Population dynamics of the endangered plant, Phaedranassa tunguraguae, from the Tropical Andean hotspot

The Tropical Andes is a diversity hotspot for plants, but there is a scant knowledge about patterns of genetic variation within its constituent species. Phaedranassa tunguraguae is an IUCN endangered plant species endemic to a single valley in the Ecuadorian Andes. We estimate the levels of genetic differentiation across the geographic distribution of P. tunguraguae using 12 microsatellite loci. We discuss factors that might influence the genetic structure of this species. Genetic distance was used to evaluate relationship among populations and geographic patterns. Bayesian methods were used to investigate population structure, migration, evidence of recent bottlenecks, and time of divergence. The 7 populations form 2 genetic clusters. These clusters show highly significant differentiation between them, along with isolation by distance. Allele richness decreases from the most diverse westernmost population to the least diverse easternmost population. The species overall shows an excess of homozygotes, with highest levels of inbreeding in the easternmost population. We found evidence of recent bottleneck events. Migration rates were in general low but were higher between populations within each of the clusters. Time of divergence between populations was related to historical volcanic activity in the area. Based on our results, we propose 2 management units for P. tunguraguae.     

Genetic variation in Costa Rican populations of the tropical timber species Cedrela odorata L., assessed using RAPDs

Cedrela odorata L. (Spanish cedar), an economically important timber species native to the American tropics, is the focus of increasing conservation concern due to high rates of deforestation within its native range. To assess the extent of the genetic diversity within and between populations of this species, samples were obtained from 10 widely dispersed populations within Costa Rica and analysed for random amplified polymorphic DNA (RAPD) variation. Fourteen 10-mer primers were used to generate 97 polymorphic RAPD bands. Presence/absence data for all bands were subjected to a pairwise genetic distance analysis, according to Jaccard's coefficient, then neighbour-joining cluster analysis was performed on these distances, as was an analysis of molecular variance ( AMOVA ), to assess levels of differentiation between populations and regions, and Shannon's Diversity Index was used to quantify levels of diversity within and between populations. Results indicated highly significant genetic differentiation ( P < 0.004, AMOVA ) between populations originating from the North Pacific and Atlantic/South Pacific regions of Costa Rica, with 35.3% of the total variation attributable to a difference between these areas. Little differentiation was recorded between populations from within the same region ( P = 0.757, AMOVA ), and 65.1% of the total variance was attributable to variation within populations. Estimated values for within-population diversity, calculated as H _pop/ H _sp by means of Shannon's Diversity Index, were found to vary greatly between primers, but the overall within-population component of genetic diversity was 0.45. Possible reasons for the high degree of intraspecific genetic variation within this species are discussed and the implications of these results for the conservation and use of its genetic resources are described.     

都支杜鹃遗传多样性的ISSR分析

通过ISSR分子标记对都支杜鹃(Rhododendron shanii)5个居群114个个体的遗传多样性进行了分析。8个引物共检测到69个位点,其中多态位点36个,多态位点百分率 （P） 为52.17%;物种水平的Shannon多样性指数（I）为0.2536,Nei指数（H）为0.1659;居群水平的P、I和H分别平均为32.46%、0.1955和0.1344;Nei’s基因分化系数GST=0.1845,基因流Nm=2.2104;遗传结构的AMOVA分析显示,总的遗传变异中88.3%存在于居群内,11.7%存在于居群间;PCA分析和Splite Tree构建的NJ树均显示居群间分化小;遗传距离与地理距离显著相关。较强的基因流、多年生木本及异交与分布区狭窄等可能是导致都支杜鹃遗传多样性较低的主要原因。目前该种的保护应以就地保护为主,尤其要注意对大居群的保护。     

Primula farinosa in Denmark; genetic diversity and population management

During the past centuries Danish populations of Primula farinosa have seriously declined in number. We investigated the genetic structure and genetic diversity of plants of seven populations from two different regions, Zealand and Bornholm in Denmark, using three AFLP markers. Two populations from nearby Scania, Sweden were included as reference. We found 54 unambiguously polymorphic loci. The genetic structure analysis suggested division of the 268 plants into three distinct groups, to a large extent matching the geographical distribution of the populations. Analysis of molecular variance (AMOVA) indicated significant genetic differentiation of 67% within populations and 33% among the populations. Our results suggest that genetic differentiation among regions and unique local genetic diversity should carefully be considered in future conservation attempts if we are to maintain as much genetic variation as possible. We present a historical overview of the decline in Danish populations and discuss conservation management and restoration strategies.     

Genetic Diversity and Structure of Dalmatian Pyrethrum (Tanacetum cinerariifolium Trevir. /Sch./ Bip., Asteraceae) within the Balkan Refugium

Dalmatian pyrethrum (Tanacetum cinerariifolium Trevir. /Sch./ Bip.) is an outcrossing, perennial insecticidal plant, restricted to the eastern Adriatic coast (Mediterranean). Amplified fragment-length polymorphisms (AFLP) were used to investigate the genetic diversity and structure within and among 20 natural plant populations. The highest level of gene diversity, the number of private alleles and the frequency down-weighted marker values (DW) were found in northern Adriatic populations and gradually decreased towards the southern boundary of the species range. Genetic impoverishment of these southern populations is most likely the result of human-related activities. An analysis of molecular variance (AMOVA) indicated that most of the genetic diversity was attributed to differences among individuals within populations (85.78%), which are expected due to the outcrossing nature of the species. A Bayesian analysis of the population structure identified two dominant genetic clusters. A spatial analysis of the genetic diversity indicated that 5.6% of the genetic differentiation resulted from isolation by distance (IBD), while 12.3% of the genetic differentiation among populations followed the pattern of isolation by environmental distance (IBED). Knowledge of the genetic diversity patterns of the natural populations and the mechanism behind these patterns is required for the exploitation and possible conservation management of this endemic and economically important species.     

RAPD Profiling in Detecting Genetic Variation in Endemic Coelonema (Brassicaceae) of Qinghai-Tibet Plateau of China

Random amplified polymorphic DNA (RAPD) markers were used to measure genetic diversity of Coelonema draboides (Brassicaceae), a genus endemic to the Qilian Mountains of the Qinghai-Tibet Plateau. We sampled 90 individuals in 30 populations of Coelonema draboides from Datong and Huzhu counties of Qinghai Province in P.R. China. A total of 186 amplified bands were scored from the 14 RAPD primers, with a mean of 13.3 amplified bands per primer, and 87% (161 bands) polymorphic bands (PPB) was found. Analysis of molecular variance (AMOVA) shows that a large proportion of genetic variation (84.2%) resides among individuals within populations, while only 15.8% resides among populations. The species shows higher genetic diversity between individuals than other endemic and endangered plants. The RAPDs provide a useful tool for assessing genetic diversity of rare, endemic species and for resolving relationships among populations. The results show that the genetic diversity of this species is high, possibly allowing it to adapt more easily to environmental variations. The main factor responsible for the high level of differentiation within populations and the low level of diversity among populations is probably the outcrossing and long-lived nature of this species. Some long-distance dispersal, even among far separated populations, is also a crucial determinant for the pattern of genetic variation in the species. This distributive pattern of genetic variation of C. draboides populations provides important baseline data for conservation and collection strategies for the species. It is suggested that only populations in different habitats should be studied and protected, not all populations, so as to retain as much genetic diversity as possible.     

ISSR analysis of genetic diversity of the Qinghai-Tibet Plateau endemic Rhodiola chrysanthemifolia (Crassulaceae)

Inter-simple sequence repeat markers (ISSR) were used to estimate genetic diversity within and among 10 populations of Rhodiola chrysanthemifolia along Nianqingtangula Mountains and Brahmaputra, a species endemic to the Qinghai-Tibet Plateau and an endangered medicinal plant. Of the 100 primers screened, 13 produced highly polymorphic DNA fragments. Using these primers, 116 discernible DNA fragments were generated of which 104 (89.7%) were polymorphic, indicating substantial genetic diversity at the species level. Genetic diversity measured by the percentage of polymorphic bands (PPB) at the population level ranged from 21.97% to 48.8%. Analysis of molecular variance (AMOVA) showed that the genetic variation was found mainly among populations (77.3%), but no regional differentiation was discernible. Variance within populations was only 22.7%. The main factor responsible for this high level of differentiation among populations is probably the historical geographical and genetic isolation of populations in a harsh mountainous environment. Concerning the management of R. chrysanthemifolia, the high genetic differentiation of populations indicates the necessity of conserving the maximum possible number of populations.     

Patterns of genetic and phenotypic variation in Iris haynei and I. atrofusca (Iris sect. Oncocyclus = the royal irises) along an ecogeographical gradient in Israel and the West Bank

Iris haynei and I. atrofusca are two closely related narrow endemics distributed vicariously along an ecogeographical north-south gradient in Israel and the West Bank. To obtain baseline information of the taxonomic status, conservation and population history of these taxa, we investigated patterns of phenotypic variation and the partitioning of genetic variation within and among populations using dominant random amplified polymorphic DNA (RAPD) markers. Multivariate (principal components analysis) and taxonomic distance analyses based on morphometric traits from eight populations revealed no unambiguous separation into two distinct groups. Results of genetic analyses for nine populations differed only slightly when either allele- or marker-based approaches were employed. Mean within-population diversity was high (0.258 for Nei's expected heterozygosity), but there was no significant relationship between genetic diversity and either population size or latitude. Although the range-wide estimate of GST ( approximately 0.20) revealed relatively high differentiation among populations this value was inflated because of a small, but significant, component of molecular variance among regions viz. taxa ( approximately 5%). Limited long-distance dispersal capabilities in conjunction with a linearized habitat distribution are proposed to contribute to the approximate isolation by distance pattern observed. It also appears that extant populations are currently deviating from equilibrium conditions because of primary divergence of a formerly more widespread ancestral population. Given the absence of deep genetic and phenotypic subdivision among northern (I. haynei) vs. central/southern (I. atrofusca) populations, we argue for a revision of their species status. Nonetheless, we recommend conservation attention to these geographically differentiated segments as separate management units, which can be seen as an instructive example of incipient species formation.     

Genetic Diversity and Population Structure in Fragmented Natural Populations of Melia dubia Cav. Revealed by SSR Markers—Its Implications on Conservation

Melia dubia, a fast-growing tree species with multi-various uses, is suitable species for agro and farm forestry. In an extensive survey in eight districts of Karnataka, India, it was observed that the majority of M. dubia natural populations are fragmented and tree number is very less. Sixty trees were selected to assess the genetic variability using SSR markers. Analysis revealed a moderate level of genetic diversity (Ho?=?0.47; He?=?0.69) and inbreeding as evinced by overall positive fixation index of 0.30. Mean Fst observed was 0.16 indicating moderate genetic differentiation among populations. The analysis of molecular variance ascribed 99% of total genetic diversity to within population variation. Cluster analysis by unweighted pair group method and genetic differentiation through structure analysis did not differentiate 10 populations as per geographic location, showing that moderate genetic diversity was not due to geographic distance. As genetic diversity was more within population, selection of individual plants would be more effective for genetic improvement to capture the natural variation within the population. An understanding of genetic diversity and differentiation of M. dubia natural populations will help in exploiting the genetic resource for tree improvement and also in formulating management and conservation strategies for this species.

     

Genetic variation of Calycophyllum spruceanum in the Peruvian Amazon Basin, revealed by amplified fragment length polymorphism (AFLP) analysis

An understanding of the level, structure and origin of genetic variation within and among populations of tropical trees is essential for devising optimum management strategies for their sustainable utilization and conservation. Here, amplified fragment length polymorphism (AFLP) analysis was used to partition genetic variation within and among nine populations of the predominantly riverine tree, Calycophyllum spruceanum , sampled across a wide geographical range along river tributaries of the Peruvian Amazon Basin. Analysis of molecular variance ( AMOVA ) employed 65 AFLP markers and revealed most variation among individuals within populations (91%), although variation among populations was highly significant ( P < 0.001). Calculation of genetic distances and nested AMOVA indicated a degree of structuring among populations based on geographical proximity, although clustering did not depend on geographical distance alone. No firm evidence was obtained for unidirectional seed dispersal by water playing an important role in determining genetic structure over the geographical range sampled. Implications of data for optimising genetic management of the species are discussed and areas for further study identified.     

Assessing genetic diversity of Elymus sibiricus (Poaceae: Triticeae) populations from Qinghai-Tibet Plateau by ISSR markers

Inter-simple sequence repeats (ISSR) markers were used to assess the genetic diversity and population structure in eight populations of Elymus sibiricus L. from the southeast of Qinghai-Tibet Plateau of China. Of the 100 primers screened, 13 produced highly reproducible ISSR bands. Using these primers, 193 discernible DNA fragments were generated with 149 (77.2%) being polymorphic, indicating considerable genetic variation at the species level. In contrast, there were relatively low levels of polymorphism at the population level with the percentage of polymorphic bands (PPB) ranging from 44.04 to 54.92%. The mean gene diversity (H_E) was estimated to be 0.181 within populations (range 0.164–0.200), and 0.274 at the species level. A high level of genetic differentiation among populations was detected based on Nei's genetic diversity analysis (33.1%), Shannon's index analysis (34.5%), Bayesian method (33.2%) and AMOVA analysis (42.5%). No significant statistical differences (analysis of molecular variance [AMOVA], P = 0.08) in ISSR variation were found between the sample collection regions. However, among populations (42.5% of the variance) and within populations (57.5% of the variance), there were significant differences (P < 0.001). Populations shared high levels of genetic identity. This pattern of genetic variation was different from that for most of inbreeding Triticeae species reported. In addition, a geographical pattern of population differentiation, where the populations from south and north of sampling sites were clearly separated from each other, was revealed by both the cluster and principal coordinates analyses. Generally, the result of this study indicates that E. sibiricus contains high molecular variation in its populations. The implications of these results for the conservation of the species are discussed.     

High genetic diversity in isolated populations of Thesium ebracteatum at the edge of its distribution range

The aim of this study was to estimate the degree and distribution of genetic diversity within Central-European populations of Thesium ebracteatum—one of the most endangered plant species in Europe. By analyzing allozymes from 17 populations, we estimated the distribution of genetic diversity and suggest the most valuable populations for conservation. Analysis of molecular variance results showed the highest variance existed between populations (54 %), whereas the mean variance within populations was 46 %. A surprisingly low degree of variance (less than 1 %) was found between the six studied regions. We also observed no correlation between geographical and genetic distance, which supports the idea that individual populations are strongly isolated. T. ebracteatum undergoes extensive clonal growth and may survive for very long periods of time without generative reproduction. Consistent with this, we found a strong and significant relationship between genetic diversity and population size. All populations occupying an area greater than 300 m² showed high genetic diversity, whereas small populations contained less genetic diversity. Therefore, conservation priorities could generally be decided based on population size. Because this species is a weak competitor, existing localities should also be managed to prevent species loss from habitat degradation, by mowing or from time to time otherwise disturbing population areas to create open areas for growth.     

武夷山地伯乐树种群遗传多样性的ISSR分析

伯乐树（Bretschneidera sinensis Hemsl.）为我国特有单型科珍稀濒危植物,具重要的科研价值。本研究采用ISSR分子标记对武夷山脉分布的5个伯乐树天然种群和1个移栽种群进行遗传多样性分析。结果表明伯乐树物种水平遗传多样性较高（PPB：75.70%;H_ES：0.304 5;H：0.450 1）,种群水平则较低（PPB：60.13%;H_EP：0.238 1;H：0.347 5）,MJY种群和BSZ种群分别是所有种群中遗传多样性最高和最低的。5个地理种群间遗传分化程度较高（G_st=0.218 1）,原因可能源于伯乐树的繁殖方式及生境片段化,Mantel检验也证实了地理距离与遗传距离具有显著相关性（r=0.626 7,P＜0.05）。针对伯乐树种群遗传多样性现状,建议加强现有自然种群的就地保护,促进种群自然更新。     

A comparison of the genetic diversity in Dipteronia sinensis Oliv. and Dipteronia dyeriana Henry

Dipteronia is an endemic genus to China and includes only two species, Dipteronia sinensis and D.dyeriana.Based on random amplified polymorphic DNA (RAPD) markers,a comparative study of the genetic diversity and genetic structure of Dipteronia was performed.In total,128 and 103 loci were detected in 17 D.sinensis populations and 4 D.dyeriana populations,respectively,using 18 random primers.These results showed that the proportions of polymorphic loci for the two species were 92.97% and 81.55%,respectively,indicating that the genetic diversity of D.sinensis was higher than that of D.dyeriana.Analysis,based on similarity coefficients,Shannon diversity index and Nei gene diversity index,also confirmed this result.AMOVA analysis demonstrated that the genetic variation of D.sinensis within and among populations accounted for 56.89% and 43.11% of the total variation,respectively,and that of D.dyeriana was 57.86% and 42.14%,respectively.The Shannon diversity index and Nei gene diversity index showed similar results.The abovementioned characteristics indicated that the genetic diversity levels of these two species were extremely similar and that the interpopulational genetic differentiation within both species was relatively high.Analysis of the genetic distance among populations also supported this conclusion.Low levels of interpopulational gene flow within both species were believed to be among the leading causes for the above-mentioned phenomenon.The correlation analysis between genetic and geographical distances showed the existence of a remarkably significant correlation between the genetic distance and the longitudinal difference among populations of D.sinensis (p＜0.01),while no significant correlation was found between genetic and geographical distances among populations of D.dyeriana.This indicated that genetic distance was correlated with geographical distances on a large scale rather than on a small scale.This result may be related to differences in the selection pressure on species by their habitats with different distribution ranges.We suggest that in situ conservation efforts should focus on establishing more sites to protect the natural populations and their habitats.Ex situ conservation efforts should focus on enhancing the exchange of seeds and seedlings among populations to facilitate gene exchange and recombination,and to help conserve genetic diversity.     

金钱槭和云南金钱槭遗传多样性比较研究

金钱槭属(Dipteronia)是我国特有少种属,属下仅金钱槭(D. sinensis)和云南金钱槭(D. dyeriana)两种。该文用RAPD标记揭示了金钱槭的遗传多样性和遗传结构,并与云南金钱槭的RAPD研究结果进行了比较。同时,对两物种遗传距离与地理距离的相关性进行了分析,结果有助于阐释该属植物遗传变异的产生机制。研究显示,18条随机引物在17个金钱槭居群(226个个体)中检测到128个扩增位点,物种水平的多态位点比率为92.97%,在4个云南金钱槭居群(45个个体)中则检测到103个扩增位点,物种水平的多态位点比率为81.55%,金钱槭的多态位点比率高于云南金钱槭。相似性系数值、Shannon多样性指数和Nei基因多样性指数分析反映了与多态位点比率相一致的结果。AMOVA(Analysis of molecular variance)分析结果显示,金钱槭居群内、居群间的遗传变异分别占总变异量的56.89%和43.11%。云南金钱槭居群内、居群间的遗传变异分别占总变异量的57.86 %和42.14%。Shannon多样性指数、Nei基因多样性指数的分析结果与AMOVA分析结果趋势相同。上述特征值揭示,金钱槭和云南金钱槭居群间的遗传分化均已达到较高水平,推测居群间低水平的基因流可能是导致上述现象产生的原因之一。遗传距离与地理距离的相关分析结果显示,金钱槭居群间的遗传距离与经度差异存在极显著水平的相关性(p<0.01),云南金钱槭居群间的遗传距离与地理隔离则无显著相关关系。说明在大尺度上遗传距离与地理距离相关而在小范围内则无上述关系,该结果可能与位于不同分布区内的物种所承受的生境选择压力不同有关。建议在对该属植物进行就地保护时,应设立多个保护点,保护自然居群及其周围生境;在迁地保护时,应通过加大居群间种子和幼苗的交换,人为创造基因交流和重组的条件,保存该属植物的遗传多样性。     

Genetic differentiation in endangered Gynostemma pentaphyllum (Thunb.) Makino based on ISSR polymorphism and its implications for conservation

Studies were performed to investigate the genetic variation of 14 natural populations of Gynostemma pentaphyllum (Thunb.) Makino, an outcrossing clonal plant species in China, using inter-simple sequence repeat (ISSR) markers. Fourteen selected primers were used to amplify DNA samples from 140 individuals, and totally 194 loci were detected. The percentage of polymorphic bands (PPBs) showed that the genetic diversity was pretty high at the species level (PPB = 96.39%) but quite low at the population level (PPB = 1.03–25.26%). Shannon's information index (I) and Nei's gene diversity (h) displayed a similar trend to PPB. According to the hierarchical analysis of molecular variance (AMOVA) and Nei's analysis of gene diversity, the percentages of genetic variation among populations were 88.66 and 88.94%, respectively, indicating a high level of inter-population genetic differentiation. The low levels of genetic diversity within populations and high genetic differentiation among populations were assumed to result from the limited gene flow, the clonal nature and genetic drift. Based on the genetic data, effective conservation strategies were proposed for conserving this traditional Chinese medicinal herb. Concerning the management of G. pentaphyllum, we suggested that in situ conservation be an important and practical measure for maintaining the genetic diversity and that a possibly maximum number of populations be conserved. Populations EMS and HLT, in which particularly low levels of genetic variation were characterized, should be given the priority for ex situ conservation.     

Genetic variation and clonal diversity of Bromus ircutensis Kom. in the Otingdag sandy land detected by ISSR markers

Genetic variation and clonal diversity of nine populations of Bromus ircutensis Kom. from the Otingdag sandy land were investigated using Inter Simple Sequence Repeat (ISSR) markers. A total of 102 bands were amplified by using II ISSR primers chosen for the study. Among those 99% were polymorphic indicating high level of genetic variation at the species level with a mean genetic diversity (H) of 0.292 and Shannon information index (1) of 0.450. Percentage of polymorphic loci (PPL) of nine populations was 76.48% on average, which provides more evidence of considerable genetic variation at the population level. AMOVA analysis revealed that total genetic variation was higher within populations (87.06%) than between populations (12.94%), which is mainly the result of the extensive gene flow (Nm = 1.682) among B. ircutensis populations. UPGMA cluster analysis divided the nine populations into two groups. There was significant or moderate negative correlations between genetic diversity parameters (PPL, H, 1) and longitude or latitude. Mantel test also showed a significant correlation between geographical distance and genetic distance (r = 0.681, p = 0.002). Our findings indicated that distribution of B. ircutensis populations was influenced by geographical and ecological factors. Clonal diversity was also high with 108 individuals identified by 11 ISSR primers being all of different genets. Our results provide a molecular basis for sustainable management and conservation ofB. ircutensis in the study area.     

省沽油群体遗传多样性的AFLP分析

利用4对AFLP引物对来自安徽石台、湖北大悟和河南桐柏的3个省沽油群体进行遗传多样性分析,共扩增出489条带,其中多态性条带460条,多态性百分比为93.99%。不同群体Nei’s基因多样性指数(H)和Shannon’s信息指数(I)变化范围分别为0.1920～0.2046和0.2937～0.3151,其中湖北大悟群体遗传多样性最高。物种水平和种群水平的H分别为0.2190和0.1964,群体内变异占总变异的89.68%,表明省沽油遗传变异主要存在于各群体内部。3个群体的平均遗传距离为0.0292,UPGMA聚类分析结果说明省沽油各群体间亲缘关系较近并和地域具有相关性。建议省沽油的遗传资源保护应以种内遗传多样性的保护为主。     

Genetic differentiation in natural populations of a Keystone Bunchgrass (<Emphasis Type="Italic">Aristida stricta</Emphasis>) across its native range

Aristida stricta Michx. (Poaceae) is a perennial bunchgrass native to the Southeastern Coastal Plain of North America where it is a keystone species in the longleaf pine savannas and slash pine flatwoods from southeastern North Carolina to Florida, and westward to the coast of Mississippi. We examined genetic relationships within and among ten populations of A. stricta by using eight inter-simple sequence repeat (ISSR) markers to generate band frequency data for 32 individuals from each sampled population. An analysis of molecular variance showed that 38% of the variation resided among populations while 62% was attributable to variation within populations. Grouping the populations by habitat or by geographic location did not show significant differentiation between the groups. Overall, pair-wise geographic and genetic distances were not correlated. Data indicate that while individuals within each population are genetically diverse, there seemingly are barriers to gene flow across populations leading to their divergence. Each population contains several exclusive loci suggesting that limited gene flow and/or genetic drift are likely leading to this pattern of localization. Our results, coupled with those of the previous studies that presented evidence for local adaptation and phenotypic differences among populations, suggest that there is sufficient differentiation among populations of this species to warrant: (1) maintenance of the existing genetic diversity at individual sites, and (2) use of local seed and plant sources for conservation projects.     

Genetic Evaluation of the Efficacy of In Situ and Ex Situ Conservation of <Emphasis Type="Italic">Parashorea chinensis</Emphasis> (Dipterocarpaceae) in Southwestern China

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.