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1.
Chin-Sung Chang Do Yol Choi Hui Kim Tae Yoon Park Yong-Sik Kim 《Journal of Plant Biology》2005,48(4):339-350
Patterns of variation at 27 allozyme loci were investigated in the endangered endemic plantMegaleranthis saniculifolia. Levels of allozyme variation (A = 1.47,P = 40%,He = 0.088) were also compared with other endemic plant species. Genetic divergence between populations was very high (G
st
= 0.271 ), with moderate to high interpopulation differentiation, which probably arose through historical bottlenecks in
a landscape of habitat fragmentation and/or human influence. The percentage of polymorphic loci, heterozygosity, and mean
number of alleles per locus were positively related to population size, probably due to the stochastic loss of rare alleles
in the smaller populations. Individuals in the small and marginal populations (TB, KD, and CJ) showed higher proportions of
fixed loci. These ecologically marginal populations were typically more distant from the nearest neighboring population and
were more genetically distinct from one another. The genetic structure of the current population ofM. saniculifolia is probably the result of local extinctions of intervening populations. This, in turn, is due to the Pleistocene climatic
change and increased habitat destruction. A positive association appears to exist between genetic diversity and population
size. Although these small population sizes are more sensitive to stochastic events, securing a certain number of individuals
from the three larger populations (SB, JB, and TG) could be accomplished as part of a conservation strategy. In addition,
it is important to prioritize populations in different regions in order to limit population declines caused by large-scale
environmental catastrophes. 相似文献
2.
Genetic diversity in fragmented populations of Berchemiella wilsonii var. pubipetiolata (Rhamnaceae) 总被引:6,自引:0,他引:6
BACKGROUD AND AIMS: Berchemiella wilsonii var. pubipetiolata (Rhamnaceae) is distributed in fragmented habitat patches in eastern China. It is highly endangered because of severe disturbance by anthropogenic activities. Information on genetic variation and structure is critical for developing successful conservation strategies for this species. METHODS: Allozyme variation of population genetic diversity and structure was investigated for a total of 98 individuals sampled from four extant populations using isoelectric focusing in thin-layer polyacrylamide slab gels. KEY RESULTS: Based on 20 loci scored from the nine enzymes examined, a high genetic diversity was detected at both the species and population level, while there was a loss of low frequency alleles (<0.1) in all populations. Most loci showed deviation from Hardy-Weinberg equilibrium due to excess of heterozygotes in all populations, suggesting that selection for heterozygotes has occurred in this species. The genetic diversity was mainly found within populations with a moderate genetic differentiation (F(ST) = 0.13), but the two geographically discontinuous population groups showed significant differences, with F-statistic values of 0.078 for the Zhejiang populations and 0.014 for the Anhui populations, respectively. CONCLUSIONS: It appears most likely that this species has experienced a recent decrease in population size, and genetic drift in small populations has resulted in a loss of alleles occurring at low frequency. The differentiation into two population groups reflects a population genetic consequence that has been influenced by the different land-use in the two regions. Some conservation concerns are discussed together with possible strategies for implementing in situ and ex situ conservation. 相似文献
3.
García JT Suárez F Garza V Calero-Riestra M Hernández J Pérez-Tris J 《Molecular phylogenetics and evolution》2008,46(1):237-251
Identifying genetically and phenotypically distinct populations of threatened species is critical if we are to delineate appropriate plans for their conservation. We conducted an integrated analysis of population genetic structure, historical demographic events, current gene flow (all based on mtDNA sequences) and morphological variation of three geographically separated groups of populations of Dupont's lark Chersophilus duponti, located in the Iberian Peninsula (three populations), Morocco (two populations), and Tunisia (one population). Unusually, this lark species is the only one among the genus Chersophilus. Our results revealed the early historical divergence of an eastern Dupont's lark lineage (in Tunisia) and a western lineage (in Morocco and Spain), consistent with subspecies taxonomy and distribution. The western lineage subsequently split into two lineages, following the isolation of Iberian and African populations. Such pattern of historical differentiation caused great population genetic structure, with differences among geographic areas explaining more than 80% of total genetic variation. Mismatch distributions and coalescent estimates of divergence time showed that lineage divergence was associated with sudden population expansion events, which apparently took place during the last glaciation, when steppe habitats were widespread across the Mediterranean region. Extant populations from different geographic areas hardly shared any haplotype (only one out of 16 ND2 haplotypes was shared by Tunisian and Moroccan Dupont's larks), and consequently gene flow between geographic areas was found to be virtually absent. Apart from showing great genetic differentiation, Dupont's larks from different geographic areas were morphologically distinct, showing substantial variation in body size and feeding-related traits (length of feet and bill). We conclude that Dupont's lark populations isolated in the Iberian Peninsula, Morocco, and Tunisia are distinct evolutionary entities and should be considered as such in conservation plans. Such circumstance sets a daunting conservation challenge that exemplifies the need of incorporating knowledge of historical processes to our general understanding of the demography of threatened species. 相似文献
4.
Nelli Rnk Veli‐Matti Pakanen Donald Blomqvist Victor Degtyaryev Mikhail Golovatin Gennady Isakov Natalia Karlionova Aija Lehikoinen Vladimir Morozov Sergey Paskhalny Angela Pauliny Pavel Pinchuk Pentti Rauhala Pavel Tomkovich Evgeny Zakharov Kari Koivula Laura Kvist 《Ibis》2019,161(3):632-647
Populations from different parts of a species range may vary in their genetic structure, variation and dynamics. Geographically isolated populations or those located at the periphery of the range may differ from those located in the core of the range. Such peripheral populations may harbour genetic variation important for the adaptive potential of the species. We studied the distribution‐wide population genetic structure of the Terek Sandpiper Xenus cinereus using 13 microsatellite loci and the mitochondrial DNA (mtDNA) control region. In addition, we estimated whether genetic variation changes from the core towards the edge of the breeding range. We used the results to evaluate the management needs of the sampled populations. Distribution‐wide genetic structure was negligible; the only population that showed significant genetic differentiation was the geographically isolated Dnieper River basin population in Eastern Europe. The genetic variation of microsatellites decreased towards the edge of the distribution, supporting the abundant‐centre hypotheses in which the core area of the distribution preserves the most genetic variation; however, no such trend could be seen with mtDNA. Overall genetic variation was low and there were signs of past population contractions followed by expansion; this pattern is found in most northern waders. The current effective population size (Ne) is large, and therefore global conservation measures are not necessary. However, the marginal Dnieper River population needs to be considered its own management unit. In addition, the Finnish population warrants conservation actions due to its extremely small size and degree of isolation from the main range, which makes it vulnerable to genetic depletion. 相似文献
5.
Manja U. Böhme Norbert Schneeweiß Uwe Fritz Martin Schlegel Thomas U. Berendonk 《Conservation Genetics》2007,8(3):555-563
Edge and central populations can show great differences regarding their genetic variation and thereby also in their probability
of extinction. This fact might be of great importance for the conservation strategies of endangered species. In this study
we examine the level of microsatellite variability within three threatened edge populations of the green lizard subspecies
Lacerta viridis viridis (Laur.) in Brandenburg (Germany) and compare the observed variation to other edge and central populations within the northern
species range. We demonstrate that the northernmost edge populations contain less genetic variation in comparison to the central
population. However, there were no observable significant differences to the other edge population included in this study.
Surprisingly, we observed a high genetic differentiation in a small geographical range between the three endangered populations
in Brandenburg, which can be explained by processes like fragmentation, isolation, genetic drift and small individual numbers
within these populations. We also detected unique genetic variants (alleles), which only occurred in these populations, despite
a low overall genetic variation. This study demonstrates the potential of fast evolving markers assessing the genetic status
of endangered populations with a high resolution. It also illustrates the need for a comparative analysis of different regions
within the species range, achieving a more exact interpretation of the genetic variation in endangered populations. This will
aid future management decisions in the conservation of genetic diversity in threatened species. 相似文献
6.
Wild rice, Oryza rufipogon, has endangered species conservation status and it is subject to in situ conservation in China. To understand the potential of the seed bank in species conservation and population restoration, this study compared the genetic diversity of O. rufipogon plants with that of its soil seed banks in two marshes. A total of 11 pairs of rice SSR primers were used and 9 were polymorphic. Allele frequencies of the seeds differed significantly from those of surface plants and varied between soil layers. Relatively more alleles and higher genetic diversity (H
e) were found in plant populations, relative to seed banks. The numbers of germinable seeds and the level of genetic variation in seed banks decreased with the increasing of soil depth, indicating a rapid seed loss. Genetic differentiation was detected between sites and between plant and seed populations, as well as among seeds of different soil strata. Rapid seed loss, partly dormancy loss, and nonrandom seed mortality are discussed as the possible contributors to the pattern of reduced genetic variation within seed banks, compared to plants. These could also be responsible for the considerable genetic differentiation between populations. The seed population held about 72% of the total genetic variation of O. rufipogon in each marsh, indicating the potential of seed banks for restoring population variabilities if the plant populations were lost. 相似文献
7.
Omphalogramma souliei Franch. is an endangered perennial herb only distributed in alpine areas of SW China. ISSR markers were applied to determine the genetic variation and genetic structure of 60 individuals of three populations of O. souliei in NW Yunnan, China. The genetic diversity at the species level is low with P=42.5% (percentage of polymorphic bands) and Hsp=0.1762 (total genetic diversity). However, a high level of genetic differentiation among populations was detected based on different measures (Nei's genetic diversity analysis: Gst=0.6038; AMOVA analysis: Fst=0.6797). Low level of genetic diversity within populations and significant genetic differentiation among populations might be due to the mixed mating system in which xenogamy predominated and autogamy played an assistant role in O. souliei. The genetic drift due to small population size and limited current gene flow also resulted in significant genetic differentiation. The assessment of genetic variation and differentiation of the endangered species provides important information for conservation on a genetic basis. Conservation strategies for this rare endemic species are proposed. 相似文献
8.
Patricia Delgado Daniel Pinero Alvaro Chaos Nidia Pe´rez-Nasser Elena R. Alvarez-Buylla 《American journal of botany》1999,86(5):669-676
Pinus rzedowskii is an endangered pine species from Michoaca´n (central Me´xico), which has been previously reported from only three localities. Classified within the subgenus Strobus, it exhibits intermediate morphological characters between subgenera Strobus and Pinus. We analyzed genetic aspects that could shed light on the evolution and conservation of this species. The genetic structure of nine populations was examined using 14 isozyme loci. Pinus rzedowskii has a relatively high level of genetic variation with 46.8% of the loci assayed being polymorphic, a total of 35 alleles, and a mean heterozygosity per population of 0.219. We calculated Wright's FST statistic to estimate gene flow indirectly and to evaluate whether or not there was genetic structuring among populations. We found a marked differentiation among populations (FST = 0.175) and significant inbreeding (FIS = 0.247). No pattern of isolation by distance was found. We also constructed a dendrogram based on a genetic distance matrix to obtain an overview of the possible historical relationships among populations. Finally, we found a convex relationship between the genetic distance among populations and the number of ancestral lineages, suggesting that demographically this species has not been at risk recently. Although endangered, with small and fragmented populations, P. rzedowskii shows higher levels of genetic variation than other conifer species with larger populations or similar conservation status. 相似文献
9.
Genetic diversity in the northernmost<Emphasis Type="Italic"> Oryza rufipogon</Emphasis> populations estimated by SSR markers 总被引:16,自引:0,他引:16
Song ZP Xu X Wang B Chen JK Lu BR 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2003,107(8):1492-1499
To estimate genetic diversity of the residual northern populations of Oryza rufipogon, a total of 232 individuals from six populations were analyzed using microsatellites (SSRs). The O. rufipogon populations with different status included three from Dongxiang (Jiangxi Province) and three from Chaling (Hunan Province) in China. The 23 rice SSR primer pairs selected from the RiceGenes Database detected a total of 115 alleles, indicating that all the SSR loci were polymorphic in this study. The total gene diversity was 0.919 in the six O. rufipogon populations, and the Donxiang populations showed higher diversity than the Chaling populations. More significant genetic differentiation and less gene flow were found among the Dongxiang populations than those from Chaling. The two putative introgressed populations showed relatively high genetic variation. One in situ conserved population from Dongxiang had the lowest level of genetic diversity. The re-introduced population from Chaling restored about 90% of the genetic variation, compared with the original source population. It is concluded from these results that a relatively high level of genetic variation resided in the northern O. rufipogon populations and continued efforts of conservation of these populations are needed; and that the conservation of some Chaling and Dongxiang populations has been effective in preventing gene flow from cultivated rice. Introgression of cultivated rice demonstrated significant impacts on genetic variability of the O. rufipogon populations, and should be carefully considered in conserving this wild rice. This study also suggested that re-introduction to its original habitats is an effective approach to restore O. rufipogon populations.Communicated by J.S. Heslop-Harrison 相似文献
10.
Ting-Long Guan Bo Zeng Que-Kun Peng Bi-Song Yue Fang-Dong Zou 《Biochemical Systematics and Ecology》2009,37(3):166-173
Forest musk deer (Moschus berezovskii) are rare as a result of poaching for musk and habitat loss. Some captive populations of forest musk deer have been established for decades in China. However, little genetic information is available for conservation management. In this paper, genetic variations, population structures, and the genetic bottleneck hypothesis were examined using 11 microsatellite loci from captive populations in Miyalo, Jinfeng and Maerkang in Sichuan Province, China. Estimates of genetic variability revealed substantial genetic variation in the three populations. A total of 142 different alleles were observed in 121 forest musk deer and the effective number of alleles per locus varied from 6.76 to 12.95. The average values of observed heterozygosity, expected heterozygosity, and Nei's expected heterozygosity were 0.552, 0.899 and 0.894 respectively. The overall significant (P < 0.001) deficit of heterozygotes because of inbreeding within breeds amounted to 34.5%. The mean FST (P < 0.001) showed that approximately 90.2% of the genetic variation was within populations and 9.8% was across populations. The UPGMA diagram, based on Nei's unbiased genetic distance, indicated that the three populations were differentiated into two different groups and it agreed with their origin and history. Bottleneck tests indicated that all three populations have undergone a population bottleneck, suggesting a small effective population size. Acknowledging that the genetic structure of populations has crucial conservation implications, the present genetic information should be taken into account in management plans for the conservation of captive forest musk deer. 相似文献
11.
Heptacodium miconioides Rehd. is an endangered species endemic to China and has suffered rapid decrease of distribution range and population size.
This species has been disappeared in central China where the modal specimen was collected. We analyzed the genetic variation
of the remaining populations to reveal whether the genetic diversity also suffered decrease and to provide some suggestions
for conservation. All the nine known remaining populations were sampled. Genetic variation was analyzed based on RAPD markers
and two fragments of cpDNA sequence, intergenic spacers of petG-trnP and trnS-trnG. No variation was observed in the two fragments of cpDNA sequence. However, the species exhibited high level of RAPD variation
compared to other threatened or rare plants. Measures of genetic diversity within populations were strongly related to the
log of estimated population size, indicating that large populations usually have more genetic diversity than that of small
ones. About 25% of the variation was partitioned among populations. Significant relationship was observed between differentiation
and geographical distance, indicating a pattern of isolation-by-distance. Given for few populations remaining, all the populations
should be protected and urgent efforts be paid on the small populations to avoid their local extinction. 相似文献
12.
Thulin CG Simberloff D Barun A McCracken G Pascal M Islam MA 《Molecular ecology》2006,15(13):3947-3956
The combination of founder events, random drift and new selective forces experienced by introduced species typically lowers genetic variation and induces differentiation from the ancestral population. Here, we investigate microsatellite differentiation between introduced and native populations of the small Indian mongoose (Herpestes auropunctatus). Many expectations based on introduction history, such as loss of alleles and relationships among populations, are confirmed. Nevertheless, when applying population assignment methods to our data, we observe a few specimens that are incorrectly assigned and/or appear to have a mixed ancestry, despite estimates of substantial population differentiation. Thus, we suggest that population assignments of individuals should be viewed as tentative and that there should be agreement among different algorithms before assignments are applied in conservation or management. Further, we find no congruence between previously reported morphological differentiation and the sorting of microsatellite variation. Some introduced populations have retained much genetic variation while others have not, irrespective of morphology. Finally, we find alleles from the sympatric grey mongoose (Herpestes edwardsii) in one small Indian mongoose within the native range, suggesting an alternative explanation for morphological differentiation involving a shift in female preferences in allopatry. 相似文献
13.
Costello AB Down TE Pollard SM Pacas CJ Taylor EB 《Evolution; international journal of organic evolution》2003,57(2):328-344
An understanding of the relative roles of historical and contemporary factors in structuring genetic variation is a fundamental, but understudied aspect of geographic variation. We examined geographic variation in microsatellite DNA allele frequencies in bull trout (Salvelinus confluentus, Salmonidae) to test hypotheses concerning the relative roles of postglacial dispersal (historical) and current landscape features (contemporary) in structuring genetic variability and population differentiation. Bull trout exhibit relatively low intrapopulation microsatellite variation (average of 1.9 alleles per locus, average He = 0.24), but high levels of interpopulation divergence (F(ST) = 0.39). We found evidence of historical influences on microsatellite variation in the form of a decrease in the number of alleles and heterozygosities in populations on the periphery of the range relative to populations closer to putative glacial refugia. In addition, one region of British Columbia that was colonized later during deglaciation and by more indirect watershed connections showed less developed and more variable patterns of isolation by distance than a similar region colonized earlier and more directly from refugia. Current spatial and drainage interconnectedness among sites and the presence of migration barriers (falls and cascades) within individual streams were found to be important contemporary factors influencing historical patterns of genetic variability and interpopulation divergence. Our work illustrates the limited utility of equilibrium models to delineate population structure and patterns of genetic diversity in recently founded populations or those inhabiting highly heterogeneous environments, and it highlights the need for approaches incorporating a landscape context for population divergence. Substantial microsatellite DNA divergence among bull trout populations may also signal divergence in traits important to population persistence in specific environments. 相似文献
14.
Theory predicts that genetic diversity and genetic differentiation may strongly vary among populations of the same species depending on population turnover and local population sizes. Yet, despite the importance of these predictions for evolutionary and conservation issues, empirical studies comparing high‐turnover and low‐turnover populations of the same species are scarce. In this study, we used Daphnia magna, a freshwater crustacean, as a model organism for such a comparison. In the southern/central part of its range, D. magna inhabits medium‐sized, stable ponds, whereas in the north, it occurs in small rock pools with strong population turnover. We found that these northern populations have a significantly lower genetic diversity and higher genetic differentiation compared to the southern/central populations. Total genetic diversity across populations was only about half and average within‐population diversity only about a third of that in southern/central populations. Moreover, an average southern population contains more genetic diversity than the whole metapopulation system in the north. We based our analyses both on silent sites and microsatellites. The similarity of our results despite the contrasting mutation rates of these markers suggests that the differences are caused by contemporary rather than by historical processes. Our findings show that variation in population turnover and population size may have a major impact on the genetic diversity and differentiation of populations, and hence may lead to differences in evolutionary processes like local adaptation, hybrid vigour and breeding system evolution in different parts of a species range. 相似文献
15.
Sanne Boessenkool Sabrina S. Taylor Carolyn K. Tepolt Jan Komdeur Ian G. Jamieson 《Conservation Genetics》2007,8(3):705-714
For conservation purposes islands are considered safe refuges for many species, particularly in regions where introduced predators
form a major threat to the native fauna, but island populations are also known to possess low levels of genetic diversity.
The New Zealand archipelago provides an ideal system to compare genetic diversity of large mainland populations where introduced
predators are common, to that of smaller offshore islands, which serve as predator-free refuges. We assessed microsatellite
variation in South Island robins (Petroica australis australis), and compared large mainland, small mainland, natural island and translocated island populations. Large mainland populations
exhibited more polymorphic loci and higher number of alleles than small mainland and natural island populations. Genetic variation
did not differ between natural and translocated island populations, even though one of the translocated populations was established
with five individuals. Hatching failure was recorded in a subset of the populations and found to be significantly higher in
translocated populations than in a large mainland population. Significant population differentiation was largely based on
heterogeneity in allele frequencies (including fixation of alleles), as few unique alleles were observed. This study shows
that large mainland populations retain higher levels of genetic diversity than natural and translocated island populations.
It highlights the importance of protecting these mainland populations and using them as a source for new translocations. In
the future, these populations may become extremely valuable for species conservation if existing island populations become
adversely affected by low levels of genetic variation and do not persist. 相似文献
16.
17.
Allozyme variations in six natural populations of scots pine (<Emphasis Type="Italic">Pinus sylvestris</Emphasis>) in Turkey 总被引:3,自引:0,他引:3
Genetic variation in six natural populations of Scots pine (Pinus sylvestris L.) was determined with isoenzyme analyses. For this purpose, haploid female gametophytes of seeds and horizontal starch
gel electrophoresis technique were used. A total of 17 loci and 58 alleles were observed in studying 10 enzyme systems. The
average proportion of polymorphic loci for populations ranged from 58.8% to 70.6%. The average number of alleles per locus
per population was 2.65. The mean estimated expected heterozygosity (He) of populations was 0.294. A rather high proportion
of genetic diversity (96.4%) was due to within-population variation and the remaining (3.6%) was due to variation among populations.
The level of gene flow (Nem) was found to be 6.69 per generation. Nei’s genetic distance coefficient ranged from 0.006 to 0.027 (mean 0.017) among all
possible population pairs. The mean value of Nei’s genetic distance is similar to the values reported for other European Scots
pine populations. The low mean value of Nei’s genetic distance among populations is enough to explain low interpopulation
variation. According to genetic variation parameters, three out of six populations (Akdagmadeni-Yozgat, Refahiye-Erzincan
and Vezirkopru-Samsun) appear to be preferable populations for genetic conservation and forest tree breeding programs. 相似文献
18.
Emma Carlson Anna J. MacDonald Aaron Adamack Tim McGrath Lisa I. Doucette William S. Osborne Bernd Gruber Stephen D. Sarre 《Conservation Genetics》2016,17(4):761-774
Species are the most commonly recognised unit for conservation management, yet significant variation can exist below the level of taxonomic recognition and there is a lack of consensus around how a species might be defined. This definition has particular relevance when species designations are used to apportion conservation effort and when definitions might be made through legislation. Here, we use microsatellite DNA analyses to test the proposition that the last remaining populations of the endangered grassland earless dragon (Tympanocryptis pinguicolla) harbour substantial cryptic genetic variation. Our study provides strong evidence that long historical isolation and the recent impacts of urbanization, have led to genetic differentiation in microsatellite DNA allele frequencies and high numbers of private alleles among three genetic clusters. This differentiation is partially concordant with previous mitochondrial DNA analyses, which show the two regions (Canberra and Monaro) where this species exists, to be reciprocally monophyletic, but differs through the identification of a third genetic cluster that splits a northern Canberra cluster from that of southern Canberra. Our data also identify a stark contrast in population genetic structure between clusters such that high levels of genetic structure are evident in the highly urbanised Canberra region but not in the largely rural Monaro region. We conclude that this species, like many reptiles, harbours considerable cryptic variation and currently comprises three distinct and discrete units. These units could be classified as separate species for the purpose of conservation under the relevant Australian and international Acts drawing management appropriate to that status. 相似文献
19.
The common hamster (Cricetus cricetus L.), a rodent of the Eurasian steppes and agricultural areas, is threatened by habitat loss. Remnant populations in Western and Central Europe are small, isolated and genetically impoverished. The populations of Belgium, The Netherlands and North Rhine-Westphalia, Germany (BNN), for which Nehring proposed the epiphet canescens, are most affected by this decline. They are distinguished from more eastern populations by large, white areas on throat, chest and forelegs. These traits are sometimes also found in other populations, which casts doubt on their value as diagnostic characteristics. Here, we show that the frequency of occurrence of relatively large chest spots, chin streaks and cuffs on the forelegs is highest in BNN, where a white chest spot occurs in 67–100 % of the sampled individuals, compared to 0–8 % in Central and Eastern European populations. Additionally, hamsters from the Upper Rhine area also display relatively high frequencies of these characters (7–44 %). This suggests a common origin of BNN and Upper Rhine hamsters and an ancient expansion route along the Rhine Valley. A supplementary genetic study of two mitochondrial genes revealed extremely low diversity in both BNN and Upper Rhine hamsters but also clear differentiation and isolation between the two remaining relict populations of North Rhine-Westphalia. 相似文献
20.
The majority of research in genetic diversity yields recommendations rather than actual conservation achievements. We assessed
the efficacy of actual in situ and ex situ efforts to conserve Parashorea chinensis (Dipterocarpaceae) against the background of the geographic pattern of genetic variation of this species. Samples from seven
natural populations, including three in a nature reserve, and one ex situ conservation population were studied. Across the
natural populations, 47.8% of RAPD loci were polymorphic; only 20.8% on average varied at the population level. Mean population
genetic diversity was 0.787 within natural populations and 1.410 for the whole species. Significant genetic differentiation
among regions and isolation by distance were present on larger scales (among regions). AMOVA revealed that the majority of
the among-population variation occurred among regions rather than among populations within regions. Regression analysis, Mantel
test, principal coordinates analysis, and cluster analysis consistently demonstrated increasing genetic isolation with increasing
geographic distance. Genetic differentiation within the region was quite low compared to that among regions. Multilocus spatial
autocorrelation analysis of these three populations revealed random distribution of genetic variation in two populations,
but genetic clustering was detected in the third population. The ex situ conserved population contained a medium level of
genetic variation compared with the seven natural populations; it contained 77.1% of the total genetic variation of this species
and 91% of the moderate to high frequency RAPD fragments (f > 0.05). Exclusive bands were detected in natural populations,
but none were found in the ex situ conserved population. The populations protected in the nature reserve contained most of
the genetic variation of the whole species, with 81.4% of the total genetic variation and 95.7% of the fragments with moderate
to high frequency (f > 0.05) of this species conserved. The results show that the ex situ conserved population does not contain
enough genetic variation to meet the need of release in the future, and that more extensive ex situ sampling in natural populations
TY, NP, HK, and MG is needed. The in situ conserved population contains representative genetic variation to maintain long-term
survival and evolutionary processes of P. chinensis. 相似文献