Genetic diversity in inter‐simple sequence repeat profiles across natural populations of Indian pomegranate (Punica granatum L.)

Pomegranate (Punica granatum L.), in the monogeneric family Punicaceae, is found in Iran, Afghanistan, India and Mediterranean countries. Iran is considered to be its primary centre of origin. In India, pomegranate occurs naturally only in the Western Himalayan regions of Jammu and Kashmir, Himachal Pradesh and Uttarakhand States. However, there is no information about genetic variation in wild pomegranate at population level. In this paper, we describe genetic diversity across natural populations of Indian pomegranate based on inter‐simple sequence repeat (ISSR) markers. Forty‐nine accessions representing eight populations from two regions were analysed using ISSR. Seventeen ISSR primers resulted in 268 polymorphic bands, with 87.01% polymorphism throughout the accessions. Pair‐wise population genetic distances ranged from 0.05 to 0.45, with a mean of 0.25 between populations. amova and Nei’s genetic diversity analyses revealed higher genetic variation within populations than among populations. A higher genetic differentiation (G_ST) was observed between the spatially distant populations, indicating a low level of genetic exchange (Nm) among these populations. However, clustering of populations was not in accordance with their geographical affiliations in the tree. The results indicate that the ISSR method is sufficiently informative and powerful to assess genetic variability in pomegranate, and that patterns of genetic variability observed among populations of wild pomegranate from the Western Himalaya differ. Estimation of genetic variation reported here provides a significant insight for in situ conservation and exploitation of genetic resources for this economically important species as potential breeding material.     

Genetic diversity of the cultured giant freshwater prawn (Macrobrachium rosenbergii) in China based on microsatellite markers

The Giant freshwater prawn (GFP), Macrobrachium rosenbergii, is one of the most important crustacean species cultured in China, but information on the genetic diversity of GFP in China is still limited. In this study we analyzed the genetic diversity of 6 cultured GFP populations collected in China, and 2 wild populations from Viet Nam. The wild populations were included as a reference so that the genetic diversity of the introduced cultured GFP populations could be evaluated. We used six polymorphic primer pairs to estimate genetic diversity. Results showed that the number of alleles per locus ranged from 6 to 19. The mean observed heterozygosity (0.364 ± 0.090) was less than the expected heterozygosity (0.893 ± 0.016); highly significant deficiencies in heterozygotes were detected (100%). The polymorphism information content (PIC) of 8 populations at 6 loci was greater than 0.5 (varying from 0.616 to 0.912). Pair-wise genetic differentiation (F_ST) varied from 0.006 to 0.129 among the eight populations. The dendrogram based on genetic distance showed six populations distributed on the same major branch, suggesting that they have closely genetic distance and two populations (ZJC and GDB) distributed on the other branch, so they also have closely genetic distance. The results of study provide a baseline assessment of genetic diversity in some populations in China and Viet Nam that will be useful for the development of breeding programmes in the future.     

Genetic variation in field and laboratory populations of the spined soldier bug,Podisus maculiventris

The predatory spined soldier bug, Podisus maculiventris (Say) (Heteroptera: Pentatomidae), is an economically important and highly valued biological control agent. There is substantial information on the biology, ecology, behavior, and rearing of this stink bug. However, virtually nothing is known of its genetic variation, in natural or domesticated populations. To address this lacuna, we used amplified fragment length polymorphism (AFLP) to assess the genetic variability of field and laboratory populations. Four AFLP universal primer combinations yielded a total of 209 usable loci. The AFLP results showed greater genetic variability between populations from Missouri and Mississippi (both USA), and relatively low variability within Missouri populations. We infer little genetic isolation among Missouri field populations and within laboratory populations, but a significant genetic isolation between Missouri and Mississippi populations.     

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.     

Genetic structure and differentiation of four populations of Afghan Pika (Ochotona rufescens) in Iran based on mitochondrial cytochrome b gene

The population genetics of the Afghan Pika (Ochotona rufescens) was studied in Northern Khorasan Province, Iran. For prediction of the genetic differentiation of four populations, the DNA of mitochondrial cytochrome b of 32 individuals from four areas was sequenced and a Bayesian analysis based on the HKY model was constructed. In total, 15 polymorphic sites, 1125 conserved sites (98.7%) and 14 different haplotypes were found. The phylogenetic tree resulting from the Bayesian analysis and network analysis showed that all samples were clustered in two major groups and the haplotypes of the four populations did not separate geographically. An analysis of molecular variance (AMOVA) indicated that a large majority of the genetic variance was due to the variance within populations. The results of fixation indices showed significant genetic structure among populations in both methods. The pairwise F_st revealed that two northern populations have a significant genetic differentiation from two southern populations, but no significance pairwise F_st value was demonstrated between the closed populations. Nei's genetic distances between closed populations were not significant, while significant values occurred between distant populations. It seems that there is not a major discontinuity between populations of Afghan Pika based on cyt-b mitochondrial gene. However, phylogenetic analysis did not separate populations and a large majority of the genetic variance was found within populations. However, AMOVA analysis showed a significant level of genetic structure among populations (p?<?0.001) and between groups (p?<?0.5). It seems that these results suggest shallow genetic differentiation between populations of different geographic groups.     

Genetic diversity of SSR markers in wild populations of Tapiscia sinensis,an endangered tree species

Tapiscia sinensis is a Tertiary relict and endangered tree species with unique scientific research value and great economic value. In this study, we assessed the genetic diversity of five wild T. sinensis populations from different geographical regions using 10 polymorphic simple sequence repeat (SSR) markers. Our results reveal that the natural populations of T. sinensis have rich genetic diversity (PPL = 100%, He = 0.6904, I = 1.4368), with Shannon's index indicating that the T. sinensis populations are at a relatively stable stage. Of the genetic relationships among populations, the distance between the Hunan Yanling (YL) and Guizhou Xifeng (XF) populations is the smallest (0.4829); the genetic distance between the Shaanxi Ningshan (NS) and the Guizhou Xifeng (XF) populations is the largest (0.9821). A Mantel test shows that there is no correlation among the populations between geographic distance and genetic distance. AMOVA suggest that 33.3% of the genetic variation arose among the populations, while 66.7% of the variation arose within them. The moderate gene flow among populations (Nm = 0.7274) is not sufficient to counteract genetic drift within the populations and result in significant differentiation (Fst = 0.2987). Our results will benefit the conservation and exploitation of T. sinensis and provide a theoretical basis for further study of the evolution and phylogeography of the species.     

RAPD variation in relation to population size and plant fitness in the rare Gentianella germanica (Gentianaceae)

We investigated the distribution of genetic variation and the relationship between population size and genetic variation in the rare plant Gentianella germanica using RAPD (random amplified polymorphic DNA) profiles. Plants for the analysis were grown from seeds sampled from 72 parent plants in 11 G. germanica populations of different size (40-5000 fruiting individuals). In large populations, seeds were sampled from parents in two spatially distinct subpopulations comparable in area to the total area covered by small populations. Analysis of molecular variance revealed significant genetic variation among populations (P <0.001), while genetic variation among subpopulations was marginally significant (P <0.06). Average molecular variance within subpopulations in large populations did not differ significantly from whole-population values. There was a positive correlation between genetic variation and population size (P <0.01). Genetic variation was also positively correlated with the number of seeds per plant in the field (P <0.02) and the number of flowers per planted seed in a common garden experiment (P <0.051). We conclude that gene flow among natural populations is very limited and that reduced plant fitness in small populations of G. germanica most likely has genetic causes. Management should aim to increase the size of small populations to minimize further loss of genetic variation. Because a large proportion of genetic variation is among populations, even small populations are worth preserving.     

广东高州7个普通野生稻居群遗传结构的SSR分析

利用32对SSR引物对来自全部7个自然居群的217份广东高州普通野生稻(简称“高野”)材料进行遗传结构、多样性和遗传聚类分析。结果表明, 高野各居群因遗传结构存在差异而相对独立, 但各居群之间由于存在基因渗透又具有一定的相似性。高野总体多样性指数(Ht)为0.65, 居群内的多样性(HS=0.431)略大于居群间的多样性(DS=0.392), 二者差异并不显著。居群间的遗传分化系数(GST)为0.611, 说明高野群体的遗传差异是由居群内和居群间的遗传分化共同作用的结果。其中A、B、E居群间, D、F、G居群间遗传相似性较高, C居群与其它居群之间存在较大差异。根据7个居群的遗传结构, 结合其地理分布状况, 认为遗传多样性最大的B和E居群以及遗传分化最小的C居群应作为重点对象进行保护。     

基于RAPD数据探讨中华蓑藓(Macromitrium cavaleriei Card.& Thér.)形态变异的遗传基础

中华蓑藓(Macromitrium cavaleriei Card.&;Thér.)的形态变异强烈,为了解形态变异是否具有遗传学背景,本研究以采自浙南凤阳山、浙中金华北山、浙西北的天目山和江西庐山4个种群的中华蓑藓为材料,运用随机扩增多态性DNA(RAPD)探讨了中华蓑藓的遗传多样性。从100条随机引物中筛选出了15条有效引物,利用它们共获得183个条带,其中多态性条带占79.69%,中华蓑藓各种群间的Dice遗传距离为0.0732~0.1514。POPGENE32软件分析得到种的Nei基因多样性指数(H)为0.3378,Shannon指数(I)为0.5126,遗传分化系数(G_st)为0.1670;基因流(N_m)为2.4947;种群内遗传多样性指数为0.4055,占种群总的遗传多样性的79.11%,反映出研究区域内的中华蓑藓遗传变异大多数存在于种群内,中华蓑藓形态变异并没有多少遗传背景,很可能是生态环境因素引起的可塑性变异。聚类分析表明,中华蓑藓种群遗传距离与地理距离之间无直接相关关系,遗传多样性水平与物种特性和所处不同群落有关。虽然4个种群内的形态变异丰富,但是属于同一物种的范围。     

Genetic Differentiation of Native Sheep Populations in East and South Asia

Variations of four sheep populations in China were examined by multiloci electrophoresis, and similar data are quoted to analyze the degree of genetic differentiation of native sheep populations in East and South Asia. Among 15 populations, the average heterozygosity is 0.2746, and the effective number of alleles is 1.559. Mongolian sheep possess the highest genetic diversity, and diversity decreases sequentially in the Chinese, Vietnamese, Bangladeshi, and Nepalese populations. Coefficients of genetic differentiation are 0.0126–0.3083, with an average of 0.148, demonstrating that the major genetic variation (85%) exists within populations. Genetic identity and genetic distance all show relatively low genetic differentiation. No relationship was found between geographic distance and genetic distance. Gene flow is common among the mass of populations, which leads to the inconsistency between geographic distance and genetic distance. The 15 native sheep populations in East and South Asia can be divided into two groups, one group including part of the Chinese and Mongolian populations and another including theYunnan population of China and part of the Nepalese and Bangladeshi populations. Other populations did not separate into groups, merging instead into the two main groups.     

Contrasting levels of genetic diversity between the historically rare orchid Cypripedium japonicum and the historically common orchid Cypripedium macranthos in South Korea

Many terrestrial orchids are historically rare and occur in small, spatially isolated populations. Theory predicts that such species will harbour low levels of genetic variation within populations and will exhibit a high degree of population genetic divergence, primarily as a result of genetic drift. If the origin of the present‐day populations is relatively recent from the same genetically depauperate source population, a complete lack of genetic differentiation between conspecific populations is expected. If a terrestrial orchid was historically common with moderate or high levels of genetic diversity, but has experienced more recent anthropogenic disturbance as a result of over‐collection, it would still exhibit initial levels of genetic variation within populations and a low degree of genetic divergence between populations. To test these predictions, we examined the genetic diversity in six populations (N = 131) of the historically and currently rare Cypripedium japonicum and in four populations (N = 94) of the historically common but now rare C. macranthos from South Korea. Fourteen putative allozyme loci resolved from eight enzyme systems revealed no variation either within or among populations of C. japonicum, which supports the first prediction. In contrast, populations of C. macranthos harboured high levels of genetic variation (mean percentage of polymorphic loci %P = 46.7; mean expected heterozygosity H_e = 0.185) and exhibited a low degree of population genetic divergence (G_ST = 0.059), supporting the second prediction. The lack of genetic variation both within and among conspecific populations of C. japonicum may suggest that populations originated from the same genetically depauperate ancestral population. The high levels of genetic diversity maintained in populations of C. macranthos suggest that the collection‐mediated decrease in the number of individuals is still too recent for long‐term effects on genetic variation. Based on current demographic and genetic data, in situ and ex situ conservation strategies should be provided to preserve genetic variation and to ensure the long‐term survival of the two species in the Korean Peninsula. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 119–129.     

Genetic diversity of invasive Oreochromis spp. (tilapia) populations in Guangdong province of China using microsatellite markers

Ten microsatellites were used to assess the genetic diversity and genetic differences of six wild Oreochromis spp. populations in the primary rivers of Guangdong Province of China, where natural populations have been established. Significant genetic differentiation was observed in Oreochromis spp. populations using “FST” and exact tests. The six populations can be divided into two groups based on the genetic similarity indices. The phylogenetic tree indicated that the HUI (Huizhou) and the SG (Shaoguan) populations formed one cluster, whereas the H (Huazhou), M (Meihua), MU (Muzhou), and ZQ (Zhaoqing) populations formed another cluster. The average mean levels of the observed heterozygosity in the six populations were 0.3972, 0.4264, 0.6977, 0.6335, 0.6680, and 0.6829, respectively. The high genetic diversity observed in most wild tilapia populations suggests that most wild populations are large in size, which is a finding that is supported by field investigations.     

Phylogeography and Conservation Genetics of the Common Wall Lizard,Podarcis muralis,on Islands at Its Northern Range

Populations at range limits are often characterized by lower genetic diversity, increased genetic isolation and differentiation relative to populations at the core of geographical ranges. Furthermore, it is increasingly recognized that populations situated at range limits might be the result of human introductions rather than natural dispersal. It is therefore important to document the origin and genetic diversity of marginal populations to establish conservation priorities. In this study, we investigate the phylogeography and genetic structure of peripheral populations of the common European wall lizard, Podarcis muralis, on Jersey (Channel Islands, UK) and in the Chausey archipelago. We sequenced a fragment of the mitochondrial cytochrome b gene in 200 individuals of P. muralis to infer the phylogeography of the island populations using Bayesian approaches. We also genotyped 484 individuals from 21 populations at 10 polymorphic microsatellite loci to evaluate the genetic structure and diversity of island and mainland (Western France) populations. We detected four unique haplotypes in the island populations that formed a sub-clade within the Western France clade. There was a significant reduction in genetic diversity (H_O, H_E and A_R) of the island populations in relation to the mainland. The small fragmented island populations at the northern range margin of the common wall lizard distribution are most likely native, with genetic differentiation reflecting isolation following sea level increase approximately 7000 BP. Genetic diversity is lower on islands than in marginal populations on the mainland, potentially as a result of early founder effects or long-term isolation. The combination of restriction to specific localities and an inability to expand their range into adjacent suitable locations might make the island populations more vulnerable to extinction.     

Connectivity in a pond system influences migration and genetic structure in threespine stickleback

Neutral genetic structure of natural populations is primarily influenced by migration (the movement of individuals and, subsequently, their genes) and drift (the statistical chance of losing genetic diversity over time). Migration between populations is influenced by several factors, including individual behavior, physical barriers, and environmental heterogeneity among populations. However, drift is expected to be stronger in populations with low immigration rate and small effective population size. With the technological advancement in geological information systems and spatial analysis tools, landscape genetics now allows the development of realistic migration models and increased insight to important processes influencing diversity of natural populations. In this study, we investigated the relationship between landscape connectivity and genetic distance of threespine stickleback (Gasterosteus aculeatus) inhabiting a pond complex in Belgjarskógur, Northeast Iceland. We used two landscape genetic approaches (i.e., least-cost-path and isolation-by-resistance) and asked whether gene flow, as measured by genetic distance, was more strongly associated with Euclidean distance (isolation-by-distance) or with landscape connectivity provided by areas prone to flooding (as indicated by Carex sp. cover)? We found substantial genetic structure across the study area, with pairwise genetic distances among populations (D_PS) ranging from 0.118 to 0.488. Genetic distances among populations were more strongly correlated with least-cost-path and isolation-by-resistance than with Euclidean distance, whereas the relative contribution of isolation-by-resistance and Euclidian distance could not be disentangled. These results indicate that migration among stickleback populations occurs via periodically flooded areas. Overall, this study highlights the importance of transient landscape elements influencing migration and genetic structure of populations at small spatial scales.     

高山嵩草种群在放牧干扰下遗传多样性的变化

利用SRAP (Sequence-related amplified polymorphism)分子标记, 对放牧干扰下的高山嵩草(Kobresia pygmaea)种群进行了遗传多样性研究, 获得了下述结果: 1) 20对SRAP引物组合共检测出448条清晰条带, 其中376条条带具有多态性, 多态位点百分率为83.93%, 随着放牧强度的增加, 高山嵩草种群多态位点百分数、Nei’s遗传多样性指数、Shannon信息指数均下降。2)高山嵩草种群具有较高的遗传多样性和较低的遗传分化(总的遗传多样性H_t为0.276 6, 种群内遗传多样性H_s为0.243 6, 遗传分化系数G_st为0.119 4, 基于G_st估计的基因流N_m^*为1.843 4), 但随着放牧强度的增加, G_st增加, N_m^*降低, 说明放牧限制了种群间的基因交流, 使种群发生遗传分化。3)不同放牧梯度的高山嵩草种群间的遗传距离很小, 但是随着放牧强度的增加, 种群间的遗传距离逐渐增加, 遗传一致度降低。根据遗传距离所构建的UPGMA聚类图中高山嵩草4个种群随着牧压的增加, 逐级聚在一起。     

Allozyme variations in six natural populations of scots pine (<Emphasis Type="Italic">Pinus sylvestris</Emphasis>) in Turkey

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 (N_em) 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.     

Genetic diversity and structure in two species of Leavenworthia with self-incompatible and self-compatible populations

Self-fertilization is a common mating system in plants and is known to reduce genetic diversity, increase genetic structure and potentially put populations at greater risk of extinction. In this study, we measured the genetic diversity and structure of two cedar glade endemic species, Leavenworthia alabamica and L. crassa. These species have self-incompatible (SI) and self-compatible (SC) populations and are therefore ideal for understanding how the mating system affects genetic diversity and structure. We found that L. alabamica and L. crassa had high species-level genetic diversity (H_e=0.229 and 0.183, respectively) and high genetic structure among their populations (F_ST=0.45 and 0.36, respectively), but that mean genetic diversity was significantly lower in SC compared with SI populations (SC vs SI, H_e for L. alabamica was 0.065 vs 0.206 and for L. crassa was 0.084 vs 0.189). We also found significant genetic structure using maximum-likelihood clustering methods. These data indicate that the loss of SI leads to the loss of genetic diversity within populations. In addition, we examined genetic distance relationships between SI and SC populations to analyze possible population history and origins of self-compatibility. We find there may have been multiple origins of self-compatibility in L. alabamica and L. crassa. However, further work is required to test this hypothesis. Finally, given their high genetic structure and that individual populations harbor unique alleles, conservation strategies seeking to maximize species-level genetic diversity for these or similar species should protect multiple populations.     

Genetic biogeography of the rare “copper moss,” Mielichhoferia elongata (Bryaceae)

Mielichhoferia elongata, one of the so-called “copper mosses,” has a broad but highly disjunctive geographic distribution and is rare throughout its range. A genetic analysis of 30 populations based on a survey of 21 allozyme loci reveals the following. 1) Total gene diversity at the specific level is high (0.41). 2) Within-population diversity is low, and over 90% of all genetic variation is among rather than within populations (mean G_ST = 0.93). 3) There is little differentiation in allele frequencies between North American and European populations. 4) Populations consist of one to six multilocus genotypes; 13 of the populations appear to consist of a single clone. 5) Colorado populations contain a tremendous reservoir of genetic variation (88% of all alleles found in the species in North America and Europe occur in one or more Colorado populations). 6) Populations in the eastern and western United States, and in Europe, contain subsets of the allelic diversity found in Colorado. The genetic structure of M. elongata suggests repeated dispersal and founding of populations.     

Genetic diversity and structure of Cordyceps sinensis populations from extensive geographical regions in China as revealed by inter-simple sequence repeat markers

Cordyceps sinensis is one of the most valuable medicinal caterpillar fungi native to China. However, its productivity is extremely limited and the species is becoming endangered. The genetic diversity of eighteen C. sinensis populations across its major distributing regions in China was evaluated by inter-simple sequence repeat (ISSR) markers. A total of 141 markers were produced in 180 individuals from the 18 populations, of which 99.3% were polymorphic. The low average of Shannon (0.104) and Nei index (0.07) of the 18 populations indicates that there are little genetic variations within populations. For all 18 populations, estimates of total gene diversity (H_T), gene diversity within populations (H_S), coefficient of genetic differentiation (G_ST), and gene flow (Nm) were 0.170, 0.071, 0.583, and 0.357, respectively. This pattern suggests that the genetic diversity of C. sinensis is low and most of the ISSR variations are found among populations with little gene exchange. The 18 populations are divided into five groups based on the genetic distance and the grouping pattern matches with the geographic distribution along the latitudinal gradient. The five groups show obvious difference in the G_ST and Nm values. Therefore, the genetic diversification of C. sinensis populations may be determined by geographic isolation and the combined effects of life history characters and the interaction with host insect species. The information illustrated by this study is useful for selecting in situ conservation sites of C. sinensis.     

Genetic structure in peripheral populations of the natterjack toad, <Emphasis Type="Italic">Bufo calamita</Emphasis>, as revealed by AFLP

Decreased fitness due to loss of genetic variation is a well recognised issue in conservation biology. Along the Swedish west coast, the endangered natterjack toad (Bufo calamita) occurs on, for the species, highly unusual habitat of rocky islands. Although the toads inhabit a restricted geographical area (maximum distance between the populations is 71 km), the fragmented nature of the landscape makes the genetic properties of the populations of conservation interest. However, lack of genetic variation found using conventional methods (microsatellites) has impeded genetic studies within these peripheral populations so far. In this study we assess population structure and genetic variation among seven of these fringe populations using 105 polymorphic Amplified Fragment Length Polymorphism (AFLP) loci. We found a well-defined population structure without evidence for isolation by distance, implying restricted gene flow between populations. Additionally, the populations differed in their amount of genetic variation, emphasizing the need to monitor genetically impoverished populations for possible declines mediated by inbreeding depression and reduced adaptive potential. Conservation implications for these unique populations are discussed in the light of our results.