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1.
Investigation of linkage disequilibrium block architecture in human genome is modern, intensely investigated field of molecular genetics. In the present study, genetic differentiation and linkage disequilibrium pattern in the methylenetetrahydrofolate reductase (MTHFR) locus was examined in the populations of Russians, Tuvinians, and Northern and Southern Kyrgyzes. Methylenetetrahydrofolate reductase is the key enzyme of folate cycle, responsible for reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. Decreased enzymatic activity of this protein often caused by certain associations of MTHFR alleles results in the increased plasma homocysteine levels. In the population groups examined, genotype and allele frequencies at five polymorphic MTHFR loci: rs17037397, rs4846052, rs1801133, rs1801131, and rs1537516 were evaluated. Statistically significant genetic differences between the population group of Southern Kyrgyzes and the other groups, as well as between Russians and Tuvinians, were demonstrated. In the MTHFR gene from the population of Southern Kyrgyzes one block was revealed; in the populations of Russians, Tuvinians, and Northern Kyrgyzes two blocks were detected. Thus, the structure of linkage disequilibrium in the MTHFR locus demonstrated population-specific pattern.  相似文献   

2.
We carried out an allozyme analysis to investigate polymorphism and genetic structure of the populations of D. incarnata and D. ochroleuca in regions of their joint growth in Russia and Belarus. We found that D. ochroleuca individuals in the populations of the Urals and Siberia, which are distant fragments from the main range of the species, do not differ significantly from individuals within the main part of the area (Belarus) on the basis of the allelic composition of eight gene loci. We revealed that D. ochroleuca and D. incarnata are differentiated by different alleles of the GDH locus. Thus, we established a genetic marker suitable to distinguish these closely related taxa. In addition to the GDH locus, D. ochroleuca and D. incarnata in the places of their joint growth, differ in the allelic structure of the PGI and NADHD loci. D. incarnata from the Urals and Siberia were polymorphic for both loci, and individuals from Belarus were polymorphic for one locus (PGI). In contrast, all D. ochroleuca individuals growing in sympatric populations with polymorphic D. incarnata were homozygous for the same alleles. Thus, comparison of the genetic structure of D. ochroleuca and D. incarnata points to the existence of a genetic isolation and a functioning isolation mechanism even under conditions of their joint growth. We found that the GDH locus in D. incarnata is polymorphic only in populations which grow together with D. ochroleuca, with exception a few examples. Thus, we conclude that variability of the GDH locus in D. incarnata is associated with hybridization with D. ochroleuca.  相似文献   

3.
The objectives of conservation and sustainable forest management require in depth study of genomes of woody plants and definition of their intraspecific genetic diversity. In recent years, an approach was developed based on the study of “candidate genes” that can potentially be involved in the formation of adaptive traits. In this study, we investigated nucleotide polymorphism of several adaptive candidate genes in the populations of Siberian larch (Larix sibirica Ledeb.) in the Urals. Representatives of this genus are among the most valuable and widely distributed forest tree species in Russia. From ten selected gene loci in the genome of L. sibirica, we isolated and investigated three loci, one of which (ABA-WDS) was sequenced in L. sibirica for the first time. The total length of the analyzed sequence in each individual amounted to 2865 bp. The length of locus alignment was from 360 bp to 1395 bp. In total, we identified 200 polymorphic positions. The most conservative is locus 4CL1-363, and the most polymorphic is locus sSPcDFD040B03103-274. The studied populations of L. sibirica are characterized by a high level of nucleotide polymorphism in comparison with other species and genuses (Picea, Pinus, Pseudotsuga, Abies) conifers plants (Hd = 0.896; π = 0.007; θW = 0.015). The most selectively neutral polymorphism (D T =–0.997) was attributed to locus 4CL1-363, and polymorphism with high probability of adaptability (D T =–1.807) was determined for the ABA-WDS locus. We identified 54 SNP markers, only five of which were nonsynonymous (9.26%) replacements. The average frequency of SNPs in the three studied loci of L. sibirica was one SNP in 53 bp. We detected unique SNP markers for eight populations, which could potentially be used to identify populations. Populations that are characterized by the highest number of unique SNP markers can be recommended for selection in order to preserve the gene pool of the species.  相似文献   

4.
Codominant marker systems are better suited to analyze population structure and assess the source of an individual in admixture analyses. Currently, there is no codominant marker system using microsatellites developed for the sea sandwort, Honckenya peploides (L.) Ehrh., an early colonizer in island systems. We developed and characterized novel microsatellite loci from H. peploides, using reads collected from whole genome shotgun sequencing on a 454 platform. The combined output from two shotgun runs yielded a total of 62,669 reads, from which 58 loci were screened. We identified 12 polymorphic loci that amplified reliably and exhibited disomic inheritance. Microsatellite data were collected and characterized for the 12 polymorphic loci in two Alaskan populations of H. peploides: Fossil Beach, Kodiak Island (n?=?32) and Egg Bay, Atka Island (n?=?29). The Atka population exhibited a slightly higher average number of alleles (3.9) and observed heterozygosity (0.483) than the Kodiak population (3.3 and 0.347, respectively). The overall probability of identity values for both populations was PID?=?2.892e?6 and PIDsib?=?3.361e?3. We also screened the 12 polymorphic loci in Wilhelmsia physodes (Fisch. ex Ser.) McNeill, the most closely related species to H. peploides, and only one locus was polymorphic. These microsatellite markers will allow future investigations into population genetic and colonization patterns of the beach dune ruderal H. peploides on new and recently disturbed islands.  相似文献   

5.
Ten polymorphic microsatellite loci were isolated and characterized from Spodoptera exigua (Hübner), which is a worldwide economic pest on various crops. The isolated loci were polymorphic, with 3–15 alleles in 40 individuals from four regional populations in Korea. The analyses revealed that 40 individuals had different multilocus genotypes, with the expected heterozygosity ranging from 0.133 to 0.899. Eight of the ten loci did not deviate significantly from Hardy-Weinberg equilibrium. The isolated markers will facilitate population genetic studies of S. exigua.  相似文献   

6.
A total of 18 polymorphic microsatellite loci were isolated and characterized from RAPD products in the Xinjiang Arctic Grayling (Thymallus arcticus grubei). The number of alleles (Na) per locus varied from 2 to 10. Observed (Ho) and expected (He) heterozygosities ranged from 0.64 to 0.92, and from 0.63 to 0.88, respectively. Considerable differences were found among HBH, FH and FY populations in the number of alleles, effective number of alleles, number of genotypes at all of these loci. These new RAPD-SSR markers have provided a helpful tool for genetic analyses and resources conservation of T. arcticus grubei. Five additional fish species, Amur grayling (Thymallus grubii), Taimen (Hucho taimen), Sea perch (Lateolabrax japonicus), Lenok (Brachymystax lenok) and Red seam bream (Pagrosomus major) were assessed for cross-species amplification. Three of the five species showed at least one polymorphic locus. In addition, seven loci were found to be polymorphic in at least one species.  相似文献   

7.
Distribution of several widespread, extensively studied polymorphic variants of genes of the cytosol glutathione-S-transferase subfamily (GSTA1, GSTM1, GSTM3, GSTP1, and GSTT1) has been studied in samples from Russian populations of European Russia, as well as Komi and Yakut populations used for comparison. Analysis of the GSTP1 and GSTM3 polymorphisms has not revealed significant differences in the distribution of alleles of the loci, including two-site GSTP1 haplotypes, in most Russian populations and between Komi populations. Only in the Yakut sample have a significant difference been found with respect to these loci in each pairwise comparison. Regarding the GSTT1 and GSTA1 genes, in addition to differences between the Yakut population and all other populations with respect to the GSTA1 gene, it has been found that the frequencies of the GSTT1 0/0 deletion genotype and GSTA1 ?69T allele in the Russian sample from Mezen’ (Arkhangel’sk oblast) are substantially lower than in other Russian populations and Komi populations. The significance of these differences has been confirmed by tests for heterogeneity of the entire pool of Russian populations.  相似文献   

8.
Climatic shifts within recent decades created favorable conditions for invasive species flourishing in more Northern parts of Europe. Our study was aimed at evaluation of genetic variability and habitat features of Impatiens parviflora populations growing in Lithuania. Twenty one populations were selected and analysed using simple sequence repeat (SSR) and randomly amplified polymorphic DNA (RAPD) assays. Evaluated by SSRs, 315 individuals were all monomorphic and homozygous at 4 loci and heterozygous at 1 locus. RAPD analyses revealed that the percentage of polymorphic DNA loci (% P) per population ranged from 7 to 39% and genetic differentiation between populations was ΦPT=0.790 (P<0.01). Genetic distances among populations (0.135–0.426) correlated significantly with geographical distances (r=0.183; P<0.008). Populations in overmoistured soil contained higher % P (28.3) when compared to drier soil (18.7; P<0.05). All recorded populations were close to roads; their % P did not depend on proximity to buildings, light intensity or population size. Our RAPD analyses indicate multiple introductions of this species in Lithuania. Analyses of I. parviflora at SSR and RAPD loci show that the invasion process is reflected in genetic structure.  相似文献   

9.
The stock characterization of wild populations of Silonia silondia is important for its scientific management. At present, the information on genetic parameters of S. silondia is very limited. The species-specific microsatellite markers were developed in current study. The validated markers were used to genotype individuals from four distant rivers. To develop de novo microsatellite loci, an enriched genomic library was constructed for S. silondia using affinity–capture approach. The markers were validated for utility in population genetics. A total number of 76 individuals from four natural riverine populations were used to generate data for population analysis. The screening of isolated repeat sequences yielded eleven novel polymorphic microsatellite loci. The microsatellite loci exhibited high level of polymorphism, with 6–24 alleles per locus and the PIC value ranged from 0.604 to 0.927. The observed (Ho) and expected (He) heterozygosities ranged from 0.081 to 0.84 and 0.66 to 0.938, respectively. The AMOVA analysis indicated significant genetic differentiation among riverine populations (overall FST = 0.075; P < 0.0001) with maximum variation (92.5 %) within populations. Cross-priming assessment revealed successful amplification (35–38 %) of heterologous loci in four related species viz. Clupisoma garua, C. taakree, Ailia coila and Eutropiichthys vacha. The results demonstrated that these de novo polymorphic microsatellite loci are promising for population genetic variation and diversity studies in S. silondia. Cross-priming results indicated that these primers can help to get polymorphic microsatellite loci in the related catfish species of family Schilbidae.  相似文献   

10.
RAPD and ISSR analyses revealed genetic diversity and relationships among 11 populations of two closely related northeast China Vicia species, Vicia ramuliflora and V. unijuga. Both methods yielded similar and complementary results, showing high genetic diversity. Vicia ramuliflora had 100% polymorphic loci in both RAPD and ISSR, and V. unijuga had 100% polymorphic loci for RAPD and 98.96% for ISSR. Genetic differentiation was moderate among populations of each species. Genetic variation was distributed mainly within populations for the two species. The high level of gene flow was important for the allocation of genetic variation. The UPGMA dendrogram and principal coordinates analysis at the level of individuals and populations showed that V. ramuliflora and V. unijuga were more closely related than either of them was to the outgroup species, V. cracca. The small molecular variance of V. ramuliflora and V. unijuga supports the conclusion that these two species had a common ancestor.  相似文献   

11.
The population genetic variation of the tetraploid species Oxytropis chankaensis Jurtz. (Fabaceae), a local endemic of the western coast of Khanka Lake (Primorye), was examined. Five populations were analyzed using 28 isozyme loci encoding 16 enzyme systems. Significant allelic heterogeneity among the populations was found for six out of twelve polymorphic loci. The heterozygosity of the samples (total sample size 294 plants) H e = 0.301 was considerable higher than the mean values in populations of endemic species (0.076). Based on the results of this study, we identified two groups of O. chankaensis populations (southern and northern), in spite of the absence of marked hiatus between them. Of special interest is the population from Przhewalski Spit, which is a natural reserve of genetic diversity of the species and the putative center of formation of the autotetraploid O. chankaensis.  相似文献   

12.
We evaluated the genetic diversity of the African poplar (Populus ilicifolia) populations found in Kenya compared with reference samples of five poplar species from North America and one species introduced in Kenya from India (KEFRI-Kenya). Amplified fragment length polymorphism (AFLP) was used with the objective of providing important information for breeding and in situ/ex situ conservation of this species. Samples collected from three locations along the species’ natural range (Athi, Ewaso Nyiro, and Tana rivers) were compared with four samples of locally planted Populus deltoides stand introduced from India and ten reference samples from North America. Six AFLP primer combinations produced 521 clear bands for analysis. The percentage polymorphic loci were lowest in Tana (20.4 %) and highest in Athi (40.6 %). The average heterozygosity across the studied populations was between 0.07 and 0.3. AMOVA revealed more genetic variation partitioning within population (87 %; P?<?0.01) than among populations (13 %; P?<?0.01) suggesting significant genetic variation between populations. Further, UPGMA delineation showed two clusters of the Tana, Athi, and Ewaso Nyiro populations clustered together compared to the North America and India/KEFRI reference samples. Moreover, the study showed that the Athi population is more diverse than those of Tana and Ewaso Nyiro and may be important for conservation, domestication, and improvement studies. The genetic differentiation (F ST ?=?0.134) among Kenyan P. ilicifolia populations suggests limited possibility of gene flow between these populations.  相似文献   

13.
The population-genetic structure of the bivalve Corbicula japonica from ten estuarine localities in the Primorsky Region was investigated using nine allozyme loci as gene markers. This study revealed spatial genetic heterogeneity between the investigated populations (G st = 0.05); its degree was dependent on the distance between populations. No linkage disequilibrium was found for any pair of loci. The index of genetic similarity between pairs of populations varied from 0.916 to 0.994. The genetic heterogeneity of the C. japonica populations is probably a result of genetic drift balanced by an irregular gene flow. Such an equilibrium may indicate a relatively recent expansion of C. japonica, which may have occurred during the Holocene climatic optimum (about 7500 years ago).  相似文献   

14.
Using the method of ISSR analysis, the genetic diversity of 18 natural populations of Tulipa gesneriana L. from the north of the Lower Volga region was examined. The ten ISSR primers used in the study provided identification of 102 PCR fragments, of which 50 were polymorphic (49.0%). According to the proportion of polymorphic markers, two population groups were distinguished: (1) the populations in which the proportion of polymorphic markers ranged from 0.35 to 0.41; (2) the populations in which the proportion of polymorphic markers ranged from 0.64 to 0.85. UPGMA clustering analysis provided subdivision of the sample into two large clusters. The unrooted tree constructed using the Neighbor Joining algorithm had similar topology. The first cluster included slightly variable populations and the second cluster included highly variable populations. The AMOVA analysis showed statistically significant differences (FCT = 0.430; p = 0.000) between the two groups. Local populations are considerably genetically differentiated from each other (FST = 0.632) and have almost no links via modern gene flow, as evidenced by the results of the Mantel test (r =–0.118; p = 0.819). It is suggested that the degree of genetic similarities and differences between the populations depends on the time and the species dispersal patterns on these territories.  相似文献   

15.
Eutrema edwardsii R.Br. (Brassicaceae) is an arctic-alpine mustard with a circumpolar distribution. Its closest relative, Eutrema penlandii Rollins, is a federally listed, threatened species that is endemic to the Mosquito Range in the Southern Rocky Mountains of Colorado, USA. As part of a larger project addressing the systematics of this species complex in North America, we conducted chromosome counts, flow cytometry, and allozyme analysis to test the hypothesis that these taxa comprise an autopolyploid complex. Within that context, it should be noted that a chromosome count has not been reported previously for E. penlandii. Results obtained from mitotic counts obtained for two populations of E. penlandii reveal this taxon to be diploid. Diploidy was confirmed using flow cytometry for an additional 15 individuals representing four populations. Previously published chromosome counts for E. edwardsii reveal a polyploid complex of tetraploid, hexaploid, and octaploid populations for which an autopolyploid origin has been presumed. However, allozyme analysis revealed an allopolyploid origin for E. edwardsii, as evidenced from fixed heterozygosity at six loci. Although our data suggest that E. penlandii is a close relative of one of the progenitors of E. edwardsii, the taxonomic identity of the other progenitor(s) cannot be elucidated from these data. The data reported herein support the recognition of E. penlandii as taxonomically distinct, which has implications for conservation, and reveal cryptic variation within E. edwardsii.  相似文献   

16.
Ixodiae ticks have been counted and sampled in six distant locations within the Altai-Sayan Mountain Area and northern forest steppe in 2012. In total, 1829 individuals of I. persulcatus and 719 of I. pavlovskyi ticks were collected by flagging. I. persulcatus is found in all six examined locations and I. pavlovskyi is found in Western Altai, Northeastern Altai, and Northern Altai, as well as in forest parks near Akademgorodok of Novosibirsk. In total, 16S rRNA and COI sequences have been determined in 144 and 164 I. persulcatus individuals, as well as in 60 and 55 I. pavlovskyi. Selectively equivalent mutant forms are present in I. pavlovskyi populations of Northeastern Altai and Northern Altai. The hydrothermal regime in the forest parks near Novosibirsk is optimal for the I. pavlovskyi ticks. These ticks have recently colonized the forest parks near Novosibirsk and therefore are genetically close to I. pavloskyi from the Altai–Sayan Mountain Area populations.  相似文献   

17.
The population genetic structure of plant pathogenic fungus Pyrenophora tritici-repentis was examined using microsatellite (SSR) markers. According to the geographical origin of the pathogen populations, they were designated as North Caucasian (S, 33 isolates), northwest (Nw, 39), and Omsk (Om, 43). The populations were analyzed at the nine most polymorphic SSR loci, at which 75 alleles were identified. To characterize the genetic variation within and between populations, the AMOVA algorithm as implemented in the Arlequin v. 3.5 software program was used. The number of alleles per locus ranged from 5 to 12 and their sizes varied within the range from 180 to 400 bp. The mean gene diversity at SSR loci was high for all populations (H = 0.58–0.75). The populations were considerably different in the frequencies of individual alleles of the SSR loci. Most isolates in the populations were represented by unique haplotypes. The within-population variation of the isolates at molecular markers was 86.4%; among the populations, 13.6%. Substantial interpopulation differences were found between the Om and S (Fst = 0.16) and between the Om and Nw (Fst = 0.20) populations, whereas between the S and Nw populations, these differences were small (Fst = 0.05). Thus, it was demonstrated that the population of P. tritici-repentis from Omsk oblast had the independent status of the geographical population; northwest and North Caucasian populations differed in the allelic diversity of SSR loci, and despite the low Fst value (0.05), they also belonged to independent geographical populations.  相似文献   

18.
Gliadins, seed storage proteins, are popular markers effectively employed for the analysis of common wheat. Gliadin electrophoretic patterns are genotype-specific, reproducible, not dependent on growing conditions and are suitable for germplasm identification complementary to molecular markers. Gliadins have been identified and used in wheat from various countries, but prior to this study little was known about gliadin polymorphism in wheat from Kazakhstan. In this study, 48 alleles of six gliadin-coding loci were identified in 43 cultivars of spring wheat from Northern Kazakhstan. The alleles Gli-A1 f , Gli-B1 e , Gli-D1 a , Gli-A2 p , Gli-B2 d and Gli-D2 e had maximal frequencies in each of the six loci. Identified Gli alleles in the loci formed ‘Gliadin Genetic Formula’ unique for each studied variety, and these were compared to the published data from previously analyzed wheat varieties. Pedigree analysis of 43 varieties studied for gliadin polymorphisms indicated that some Gli alleles were conserved and inherited from the progenitor cultivar Akmolinka 1. In contrast, other Gli alleles were replaced by those from modern germplasms. It is assumed that a higher frequency of gliadin alleles can be associated with the selection of genotypes with improved traits for yield and seed quality in the studied wheat cultivars from Northern Kazakhstan.  相似文献   

19.
Using monolocus PCR analysis with the pairs of primers designed for the Du215 locus of Darevskia unisexualis, allelic polymorphism at the orthologous locus in the populations of the related parthenospecies D. armeniaca was investigated. It was demonstrated that Du215 (arm) locus was polymorphic and in the populations of parthenospecies D. armeniaca (n = 127) represented by at least three allelic variants, differing from each other by the size and composition of microsatellite cluster, and by single nucleotide substitutions in flanking DNA. Unlike the Du215 locus, Du215 (arm) was shown contain not only GATA, but also (GACA) repeats, which were absent in D. unisexualis. Thus, in this study, the data on the molecular nature of allelic polymorphism at one of the microsatellite loci of the parthenospecies D. armeniaca were reported.  相似文献   

20.

Background

Urochloa humidicola is a forage grass that grows in tropical regions and is recognized for its tolerance to seasonal flooding. It is a polyploid and apomictic species with high phenotypic plasticity. As molecular tools are important in facilitating the development of new cultivars and in the classification of related species, the objectives of this study were to develop new polymorphic microsatellite markers from an enriched library constructed from U. humidicola and to evaluate their transferability to other Urochloa species.

Findings

Microsatellite sequences were identified from a previously constructed enriched library, and specific primers were designed for 40 loci. Isolated di-nucleotide repeat motifs were the most abundant followed by tetra-nucleotide repeats. Of the tested loci, 38 displayed polymorphism when screened across 34 polyploid Urochloa sp. genotypes, including 20 accessions and six hybrids of U. humidicola and two accessions each from U. brizantha, U. dictyoneura, U. decumbens and U. ruziziensis. The number of bands per Simple Sequence Repeat (SSR) locus ranged from one to 29 with a mean of 11.5 bands per locus. The mean Polymorphism Information Content (PIC) of all loci was 0.7136, and the mean Discrimination Power (DP) was 0.7873. Six loci amplified in all species tested. STRUCTURE analysis revealed six different allelic pools, and the genetic similarity values analyzed using Jaccard's coefficient ranged from 0.000 to 0.913.

Conclusions

This work reports new polymorphic microsatellite markers that will be useful for breeding programs for Urochloa humidicola and other Urochloa species as well as for genetic map development, germplasm characterization, evolutionary and taxonomic studies and marker-assisted trait selection.
  相似文献   

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