共查询到20条相似文献,搜索用时 15 毫秒
1.
The uplift of mountains and climatic oscillations are important for understanding of the demographic history and genetic structure of species. We investigated the biogeographic history of the boreal tree species Ulmus lamellosa (Ulmaceae) in China, by using a combined phylogeographic and paleodistribution modeling approach. In this study, 14 populations of endangered U. lamellosa were analyzed by using chloroplast DNA (cpDNA) sequences. A high level of genetic differentiation (Φ ST = 86.22%) among populations with a significant phylogeographic pattern (N ST > G ST, P < 0.05) was found in U. lamellosa. Ten haplotypes were detected by combining chloroplast DNA data, and haplotype 3 (H3) was found to be common and widespread. The intraspecific divergence of all U. lamellosa cpDNA haplotypes (9.27 Ma; 95% HPD 5.17–13.33 Ma) most probably began in the late Miocene. The pairwise difference among haplotypes and neutrality tests (Tajima’s D and Fu’s Fs statistic) indicated that populations of U. lamellosa, except group I, have not experienced recent sudden expansions. Multiple refuge areas were identified across the entire distribution ranges of U. lamellosa. The low level of gene flow (Nm = 0.14) among populations may have resulted from isolation resulting from distance and complex topography during climatic oscillations; this isolation was probably the major process that shaped the present distribution of haplotypes. These results support the hypothesis that U. lamellosa persisted in situ during glaciations and occupied multiple localized glacial refugia, contrary to the hypotheses of large-scale range contraction and long-distance southward migration. 相似文献
2.
Saussurea involucrata (Asteraceae) is a medicinal and second-degree national priority endangered plant that is mainly distributed in the high latitude region of the western Tianshan Mountains. The population is fragmented and isolated, and extensive human impact merits a suitable and specific conservation strategy, which can be compiled based on the genetic diversity, population structure, and demographic history. Phylogeographic studies were conducted on a total of five natural populations and 150 individuals were sampled. Data from three cpDNA intergenic spacer regions (trnL-F, matK, and ndhF-rpl32) and nrDNA ITS sequences showed that twelve haplotypes in cpDNA and five haplotypes in nrDNA indicated high genetic diversity among populations sampled (H T?=?0.820 and 0.756) and within populations sampled (H S?=?0.792 and 0.721). Additionally, the high genetic diversity did not mirror genetic structure in either cpDNA (F ST?=?0.03153, G ST?>?N ST, p?<?0.05) or nrDNA (F ST?=?0.03666, meaningless G ST and N ST). Two groups (north and south) were determined for a SAMOVA analysis. Based on this analysis, the demographic history was conducted with a Bayesian Skyline Plot and Isolation with Migration analysis, which showed sustainable and stable extension without a marked bottleneck. Divergence time was indicated at c. 6.25 Mya (90%HPD: 15.30–0.22 Mya) in the Miocene, which is consistent with the formation of the Kelasu section of Tianshan. The southern populations in the Bayanbulak and Gonglu regions require additional attention and transplanting would be an effective way to restore rare cpDNA haplotypes, increase effective population size, and migration rate. Our results suggested that in situ conservation of S. involucrata in western Tianshan should be the main strategy for protection and recovery of the species. 相似文献
3.
Evgeny V. Esin Alyona I. Nikiforova Elena V. Shulgina Ksenia V. Metal’nikova Alexandra V. Novosadova Dmitry V. Zlenko Grigorii N. Markevich Vsevolod N. Leman 《Hydrobiologia》2018,806(1):237-250
Knowledge of larval dispersal and connectivity in coral reef species is crucial for understanding population dynamics, resilience, and evolution of species. Here, we use ten microsatellites and one mitochondrial marker (cytochrome b) to investigate the genetic population structure, genetic diversity, and historical demography of the powder-blue tang Acanthurus leucosternon across more than 1000 km of the scarcely studied Eastern African region. The global AMOVA results based on microsatellites reveal a low but significant F ST value (F ST = 0.00252 P < 0.001; D EST = 0.025 P = 0.0018) for the 336 specimens sampled at ten sample sites, while no significant differentiation could be found in the mitochondrial cytochrome b dataset. On the other hand, pairwise F ST, PCOA, and hierarchical analysis failed to identify any genetic breaks among the Eastern African populations, supporting the hypothesis of genetic homogeneity. The observed genetic homogeneity among Eastern African sample sites can be explained by the lengthy post-larval stage of A. leucosternon, which can potentiate long-distance dispersal. Tests of neutrality and mismatch distribution signal a population expansion during the mid-Pleistocene period. 相似文献
4.
Rhiannon J. Crichton Sarah E. Dalrymple Sarah J. Woodin Peter M. Hollingsworth 《Conservation Genetics》2016,17(3):547-556
Melampyrum sylvaticum is an endangered annual hemiparasitic plant that is found in only 19 small and isolated populations in the United Kingdom (UK). To evaluate the genetic consequences of this patchy distribution we compared levels of diversity, inbreeding and differentiation from ten populations from the UK with eight relatively large populations from Sweden and Norway where the species is more continuously distributed. We demonstrate that in both the UK and Scandinavia, the species is highly inbreeding (global F IS = 0.899). Levels of population differentiation were high (F’ST = 0.892) and significantly higher amongst UK populations (F’ST = 0.949) than Scandinavian populations (F’ST = 0.762; P < 0.01). The isolated populations in the UK have, on average, lower genetic diversity (allelic richness, proportion of loci that are polymorphic, gene diversity) than Scandinavian populations, and this diversity difference is associated with the smaller census size and population area of UK populations. From a conservation perspective, the naturally inbreeding nature of the species may buffer the species against immediate effects of inbreeding depression, but the markedly lower levels of genetic diversity in UK populations may represent a genetic constraint to evolutionary change. In addition, the high levels of population differentiation suggest that gene flow among populations will not be effective at replenishing lost variation. We thus recommend supporting in situ conservation management with ex situ populations and human-mediated seed dispersal among selected populations in the UK. 相似文献
5.
Yaling Wang Qianlong Liang Guoqian Hao Chunlin Chen Jianquan Liu 《Biodiversity and Conservation》2018,27(9):2275-2291
With increasing temperature and anthropogenic activity, endangered alpine species in the high altitudes of the Qinghai-Tibet Plateau face high risk of extinction; however, they have received little attention in the past. In this study, we used 12 nuclear and nine chloroplast microsatellites (simple sequence repeats, SSR) to assess genetic diversity within and among the only two populations of the highly endangered alpine species Sinadoxa corydalifolia (Adoxaceae). We identified only one individual exhibiting clonal reproduction across all 160 extant plants. The levels of genetic variability were estimated to be very low, with the allele number Na = 3.2 and the expected heterozygosity He = 0.368. The genetic differentiation is extremely high between the two regional populations (FST = 0.214), with a limited rate of gene flow in the recent past. In addition, numerous endemic alleles were found for each subpopulation within each population. Our analyses suggest that it is critical not only to conserve all surviving individuals of the two populations in situ but also to mediate gene flow artificially between subpopulations within each population in this endangered species. 相似文献
6.
Understanding genetic connectivity is fundamental for ecosystem-based management of marine resources. Here we investigate the metapopulation structure of the edible sea cucumber Holothuria edulis Lesson, 1830 across Okinawa Island, Japan. This species is of economic and ecological importance and is distributed from the Red Sea to Hawai‘i. We examined sequence variation in fragments of mitochondrial cytochrome oxidase subunit I (COI) and 16S ribosomal RNA (16S), and nuclear histone (H3) at six locations across Okinawa Island. We found higher haplotype diversity for mtDNA (COI: Hd = 0.69 and 16S: Hd = 0.67) and higher heterozygosity of nDNA (H3: H E = 0.39) in populations from the west coast of Okinawa compared to individuals from populations on the east coast (COI: Hd = 0.40; 16S: Hd = 0.21; H3: H E = 0.14). Overall population structure was significant (AMOVA results for COI: Φ ST = 0.49, P < 0.0001; 16S: Φ ST = 0.34, P < 0.0001; H3: Φ ST = 0.12, P < 0.0001). One population in the east, Uruma, showed elevated pairwise Φ ST values in comparisons with all other sites and a marked reduction of genetic diversity (COI: Hd = 0.25 and 16S: Hd = 0.24), possibly as a consequence of a shift to a more dominant asexual reproduction mode. Recent reports have indicated that coastal development in this area influences many marine organisms, and ecosystem degradation in this location could cause the observed decrease of genetic diversity and isolation of H. edulis in Uruma. Our study should provide valuable data to help with the urgently needed management of sea cucumber populations in Okinawa, and indicates particular attention needs to be paid to vulnerable locations. 相似文献
7.
The elucidation of species diversity and connectivity is essential for conserving coral reef communities and for understanding the characteristics of coral populations. To assess the species diversity, intraspecific genetic diversity, and genetic differentiation among populations of the brooding coral Seriatopora spp., we conducted phylogenetic and population genetic analyses using a mitochondrial DNA control region and microsatellites at ten sites in the Ryukyu Archipelago, Japan. At least three genetic lineages of Seriatopora (Seriatopora-A, -B, and -C) were detected in our specimens. We collected colonies morphologically similar to Seriatopora hystrix, but these may have included multiple, genetically distinct species. Although sexual reproduction maintains the populations of all the genetic lineages, Seriatopora-A and Seriatopora-C had lower genetic diversity than Seriatopora-B. We detected significant genetic differentiation in Seriatopora-B among the three populations as follows: pairwise F ST = 0.064–0.116 (all P = 0.001), pairwise G′′ST = 0.107–0.209 (all P = 0.001). Additionally, only one migrant from an unsampled population was genetically identified within Seriatopora-B. Because the peak of the settlement of Seriatopora larvae is within 1 d and almost all larvae are settled within 5 d of spawning, our observations may be related to low dispersal ability. Populations of Seriatopora in the Ryukyu Archipelago will probably not recover unless there is substantial new recruitment from distant populations. 相似文献
8.
Rice is one of the most important food crops in the world. Genetic diversity is essential for cultivar improvement programs. We compared genetic diversity derived from insertion–deletion (in–del) or base substitutions by amplified fragment length polymorphism (AFLP), from transposon transposition mutations by transposon display (TD), and from cytosine methylation by methylation-sensitive amplified polymorphism (MSAP) in japonica, indica, and Tongil type varieties of Oryza sativa L. Polymorphic profiles from the three marker systems allowed us to clearly distinguish the three types of varieties. The indica type varieties showed the highest genetic diversity followed by the Tongil and japonica type varieties. Of the three marker systems, TD produced the highest marker indices, and AFLP and MSAP produced similar marker indices. Pair-wise comparisons of the three marker systems showed that the correlation between the two genetic markers systems (AFLP and TD, r = 0.959) was higher than the correlations between the genetic and epigenetic marker systems (AFLP and MSAP, r = 0.52; TD and MSAP, r = 0.505). Both genetic marker systems had similar levels of gene differentiation (G ST ) and gene flow (N m ), which differed in the epigenetic marker system. Although the G ST of the epigenetic marker system was lower than the genetic marker systems, the N m of the epigenetic marker system was higher than in the genetic marker systems, indicating that epigenetic variations have a greater influence than genetic variations among the O. sativa L. types. 相似文献
9.
Anopheles darlingi Root is a primary vector of malaria in the neotropic region, a species not just highly anthropophilic but very efficient in transmitting Plasmodium species and considered the most important vector in the Amazon region. The main goal of this study was to determine the genetic structure of the A. darlingi populations using microsatellites (STR) in western and eastern regions of Colombia. DNA extraction was done with the cited protocol of band using the Genomic Prep? cell and tissue isolation commercial kits. We used the STR reported by Conn et al (Mol Ecol Notes 1: 223-225, 2001). The analysis with STR proved there was a high genetic diversity and significant alterations of the Hardy-Weinberg equilibrium. The greatest genetic diversity was recorded in Mitu (Vaupes) (Na = 14, Ho = 0.520). The lowest was in Pueblo Nuevo (Cordoba) (Na = 12, Ho = 0.457). The eastern region and the Mitu (Vaupes) populations presented the highest number of primer alleles (Ap = 30; Ap = 13; Ap = 9), with variations between 0.010 and 0.097. The AMOVA revealed that the whole population underwent moderate genetic differentiation (F ST = 0.063, p < 0.05). The same differentiation was noticed (0.06 < F ST > 0.06, p < 0.05) with five of the six populations included in this job, and there was a low differentiation in the Las Margaritas (Santander) area (F ST = 0.02s3, p < 0.05). Our results suggest a slight positive correlation, which does not show a statistical significance between the geographic and genetic distances, probably suggesting that the moderate genetic differentiation found between pairs of populations does not need to be explained for the hypothesis of separation by distance. 相似文献
10.
Identification of population units is crucial for management and monitoring programs, especially for endangered wild species. The roughskin sculpin (Trachidermus fasciatus Heckel) is a small catadromous fish and has been listed as a second class state protected aquatic animal since 1988 in China. To achieve sustainable conservation of this species, it is necessary to clarify the existing genetic structure both between and within populations. Here, population genetic structure among eight populations of T. fasciatus were analyzed by using 16 highly polymorphic microsatellites. High levels of genetic variation were observed in all populations. All pairwise F ST estimates were significant after false discovery rate correction (overall average F ST = 0.054). Furthermore, both STRUCTURE and discriminant analysis of principal components (DAPC) analysis showed that the eight populations were grouped into six clusters. BAYESASS analysis showed generally low recent and asymmetric migration among populations. All these results suggested significant genetic structure across populations. However, there was no isolation by distance relationship among populations, likely resulting from barriers to gene flow created by habitat fragmentation. Our results highlight the need for in situ conservation efforts for T. fasciatus across its entire distribution range, through maximizing habitat size and quality to preserve overall genetic diversity and evolutionary potential. 相似文献
11.
The marine ectoparasitic copepod of salmonids, Lepeophtheirus salmonis (Krøyer), is a major pest of farmed Atlantic salmon (Salmo salar L.) causing great economic impact. The spatial scales over which L. salmonis populations in different salmon farms are typically connected, and the temporal scales over which L. salmonis from the same farm typically undergo genetic change are largely unknown. These questions were posed in a small-scale geographic study of population structure in L. salmonis from four salmon farms, along the northwest and west coasts of Ireland, using two outgroups from Norway and Canada. The temporal stability of genetic composition was also studied in samples collected quarterly during one year from one salmon farm in Ireland. Genetic composition in L. salmonis was characterised using four nuclear microsatellites. Significant but low genetic differentiation was observed between all sites (F ST = 0.08), with no evidence that differentiation was correlated with geographic distance. Temporal genetic differentiation was also evident (F ST = 0.07). An analysis of all L. salmonis samples except the ones from Norway detected two separate clusters. Each cluster contained both geographical and temporal samples. These results are consistent with a population model in which L. salmonis in salmon farms along the northwest and west coasts of Ireland are not isolated, but are potentially subject to (i) localised ecological factors at the particular farm sites or (ii) selection post-settlement or a combination thereof. 相似文献
12.
Andrew W. Gichira Zhi-Zhong Li Josphat K. Saina Guang-Wan Hu Robert W. Gituru Qing-Feng Wang Jin-Ming Chen 《Tree Genetics & Genomes》2017,13(4):72
The distribution of genetic diversity among natural populations is significantly shaped by geographical and environmental heterogeneity. The key objectives of this study were to outline the population genetic structure and to investigate the effects of historical and current factors in shaping the population structure of an endemic tropical tree, Hagenia abyssinica. We used 11 polymorphic microsatellites to estimate genetic variability and evaluate gene flow among natural populations of H. abyssinica. Further, we employed ecological niche modeling approaches, to analyze the demographic history and map potential distributions of H. abyssinica during the Last Glacial Maximum and the present. Significant levels of genetic diversity (H O = 0.477, H E = 0.439) were observed among the sampled locations. High coefficient of genetic differentiation (F ST = 0.32) and considerable genetic variation within the sampled locations (68.01%) were detected. Our results indicated the existence of three genetic groups with limited gene exchange and revealed positive correlations (r = 0.425, P < 0.05) between genetic diversity and geo-graphic distance. The ecological niche modeling (ENM) results support the existence of three distribution zones during the Last Glacial Maximum (LGM), with high probability of occurrence (0.8–1.0), and indicated slight distribution disturbances during and after the LGM. The fundamental patterns of genetic diversity and population structuring of H. abyssinica result from a combination of both environmental and geographical factors, including long-term isolation by distance and characteristic life history of this species. Our ENM results identified three zones that could have served as glacial refugia for this species and lay a foundation for further studies, outlining demographic histories and population structures of Afromontane species. 相似文献
13.
Yingying Ye Zeqin Fu Yunfang Tian Jiji Li Baoying Guo Zhenming Lv Changwen Wu 《Genes & genomics.》2018,40(11):1213-1223
Pelagic larval dispersal habits influence the population genetic structure of marine mollusk organisms via gene flow. The genetic information of the clam Gomphina aequilatera (short larval stage, 10 days) which is ecologically and economically important in the China coast is unknown. To determine the influence of planktonic larval duration on the genetic structure of G. aequilatera. Mitochondrial markers, cytochrome oxidase subunit i (COI) and 12S ribosomal RNA (12S rRNA), were used to investigate the population structure of wild G. aequilatera specimens from four China Sea coastal locations (Zhoushan, Nanji Island, Zhangpu and Beihai). Partial COI (685 bp) and 12S rRNA (350 bp) sequences were determined. High level and significant FST values were obtained among the different localities, based on either COI (FST?=?0.100–0.444, P?<?0.05) or 12S rRNA (FST?=?0.193–0.742, P?<?0.05), indicating a high degree of genetic differentiation among the populations. The pairwise Nm between Beihai and Zhoushan for COI was 0.626 and the other four pairwise Nm values were >?1, indicating extensive gene flow among them. The 12S rRNA showed the same pattern. AMOVA test results for COI and 12S rRNA indicated major genetic variation within the populations: 77.96% within and 22.04% among the populations for COI, 55.73% within and 44.27% among the populations for 12S rRNA. A median-joining network suggested obvious genetic differentiation between the Zhoushan and Beihai populations. This study revealed the extant population genetic structure of G. aequilatera and showed a strong population structure in a species with a short planktonic larval stage. 相似文献
14.
Toshihisa Yashiro Yuki Mitaka Tomonari Nozaki Kenji Matsuura 《Applied Entomology and Zoology》2018,53(2):215-221
Numerous termite species have been introduced outside their native ranges by human transport, and some have become invasive. The dampwood termite Zootermopsis nevadensis (Hagen), which is native to western North America, has been introduced to and become established in Kawanishi City, Hyogo Prefecture, Japan. Zootermopsis nevadensis is subdivided into two subspecies based on cuticular hydrocarbon (CHC) phenotypes: Z. nevadensis nevadensis and Z. nevadensis nuttingi (Haverty and Thorne). Here, we identified Z. nevadensis in Japan as hybrids between the two subspecies. Chemical analysis showed the presence of 7,15-dimethylhenicosane and 5,17-dimethylhenicosane in the CHCs of Z. nevadensis in Japan, corresponding to the CHC phenotype of Z. n. nevadensis. Conversely, all mitochondrial cytochrome c oxidase subunit I sequences of Z. nevadensis in Japan were identical to sequences from Z. n. nuttingi and hybrids between the two subspecies from a native hybrid zone in California, USA. In addition, phylogenetic analysis showed that Z. nevadensis in Japan formed a clade with Z. n. nuttingi and hybrids between the two subspecies. Our results show discordance between the chemical and genetic features of Z. nevadensis in Japan, indicating that individuals of Z. nevadensis in Japan are hybrids between the two subspecies. 相似文献
15.
Wei Lei Wenzhen Fang Xiaoping Zhou Qingxian Lin Xiaolin Chen 《Conservation Genetics》2016,17(6):1459-1468
Major histocompatibility complex (MHC) genes are excellent markers for the study of adaptive genetic variation occurring over different geographical scales. The Chinese egret (Egretta eulophotes) is a vulnerable ardeid species with an estimated global population of 2600–3400 individuals. In this study, we sampled 172 individuals of this egret (approximately 6 % of the global population) from five natural populations that span the entire distribution range of this species in China. We examined their population genetic diversity and geographical differentiation at three MHC class II DAB genes by identifying eight exon 2 alleles at Egeu-DAB1, eight at Egeu-DAB2 and four at Egeu-DAB3. Allelic distributions at each of these three Egeu-DAB loci varied substantially within the five populations, while levels of genetic diversity varied slightly among the populations. Analysis of molecular variance showed low but significant genetic differentiation among five populations at all three Egeu-DAB loci (haplotype-based ?ST: 0.029, 0.020 and 0.042; and distance-based ?ST: 0.036, 0.027 and 0.043, respectively; all P < 0.01). The Mantel test suggested that this significant population genetic differentiation was likely due to an isolation-by-distance pattern of MHC evolution. However, the phylogenetic analyses and the Bayesian clustering analysis based on the three Egeu-DAB loci indicated that there was little geographical structuring of the genetic differentiation among five populations. These results provide fundamental population information for the conservation genetics of the vulnerable Chinese egret. 相似文献
16.
17.
John S. Hargrove Debra J. Murie Daryl C. Parkyn Emily V. Saarinen James D. Austin 《Genetica》2018,146(4-5):393-402
The greater amberjack (Seriola dumerili) is a commercially and recreationally important marine fish species in the southeastern United States, where it has been historically managed as two non-mixing stocks (Gulf of Mexico and Atlantic). Mark-recapture studies and analysis of mitochondrial DNA have suggested the two stocks are demographically independent; however, little is currently known about when and where spawning occurs in Gulf of Mexico amberjack, and whether stock mixture occurs on breeding grounds. The primary objective of this study was to quantify stock mixture among breeding populations of amberjack collected from the Atlantic and Gulf of Mexico. Genetic data based on 11 loci identified very low, though statistically significant differentiation among Gulf of Mexico samples (GST = 0.007, \(G_{{{\text{ST}}}}^{\prime }\) = 0.009; all P?=?0.001) and between reproductive adults collected from two spawning areas (GST = 0.007, \(G_{{{\text{ST}}}}^{\prime }\) = 0.014; all P?=?0.001). Naïve Bayesian mixture analysis supported a single genetic cluster [p(S|data)?=?0.734] whereas trained clustering (using Atlantic and Gulf spawning fish) gave the highest support to a two-cluster model (p(S|data)?=?1.0). Our results support the argument that the genetic structuring of greater amberjack is more complex than the previously assumed two, non-mixing stock model. Although our data provide evidence of limited population structure, we argue in favour of non-panmixia among reproductive fish collected from the Gulf of Mexico and Florida Keys. 相似文献
18.
Analyses of genetic variability and allelic composition in a species exhibiting reproductive fidelity to natal sites may provide important ecological indication of temporal population dynamics, facilitating understanding responses to past disturbances and future climate change. The walleye is an ecologically and economically valuable species, whose largest fishery centers in Lake Erie of the Laurentian Great Lakes; it exhibits reproductive site fidelity, despite otherwise wide-ranging dispersal. We tested whether genetic composition and diversity have remained temporally stable in Lake Erie’s Maumee River, which is the largest and most highly fished spawning run. This population has experienced over a century of exploitation, habitat alterations, and pollution, which may have affected genetic structure and might influence future sustainability. Fourteen nuclear DNA microsatellite loci were analyzed from 744 spawning run walleye to test genetic patterns across: (1) years (N = 12, spanning 1995–2013), (2) birth year cohorts, (3) the sexes, (4) those reproducing earlier (ages 2–6) versus later (7 or older) in life, and (5) the adults versus larvae. Results indicated stability in genetic diversity levels (mean H O = 0.76 ± 0.03) and allelic composition across years (F ST = 0.000–0.006, NS), cohorts (F ST = 0.000–0.013, NS), sexes (F ST = 0.000, NS), earlier versus later reproduction (F ST = 0.000, NS), and between the larvae and adults (F ST = 0.000–0.004, NS). Number of breeders and effective population size were substantial and consistent. This reproductive population thus has maintained genetic stability and high diversity, despite intensive anthropogenic pressures. 相似文献
19.
N. N. Red’kina R. Yu. Mullagulov Yu. A. Yanbaev A. A. Muldashev R. Z. Akilov 《Contemporary Problems of Ecology》2008,1(6):707-711
Hybrid peony (Paeonia hybrida Pall.) is listed as endangered in Russian Federation (since 1988) and in several regions of Russia. The structure of the isolated population from Bashkir Trans-Uralian region, separated by 1500 km from the main geographic range of this species, has been studied using isoenzyme markers from 11 loci. The population is split between two geographical locations, both characterized by a relatively high genetic diversity (mean allele number A = 1.9±0.3, percentage of polymorphic loci P = 0.54, observed heterozigosity H O = 0.223±0.068, expected heterozigosity H E = 0.229±0.067) and a quite low intergroup genetic differentiation (fixation index F ST = 0.008, Nei’s genetic distance D = 0.011). In a subpopulation located near a swampy lake in dense cereal grass and steppe shrubby vegetation, autocorrelation analysis has revealed spatial structuring of genetic variability. In the other location, a stipa-forb steppe on a flat hill slope, a uniform spatial structure of the genotypes has been observed. The results are discussed with respect to the ecological characteristics of the species and the conservation of the genetic pool of the population in situ and ex situ. 相似文献
20.
Asiye Ciftci Hüseyin Karatay Filiz Kücükosmanoğlu Alptekin Karahan Zeki Kaya 《Tree Genetics & Genomes》2017,13(3):69
The European black poplar (Populus nigra L.) is an ecologically and economically important tree species for Turkey. The important and major genetic resources of species for future breeding and ex situ conservation purposes have been archived in a clone bank in Ankara by selecting clones from natural populations and old plantations throughout Turkey. There is no study to date assessing genetic composition these materials. Two-hundred-thirty-three P. nigra clones from six geographic region of Turkey (clone collection populations), and 32 trees from two natural populations (Tunceli and Melet) were genotyped by using 12 nuclear microsatellite DNA markers. There were nine clones which duplicated in various frequencies. The analysis carried out with removal of the duplicated clones revealed a moderately high genetic diversity in studied populations. The observed heterozygosities ranged from 0.59 in Tunceli natural to 0.69 in Central Anatolia clone collection populations. In general, there was excess of heterozygosity in the studied populations. Populations composed of clone collections were significantly differentiated from natural populations (F ST = 0.17), while there was little differentiation among those populations in the clone collection (F ST = 0.03). Two distantly located natural populations with small sizes also differed from each other (F ST = 0.17). Genetic structure analysis revealed two distinct groups (clone collection vs natural populations) with very high membership values (>92%). Clone collection populations had high level of admixture while natural populations had homogenous genetic structure. The presence of large number of clonal duplication, reduced genetic differentiation, and high level of admixture in clone collection populations indicate that genetic resources of European black poplar were highly degraded through genetic erosion and pollution caused by intensive cultural practices and extensive dispersal of clonal materials. To understand genetic diversity and its structural pattern thoroughly in the six clone collection populations, a further study with extensive and systematic sampling of European black poplar populations in major river ecosystems in Turkey will be useful. 相似文献