Genetic diversity analysis of Rhododendron aureum Georgi (Ericaceae) located on Changbai Mountain using ISSR and RAPD markers

Rhododendron aureum Georgi (Ericaceae) is a perennial alpine shrub endemic to Changbai Mountain in China. We used ISSR and RAPD markers to describe the diversity and genetic structure within and among four natural populations located at different altitudes. DNA from 66 individuals was amplified with ten ISSR markers and seven RAPD markers. High genetic diversity was observed by these two techniques at the species level. The genetic diversity of populations increased with altitudinal gradients from low to high. The coefficient of gene differentiation (G_ST 0.3652 in ISSR and 0.2511 in RAPD) and AMOVA analysis revealed that most genetic diversity was distributed within populations (61.96% in ISSR and 70.23% in RAPD). The estimate of gene flow based on G_ST was 0.8690 in ISSR and 1.4910 in RAPD. The UPGMA clustering results using ISSR and RAPD showed that all individuals from the same altitude were gathered together, and the two populations (TYD2a and YHLa) from middle altitudes always clustered together. Compared with populations from different altitudes, similar genetic diversity and low genetic differentiation were obtained from populations at the same altitudes, as revealed by ISSR markers. In addition to the reproductive strategy of R. aureum, these data highlight that local environmental conditions may play an important role in shaping the diversity and genetic structure of this species.     

Genetic diversity and morphological differentiation in Liatris helleri (Asteraceae), a threatened plant species

Liatris helleri (Asteraceae) is an insect-pollinated herbaceous perennial endemic to several high-elevation sites in the Blue Ridge Mountains of North Carolina. Allozymes were used to describe the genetic diversity and population structure in nine populations of this rare, federally listed species. Differences in leaf morphology were also examined for greenhouse-grown plants representing several populations. The proportion of the total genetic diversity found among populations, as indicated by the allozyme data, was 16%. Higher levels of population differentiation were found for differences in leaf shape; population of origin accounted for 37% of the variation in maximum leaf width, while families within populations accounted for 7%. In contrast to many endemic species, L. helleri maintains fairly high levels of genetic diversity. For the species, the percent polymorphic loci was 87.5, the average number of alleles at variable loci was 3.00 and the gene diversity was 0.276. Mean population values were percent polymorphic loci =58.4, mean number of alleles per polymorphic locus =2.59 and gene diversity =0.219. The estimated gene flow was low (Nm=0.85–1.32) and a relatively high correlation (r=0.55; p<0.005) was found between linear geographic and genetic distance. This suggests that the populations are partially isolated by distance, despite the limited range (<60 km) of the species. We recommend that population distinetiveness be maintained in restoration efforts.     

The population genetic diversity and pattern of Pteroceltis tatarinowii,a relic tree endemic to China,inferred from SSR markers

Pteroceltis tatarinowii (Cannabaceae), a relic tree endemic to China, is mainly distributed in limestone mountains and has a wide geographical range. In this study, 12 microsatellite primer pairs were assayed to analyse the genetic pattern and gene flow among 461 individuals sampled from 23 wild populations of P. tatarinowii. A high level of genetic diversity was detected based on high values of total alleles (159), the number of alleles (N_A = 6.373), expected heterozygosity (H_E = 0.696) and observed heterozygosity (H_O = 0.679). The high genetic diversity in this species may be attributed to its long‐life history, wide geographical distribution and wind dispersal. Only low genetic differentiation (G_ST = 0.137, F_ST = 0.138) was found among populations. Gene flow (migrants per generation, N_m) was estimated to be 1.56. This moderate level of gene flow possibly decrease interpopulation differentiation by buffering against genetic drift and improving gene exchange. However, spatial genetic structure was detected throughou the sampled range of the species (r = 0.311, p < 0.05) as well as in southern China (r = 0.453, p < 0.05), and may be related to terrain heterogeneity and the demographic history of P. tatarinowii. The east‐west high mountains of southern China might serve as physical barriers to seed and pollen flow. The isolation and local adaptation of different refugia may further limit gene flow. In addition, geographically remote populations might fail to effectively disperse pollen and seeds. Based on the above‐mentioned results, some suggestions for the conservation of the species are presented.     

承德光秃山不同海拔油松居群遗传多样性

为了解光秃山不同海拔下天然油松居群之间的遗传差异及探求遗传多样性与土壤因子的关联,为油松种源筛选和管理提供参考,本研究运用ISSR技术,对位于河北承德辽河源光秃山4个不同海拔油松天然居群共118个植株个体的遗传多样性进行分析。13个引物共扩增出177条清晰的条带,种群多态位点百分比(PPL)为60.2775%,Nei’s基因多样性指数(h)为0.2171,Shannon信息指数(I)为0.3222;不同种群遗传变异水平随海拔差异呈规律性变化,表现为沿海拔升高而呈低-高-低的分布规律,其中1354～1274 m范围的遗传多样性水平最高;在物种水平上油松具有较高的遗传多样性(PPL=98.33%,h=0.38142,I=0.5550),种群间的遗传分化系数Gst=0.6562。利用AMOVA软件对遗传变异的等级剖分结果表明,种群间有显著的遗传分化,约2/5的遗传变异存在种群间,种群内占3/5。Pearson相关分析表明,油松居群内遗传多样性与海拔、土壤养分(有机质、速效磷、速效钾含量)之间存在显著或一定的相关关系。Mantel检验结果显示,油松居群遗传距离与海拔差距、土壤养分因子的分异存在一定相关性。以上结果表明不同海拔区域的生态因子、低基因流等对油松居群间的遗传分化影响较大。     

Genetic diversity of Ranunculus acris L. (Ranunculaceae) populations in relation to species diversity and habitat type in grassland communities

Correlates between genetic diversity at intra- and interpopulation levels and the species diversity in plant communities are rarely investigated. Such correlates may give insights into the effect of local selective forces across different communities on the genetic diversity of local plant populations. This study has employed amplified fragment length polymorphism to assess the genetic diversity within and between 10 populations of Ranunculus acris in relation to the species diversity (richness and evenness) of grassland communities of two different habitat types, 'seminatural' and 'agriculturally improved', located in central Germany. Within-population genetic diversity estimated by Nei's unbiased gene diversity (HE) was high (0.258-0.334), and was not correlated with species richness (Pearson's r = -0.17; P = 0.64) or species evenness (Pearson's r = 0.15; P = 0.68) of the plant communities. However, the genetic differentiation between R. acris populations was significantly correlated with the difference in species evenness (Mantel's r = 0.62, P = 0.02), but not with difference in species richness of plant communities (r = -0.17, P = 0.22). Moreover, we also found that populations of R. acris from the 'seminatural' habitat were genetically different (amova, P < 0.05) from those in 'agriculturally improved' habitats, suggesting that gene flow between these habitat types is limited. The results reported in this study may indicate that habitat characteristics influence the genetic diversity of plant species.     

Genetic structure and diversity in relation to the recently reduced population size of the rare conifer, <Emphasis Type="Italic">Pseudotsuga japonica</Emphasis>, endemic to Japan

Rare species consisting of small populations are subject to random genetic drift, which reduces genetic diversity. Thus, determining the relationship between population size and genetic diversity would provide key information for planning a conservation strategy for rare species. We used six microsatellite markers to investigate seven extant populations of the rare conifer Pseudotsuga japonica, which is endemic to the Kii Peninsula and Shikoku Island regions that are geographically separated by the Kii Channel in southwest Japan. The population differentiation of P. japonica was relatively high (F_ST = 0.101) for a coniferous species, suggesting limited gene flow among populations. As expected, significant regional differentiation (AMOVA; p?<?0.05) indicated genetic divergence across the Kii Channel. A strong positive correlation between census population size and the number of rare alleles (r?=?0.862, p?<?0.05) was found, but correlations with major indices of genetic diversity were not significant (allelic richness: r?=?0.649, p?=?0.104, expected heterozygosity: r?=?0.361, p?=?0.426). The observed order of magnitude of correlation with three genetic diversity indices corresponded with the theoretically expected order of each index’ sensitivity (i.e., the rate of decline per generation) to the bottleneck event. Thus, features that exhibit a faster response, i.e., the number of rare alleles, would have been subject to deleterious effects of the recent decline in population size, which is presumably caused by the development of extensive artificial plantations of other tree species over the last several decades. Finally, we propose a conservation plan for P. japonica based on our findings.     

Genetic Connectivity of the Moth Pollinated Tree Glionnetia sericea in a Highly Fragmented Habitat

Long-distance gene flow is thought to be one prerequisite for the persistence of plant species in fragmented environments. Human influences have led to severe fragmentation of native habitats in the Seychelles islands, with many species surviving only in small and isolated populations. The endangered Seychelles endemic tree Glionnetia sericea is restricted to altitudes between 450 m and 900 m where the native forest vegetation has been largely lost and replaced with exotic invasives over the last 200 years. This study explores the genetic and ecological consequences of population fragmentation in this species by analysing patterns of genetic diversity in a sample of adults, juveniles and seeds, and by using controlled pollination experiments. Our results show no decrease in genetic diversity and no increase in genetic structuring from adult to juvenile cohorts. Despite significant inbreeding in some populations, there is no evidence of higher inbreeding in juvenile cohorts relative to adults. A Bayesian structure analysis and a tentative paternity analysis indicate extensive historical and contemporary gene flow among remnant populations. Pollination experiments and a paternity analysis show that Glionnetia sericea is self-compatible. Nevertheless, outcrossing is present with 7% of mating events resulting from pollen transfer between populations. Artificial pollination provided no evidence for pollen limitation in isolated populations. The highly mobile and specialized hawkmoth pollinators (Agrius convolvuli and Cenophodes tamsi; Sphingidae) appear to promote extensive gene flow, thus mitigating the potential negative ecological and genetic effects of habitat fragmentation in this species. We conclude that contemporary gene flow is sufficient to maintain genetic connectivity in this rare and restricted Seychelles endemic, in contrast to other island endemic tree species with limited contemporary gene flow.     

濒危物种巴东木莲的等位酶遗传多样性及其保护策略

为了确定中国特有濒危植物巴东木莲(Manglietia patungensis)的就地保护优先单元和制定迁地保护的取样策略,采用超薄平板聚丙烯酰胺等电聚焦电泳技术对巴东木莲的7个野生居群的等位酶遗传多样性及遗传结构进行了分析。通过对8个酶系统19个酶位点的分析结果来看,巴东木莲具有较高的遗传多样性和一定程度的遗传分化。每位点平均等位基因数（A）为1.57,多态位点百分率（P）为48.1%,平均预期杂合度（H_e）为0.192。巴东木莲居群间的遗传分化系数（G_ST）为0.165,说明其16.5％的遗传变异存在于居群间;基于遗传分化系数计算的基因流（N_m）为1.27,说明居群间存在适度的基因流;固定指数(F)为-0.191,显示巴东木莲居群杂合体轻微过量,纯合体略显不足。本研究表明,目前巴东木莲仍具有较高的遗传多样性并且在其适宜生境中可以完成自然更新,因此应采取以就地保护为主的综合保育策略。     

Genetic Structure of the Carnivorous Plant Pinguicula moranensis (Lentibulariaceae) on the Transvolcanic Mexican Belt

Most species of Pinguicula present a montane distribution with populations located at high altitudes. In this context, we proposed that populations of Pinguicula species could be genetically differentiated even at a local scale. This study supported that prediction, as a RAPD-based analysis of molecular variance revealed a high degree of genetic structure (Φ (st) = 0.157, P = 0.001) and low gene flow (Nm = 1.0) among four central populations of Pinguicula moranensis in Mexico, with a maximum geographic separation of about 140 km. The four populations also exhibited high levels of genetic diversity (mean Nei's genetic diversity = 0.3716; % polymorphism = 95.45%). The evolutionary implications of the genetic structure found in P. moranensis for other species in the genus are discussed in the context of the naturally fragmented distribution and a set of life history traits shared by most Pinguicula species that could promote geographic isolation and limited gene flow.     

Comparison of the population genetics and densities of five pinanga palm species at kuala belalong, brunei

This study investigated the effect of population density on the population genetic structure of five co-occurring congeneric understorey palm species: Pinanga aristata, P. sp. aff. brevipes, P. dumetosa, P. tenella var. tenella and P. veitchii, all endemic to northern Borneo. The average population densities of the study species varied across a wide spectrum, ranging from 343 (plants per ha) in P. tenella to 10 (plants per ha) in P. veitchii. All species of Pinanga palms studied had quite high levels of genetic diversity (HE: 0.379, 0.256, 0.294, 0.133, 0.352). Genetic diversity (HE) was correlated with population density (D; rs = - 0.433, P < 0.01) and the average distance to the nearest conspecific neighbour (NN; rs = 0.576, P < 0.001) such that the most-dense species had less genetic diversity and the less-dense species had greater genetic diversity. Gene flow (Nm) among populations approximately followed a gradient of increasing species density and abundance, such that the most common species P. dumestosa had the greatest gene flow (Nm = 2.268) between its populations and the rarest, most sparsely distributed species P. sp. aff. brevipes had the lowest (Nm = 0.698). All species of Pinanga were effectively inbred (F: 0.760, 0.856, 0.640, 0.753, 0.674). The amount of homozygosity and inbreeding (HO, F) were not correlated (P > 0.05) with population density (D) or the distance between nearest neighbouring plants of the same species (NN).     

用ISSR标记分析不同地区紫茎泽兰种群的遗传变异

利用ISSR标记技术分析了我国32个紫茎泽兰地理种群的遗传多样性,结果表明入侵我国的紫茎泽兰具有较大的遗传多样性,物种水平上的Nei's基因多样性为0．235,shannon's指数为0．372。种群间的遗传分化研究表明,大部分变异存在于种群内,总体遗传多样性中仅34．5%来源于种群之间。紫茎泽兰种群间的遗传距离矩阵和空间距离矩阵之间呈轻度正相关(r=0．542,P＜0．001),说明地理隔离可能是阻碍紫茎泽兰种群间基因交流的原因之一。不同海拔高度紫茎泽兰种群的遗传多样性水平呈现随海拔升高而降低的趋势(r=0．368,P＜0．001),各海拔区域种群的平均ISSR标记Nei's基因多样性和Shannon's指数均随海拔升高而有所降低。     

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。     

Genetic Structure Within and Among Populations of Saruma henryi, an Endangered Plant Endemic to China

The endangered perennial plant Saruma henryi Oliv. is endemic to China and has phylogenetic, ecological, and medicinal value. We used 10 microsatellite (SSR) loci to investigate genetic diversity and differentiation in 16 natural populations. Genetic diversity was high at the species level (H(E) = 0.9427, h = 0.9410, I = 3.0213) and low at the population level (H(E) = 0.4441, h = 0.4307, I = 0.6822). Pronounced genetic differentiation was detected among populations (G(ST) = 0.5428, F(ST) = 0.5524), in line with the limited among-population gene flow (Nm = 0.21). The significant isolation-by-distance pattern revealed by a Mantel test (r = 0.311, P = 0.001) suggested a clear geographic tendency in the distribution of genetic variability. Bayesian assignment and principal coordinates analyses supported the clustering of 16 populations into three groups. The present SSR results were also compared with previously published ISSR results. These results have significant implications for conservation of the species.     

Comparisons of genetic diversity in a narrow endemic, Impatiens hypophylla, and in its widespread congener, I. textori (Balsaminaceae)

Genetic diversity in two species of Impatiens in Korea was investigated using starch gel electrophoresis. Impatiens hypophylla is a rare species endemic to southwestern Japan and southeastern Korea, whereas I. rextori is widespread in East Asia. Impatiens textori has considerably higher genetic diversity than I. hypophylla . For example, mean values of genetic diversity within populations (He) of I. textori and I. hypophylla were 0.206 and 0.102, respectively. The high outcrossing rate (mean 1 = 0.89), abundance and widespread distribution, and large population size may be factors responsible for the maintenance of high levels of genetic variation in I. textori . Analyss of fixation indices indicated that considerable population substructuring within populations of I. hypophylla , partly resulting from inbreeding and/or genetic drift in small populations coupled with limited gene flow (mean F_IS= 0.699). However, the degree of population divergence observed in I. hypophylla (mean G_ST= 0.059) was considerably lower than that in other plants with similar life history traits. It is supposed that similar selection at populations of I. hypophylla examined might maintain similar gene frequencies in isolated populations.     

Patterns of Genetic Variation across Altitude in Three Plant Species of Semi-Dry Grasslands

Background

Environmental gradients caused by altitudinal gradients may affect genetic variation within and among plant populations and inbreeding within populations. Populations in the upper range periphery of a species may be important source populations for range shifts to higher altitude in response to climate change. In this study we investigate patterns of population genetic variation at upper peripheral and lower more central altitudes in three common plant species of semi-dry grasslands in montane landscapes.

Methodology/Principal Findings

In Briza media, Trifolium montanum and Ranunculus bulbosus genetic diversity, inbreeding and genetic relatedness of individuals within populations and genetic differentiation among populations was characterized using AFLP markers. Populations were sampled in the Swiss Alps at 1800 (upper periphery of the study organisms) and at 1200 m a.s.l. Genetic diversity was not affected by altitude and only in B. media inbreeding was greater at higher altitudes. Genetic differentiation was slightly greater among populations at higher altitudes in B. media and individuals within populations were more related to each other compared to individuals in lower altitude populations. A similar but less strong pattern of differentiation and relatedness was observed in T. montanum, while in R. bulbosus there was no effect of altitude. Estimations of population size and isolation of populations were similar, both at higher and lower altitudes.

Conclusions/Significance

Our results suggest that altitude does not affect genetic diversity in the grassland species under study. Genetic differentiation of populations increased only slightly at higher elevation, probably due to extensive (historic) gene flow among altitudes. Potentially pre-adapted genes might therefore spread easily across altitudes. Our study indicates that populations at the upper periphery are not genetically depauperate or isolated and thus may be important source populations for migration under climate change.     

Genetic diversity analysis of Hepatacodium miconioides at different altitude in Tiantai Mountain, Zhejiang Province, China and its relationship with environmental factors

The genetic diversity within and among populations of Hepatacodium miconioides collected at three different altitudes in Tiantai Mountain, Zhejiang Province and its relationships to environmental factors were analyzed by random amplified polymorphic DNA (RAPD) technique. Amplification using 12 random primers of 60 plants and 122 repetitive loci were produced. The percentage of polymorphic loci of three populations ranged from 18.85% to 23.77% with an average of 21.86%, indicating the relatively low genetic diversity of H. miconioides. The average Shannon index of phenotypic diversity (0.1329) and Nei index (0.0925) within populations were relatively low. A distinct genetic differentiation existed among populations of H. miconioides in spite of the relatively small geographical distribution. The average genetic diversity within populations of H. miconioides accounted for 33.58% of the total genetic diversity while the genetic diversity among populations accounted for 66.42% as estimated by the Shannon index of phenotypic diversity, The genetic differentiation among populations of H. miconioides was 0.6546, as estimated by Nei index. The gene flow estimated from G _ST was only 0.2656 and it indicated that gene flow among populations of H. miconioides was relatively low. The mean value of the genetic identity among populations of H. miconioides was 0.7126 and the average of genetic distance of H. miconioides was 0.3412. The genetic identity between populations at the elevation of 990 m and at the elevation of 780 m was the highest. The genetic identity between population at the elevation 500 m and other two populations was relatively low. The correlation analysis showed that the genetic diversity within populations was significantly related with the soil total nitrogen.     

Global patterns of genetic variation in plant species along vertical and horizontal gradients on mountains

Aim To understand global patterns of genetic variation in plant species on mountains and to consider the significance of mountains for the genetic structure and evolution of plant species. Location Global. Methods We review published studies. Results Genetic diversity within populations can vary along altitudinal gradients in one of four patterns. Eleven of 42 cited studies (26% of the total) found that populations at intermediate altitudes have greater diversity than populations at lower and higher altitudes. This is because the geographically central populations are under optimal environmental conditions, whereas the peripheral populations are in suboptimal situations. The second pattern, indicating that higher populations have less diversity than lower populations, was found in eight studies (19%). The third pattern, indicating that lower populations have lower diversity than higher populations, was found in 10 studies (24%). In 12 studies (29%), the intrapopulation genetic variation was found to be unaffected by altitude. Evidence of altitudinal differentiation was found in more than half of these studies, based on measurements of a range of variables including genome size, number of chromosomes or a range of loci using molecular markers. Furthermore, great variation has been found in phenotypes among populations at different altitudes in situ and in common garden experiments, even in cases where there was no associated variation in molecular composition. Mountains can be genetic barriers for species that are distributed at low elevations, but they can also provide pathways for species that occupy high‐elevation habitats. [Correction added after publication 9 October 2007: ‘less diversity’ changed to ‘greater diversity’ in the second sentence of the Results section of the Abstract] Main conclusions Genetic diversity within populations can vary along altitudinal gradients as a result of several factors. The results highlight the importance of phenotypic examinations in detecting altitudinal differences. The influence of mountain ridges on genetic differentiation varies depending, inter alia, on the elevation at which the species occurs. Based on these findings, zoning by altitudes or ridges would be helpful for the conservation of tree populations with the onset of global warming.     

七筋菇自然居群的遗传结构分析

采用ISSR分子标记,对七筋菇(Clintonia udensis)17个居群的遗传多样性与遗传结构进行了研究。结果表明:七筋菇不同居群的多态位点百分率PPB为11.90%~59.52%,总的多态位点百分率PPB为98.8%,具有高的遗传多样性。Shannon多样性指数(0.6903)和基因分化系数(GST=0.6944)均揭示出七筋菇居群间存在明显的遗传差异,AMOVA分析结果也显示遗传变异主要发生在居群之间(81.47%),而居群内部的遗传变异仅为18.53%。七筋菇居群间的遗传距离从0.1871~0.6632,平均为0.3838,大于同一物种居群间的平均遗传距离值(0.05),同样表明七筋菇居群间的遗传多样性存在较大差异。七筋菇居群间的基因流Nm=0.2200,远远低于一般广布种植物的基因流(Nm=1.881)。Mantel检测显示居群间的遗传距离与地理距离之间没有显著相关性(r=0.029,P=0.3196)。七筋菇分布范围广以及其进化历史是其具有高遗传多样性的原因;居群间存在较高遗传变异可能是由于七筋菇本身的生物学特性、有限的基因流以及遗传漂变等原因造成的。     

Genetic diversity analysis of Hepatacodium miconioides at different altitude in Tiantal Mountain,Zhejiang Province,China and its relationship with environmental factors

The genetic diversity within and among populations of Hepatacodium miconioides collected at three different altitudes in Tiantai Mountain,Zhejiang Province and its relationships to environmental factors were analyzed by random amplified polymorphic DNA(RAPD)technique.Amplification using 12 random primers of 60 plants and 122 repetitive loci were produced.The percentage of polymorphic loci of three populations ranged from 18.85% to 23.77% with an average of 21.86%,indicating the relatively low genetic diversity of H.miconioides.The average Shannon index of phenotypic diversity(0.1329)and Nei index(0.0925)within populations were relatively low.A distinct genetic differentiation existed among populations Of H miconioides in spite of the relatively small geographical distribufion.The average genetic diversity within populations of H.miconioides accounted for 33.58% of the total genetic diversity while the genetic diversity among populations accounted for 66.42% as estimated by the Shannon index of phenotypic diversity,The genetic differentiation among populations of H.miconioides was 0.6546,as estimated by Nei index.The gene flow estimated from Gsr was only 0.2656 and it indicated that gene flow among populations of H.miconioides was relatively low.The mean value of the genetic identity among populations of H.miconioides was 0.7126 and the average of genetic distance of H.miconioides was 0.3412.The genetic identity between populations at the elevation of 990m and at the elevation of 780 m was the highest.The genetic identity between population at the elevation 500 m and other two populations was relatively low.The correlation analysis showed that the genetic diversity within populations was significantly related with the soil total nitrogen.     

Genetic variation and population structure in Korean populations of eurya japonica (Theaceae)

We investigated levels of genetic diversity, population genetic structure, and gene flow in Eurya japonica, a widespread and broad-leaved evergreen dioecious tree native to Japan, China, Taiwan, and the southern and southwestern coast of the Korean Peninsula. Starch-gel electrophoresis was conducted on leaves collected from 1,000 plants in 20 Korean populations. All 12 loci examined were polymorphic in at least one population, and the mean number of alleles per locus was 3.79. In addition, mean observed population heterozygosity (Ho_p = 0.425), expected heterozygosity (He_p = 0.462), and total genetic diversity (H_T = 0.496) were substantially higher than average values for species with similar life history traits. Although significant differences in allele frequency were detected between populations at all loci (P < 0.001), <7% of the genetic variation was found among populations (F_ST = 0.069). There was a significant negative correlation between genetic identity and distance between populations (r = -0.341; P < 0.05), but this explained only a small amount of the diversity among populations. Indirect estimates of the number of migrants per generation (Nm) (3.37, calculated from F_ST; 3.74, calculated from the mean frequency of eight private alleles) indicate that gene flow is extensive among Korean populations of E. japonica. Factors contributing to the high levels of genetic diversity found within populations of E. japonica include large and contiguous populations, obligating outcrossing (dioecious plant), high fecundity, and long generation time. Occasional seed dispersal by humans and pollen movement by domesticated honey bees may further enhance gene flow within the species.