. These results confirm the presence of a single hare species in Tunisia, but a sound inference on

  1. [Phylogeography of mitochondrial DNA in South Asian Dolly Varden char Salvelinus curilus Pallas, 1814 (Salmoniformes, Salmonidae): mediated gene introgression?].

    Science.gov (United States)

    Shed'ko, S V; Ginatulina, L K; Miroshnichenko, I L; Nemkova, G A

    2007-02-01

    In 41 individuals of South Asian Dolly Varden char Salvelinus curilus, nucleotide sequences of tRNA-Pro gene fragment (27 bp) and mtDNA control region (483-484 bp) were analyzed. The fish were collected in 20 localities covering virtually the whole range of the species: Kuril Islands, Sakhalin Island. and Primorye. In addition, six individuals of three other char species (S. albus, S. malma, and S. leucomaenis), which are closely related to S. curilus and inhabit the Russian Far East, were examined. In all, we detected 12 different variants of mtDNA haplotypes that formed three distinct groups differing in 14--20 nucleotide positions. The first group consisted of six haplotypes found in S. curilus in Kuril Islands, Sakhalin, and Primorye (mtDNA phylogroup OKHOTSKIA). The second group comprised four haplotypes representing the mtDNA phylogroup BERING, which had been described earlier (Brunner et al, 2001); they were found in S. curilus in Kuril Islands and Sakhalin, as well as in S. albus and S. malma in Kamchatka and northern Kurils. The third group included two haplotypes detected in S. leucomaenis. The existence of two mtDNA lineages (OKHOTSKIA and BERING) in S. curilus from Kurils and Sakhalin was explained by hybridization and DNA transfer from S. malma to S. curilus. The absence of the BERING haplotypes in S. curilus from Primorye water reservoirs is related to the physical isolation of the Sea of Okhotsk and Sea of Japan basins in past epochs. On the basis of comparing phylogenetic trees, constructed from the data on allozyme and mtDNA variation, we suggest that in this case, an indirect transfer of mtDNA in Alpinoid chars--> S. malma-->S. curilus chain could occur.

  2. Stock origins of Dolly Varden collected from Beaufort Sea coastal sites of Arctic Alaska and Canada

    Science.gov (United States)

    Krueger, C.C.; Wilmot, R.L.; Everett, R.J.

    1999-01-01

    Anadromous northern Dolly Varden Salvelinus malma support a summer subsistence fishery in Beaufort Sea coastal waters. These same waters coincide with areas of oil and gas exploration and development. The purpose of this study was to assess variation in stock origins of Dolly Varden collected from sites along 400 km of Beaufort Sea coast. Mixed-stock analyses (MSA) of allozyme data were used to compare collections from four sites (Endicolt near Prudhoe Bay, Mikkelsen Bay, and Kaktovik in Alaska and Phillips Bay in Canada) and to assess variation in stock contributions among summer months and between 1987 and 1988. The MSA estimates for individual stocks were summed into estimates for three stock groups: western stocks from the area near Sagavarnirktok River and Prudhoe Bay (SAG), Arctic National Wildlife Refuge stocks (Arctic Refuge), and Canadian stocks. The MSA of Endicott samples taken in 1987 and 1988 did not differ among months in terms of contributions from local SAG stocks (range, 71-95%). Contributions from nonlocal (>100 km distant) Canadian and Arctic Refuge stocks were not different from zero in 1987, but contributions from Canadian stocks were so in July (17%) and August (20%) but not in September of 1988. Thus, stock contributions to Endicott collections were different between 1987 and 1988. Samples from the Kaktovik area in 1988 were different between months in terms of contributions from nonlocal SAG stocks (July, 7%; August, 27%). Significant contributions to these samples were made both months by Canadian (25% and 17%) and local Arctic Refuge stocks (68% and 56%). Among the four coastal sites, local stocks typically contributed most to collections; however, every site had collections that contained significant contributions from nonlocal stocks. The MSA estimates clearly revealed the movement of Dolly Varden between U.S. and Canada coastal waters. If local stocks are affected by oil and gas development activities, distant subsistence fisheries

  3. Population Genomics of the Euryhaline Teleost Poecilia latipinna.

    Science.gov (United States)

    Nunez, J C B; Seale, T P; Fraser, M A; Burton, T L; Fortson, T N; Hoover, D; Travis, J; Oleksiak, M F; Crawford, D L

    2015-01-01

    Global climate change and increases in sea levels will affect coastal marine communities. The conservation of these ecologically important areas will be a challenge because of their wide geographic distribution, ecological diversity and species richness. To address this problem, we need to better understand how the genetic variation of the species in these communities is distributed within local populations, among populations and between distant regions. In this study we apply genotyping by sequencing (GBS) and examine 955 SNPs to determine Sailfin molly (Poecilia latipinna) genetic diversity among three geographically close mangrove salt marsh flats in the Florida Keys compared to populations in southern and northern Florida. The questions we are asking are whether there is sufficient genetic variation among isolated estuarine fish within populations and whether there are significant divergences among populations. Additionally, we want to know if GBS approaches agree with previous studies using more traditional molecular approaches. We are able to identify large genetic diversity within each saltmarsh community (π ≈ 36%). Additionally, among the Florida Key populations and the mainland or between southern and northern Florida regions, there are significant differences in allele frequencies seen in population structure and evolutionary relationships among individuals. Surprisingly, even though the cumulative FST value using all 955 SNPs within the three Florida Key populations is small, there are 29 loci with significant FST values, and 11 of these were outliers suggestive of adaptive divergence. These data suggest that among the salt marsh flats surveyed here, there is significant genetic diversity within each population and small but significant differences among populations. Much of the genetic variation within and among populations found here with GBS is very similar to previous studies using allozymes and microsatellites. However, the meaningful difference

  4. Population Genomics of the Euryhaline Teleost Poecilia latipinna.

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    J C B Nunez

    Full Text Available Global climate change and increases in sea levels will affect coastal marine communities. The conservation of these ecologically important areas will be a challenge because of their wide geographic distribution, ecological diversity and species richness. To address this problem, we need to better understand how the genetic variation of the species in these communities is distributed within local populations, among populations and between distant regions. In this study we apply genotyping by sequencing (GBS and examine 955 SNPs to determine Sailfin molly (Poecilia latipinna genetic diversity among three geographically close mangrove salt marsh flats in the Florida Keys compared to populations in southern and northern Florida. The questions we are asking are whether there is sufficient genetic variation among isolated estuarine fish within populations and whether there are significant divergences among populations. Additionally, we want to know if GBS approaches agree with previous studies using more traditional molecular approaches. We are able to identify large genetic diversity within each saltmarsh community (π ≈ 36%. Additionally, among the Florida Key populations and the mainland or between southern and northern Florida regions, there are significant differences in allele frequencies seen in population structure and evolutionary relationships among individuals. Surprisingly, even though the cumulative FST value using all 955 SNPs within the three Florida Key populations is small, there are 29 loci with significant FST values, and 11 of these were outliers suggestive of adaptive divergence. These data suggest that among the salt marsh flats surveyed here, there is significant genetic diversity within each population and small but significant differences among populations. Much of the genetic variation within and among populations found here with GBS is very similar to previous studies using allozymes and microsatellites. However, the

  5. Genetic markers in the study of Anisakis typica (Diesing, 1860): larval identification and genetic relationships with other species of Anisakis Dujardin, 1845 (Nematoda: Anisakidae).

    Science.gov (United States)

    Mattiucci, S; Paggi, L; Nascetti, G; Portes Santos, C; Costa, G; Di Beneditto, A P; Ramos, R; Argyrou, M; Cianchi, R; Bullini, L

    2002-03-01

    Genetic variation at 21 gene-enzyme systems was studied in a sample of an adult population of Anisakis typica (Diesing, 1860) recovered in the dolphin Sotalia fluviatilis from the Atlantic coast of Brazil. The characteristic alleles, detected in this population, made it possible to identify as A. typica, Anisakis larvae with a Type I morphology (sensu Berland, 1961) from various fishes: Thunnus thynnus and Auxis thazard from Brazil waters, Trachurus picturatus and Scomber japonicus from Madeiran waters, Scomberomorus commerson, Euthynnus affinis, Sarda orientalis and Coryphaena hippurus from the Somali coast of the Indian Ocean, and Merluccius merluccius from the Eastern Mediterranean. Characteristic allozymes are given for the identification, at any life-stage and in both sexes, of A. typica and the other Anisakis species so far studied genetically. The distribution of A. typica in warmer temperate and tropical waters is confirmed; the definitive hosts so far identified for this species belong to delphinids, phocoenids and pontoporids. The present findings represent the first established records of intermediate/paratenic hosts of A. typica and extend its range to Somali waters of the Indian Ocean and to the Eastern Mediterranean Sea. A remarkable genetic homogeneity was observed in larval and adult samples of A. typica despite their different geographical origin; interpopulation genetic distances were low, ranging from D(Nei)=0.004 (Eastern Mediterranean versus Somali) to D(Nei)=0.010 (Brazilian versus Somali). Accordingly, indirect estimates of gene flow gave a rather high average value of Nm = 6.00. Genetic divergence of A. typica was, on average, D(Nei)=1.12 from the members of the A. simplex complex (A. simplex s.s, A. pegreffii, A. simplex C) and D(Nei)=1.41 from A. ziphidarum, which all share Type I larvae; higher values were found from both A. physeteris (D(Nei)=2.77)

  6. Regional structuring of genetic variation in short-lived rock pool populations of Branchipodopsis wolfi (Crustacea: Anostraca).

    Science.gov (United States)

    Brendonck, L; De Meester, L; Riddoch, B J

    2000-06-01

    The genetic structure of three metapopulations of the southern African anostracan Branchipodopsis wolfi was compared by analysing allozyme variation at four loci (PGM, GPI, APK, AAT). In total, 17 local populations from three sites (metapopulations) were analysed from rock pools in south-eastern Botswana ranging from 0.2 to 21 m(2) in surface area. In three populations we found significant deviations from Hardy-Weinberg (H-W) equilibrium at one or more loci due to heterozygote deficiencies. Genetic variability at one site was significantly lower than at the other sites, which may be linked to a greater incidence of extinction and recolonisation, as the basins at this site are shallower and have shorter hydrocycles. Across all local populations, a significant level of population differentiation was revealed. More than 90% of this variation was explained by differentiation among sites (metapopulations), although this differentiation did not correlate with geographic distance, or with environmental variables. Genetic differentiation among populations within metapopulations was low, but significant at all sites. At only one of the sites was a significantly positive association measured between genetic and geographic distance among local populations. Our data suggest that persistent stochastic events and limited effective long-range dispersal appear to dominate genetic differentiation among populations of B. wolfi inhabiting desert rock pools. The lack of association between geographic distance and genetic or ecological differences between rock pool sites is indicative of historical stochastic events. Low heterozygosity, the significant deviations from H-W equilibrium, and the large inter- but low intra-site differentiation are suggestive of the importance of short-range dispersal. Gene flow between metapopulations of B. wolfi appears to be seriously constrained by distances of 2 km or even less.

  7. Molecular phylogeny and phylogeography of the Australian freshwater fish genus Galaxiella, with an emphasis on dwarf galaxias (G. pusilla.

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    Peter J Unmack

    Full Text Available The freshwater fauna of Southern Australia is primarily restricted to the southwestern and southeastern corners of the continent, and is separated by a large, arid region that is inhospitable to this biota. This geographic phenomenon has attracted considerable interest from biogeographers looking to explain evolutionary diversification in this region. Here, we employed phylogenetic and phylogeographic approaches to evaluate the effect of this barrier on a group of four galaxiid fish species (Galaxiella endemic to temperate Southern Australia. We also tested if continental shelf width has influenced connectivity among populations during low sea levels when rivers, now isolated, could have been connected. We addressed these questions by sampling each species across its range using multiple molecular markers (mitochondrial cytochrome b sequences, nuclear S7 intron sequences, and 49 allozyme loci. These data also allowed us to assess species boundaries, to refine phylogenetic affinities, and to estimate species ages. Interestingly, we found compelling evidence for cryptic species in G. pusilla, manifesting as allopatric eastern and western taxa. Our combined phylogeny and dating analysis point to an origin for the genus dating to the early Cenozoic, with three of the four species originating during the Oligocene-Miocene. Each Galaxiella species showed high levels of genetic divergences between all but the most proximate populations. Despite extensive drainage connections during recent low sea levels in southeastern Australia, populations of both species within G. pusilla maintained high levels of genetic structure. All populations experienced Late Pleistocene-Holocene population growth, possibly in response to the relaxation of arid conditions after the last glacial maximum. High levels of genetic divergence and the discovery of new cryptic species have important implications for the conservation of this already threatened group of freshwater

  8. Molecular phylogeny and phylogeography of the Australian freshwater fish genus Galaxiella, with an emphasis on dwarf galaxias (G. pusilla).

    Science.gov (United States)

    Unmack, Peter J; Bagley, Justin C; Adams, Mark; Hammer, Michael P; Johnson, Jerald B

    2012-01-01

    The freshwater fauna of Southern Australia is primarily restricted to the southwestern and southeastern corners of the continent, and is separated by a large, arid region that is inhospitable to this biota. This geographic phenomenon has attracted considerable interest from biogeographers looking to explain evolutionary diversification in this region. Here, we employed phylogenetic and phylogeographic approaches to evaluate the effect of this barrier on a group of four galaxiid fish species (Galaxiella) endemic to temperate Southern Australia. We also tested if continental shelf width has influenced connectivity among populations during low sea levels when rivers, now isolated, could have been connected. We addressed these questions by sampling each species across its range using multiple molecular markers (mitochondrial cytochrome b sequences, nuclear S7 intron sequences, and 49 allozyme loci). These data also allowed us to assess species boundaries, to refine phylogenetic affinities, and to estimate species ages. Interestingly, we found compelling evidence for cryptic species in G. pusilla, manifesting as allopatric eastern and western taxa. Our combined phylogeny and dating analysis point to an origin for the genus dating to the early Cenozoic, with three of the four species originating during the Oligocene-Miocene. Each Galaxiella species showed high levels of genetic divergences between all but the most proximate populations. Despite extensive drainage connections during recent low sea levels in southeastern Australia, populations of both species within G. pusilla maintained high levels of genetic structure. All populations experienced Late Pleistocene-Holocene population growth, possibly in response to the relaxation of arid conditions after the last glacial maximum. High levels of genetic divergence and the discovery of new cryptic species have important implications for the conservation of this already threatened group of freshwater species.

  9. Dual African origins of global Aedes aegypti s.l. populations revealed by mitochondrial DNA.

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    Michelle Moore

    Full Text Available BACKGROUND: Aedes aegypti is the primary global vector to humans of yellow fever and dengue flaviviruses. Over the past 50 years, many population genetic studies have documented large genetic differences among global populations of this species. These studies initially used morphological polymorphisms, followed later by allozymes, and most recently various molecular genetic markers including microsatellites and mitochondrial markers. In particular, since 2000, fourteen publications and four unpublished datasets have used sequence data from the NADH dehydrogenase subunit 4 mitochondrial gene to compare Ae. aegypti collections and collectively 95 unique mtDNA haplotypes have been found. Phylogenetic analyses in these many studies consistently resolved two clades but no comprehensive study of mtDNA haplotypes have been made in Africa, the continent in which the species originated. METHODS AND FINDINGS: ND4 haplotypes were sequenced in 426 Ae. aegypti s.l. from Senegal, West Africa and Kenya, East Africa. In Senegal 15 and in Kenya 7 new haplotypes were discovered. When added to the 95 published haplotypes and including 6 African Aedes species as outgroups, phylogenetic analyses showed that all but one Senegal haplotype occurred in a basal clade while most East African haplotypes occurred in a second clade arising from the basal clade. Globally distributed haplotypes occurred in both clades demonstrating that populations outside Africa consist of mixtures of mosquitoes from both clades. CONCLUSIONS: Populations of Ae. aegypti outside Africa consist of mosquitoes arising from one of two ancestral clades. One clade is basal and primarily associated with West Africa while the second arises from the first and contains primarily mosquitoes from East Africa.

  10. Phylogeny and taxonomy of the North American clade of the Ceratocystis fimbriata complex.

    Science.gov (United States)

    Johnson, Jason A; Harrington, Thomas C; Engelbrecht, C J B

    2005-01-01

    Ceratocystis fimbriata is a widely distributed, plant pathogenic fungus that causes wilts and cankers on many woody hosts. Earlier phylogenetic analyses of DNA sequences revealed three geographic clades within the C. fimbriata complex that are centered respectively in North America, Latin America and Asia. This study looked for cryptic species within the North American clade. The internal transcribed spacer regions (ITS) of the rDNA were sequenced, and phylogenetic analysis indicated that most isolates from the North American clade group into four host-associated lineages, referred to as the aspen, hickory, oak and cherry lineages, which were isolated primarily from wounds or diseased trees of Populus, Carya, Quercus and Prunus, respectively. A single isolate collected from P. serotina in Wisconsin had a unique ITS sequence. Allozyme electromorphs also were highly polymorphic within the North American clade, and the inferred phylogenies from these data were congruent with the ITS-rDNA analyses. In pairing experiments isolates from the aspen, hickory, oak and cherry lineages were interfertile only with other isolates from their respective lineages. Inoculation experiments with isolates of the four host-associated groupings showed strong host specialization by isolates from the aspen and hickory lineages on Populus tremuloides and Carya illinoensis, respectively, but isolates from the oak and cherry lineages did not consistently reveal host specialization. Morphological features distinguish isolates in the North American clade from those of the Latin American clade (including C. fimbriata sensu stricto). Based on the phylogenetic evidence, interfertility, host specialization and morphology, the oak and cherry lineages are recognized as the earlier described C. variospora, the poplar lineage as C. populicola sp. nov., and the hickory lineage as C. caryae sp. nov. A new species associated with the bark beetle Scolytus quadrispinosus on Carya is closely related to C

  11. Effective population size of natural populations of Drosophila buzzatii, with a comparative evaluation of nine methods of estimation.

    Science.gov (United States)

    Barker, J S F

    2011-11-01

    Allozyme and microsatellite data from numerous populations of Drosophila buzzatii have been used (i) to determine to what degree N(e) varies among generations within populations, and among populations, and (ii) to evaluate the congruence of four temporal and five single-sample estimators of N(e) . Effective size of different populations varied over two orders of magnitude, most populations are not temporally stable in genetic composition, and N(e) showed large variation over generations in some populations. Short-term N(e) estimates from the temporal methods were highly correlated, but the smallest estimates were the most precise for all four methods, and the most consistent across methods. Except for one population, N(e) estimates were lower when assuming gene flow than when assuming populations that were closed. However, attempts to jointly estimate N(e) and immigration rate were of little value because the source of migrants was unknown. Correlations among the estimates from the single-sample methods generally were not significant although, as for the temporal methods, estimates were most consistent when they were small. These single-sample estimates of current N(e) are generally smaller than the short-term temporal estimates. Nevertheless, population genetic variation is not being depleted, presumably because of past or ongoing migration. A clearer picture of current and short-term effective population sizes will only follow with better knowledge of migration rates between populations. Different methods are not necessarily estimating the same N(e) , they are subject to different bias, and the biology, demography and history of the population(s) may affect different estimators differently.

  12. Population genetic differences along a latitudinal cline between original and recently colonized habitat in a butterfly.

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    Sofie Vandewoestijne

    Full Text Available BACKGROUND: Past and current range or spatial expansions have important consequences on population genetic structure. Habitat-use expansion, i.e. changing habitat associations, may also influence genetic population parameters, but has been less studied. Here we examined the genetic population structure of a Palaeartic woodland butterfly Pararge aegeria (Nymphalidae which has recently colonized agricultural landscapes in NW-Europe. Butterflies from woodland and agricultural landscapes differ in several phenotypic traits (including morphology, behavior and life history. We investigated whether phenotypic divergence is accompanied by genetic divergence between populations of different landscapes along a 700 km latitudinal gradient. METHODOLOGY/PRINCIPAL FINDINGS: Populations (23 along the latitudinal gradient in both landscape types were analyzed using microsatellite and allozyme markers. A general decrease in genetic diversity with latitude was detected, likely due to post-glacial colonization effects. Contrary to expectations, agricultural landscapes were not less diverse and no significant bottlenecks were detected. Nonetheless, a genetic signature of recent colonization is reflected in the absence of clinal genetic differentiation within the agricultural landscape, significantly lower gene flow between agricultural populations (3.494 than between woodland populations (4.183, and significantly higher genetic differentiation between agricultural (0.050 than woodland (0.034 pairwise comparisons, likely due to multiple founder events. Globally, the genetic data suggest multiple long distance dispersal/colonization events and subsequent high intra- and inter-landscape gene flow in this species. Phosphoglucomutase deviated from other enzymes and microsatellite markers, and hence may be under selection along the latitudinal gradient but not between landscape types. Phenotypic divergence was greater than genetic divergence, indicating directional

  13. Gene flow rise with habitat fragmentation in the bog fritillary butterfly (Lepidoptera: Nymphalidae

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    Descimon Henri

    2008-03-01

    Full Text Available Abstract Background The main components of the spatial genetic structure of the populations are neighbourhood size and isolation by distance. These may be inferred from the allele frequencies across a series of populations within a region. Here, the spatial population structure of Proclossiana eunomia was investigated in two mountainous areas of southern Europe (Asturias, Spain and Pyrenees, France and in two areas of intermediate elevation (Morvan, France and Ardennes, Belgium. Results A total of eight polymorphic loci were scored by allozyme electrophoresis, revealing a higher polymorphism in the populations of southern Europe than in those of central Europe. Isolation by distance effect was much stronger in the two mountain ranges (Pyrenees and Asturias than in the two areas of lower elevation (Ardennes and Morvan. By contrast, the neighbourhood size estimates were smaller in the Ardennes and in the Morvan than in the two high mountain areas, indicating more common movements between neighbouring patches in the mountains than in plains. Conclusion Short and long dispersal events are two phenomena with distinct consequences in the population genetics of natural populations. The differences in level of population differentiation within each the four regions may be explained by change in dispersal in lowland recently fragmented landscapes: on average, butterflies disperse to a shorter distance but the few ones which disperse long distance do so more efficiently. Habitat fragmentation has evolutionary consequences exceeding by far the selection of dispersal related traits: the balance between local specialisation and gene flow would be perturbed, which would modify the extent to which populations are adapted to heterogeneous environments.

  14. Q192R Paraoxonase (PON)1 Polymorphism, Insulin Sensitivity, and Endothelial Function in Essential Hypertensive Men

    Science.gov (United States)

    Dell’Omo, Giulia; Penno, Giuseppe; Pucci, Laura; Lucchesi, Daniela; Prato, Stefano Del; Pedrinelli, Roberto

    2014-01-01

    AIMS Essential hypertension is characterized by increased reactive oxygen species (ROS) generation harmful for insulin sensitivity and nitric oxide (NO)-mediated vasomotor function, a noxious effect that paraoxonase (PON)1, an antioxidant circulating high-density lipoprotein (HDL)-bound esterase, may counteract. The PON1 gene contains several polymorphisms including a glutamine (Q) to arginine (R) transition at position 192 encoding circulating allozymes with higher antioxidant activity that might influence both parameters. METHODS Q192R was determined by polymerase chain reaction in 72 never-treated, glucose-tolerant, uncomplicated essential hypertensive men. Insulin sensitivity was assessed by homeostasis model assessment (HOMA) and endothelial function by forearm vasodilation (strain-gage venous plethysmography) to intra-arterial acetylcholine (ACH) with sodium nitroprusside (NIP) as a NO-independent control. Additional evaluation variables included 24-hour blood pressure (BP), lipids, BMI, smoking status, and metabolic syndrome (MetS) by Adult Treatment Panel (ATP)-III criteria. R192 was considered as the rare allele, and its associations analyzed by dominant models (Q/Q vs. Q/R + R/R). RESULTS Genotype frequencies were consistent with the Hardy–Weinberg equilibrium. HOMA was lower and insulin resistance (the upper fourth of HOMA values distribution) less prevalent in Q/R + R/R carriers in whom ACH-mediated vasodilatation was greater and endothelial dysfunction (the bottom fourth of ACHAUC values distribution) less frequent than in Q/Q homozygotes. Q192R polymorphism and MetS were unrelated parameters despite their common association with insulin resistance. 24-hour BP, BMI, lipids, and smoking habits were homogeneously distributed across genotypes. CONCLUSIONS Q192R polymorphism associates differentially with insulin sensitivity and endothelial function in essential hypertensive men. PMID:25089090

  15. The genetics and conservation of Araucaria angustifolia: I. Genetic structure and diversity of natural populations by means of non-adaptive variation in the state of Santa Catarina, Brazil

    Directory of Open Access Journals (Sweden)

    Neiva Maria Frizon Auler

    2002-01-01

    Full Text Available The objective of this study was to generate information relative to the allele distribution and dynamics within and among populations of Araucaria angustifolia, a naturally-occurring conifer in the south of Brazil, being known popularly as "pinheiro-do-Paraná", "araucaria" or pine tree. In order to elucidate the levels and the distribution of the genetic variability, the population's genetic structure and the genetic distance among natural populations of this species with different levels of disturbance in different geographical areas were studied in detail. For this, samples of leaf tissue were collected from 328 adult individuals in nine natural populations in Santa Catarina State. To analyze the samples, the allozyme technique was applied in starch gel electrophoresis (penetrose 13%, with citrate/morfholine buffer. Nine enzymatic systems (PGM, PGI MDH, PRX, SKDH, 6PGDH, ACP, IDH and G6PDH revealed 15 loci. The analysis provided values for He and Ho of 0.084 and 0.072, respectively. The general average of polymorphic loci was 73% in the species and 26.6% in the studied populations and the allele number per locus was 1.6. Wright's F-statistical estimates indicated the existence of inbreeding in populations (F IS= 0.148 and a low divergence among populations (F ST = 0.044. However, the inbreeding values were variable in different populations. Taken together, the results indicated that the greater part of the genetic variability is contained within populations. The working hypothesis that originally there was greater genetic diversity can be supported by these results which indicate that in the degraded populations the diversity indexes are lower in the degraded populations than those found in better-conserved populations. Thus the fragmentation of the forest followed by "araucaria" exploitation could have contributed to the genetic differentiation expressed through the allele frequency of the studied population.

  16. Hybridization in the Ensatina Ring Species, Strong selection against hybrids at a hybrid zone in the ensatina ring species complex and its evolutionary implications

    Energy Technology Data Exchange (ETDEWEB)

    Alexandrino, Joao; Baird, Stuart J.E.; Lawson, Lucinda; Macey, J. Robert; Moritz, Craig; Wake, David B.

    2005-04-22

    The analysis of interactions between lineages at varying levels of genetic divergence can provide insights into the process of speciation through the accumulation of incompatible mutations. Ring species, and especially the Ensatina eschscholtzii system exemplify this approach. The plethodontid salamanders Ensatina eschscholtzii xanthoptica and Ensatina eschscholtzii platensis hybridize in the Central Sierran foothills of California. We compared the genetic structure across two transects (southern and northern Calaveras Co.), one of which was re-sampled over 20 years, and examined diagnostic molecular markers (eight allozyme loci and mitochondrial DNA) and a diagnostic quantitative trait (color pattern). Key results across all studies were: (i) cline centers for all markers were coincident and the zones were narrow, with width estimates of 730m to 2000m; (ii) cline centers at the northern Calaveras transect were coincident between 1981 and 2001, demonstrating repeatability over 5 generations; (iii) there are very few if any putative F1's, but a relatively high number of backcrossed individuals (57-86 percent) in the central portion of transects; (iv) we found substantial linkage disequilibrium in all three studies and strong heterozygote deficit both in northern Calaveras, in 2001, and southern Calaveras. Both linkage disequilibrium and heterozygote deficit show maximum values near the center of the zones (R and Fis, approx. equal to 0.5). Using estimates of cline width and dispersal, we infer strong selection against hybrids (s* approx. equal to 46-75 percent). This is sufficient to promote accumulation of differences at loci that are neutral or under divergent selection, but would still allow for introgression of adaptive alleles. The evidence for strong, but incomplete isolation across this centrally located contact is consistent with theory suggesting a gradual increase in postzygotic incompatibility between allopatric populations subject to divergent

  17. Invasion genetics:Lessons from a ubiquitous bird, the house sparrowPasser domesticus

    Institute of Scientific and Technical Information of China (English)

    Andrea L LIEBL; Aaron W SCHREY; Samuel C ANDREW; Elizabeth L SHELDON; Simon C GRIFFITH

    2015-01-01

    Following an introduction, non-native species are exposed to environments that differ from those found in their native range; further, as these non-native species expand beyond the site of introduction, they must constantly adapt to novel environ-ments. Although introduced species are present across most ecosystems, few species have successfully established themselves on a truly global scale. One such species, the house sparrowPasser domesticus, is now one of the world’s most broadly distributed vertebrate species and has been introduced to a great part of its current range. To date, work on four continents suggests both ge-netic and phenotypic variation exists between native and introduced ranges. As such, house sparrows represent an excellent op-portunity to study adaptations to novel environments and how these adaptations are derived. The global distribution of this spe-cies and the multiple independent introductions to geographically isolated sites allow researchers to ask questions regarding ge-netic variation and adaptation on a global scale. Here, we summarize the molecular studies of invasive house sparrows from the earliest work using allozymes through more recent work on epigenetics; using these studies, we discuss patterns of dispersal of this species. We then discuss future directions in techniques (e.g. next generation sequencing) and how they will provide new in-sight into questions that are fundamental to invasion biology. Finally, we discuss how continued research on the house sparrow in light of these genetic changes and adaptations will elucidate answers of adaptation, invasion biology, range expansion, and resi-lience in vertebrate systems generally [Current Zoology 61 (3): 465–476, 2015].

  18. Preliminary analysis of population genetics of Myotis punicus (Chiroptera: Vespertilionidae in the maltese islands: implications for its conservation

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    Byron Baron

    2010-08-01

    Full Text Available By combining cellulose acetate allozyme electrophoresis with a non-lethal sampling technique, it was possible to undertake a preliminary study of the population structure of Myotis punicus Felten, 1977 in the Maltese Islands. Since previous local ecological studies indicated declining numbers, it was considered important to undertake a combinatorial study including molecular genetic techniques. Twelve sites spread around the Maltese Islands were investigated and a total of 36 individuals found in four of these sites were sampled over a period of 6 months. The use of 4mm biopsy punches (a non-lethal method was adopted to obtain tissue for analysis. Morphometric data was also collected involving measurements of forearm length, ear length, tragus length, wing-span and weight. Comparison of average values for these measurements between the sexes (using chi-square at p = 0.05 gave an indication of sexual dimorphism, with females being the larger sex. A recapture rate of 19% was achieved in this study. Nei’s (1978 Genetic Identity (I showed values from 0.954 to 0.686, while Genetic Distance (D values ranged from 0 to 0.047. The results obtained in this study indicate that the population on the Maltese Islands is as yet a single panmictic unit, even though the overall FST value of 0.272 indicates that these sites are approaching the threshold beyond which there will be isolated mating systems.

    doi:10.4404/hystrix-21.1-4453

  19. Capacities for population-genetic variation and ecological adaptations

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    Marinković Dragoslav

    2007-01-01

    complex gene-enzyme system, is estimated to be smaller than 0.2%. For an allozymic system based on 9 loci at three D. melanogaster chromosomes, the estimate is that chromosomal types are reduced, on the average, to ca. 3% during meiotic divisions, and that available gene-enzyme combinations are reduced further 15 times in gamete selection. So finalized metabolic or adaptive developmental programs are emphasized to be the basic targets of Darwinian selection, rather than chromosomes or individual genes, that are involved in these programs.

  20. Expression pattern, ethanol-metabolizing activities, and cellular localization of alcohol and aldehyde dehydrogenases in human large bowel: association of the functional polymorphisms of ADH and ALDH genes with hemorrhoids and colorectal cancer.

    Science.gov (United States)

    Chiang, Chien-Ping; Jao, Shu-Wen; Lee, Shiao-Pieng; Chen, Pei-Chi; Chung, Chia-Chi; Lee, Shou-Lun; Nieh, Shin; Yin, Shih-Jiun

    2012-02-01

    Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are principal enzymes responsible for metabolism of ethanol. Functional polymorphisms of ADH1B, ADH1C, and ALDH2 genes occur among racial populations. The goal of this study was to systematically determine the functional expressions and cellular localization of ADHs and ALDHs in human rectal mucosa, the lesions of adenocarcinoma and hemorrhoid, and the genetic association of allelic variations of ADH and ALDH with large bowel disorders. Twenty-one surgical specimens of rectal adenocarcinoma and the adjacent normal mucosa, including 16 paired tissues of rectal tumor, normal mucosae of rectum and sigmoid colon from the same individuals, and 18 surgical mixed hemorrhoid specimens and leukocyte DNA samples from 103 colorectal cancer patients, 67 hemorrhoid patients, and 545 control subjects recruited in previous study, were investigated. The isozyme/allozyme expression patterns of ADH and ALDH were identified by isoelectric focusing and the activities were assayed spectrophotometrically. The protein contents of ADH/ALDH isozymes were determined by immunoblotting using the corresponding purified class-specific antibodies; the cellular activity and protein localizations were detected by immunohistochemistry and histochemistry, respectively. Genotypes of ADH1B, ADH1C, and ALDH2 were determined by polymerase chain reaction-restriction fragment length polymorphisms. At 33mM ethanol, pH 7.5, the activity of ADH1C*1/1 phenotypes exhibited 87% higher than that of the ADH1C*1/*2 phenotypes in normal rectal mucosa. The activity of ALDH2-active phenotypes of rectal mucosa was 33% greater than ALDH2-inactive phenotypes at 200μM acetaldehyde. The protein contents in normal rectal mucosa were in the following order: ADH1>ALDH2>ADH3≈ALDH1A1, whereas those of ADH2, ADH4, and ALDH3A1 were fairly low. Both activity and content of ADH1 were significantly decreased in rectal tumors, whereas the ALDH activity remained

  1. Herança e ligação em locos de isoenzimas em Genipa americana L. Inheritance and linkage in isozymes loci of Genipa americana L.

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    Alexandre Magno SEBBENN

    2004-06-01

    Full Text Available A herança e a ligação foram estudadasem quatro locos polimórficos (6pghd-1, Pgi-2,Mdh-1 e Mdh-2 de três sistemas isoenzimáticos deGenipa americana, analisados por eletroforesehorizontal em gel de amido, usando tecidoscoletados de quinze progênies de polinização aberta,procedentes de Moji-Guaçu, Estado de São Paulo.Esses locos segregaram de dois a três alelos.A segregação nesses locos foi homogênea entreárvores. Contudo, existem desvios significativos dasegregação esperada 1:1 para algumas árvores emalguns locos. Desvios significativos da razão desegregação esperada 1:1 foram detectados noslocos Mdh-2 e 6pgdh-1. Não foram detectadasevidências de ligação entre nenhum dos pares delocos avaliados em G. americana e esses podemser utilizados sem restrição para estudos do sistemade reprodução, diversidade e estrutura genética depopulações da espécie.Inheritance and linkage for fourpolymorphic loci (6pghd-1, Pgi-2, Mdh-1 andMdh-2 from three enzyme systems in Genipaamericana were analyzed by horizontal starch gelelectrophoresis using tissues collected from fiftyopen-pollinated families in Moji-Guaçu, São PauloState. These allozyme loci have segregated fromtwo to four alleles per polymorphic locus. Genesegregation on those loci was homogeneous amongtrees. However, there were significant deviationsfrom the expected segregation ratios on some lociand some individual trees. In addition, Mdh-2 and6pgdh-1 loci have shown significant deviationsfrom the 1:1 expected segregation ratio. Linkagedisequilibrium evidences were not detected betweenany two pairs of loci from G. americana and thosecan be used with no restriction to study the matingsystem, genetic diversity, and genetic structure onthe species.

  2. Testing for genetic differences in survival and growth between hatchery and wild Chinook salmon from Warm Springs River, Oregon (Study sites: Warm Springs Hatchery and Little White Salmon River; Stocks: Warm Springs hatchery and Warm Springs River wild; Year classes: 1992 and 1996): Chapter 8

    Science.gov (United States)

    Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Leonetti,; Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hayes, Michael C.

    2012-01-01

    The program at Warm Springs National Fish Hatchery in north - central Oregon was initiated with spring Chinook salmon Oncorhynchus tshawytscha from the Warm Springs River. Managers included wild fish in the broodstock most years and avoided artificial selection to minimize genetic divergence from the wild founder population. We tested for genetic differences in survival and growth between the hatchery and wild populations to ascertain whether this goal has been achieved. Progeny of hatchery x hatchery (HH), hatchery female x wild male (HW), and wild x wild (WW) crosses were genetically marked at the sSOD - 1* allozyme locus and released together as unfed fry in hatchery ponds in 1992 and 1996 and in the Little White Salmon River, in south - central Washington, in 1996. Fish were evaluated to returning adult at the hatchery and over their freshwater residence of 16 months in the stream. The three crosses differed on several measures including survival to outmigration in the stream (WW>HH>HW) and juvenile growth in the hatchery (1992 year - class; WW>HW>HH); however, results may have been confounded. The genetic marks were found to differentially effect survival in a companion study (HH mark favored over WW mark; HW mark intermediate). Furthermore, HW survival in the current study was neither intermediate, as would be expect ed from additive genetic effects, nor similar to that of HH fish as would be expected from maternal effects since HW and HH fish were maternal half - siblings. Finally, the unexpected performance of HW fish precludes ruling out maternal differences between hatchery and wild mothers as the cause of differences between HH and WW fish. The key finding that survival of HH fish in a stream was 0.91 that for WW fish, indicating a small loss of fitness for natural rearing in the hatchery population, is valid only if three conditions hold: (1) any selection on the genetic marks was in the same direction as in the companion study, (2) lower survival in

  3. Ethanol oxidation and the inhibition by drugs in human liver, stomach and small intestine: Quantitative assessment with numerical organ modeling of alcohol dehydrogenase isozymes.

    Science.gov (United States)

    Chi, Yu-Chou; Lee, Shou-Lun; Lai, Ching-Long; Lee, Yung-Pin; Lee, Shiao-Pieng; Chiang, Chien-Ping; Yin, Shih-Jiun

    2016-10-25

    Alcohol dehydrogenase (ADH) is the principal enzyme responsible for metabolism of ethanol. Human ADH constitutes a complex isozyme family with striking variations in kinetic function and tissue distribution. Liver and gastrointestinal tract are the major sites for first-pass metabolism (FPM). Their relative contributions to alcohol FPM and degrees of the inhibitions by aspirin and its metabolite salicylate, acetaminophen and cimetidine remain controversial. To address this issue, mathematical organ modeling of ethanol-oxidizing activities in target tissues and that of the ethanol-drug interactions were constructed by linear combination of the corresponding numerical rate equations of tissue constituent ADH isozymes with the documented isozyme protein contents, kinetic parameters for ethanol oxidation and the drug inhibitions of ADH isozymes/allozymes that were determined in 0.1 M sodium phosphate at pH 7.5 and 25 °C containing 0.5 mM NAD(+). The organ simulations reveal that the ADH activities in mucosae of the stomach, duodenum and jejunum with ADH1C*1/*1 genotype are less than 1%, respectively, that of the ADH1B*1/*1-ADH1C*1/*1 liver at 1-200 mM ethanol, indicating that liver is major site of the FPM. The apparent hepatic KM and Vmax for ethanol oxidation are simulated to be 0.093 ± 0.019 mM and 4.0 ± 0.1 mmol/min, respectively. At 95% clearance in liver, the logarithmic average sinusoidal ethanol concentration is determined to be 0.80 mM in accordance with the flow-limited gradient perfusion model. The organ simulations indicate that higher therapeutic acetaminophen (0.5 mM) inhibits 16% of ADH1B*1/*1 hepatic ADH activity at 2-20 mM ethanol and that therapeutic salicylate (1.5 mM) inhibits 30-31% of the ADH1B*2/*2 activity, suggesting potential significant inhibitions of ethanol FPM in these allelotypes. The result provides systematic evaluations and predictions by computer simulation on potential ethanol FPM in target tissues and hepatic

  4. A Ploidy Difference Represents an Impassable Barrier for Hybridisation in Animals. Is There an Exception among Botiid Loaches (Teleostei: Botiidae?

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    Jörg Bohlen

    Full Text Available One of the most efficient mechanisms to keep animal lineages separate is a difference in ploidy level (number of whole genome copies, since hybrid offspring from parents with different ploidy level are functionally sterile. In the freshwater fish family Botiidae, ploidy difference has been held responsible for the separation of its two subfamilies, the evolutionary tetraploid Botiinae and the diploid Leptobotiinae. Diploid and tetraploid species coexist in the upper Yangtze, the Pearl River and the Red River basins in China. Interestingly, the species 'Botia' zebra from the Pearl River basin combines a number of morphological characters that otherwise are found in the diploid genus Leptobotia with morphological characters of the tetraploid genus Sinibotia, therefore the aim of the present study is to test weather 'B.' zebra is the result of a hybridisation event between species from different subfamilies with different ploidy level. A closer morphological examination indeed demonstrates a high similarity of 'B.' zebra to two co-occurring species, the diploid Leptobotia guilinensis and the tetraploid Sinibotia pulchra. These two species thus could have been the potential parental species in case of a hybrid origin of 'B.' zebra. The morphologic analysis further reveals that 'B.' zebra bears even the diagnostic characters of the genera Leptobotia (Leptobotiinae and Sinibotia (Botiinae. In contrast, a comparison of six allozyme loci between 'B.' zebra, L. guilinensis and S. pulchra showed only similarities between 'B.' zebra and S. pulchra, not between 'B.' zebra and L. guilinensis. Six specimens of 'B.' zebra that were cytogenetically analysed were tetraploid with 4n = 100. The composition of the karyotype (18% metacentric, 18% submetacentric, 36% subtelocentric and 28% acrocentric chromosomes differs from those of L. guilinensis (12%, 24%, 20% and 44% and S. pulchra (20%, 26%, 28% and 26%, and cannot be obtained by any combination of genomes from

  5. Oxidation of methanol, ethylene glycol, and isopropanol with human alcohol dehydrogenases and the inhibition by ethanol and 4-methylpyrazole.

    Science.gov (United States)

    Lee, Shou-Lun; Shih, Hsuan-Ting; Chi, Yu-Chou; Li, Yeung-Pin; Yin, Shih-Jiun

    2011-05-30

    Human alcohol dehydrogenases (ADHs) include multiple isozymes with broad substrate specificity and ethnic distinct allozymes. ADH catalyzes the rate-limiting step in metabolism of various primary and secondary aliphatic alcohols. The oxidation of common toxic alcohols, that is, methanol, ethylene glycol, and isopropanol by the human ADHs remains poorly understood. Kinetic studies were performed in 0.1M sodium phosphate buffer, at pH 7.5 and 25°C, containing 0.5 mM NAD(+) and varied concentrations of substrate. K(M) values for ethanol with recombinant human class I ADH1A, ADH1B1, ADH1B2, ADH1B3, ADH1C1, and ADH1C2, and class II ADH2 and class IV ADH4 were determined to be in the range of 0.12-57 mM, for methanol to be 2.0-3500 mM, for ethylene glycol to be 4.3-2600mM, and for isopropanol to be 0.73-3400 mM. ADH1B3 appeared to be inactive toward ethylene glycol, and ADH2 and ADH4, inactive with methanol. The variations for V(max) for the toxic alcohols were much less than that of the K(M) across the ADH family. 4-Methylpyrazole (4MP) was a competitive inhibitor with respect to ethanol for ADH1A, ADH1B1, ADH1B2, ADH1C1 and ADH1C2, and a noncompetitive inhibitor for ADH1B3, ADH2 and ADH4, with the slope inhibition constants (K(is)) for the whole family being 0.062-960 μM and the intercept inhibition constants (K(ii)), 33-3000 μM. Computer simulation studies using inhibition equations in the presence of alternate substrate ethanol and of dead-end inhibitor 4MP with the determined corresponding kinetic parameters for ADH family, indicate that the oxidation of the toxic alcohols up to 50mM are largely inhibited by 20 mM ethanol or by 50 μM 4MP with some exceptions. The above findings provide an enzymological basis for clinical treatment of methanol and ethylene glycol poisoning by 4MP or ethanol with pharmacogenetic perspectives.

  6. Wild Barley,Hordeum spontaneum,a Genetic Resource for Crop Improvement in Cold and Arid Regions

    Institute of Scientific and Technical Information of China (English)

    Eviatar; Nevo

    2008-01-01

    Food security in cold and arid regions in the world is threatened by stressful and unpredictable environments.The sus-tainable and economically viable solution for increasing stability of food productivity in cold and arid regions is genetic improvement of crops towards high resistance to abiotic stresses,mainly cold and drought resistance.It is often empha-sized that crop genetic improvement lies in exploiting the gene pools of the wild relatives of the crop plant.Wild barley,H.spontaneum,the progenitor of cultivated barley,is a selfing annual grass of predominantly Mediterranean and Irano-Turanian distribution that penetrates into desert environments where it maintains stable populations.Wild barley is also found in cold regions,such as in Tibet.The adaptation of wild barley to the arid region in Israel and Jordan,and the cold region in Tibet has accumulated rich genetic diversities for drought,salt,and cold resistances in wild barley,which is the genetic resource for barley and other crop improvement in arid and cold regions.These genetic diversities are revealed by allozymes,DNA-based molecular markers,and morphological and physiological traits of wild barley plants.Quantita-tive trait loci(QTLs) related to drought resistance were identified in wild barley via the QTL mapping approach.Drought resistance genes such as dehydrins,hsdr4,and eibi1 were identified in wild barley based on the candidate gene approach,gene differential expression approach,and molecular genetic approach,respectively.Genetics and genomics of wild bar-ley cold resistance have not been exploited yet,remaining a huge treasure for future crop improvement of cold resistance.Advanced backcross QTL analysis,the introgression libraries based on wild barley as donors,a QTL approach based on wide crosses using wild barley,and positional cloning of natural QTLs will play prevailing roles to help us understand the molecular control of cold and drought tolerance.Integration of QTL information into a

  7. Genetic diversity in Silene sennenii Pau (Caryophyllaceae assayed through DNA-based techniques

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    Blanché, C.

    2012-12-01

    Full Text Available Silene sennenii is a narrow endemic species from the NE of the Iberian Peninsula. It is considered as EN (“Endangered” according to the IUCN criteria and is under legal protection in Catalonia. In the present work we report an assay using three different approaches for surveying the genetic diversity in this rare, endangered campion: analysis of chloroplast haplotypes, AFLPs and transferability of microsatellites previously developed for Silene latifolia. None of the nine chloroplast regions sequenced showed any variability. Five out of the 21 microsatellite loci tested were polymorphic although more loci are required in order to perform a robust population genetics study. Regarding the AFLP analysis, five out of the 26 pairs of primers tested exhibited moderate levels of variability and therefore they could be useful for further investigating the genetic structure of S. sennenii. Although preliminary, our results based on three different genetic markers are in agreement with the low values of genetic variation already reported for this species employing allozymes.Silene sennenii es una especie endémica, circunscrita a un área extremadamente reducida al NE de la Península Ibérica. Está catalogada como EN («En Peligro» según criterios UICN y se encuentra legalmente protegida en Cataluña. En el presente trabajo se expone el ensayo de tres aproximaciones diferentes al estudio de su diversidad genética: análisis de haplotipos cloroplásticos, AFLPs y transferibilidad de microsatélites diseñados previamente para Silene latifolia. Ninguna de las nueve regiones cloroplásticas secuenciadas ha presentado variabilidad. Se han obtenido cinco loci microsatélites polimórficos de los 21 ensayados, cantidad insuficiente para llevar a cabo un estudio robusto sobre genética poblacional. En cuanto a AFLPs, cinco combinaciones de cebadores de las 26 probadas han mostrado niveles moderados de variabilidad siendo así útiles para posteriores

  8. Trichinella zimbabwensis n.sp. (Nematoda), a new non-encapsulated species from crocodiles (Crocodylus niloticus) in Zimbabwe also infecting mammals.

    Science.gov (United States)

    Pozio, E; Foggin, C M; Marucci, G; La Rosa, G; Sacchi, L; Corona, S; Rossi, P; Mukaratirwa, S

    2002-12-19

    Since 1995, Trichinella larvae have been detected in 39.5% of farmed crocodiles (Crocodylus niloticus) in Zimbabwe. Morphological, biological, biochemical and molecular studies carried out on one isolate from a farmed crocodile in 2001 support the conclusion that this parasite belongs to a new species, which has been named Trichinella zimbabwensis n.sp. This species, whose larvae are non-encapsulated in host muscles, infects both reptiles and mammals. The morphology of adults and larvae is similar to that of Trichinella papuae. Adults of T. zimbabwensis cross in both directions with adults of T. papuae (i.e. male of T. zimbabwensis per female of T. papuae and male of T. papuae per female of T. zimbabwensis), producing F1 offspring which produce very few and less viable F2 larvae. Muscle larvae of T. zimbabwensis, like those of T. papuae, do not infect birds. Three allozymes (of a total of 10) are diagnostic between T. zimbabwensis and T. papuae, and five are diagnostic between T. zimbabwensis and Trichinella pseudospiralis, the third non-encapsulated species. The percentage of the pairwise alignment identity between T. zimbabwensis and the other Trichinella species for the cytochrome oxidase subunit I gene, the large subunit ribosomal-DNA (mt-lsrDNA) gene and the expansion segment five, shows that T. zimbabwensis is more similar to the two non-encapsulated species T. papuae (91% for cytochrome oxidase I; 96% for mt-lsrDNA; and 88% for expansion segment five) and T. pseudospiralis (88% for cytochrome oxidase I; 90% for mt-lsrDNA; and 66-73% for expansion segment five) than to any of the encapsulated species (85-86% for cytochrome oxidase I; 88-89% for mt-lsrDNA; and 71-79% for expansion segment five). This is the first non-encapsulated species discovered in Africa. The finding of a new Trichinella species that infects both reptiles and mammals suggests that the origin of Trichinella parasites dates back further than previously believed and can contribute to

  9. Population genetic diversity and differentiation of endemic species Tetraena mongolica on the Western Ordos%西鄂尔多斯特有种四合木种群遗传多样性及遗传分化研究

    Institute of Scientific and Technical Information of China (English)

    张颖娟; 杨持

    2001-01-01

    Genetic diversity and differentiation among four populations of Tetreana mongolica on the Western Ordos plateau were studied using vertical slab polyacrylamide gel electrophonesis.Allozyme electrophonesis indicated relatively high level of genetic variation in this species with P=0.60,A=1.6,He=0.245.There existed low degree of population differentiation among the four populations with GST value being 0.051,significant different with other endangered species.The high intrapopulation variation and low interpopulation differentiation could explained that the different populations might originate from the same one and genetic drift or inbreeding depression had not influenced primary process of genetic diversity.%利用垂直板聚丙烯酰胺凝胶电泳技术,对西鄂尔多斯高原特有种四合木(Tetraena mogolica)4个种群遗传多样性和遗传分化进行了初步研究。电泳结果表明,四合木在种和种群水平维持较高的遗传多样性,多态位点百分率P=60%,等位基因平均数A=1.6,平均期望杂合度He=0.245。4个种群之间遗传分化很小,基因分化系数GST只有0.052,明显不同于其它濒危物种。四合木种群较高的遗传多样性和极低的种群间分化,说明不同的种群可能有共同的起源,随机遗传漂变和近交衰退不是影响遗传多样性的主要过程。

  10. A Biosystematic Study on Asplenium sarelii Complex%华中铁角蕨复合体的生物系统学研究

    Institute of Scientific and Technical Information of China (English)

    王中仁; 王可青; 张方; 侯鑫

    2003-01-01

    morphology. The denomination on this group of Asplenium is very confused in the herbaria. We hope bymeans of a biosystematic study to find out their genetic relationships in the reticulate evolution, and to raise asuggestion on their taxonomic treatment. Evidence from cytology, allozyme, morphology, and palynology showsthat three ancestor diploids have formed Asplenium sarelii complex comprising 13 members. A. sarelii Hook.should be typified as a diploid. The so-called tetraploid "A. sarelii" before is an allotetraploid that comesfrom the doubled hybrid between diploid A. sarelii and A. tenuicaule Hayata, which should be treated as anew species A. wudangense Z. R. Wang et X. Hou. A. pekinense Hance is an autotetraploid that comesfrom the doubled diploid ancestor A. sarelii. A. lushanense C. Chr., a diploid species and the only ancestorof A. yunnanense group, should not been sunk as a synonym of tetraploid A. yunnanense Franeh. Most prob-ably, A. varians Wall. ex Hook. et Grey. is an autotetraploid of A. tenuicaule Hayata. Three new naturaltetraploid hybrids and their origins have been found out: they are A. × longmenense ( = A. pekinense ×varians), A. × jingyunense (= A. pekinense × yunnanense) and A. × kidoi (= A. pekinense × wu-dangense ). Three other new natural triploid hybrids have been found and their origins have been inferred: theyare A. × huawuense (= A. sarelii × wudangense ), A. × luyunense (= A. lushanense × yunnanense )and A. × tenuivaians ( = A. tenuicaule × varians ) . The method of allozyme eomparion combined with cy-tological observation is employed to reveal the complicated relationships among the members of Asplenium sare-lii complex in reticulate evolution and proved to be a highly effective tool to investigate the origin of polyploidand hybrid.

  11. Genetic differences between hatchery and wild steelhead for growth and survival in the hatchery and seaward migration after release (Study sites: Dworshak Hatchery and Clearwater Hatchery; Stocks: Dworshak hatchery and Selway River wild; Year classes: 1994 and 1995): Chapter 2

    Science.gov (United States)

    Rubin, Stephen P.; Reisenbichler, Reginald R.; Hensleigh, Jay E.; Wetzel, Lisa A.; Baker, Bruce M.; Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hayes, Michael C.

    2012-01-01

    Various studies suggest that sea ranching of anadromous salmonids can result in domestication (increased fitness in the hatchery program) and a loss of fitness for natural production; however, the mechanism has not been characterized adequately. We artificially spawned hatchery and wild steelhead Oncorhynchus mykiss from the Clearwater River, Idaho, reared the resulting genetically marked (at the PEPA allozyme locus) progeny (HxH, HxW from hatchery females and wild males, and WxW) in hatcheries, and tested for differences in survival, growth, early maturation, downstream migration, and adult returns. Rearing treatments were mixed (crosses reared together) and separate (crosses reared separately from each other) at the hatchery of origin for the hatchery population where smolts are produced in one year, and at a nearby hatchery employing lower rations, lower winter temperatures, and two years of rearing to more closely mimic the natural life history (natural smolt age = 2-4 years). The hatchery population had been artificially propagated for six generations at the onset of our study. We found little or no difference in survival in the hatchery but substantially higher rates of growth and subsequent downstream migration for HxH than for WxW fish. Faster growth for HxH fish resulted in greater size at release which contributed to their higher migration rate, but other as yet uncharacterized traits also affected migration since the migration difference between crosses was apparent even within size classes. Growth of WxW fish was slower in the mixed than in the separate treatment indicating that WxW fish were competitively inferior to HxH fish in the hatchery environment. Incidence of precocious males was higher for WxW than for HxH fish in the separate but not in the mixed treatment. Incidence of HxH precocious males was similar between treatments. Apparently, the presence of HxH fish suppressed high incidence of early maturation by WxW males. A direct effect beyond

  12. Genetic differences between hatchery and wild steelhead for survival, growth, dispersal, and male maturation in a natural stream (Study site: Twenty-Mile Creek; Stocks: Dworshak hatchery and Selway River wild; Year classes: 1994 and 1995): Chapter 3

    Science.gov (United States)

    Rubin, Stephen P.; Reisenbichler, Reginald R.; Hensleigh, Jay E.; Wetzel, Lisa A.; Baker, Bruce M.; Leonetti,; Stenberg, Karl D.; Slatton, Stacey L.; Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hayes, Michael C.

    2012-01-01

    This study was initiated in the early 1990s to provide managers with data comparing genetic fitness for natural rearing, as measured by survival of juveniles in freshwater, between steelhead Oncorhynchus mykiss from Dworshak National Fish Hatchery and wild steelhead from the Clearwater River, Idaho. We artificially spawned hatchery steelhead and wild steelhead from the Selway River, a Clearwater River tributary, released the resulting genetically marked (at the PEPA allozyme locus) progeny (HxH, HxW from hatchery females and wild males, and WxW) as unfed fry in a second order tributary of the South Fork Clearwater River, and monitored fish residing in the stream or emigrating from it for five years. Barrier falls prevented access to the stream by naturally produced steelhead. Over 90% of the emigrants were one or two years of age and too small to be smolts (mean fork length at age-2 = 103 mm). Per fry released, the HxH cross produced 0.64-0.83 times as many emigrants as the WxW cross (PWxW cross for one year-class (P=0.051) and 0.68 times as many for the other (ns). Survival from age-1 to age-4 was lower for HxH than for WxW residuals of one year-class (PWxW residuals of the other (P=0.062). Collectively, these results indicate lower survival for HxH than for WxW fish. Size was often greater for HxH than for WxW fish indicating faster growth for the former, and condition factor was also usually greater for HxH than for WxW fish. Dispersal of fry from release sites and emigration of one- and two-year olds from the study stream were greater for WxW than for HxH fish, and apparently neither was from competitive displacement of small by larger fish. Incidence of flowing milt was higher for HxH than for WxW fish at age-2. Peak incidence of flowing milt for older residuals was similar among crosses (about 50%), but the peak occurred at greater size and age for WxW than for HxH residuals. HxW fish were intermediate between HxH and WxW fish, not similar to HxH fish, in

  13. A morphology-based phylogeny of Phymaturus (Iguania: Liolaemidae with the description of four new species from Argentina

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    Fernando Lobo

    2005-01-01

    Full Text Available Phylogenetic relationships within the liolaemid lizard genus Phymaturus were studied using parsimony analysis of morphological data. The data set includes 133 characters: 28 described in the literature as apomorphies of the three genera of Liolaemidae (Ctenoblepharys, Liolaemus, and Phymaturus, 21 published characters of allozymes and karyology, 53 characters taken from external morphology across all terminals of Phymaturus, and 31 from the skeletal anatomy. This data set includes representatives of 10 of the 12 species currently recognized in the literature plus twelve other terminals considered in this study and representing independent lineages assigned to patagonicus or palluma. Four of these terminals are described in the present study as new species, one belonging to the palluma group and the other three to the patagonicus group. We performed four analyses using different methods of coding binary polymorphic characters, and a new method for treating continuous characters. The traditional division of the genus in two groups is not supported here, with the patagonicus group resulting paraphyletic in some of the analyses. The palluma group is monophyletic and supported by many characters. A majority rule consensus tree of all runs recovers a reasonably well-resolved topology of the group. All analyses recovered a northern subclade within the palluma group, formed by species distributed in Argentina from northern of San Juan province (north to 30 degrees of latitude. In this analysis palluma from El Planchón (Chile was found to be more closely related to this northern subclade than any other "palluma" form.Estudaram-se as relações dentro do gênero Phymaturus da familia Liolaemidae, usando análise de parsimônia de uma matriz formada principalmente por dados morfológicos. A matriz inclui 133 caracteres: 28 descritos na literatura como apomorfias dos três gêneros de Liolaemidae (Ctenoblepharys, Liolaemus e Phymaturus, 21 caracteres de

  14. Clonality and its population genetic conseuqneces in seagrasses%海草克隆性及其种群遗传效应

    Institute of Scientific and Technical Information of China (English)

    苗苑; 徐娜娜; 于硕; 耿艳; 陈小勇

    2009-01-01

    influences on genetic variation of seagrasses. Generally, seagrass species have relatively lower within-population genetic variation than terrestrial plants or mangroves, another group of marine flowering plants, although DNA markers, such as microsatellites, have revealed much higher variation than allozymes did and higher than that of previous thought in seagrasses. High variation in clonal diversity was found in many seagrass populations, but single or few genotypes were also found in some populations due to founder effect and strong clonality. Although gene flow usually was thought to be restricted in clonal species, it was reported that clonal fragments may be transported to a long distance and therefore to promote gene flow among populations. Effects of clonality on within-population structuring and mating system were also reviewed.

  15. Phytophthora infestans POPULATION STRUCTURE: A WORLDWIDE SCALE Estructura poblacional de Phytophthora infestans: una escala global

    Directory of Open Access Journals (Sweden)

    MARTHA CÁRDENAS

    2012-05-01

    Full Text Available Phytophthora infestans, the causal agent of late blight disease in potato and other members of the Solanaceae family, is responsible for causing the Irish potato famine and, even today, it causes enormous economic losses all over the world. For the establishment of an adequate pest management strategy, the determination of the pathogen's population structure is required. To characterize P. infestans populations worldwide two allozymes, Gpi (Glucose-6-phospate isomerase and Pep ( Pep tidase, the RG57 DNA RFLP fingerprinting probe, as well as resistance to the fungicide metalaxyl and mating type, have been used as markers. P. infestans populations in Mexico have been one of the main focuses of research in the population biology of this pathogen because this country has been considered as one of the possible centers of origin of this oomycete. In this review we present the population structure of P. infestans in Mexico, Europe, Africa, Asia, North America, and South America, expanding it on the present situation of P. infestans in Colombia. Finally, we will discuss different lines of research that are being carried out today with respect to P. infestans in Colombia, which have shown the importance of continuing the study of this devastating plant pathogen in our country.Phytophthora infestans, el agente causal del tizón tardío de la papa y otros miembros de la familia de las Solanáceas, es el responsable de la gran hambruna irlandesa y aún hoy sigue causando grandes pérdidas económicas alrededor del planeta. Para establecer estrategias de control adecuadas contra este patógeno se requiere comprender la estructura poblacional del mismo. Mundialmente se han utilizado como marcadores las aloenzimas, Gpi (Glucosa-6-fosfato isomerasa y Pep (Peptidasa y la sonda de fingerprinting de RFLP (Polimorfismos de la Longitud de los Fragmentos de Restricción, RG57. De igual forma, la resistencia al fungicida metalaxyl y el tipo de apareamiento, han sido

  16. Differences in survival and growth in hatchery and stream environments, and in maturation of residuls in a stream, between progeny of hatchery and wild steelhead (Study sites: Brushy Fork Creek and Dworshak Hatchery; Stocks:Dworshak hatchery and Fish Creek wild; Year classes: 1992 and 1993): Chapter 1

    Science.gov (United States)

    Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hensleigh, Jay E.; Leonetti,; Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hayes, Michael C.

    2012-01-01

    Freshwater survival in hatchery and natural rearing environments was compared between progeny of hatchery (H) and wild (W) steelhead Oncorhynchus mykiss from the Clearwater River drainage in Idaho. Adults from Dworshak National Fish Hatchery and wild adults from Fish Creek fish were artificially spawned, and their progeny were genetically marked at the PEPA allozyme locus and released together as unfed fry in production facilities at the hatchery and in Brushy Fork Creek, also in the Clearwater River drainage, in a common garden design. Survival was higher for H than for W progeny at the hatchery but lower for H than for W progeny in Brushy Fork, indicating reduced fitness of the hatchery population for natural rearing and suggesting domestication as the cause. Survival at the hatchery was lower than is typical due to disease outbreaks. Survival of the first year-class of experimental fish to smolt release was only 18%. Survival of H fish was 3.8 times that of W fish under these poor survival conditions. All fish from the second year-class died halfway through the scheduled 10 month rearing period. Survival of H fish was 5.2 times that of W fish to when 1% of the initial fry were still alive indicating that W fish succumbed to the epizootic sooner than did H fish. Emigrants from the Brushy Fork study reach were sampled for three years and fish residing in the study reach were sampled for six years following fry release. Most emigrants were one or two years old and too small to be smolts (mean fork length at age-2 = 93 mm). Survival in Brushy Fork was lower for H than for W fish of the first year-class. Survival of the second year-class was higher for H than for W fish during the first two months in the stream but was lower for H than for W fish thereafter, and net survival from release to ages 3 and older was also lower for H than for W fish if our emigrant samples were representative (periods of inoperative emigrant traps prevented certainty about this

  17. The origin, evolution, and diversification of rockfishes of the genus Sebastes (Cuvier).

    Science.gov (United States)

    Hyde, John R; Vetter, Russell D

    2007-08-01

    The evolutionary relationships of the livebearing rockfishes of the genus Sebastes have been a point of interest since their original description. With over 65 species found in the northeast Pacific (NEP), 27 in the northwest Pacific (NWP), seven in the Gulf of California (GC), four in the north Atlantic (NA) and at least two in the southern hemisphere (SH), they represent a fascinating lineage for studies of spatial and temporal patterns of dispersal, vicariance and speciation in the marine environment. Previous studies of Sebastes species have attempted to reconstruct their phylogeny using allozyme patterns or portions of a single mitochondrial gene while incompletely sampling the genus, resulting in a partial picture with low statistical support. In this study, genetic analyses using sequence data (5581 characters) from seven mitochondrial genes (cytochrome b, cytochrome c oxidase subunit 1, 12S rRNA, 16S rRNA, tRNA proline, tRNA threonine and the control region) and two nuclear genes (recombination activating gene 2 and internal transcribed spacer 1), along with a near complete sampling of species, have produced a well supported phylogenetic hypothesis of the relationships between Sebastes species as well as clarifying their position within the scorpaenid subfamily, Sebastinae. Though studies of similar magnitude have been conducted at the family and subfamily level, this represents the most detailed and extensive examination of biogeography and marine speciation within a single, widely distributed marine fish genus. Both Bayesian posterior and maximum parsimony analyses produced highly similar phylogenies suggesting an origin for Sebastes at high-latitudes in the NWP. The majority of previously proposed sub-generic groupings based upon morphology are found to be either para- or polyphletic. Using Bayesian-derived genetic distance measures together with rate smoothing techniques, a molecular clock was applied to the phylogeny. The clock-calibrated data suggest

  18. Genetic variability in three species of Gymnotus Linnaeus, 1758 (Gymnotiformes: Gymnotidae from Caracu stream of the upper Paraná River basin, Brazil

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    Judy Ruiz Rezende

    2009-01-01

    Full Text Available The genetic variability of three Gymnotus species from the Caracu stream, a small tributary of the left margin of Paraná River (Brazilian upper Paraná River floodplain, was estimated with data of 17 putative allozyme loci, which were obtained by using corn starch gel electrophoresis of 10 enzymatic systems: Aspartate aminotransferase (E. C. 2.6.1.1, Alcohol dehydrogenase (E. C. 1.1.1.1, Esterase (E. C. 3.1.1.1, Glucose dehydrogenase (E. C. 1.1.1.118, Glycerol-3-phosphate dehydrogenase (E. C. 1.1.1.8, Isocitrate dehydrogenase (E. C. 1.1.1.42, L-Lactate dehydrogenase (E. C. 1.1.1.27, Malate dehydrogenase (E. C. 1.1.1.37, Superoxide dismutase (E. C. 1.15.1.1 and Sorbitol dehydrogenase (E. C. 1.1.1.14. The genetic diversity was estimated as He = 0.3458 for G. pantanal, He = 0.2481 for G. inaequilabiatus, and He = 0.3152 for G. sylvius. The most divergent species were G. sylvius and G. pantanal (D = 0.117, and the most similar were G. inaequilabiatus and G. pantanal (D = 0.051. The data indicates that the observed genetic variability was very low and the expected variability estimated for these three species is very high, and the genetic differences among them are small. The data suggest that the process of speciation which produced these three species is recent.A variabilidade genética de três espécies de Gymnotus do riacho Caracu, um pequeno afluente da margem esquerda do rio Paraná (planície de inundação do alto rio Paraná foi estimada com base em 17 loci aloenzimáticos, os quais foram obtidosutilizando eletroforese em gel de amido de milho em 10 sistemas enzimáticos: Aspartato aminotransferase (E. C. 2.6.1.1, Álcool desidrogenase (E. C. 1.1.1.1, Esterase (E. C. 3.1.1.1, Glicose desidrogenase (E. C. 1.1.1.118, Glicerol-3-fosfato desidrogenase (E. C. 1.1.1.8, Isocitrato desidrogenase (E. C. 1.1.1.42, L-Lactato desidrogenase (E. C. 1.1.1.27, Malato desidrogenase (E. C. 1.1.1.37, Superóxido dismutase (E. C. 1.15.1.1 e Sorbitol

  19. Osteología, taxonomía y relaciones filogenéticas de las ranas del género Telmatobufo (Leptodactylidae Osteology, taxonomy and phylogenetic relationships of the frog genus Telmatobufo (Leptodactylidae

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    J. RAMÓN FORMAS

    2001-06-01

    Full Text Available Se hizo un análisis osteológico de las especies del género Telmatobufo (T. australis, T. bullocki, T. venustus, el que completa la definición genérica fundamentada exclusivamente en la osteología de T. bullocki y caracteres larvarios. Para cada especie se entrega nueva información distribucional, ecológica, reproductiva, morfométrica, cromosómica, alozímica y molecular. Se presenta una clave para identificar individuos adultos de las tres especies de Telmatobufo. Se publica por primera vez una lámina de Philippi perdida por casi un siglo, lo que permite aclarar de manera definitiva la identidad taxonómica de T. venustus. Con las distancias de Mahalanobis y las distancias genéticas de Rogers se determinan las similitudes morfológicas y genéticas entre las especies de Telmatobufo. Usando las secuencias para ARN 12S mitocondrial, frecuencias alélicas polarizadas de genes estructurales y caracteres morfológicos (osteológicos y morfológicos externos se propone una hipótesis de relaciones filogenéticas basada en los principios de máxima parsimonia y máxima probabilidad. Finalmente se entrega una proposición acerca de la especiación e historia evolutiva de este grupo de ranas endémicas de los bosques templados del centro-sur de ChileAn osteological analysis of the three species of the genus Telmatobufo (T. australis, T. bullocki, and T. venustus was done. That analysis completes the generic definition based mainly on the osteology of T. bullocki and on morphological larval characters. New information on morphometry, chromosomes, reproductive biology, ecology, geographical range, allozymes, and molecular data is provided for each species. A key for the taxonomic determination of adult specimens of Telmatobufo is also presented. An unedited original plate by R.A. Philippi, lost for almost a century, is published for the first time; this plate allowed the restatement of the taxonomical identity of T. venustus. Mahalanobis

  20. Genetic variability in chronic irradiated plant populations - Polymorphism and activity of antioxidant enzymes in chronic irradiated plant populations

    Energy Technology Data Exchange (ETDEWEB)

    Volkova, Polina Y.; Geras' kin, Stanislav A. [Russian Institute of Agricultural Radiology and Agroecology, 249030, Obninsk, Kievskoe shosse 109 km (Russian Federation)

    2014-07-01

    . We used index of phenotypic diversity (μ) for comparison phenotypic diversity in populations. Indexes of phenotype diversity in this populations significantly different from reference site. In order to detail allozyme structure of population we estimated proportion of rare morphs. It is shown that proportion of rare morphs is increased with rise of level anthropogenic impact. Observed and expected heterozygosity values increase with the level of radioactive contamination. There were null-mutations without protein biosynthesis in experiment. We observed significant increase of null-mutations frequency in populations from experimental sites. We obtained data about enzyme activity in studied populations. Catalase activity has significant difference from reference on site SB. Superoxide dismutase activity has not any significant changes on study sites. Peroxidase activity decrease on the most contaminated sites. It was showed that chronic radiation exposure increased general mutation frequency and proportion of rare morphs antioxidant enzymes in studied populations. So far as mutational events in seeds of Scots pine relatively rare, they doesn't make a significant contribution to observed enzymes activities. In whole our study suggests that present dose rates insufficient for form significant changes on physiological level, in spite of revealed changing in genetic structure of populations. (authors)

  1. The population genetic consequences of range expansion:a review of pattern and process,and the value of oak gallwasps as a model system%分布区扩张的群体遗传学后果:类型与过程,以栎瘿蜂为模型系统(英)

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    .We summarise a growing range of population genetic techniques that allow large changes in population size (bottlenecks and population expansions) to be inferred over a range of timescales.Finally,we illustrate some of the approaches described using data for a suite of invasions by oak gallwasps (Hymenoptera,Cynipidae,Cynipini) in Europe.We show that over timescales ranging from 500~10000 years,allele frequency data for polymorphic allozymes reveal (a) a consistent loss of genetic diversity along invasion routes,confirming the role of glacial refugia as centres of genetic diversity over these timescales,and (b) that populations in the invaded range are more subdivided genetically than those in the native range of each species.This spatial variation in population structure may be the result of variation in the patchiness of resources exploited by gallwasps,particularly host oak plants.

  2. Hierarchical structure of genetic distances: Effects of matrix size, spatial distribution and correlation structure among gene frequencies

    Directory of Open Access Journals (Sweden)

    Flávia Melo Rodrigues

    1998-06-01

    Full Text Available Geographic structure of genetic distances among local populations within species, based on allozyme data, has usually been evaluated by estimating genetic distances clustered with hierarchical algorithms, such as the unweighted pair-group method by arithmetic averages (UPGMA. The distortion produced in the clustering process is estimated by the cophenetic correlation coefficient. This hierarchical approach, however, can fail to produce an accurate representation of genetic distances among populations in a low dimensional space, especially when continuous (clinal or reticulate patterns of variation exist. In the present study, we analyzed 50 genetic distance matrices from the literature, for animal taxa ranging from Platyhelminthes to Mammalia, in order to determine in which situations the UPGMA is useful to understand patterns of genetic variation among populations. The cophenetic correlation coefficients, derived from UPGMA based on three types of genetic distance coefficients, were correlated with other parameters of each matrix, including number of populations, loci, alleles, maximum geographic distance among populations, relative magnitude of the first eigenvalue of covariance matrix among alleles and logarithm of body size. Most cophenetic correlations were higher than 0.80, and the highest values appeared for Nei's and Rogers' genetic distances. The relationship between cophenetic correlation coefficients and the other parameters analyzed was defined by an "envelope space", forming triangles in which higher values of cophenetic correlations are found for higher values in the parameters, though low values do not necessarily correspond to high cophenetic correlations. We concluded that UPGMA is useful to describe genetic distances based on large distance matrices (both in terms of elevated number of populations or alleles, when dimensionality of the system is low (matrices with large first eigenvalues or when local populations are separated

  3. Coadaptation: lessons from the brine shrimp Artemia, "the aquatic Drosophila" (Crustacea; Anostraca Coadaptación: lecciones desde el camarón de salmuera Artemia, "la Drosophila acuática" (Crustacea; Anostraca

    Directory of Open Access Journals (Sweden)

    GONZALO GAJARDO

    2001-03-01

    Full Text Available During the fifties Brncic and the Dobzhansky's school, using the fruit fly Drosophila as a test organism, introduced the term integration of the genotype, or genetic coadaptation, which has had great impact on thinking in today's evolutionary biology. In this work we use the brine shrimp Artemia - in many respects a sort of aquatic Drosophila- as a model organism to evaluate the relationship between population structure, potential for divergence and the degree of morphological and/or genetic change. These aspects, tightly linked with the organization of the genotype, are important to understanding how recombination and adaptive release of genetic and phenotypic variation affect the speciation process in Artemia. Analysis of genetic (allozyme, diploid and chromocentre numbers, morphological (Mahalanobis distances and reproductive data (cross-fertility tests available for populations of the bisexual, endemic species of the Americas, Artemia franciscana and A. persimilis, indicate that: (i A. franciscana and A. persimilis are morphologically distinct in correspondence with observed genetic differences (D Nei > 1; 2n = 42 and 44; 12.5 and 1.5 mean chromocentre numbers, respectively; (ii populations from Chile and other South American localities (mainly A. franciscana display high levels of genetic variability and a trend to develop large genetic distances between populations; (iii the plasticity of Artemia gene pool is associated, at least in part, with ecological heterogeneity. Hence an adaptive divergence mode is thought to best define the speciation process in Artemia; (iv the succesful production of laboratory hybrids in the allopatric Artemia populations studied in the Americas, a feature seen in other anostracods, could be explained by the fact that formerly allopatric populations have not achieved later sympatry, as required by the allopatric speciation paradigmEn los años cincuenta Brncic y la escuela de Dobzhansky introdujeron el t

  4. Variabilidad genética y morfológica y estructuración poblacional en Alstroemeria hookeri subsp. hookeri (Alstroemeriaceae, endémica de Chile Genetic and morphological variation and population structure in Alstroemeria hookeri subsp. hookeri (Alstroemeriaceae, endemic to Chile

    Directory of Open Access Journals (Sweden)

    EDUARDO RUIZ

    2010-12-01

    geographic ranges, with characters that contribute to this separation. The genetic variability Índices were estimated using 17 allozymic loci. We estimated population structure and also carried out an AMOVA analysis. Nei's genetic distances among all population pairs were estimated to obtain a dendrogram showing the genetic similarity relationships. The results indicate high levéis of genetic structure and low valúes of within population genetic diversity were found. The results of AMOVA indicate that the variability occurs mainly among populations. However, these results varied when populations from both geographic ranges were separately analyzed. The genetic similarities are not congruent with the morphological divergence between both geographic ranges, indicating that some populations from Central Valley are more related genetically to some from coastal populations than populations from their own geographic range.

  5. 大口黑鲈微卫星DNA指纹图谱的构建和遗传结构分析%ESTABLISHMENT OF DNA FINGERPRINTING AND ANALYSIS ON GENETIC STRUCTURE OF LARGEMOUTH BASS WITH MICROSATELLITE

    Institute of Scientific and Technical Information of China (English)

    樊佳佳; 白俊杰; 李胜杰; 任坤; 叶星

    2012-01-01

    allozymes in recent years as the genetic markers of choice for many biological problems including parentage assessment, genomic mapping and establishment DNA fingerprinting. Largemouth bass (Micropterus sal-moides) was introduced from Taiwan to Guangdong province of China in 1983, because of delicious taste, fast growth, and wide temperature tolerance, it has been bred in many region of China as a main cultured fish species with annual production of 100,000 tons. The largemouth bass consists of two subspecies, the Florida largemouth bass (M. s. floridanus), which is native to peninsular Florida, and the northern largemouth bass (M. s. salmoides), whose native range extends throughout the central and eastern U.S. as well as northeastern Mexico and southeastern Canada. Research shows that largemouth bass cultured in china attribute to the northern largemouth bass (M .s. salmoides). In this paper, the microsatellite DNA fingerprinting of four largemouth bass populations was established, including cultured stock of M. salmoides in China (CH), M. s. floridanus was introduced in 2009 (FL-09), M. s. floridanus was introduced in 2010 (FL-10) and M. s. salmoides was introduced in 2010 (NT-10), and the genetic structure of them was analyzed by 43 microsatellite markers. The results showed that a total of 246 alleles were obtained from the four largemouth bass populations, and the alleles ranged from 2-13 in each locus. The mean value of number on alleles (A) and the mean value of expected heterozygosity (He) were calculated by popgene 3.2 software. The result was that the mean value of number on alleles {A) of CH, FL-09, FL-10 and NT-10 was 2.58, 3.74, 3.70 and 4.21, the mean value of expected heterozygosity (He) was 0.4549, 0.4896, 0.5010 and 0.6138, and the mean value of polymorphism information content (PIC) was 0.3786, 0.4443, 0.4566 and 0.5546, respectively. It indicated that the genetic diversity of cultured stock on largemouth bass in China was lower than that of introduced

  6. 大竹蛏5个野生群体遗传多样性的微卫星分析%Microsatellite analysis of genetic diversity of five wild populations of Solen grandis (Dunker)

    Institute of Scientific and Technical Information of China (English)

    张志伟; 张雨; 陈爱华; 张志勇; 陆勤勤; 张朝晖; 姚国兴; 蔡永祥; 吴杨平; 曹奕

    2015-01-01

    The grand jackknife clam Solen grandis (Dunker, 1861) is a commercial marine bivalve that is found in coastal waters of China, Japan, and Korea from the shallow subtidal to depths of 20 m. It has high nutritive and medical value according to traditional Chinese medicine. In addition, it is adaptable and has high growth rates and great market potential. Currently, this clam is only available from natural sources. Over the last few decades, however, overfishing and environmental pollution have caused dramatic declines in natural stocks of S. grandis, and production is low and unstable. Fortunately, methods of artificial breeding and cultivation of the jackknife clam are developing. Previous studies on S. grandis focused primarily on morphological and ecological characteristics, allozyme analysis, and evalua-tion of its nutrition components. Little is known about the molecular ecology of S. grandis or its genetic background. Thus, it is important to evaluate genetic differences among populations along the coast of China. In this study, 14 mi-crosatellite DNA markers were used to examine the genetic diversity and differentiation among five wild populations of the grand jackknife clam. A total of 150 samples were collected from Dandong (DD) in Liaoning Province, Qinhuang-dao (QHD) in Hebei Province, Rizhao (RZ) in Shandong Province, Lyusi (LS) in Jiangsu Province, and Beihai (BH) in Guangxi Province. Comparisons of 199 alleles among the five populations showed that, in the fourteen loci, polymor-phism information content (PIC)values ranged from 0.696 to 0.853 with high polymorphism. The number of alleles ranged from 8 to 22 and the average number (AM) and richness(AR) of alleles were 14.2 and 11.05, respectively. Ex-pected (He) and observed heterozygosity (Ho) ranged 0.769–0.826 and 0.809–0.858, respectively, suggesting high levels of genetic diversity in all populations. Only the Sg16 locus in the DD population deviated significantly from Hardy-Weinberg equilibrium

  7. Ten years of demographic and genetic monitoring of Stachys maritima in Catalonia (2001-2010. Implications for a recovery plan

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    Massó, S.

    2010-12-01

    Full Text Available Stachys maritima is a species typical of the coastal dunes, with a wide distribution within the Mediterranean Basin. In spite of this, the species shows a clear regression. In Catalonia, it has been observed an important reduction of its populations since early 20th century, where it has disappeared from several localities in which it was relatively common (Tarragonès, Barcelonès. Herein we present the results of the demographic monitoring of the species during the last 10 years (2001-2010 in the known localities in Catalonia. Besides corroborating the disappearance (northern Sant Martí d’Empúries, the re-discovering (Llobregat Delta beach and the detection of new populations (inner dunes of the Montgrí, a large year-to-year fluctuation of the monitored populations is stated; the possible reasons are discussed. In addition, the present work also includes the results of the allozyme diversity analysis of the new detected populations as well as the rediscoveries of the period 2004-2008, which were not included in a former study of genetic diversity carried out in 2002-2003. It is necessary to emphasize that the contribution of the new populations to the genetic diversity of Stachys maritima is very small, which can be attributed to their limited population size and /or to founder effects. Despite that the species is included in the Annex 2 (“En Perill d’Extinció” within the Catàleg de Flora Amenaçada de Catalunya (Catalogue of Endangered Flora of Catalonia, and some “soft” conservation measures have been applied at local level (signposting of the beach accesses, environmental education, etc. coupled with other more significant measures (e.g. translocation of individuals discovered in an artificial sandbank, it would be necessary the coordinated action and the scientific support of any initiative of conservation that could be carried out. The general frame to initiate actions of conservation should be the recovery plan of

  8. 论我国兴安落叶松、长白落叶松及华北落叶松种间遗传进化关系%ON EVOLUTIONARY RELATIONSHIPS AMONG THREE LARIX TAXA IN CHINA:L.GMELINII(RUPR.)RUPR,L.OLGENSIS HENRY AND L. PRINCIPIS-RUPPRECHTII MAYR

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    析种间的进化关系(Phylogeny Re-construction),及线粒体DNA的母本遗传方式特点,但可以用群体遗传结构的研究。稀有标记的空间分布有助于进一步判断落叶松群体的形成路径和历史。%The three taxa of the genus, Larix gmelinii(Rupr.)Rupr, L.olgensis Henry and L.principis-rupprechtii Mayr., are very important timber species in China. However, the classification of these three taxa has been very arguable because different traits are employed by different authors. Thus, elucidation of their genetic relationships is of great singnificance in practice, such as the potential utility of heterosis between the taxa. Recent studies assessed using allozymes and cpDNA markers showed that there were very closely genetic relationships among the three taxa, implying that their divergences probably occurred very recently. In this review the probable process for the formation of L.olgensis and L.principis-rupprechtii was discussed in detail, including possible routes, the time scale for divergence and the definition of species. According to the concept of biological species and the genetic variation of different traits, it would be more reasonable to consider L.olgensis and L.principis-rupprechtii to be two varieties of L.gmelinii other than two separate species.

  9. 生物科学%Biological Science

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Q145 01050332 物种与物种多样性=Species and Species Diversity[刊, 中]/周红章(中科院动物所)∥生物多样性.&2000, 8(2).&215~226 分析了物种客观存在的自然属性和物种概念的局限性,认为物种的生物学属性和物种多样性的科学属性之间有着本质联系.参47 国家自然科学基金"九五”重大项目(39893360)资助 Q178 01050333 同工酶和RAPD分析用于中华绒螯蟹的基因分类=Genetic Differention within Eriochoir Sinensis (Milne, Edwards) Revealed by Allozyme and RAPD[刊, 英]/崔朝霞(中科院海洋所),相建海…∥Chinese Journal of Oceanology and Limnology.&2000, 18(3).&234~240 国家自然科学基金(39470141)资助 Q178 01050334 海洋微藻对重金属的吸附研究进展=A Review of Heavy Metal Adsorption by Microalgae[刊, 英]/潘进芬(中科院海洋所),林荣根…∥Chinese Journal of Oceanology and Limnology.&2000, 18(3).&260~264 国家自然科学基金(29677020)资助 Q178 01050335 台湾海峡南部漂浮植物=Phytoneuston in the Southern Taiwan Strait[刊, 中]/黄加祺(厦门大学),李少菁…∥海洋学报.&2000, 22(4).&67~73 国家自然科学基金重点项目(49636220)资助 Q178 01050336 4种海洋微藻对久效磷的抗性与其抗氧化能力的相关性=Relationship between Monocrotophos Resistance and Antioxidization in Four Species of Marine Microalgae[刊, 中]/唐学玺(青岛海洋大学),李永祺∥海洋与湖沼.&2000, 31(4).&414~418 国家攀登计划B资助 Q189 01050337 不同功能位点介导α干扰素的免疫调节和中枢镇痛作用=Distinct Structural Bases of the Immunoregulatory and Central Analgesic Effects of IFNα[刊, 中]/王云霞(第二军医大学),蒋春雷…∥生理学报.&2000, 52(3).&203~206 实验结果表明,IFNα分子存在着相互独立的免疫和镇痛两个功能位点,分别介导免疫调节作用和中枢镇痛作用.图3表1参8 国家自然科学基金(39570669)资助 Q245 01050338 新型小