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 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 of natural Miscanthus sinensis populations in China revealed by ISSR markers

Miscanthus sinensis is a typical perennial C₄ grass in Asia. In the present study, ISSR markers were used to evaluate the genetic variation within and among grass populations that were sampled from the Zhejiang and Guangdong Provinces of China. Based on nine ISSR primers, 206 clear and reproducible DNA fragments were generated. Relatively low levels of genetic diversity were determined among the populations. The coefficient of genetic differentiation among the populations was 0.52, which indicates that 52.3% of the total molecular variance exists among the populations. Such a high level of divergence present among the populations might be caused by the complex topography and variable climatic conditions present in the two provinces. AMOVA revealed that the majority of the genetic variation was within the populations (50.6%). The application of a novel method, which combines geographical coordinates and genetic differentiation to detect barriers for gene flow, allowed us to identify two zones of lowered gene flow.     

Genetic differentiation of the Thorn‐tailed Rayadito Aphrastura spinicauda (Furnariidae: Passeriformes) revealed by ISSR profiles suggests multiple palaeorefugia and high recurrent gene flow

Nucleotide sequence data (cytochrome b) and ISSR genomic fingerprints were used to analyse the genetic variation and population differentiation in Thorn‐tailed Rayadito, a widespread Patagonian forest bird. We included samples from eight populations of Thorn‐tailed Rayadito covering most of the distribution range of the species: from fragmented patches of Olivillo forest in northern Chile to Isla Navarino forests in the extreme south of South America. Low levels of genetic diversity were found among populations, with a large within‐population molecular variance indicating high levels of gene flow. The multivariate and cluster analyses based on ISSR markers show that the subspecies bullocki (from Mocha Island) differs significantly from all other populations. The subspecies fulva (Chiloé Island) shows less differentiation than bullocki, sharing several alleles with continental populations. Bayesian analyses suggest that the Mocha Island population contributes most to the total genetic diversity observed in the species. Mantel tests revealed no significant correlation between geographical distance and pairwise genetic distance and cytochrome b sequence analyses failed to detect differentiation among subspecies. Mocha Island might have been a palaeorefuge and this population may have diversified by genetic drift after the last glacial maximum. There is also the possibility of a postglacial colonization of the Thorn‐tailed Rayadito from an austral palaeorefugium, supporting a multiple refugia hypothesis. This study illustrates the usefulness of the rarely used ISSR genomic fingerprint method in avian phylogeography.     

Molecular diversity and genetic relationships among Sri Lankan pomegranate Punica granatum landraces assessed with inter simple sequence repeat (ISSR) regions

Pomegranate Punica granatum was first introduced to Sri Lanka, possibly through ancient trade routes, thousands of years ago. However, there is no information about the diversity of the pomegranate germplasm in the country, which is important both for breeding new varieties and for conservation efforts. We used inter‐simple sequence repeat (ISSR) regions to investigate the genetic diversity and population structure of pomegranate on the island of Sri Lanka. Hundred and twenty accessions representing seven populations from all pomegranate growing regions of the country were analyzed using 20 ISSR primers. A total of 107 loci were amplified with an average polymorphism information content of 0.3. While the average inter‐population genetic distance was 0.141, it was 0.149 between populations, indicating moderate genetic diversity both within and among populations. Analysis of molecular variance and Nei's genetic diversity revealed higher genetic variation within populations than among populations, and low genetic differentiation (G_ST) in pair‐wise comparison of populations also suggested limited population differentiation. A considerable level of among‐population gene flow (Nm) was indicated, irrespective of geographical structure and distances. The results of cluster analysis was also in agreement with above analysis and suggest human mediated gene flow and migration patterns. Cluster analysis revealed two main population clusters with several sub‐clusters. While these clusters did not show any correlation with geography, all red peeled accessions clustered into a small sub‐cluster. The results indicate that analysis of ISSR variability is sufficiently informative and powerful to assess the genetic diversity of P. granatum landraces in Sri Lanka.     

新疆地区番茄潜叶蛾遗传多样性的ISSR分析

[目的]番茄潜叶蛾已成为世界性番茄的重要害虫,对番茄产业的发展造成了严重的威胁,研究其遗传多样性有利于揭示不同地理种群的遗传变异结构。[方法]采用ISSR分子标记技术分析了20个地理种群番茄潜叶蛾的遗传多样性和遗传结构特征。[结果]15条引物扩增出137条ISSR条带,其中多态性条带占96.35%,所有个体显示了各自独特的ISSR图谱。ISSR的标记遗传多样性结果表明,20个番茄潜叶蛾地理种群遗传距离大小范围为0.0065~0.1623,遗传一致度范围为0.8502~0.9935。种群变异来源分析表明,25.36%的遗传变异来自种群间,74.64%的变异来源于种群内部。UPGMA系统发育分析结果表明,各地理种群的聚类与地理位置无较强的关联性。[结论]番茄潜叶蛾尚处在入侵早期阶段,且具备频繁入侵和多点的特征。防控上要注意加强检疫,阻绝多点入侵来源。     

Effect of Yangtze River on population genetic structure of the relict plant Parrotia subaequalis in eastern China

Parrotia subaequalis (Hamamelidaceae) is a Tertiary relic species endemic in eastern China. We used inter‐simple sequence repeat (ISSR) markers to access genetic diversity and population genetic structure in natural five populations of P. subaequalis. The levels of genetic diversity were higher at species level (H = 0.2031) but lower at population level (H = 0.1096). The higher genetic diversity at species levels might be attributed to the accumulation of distinctive genotypes which adapted to the different habitats after Quaternary glaciations. Meanwhile, founder effects on the early stage, and subsequent bottleneck of population regeneration due to its biological characteristics, environmental features, and human activities, seemed to explain the low population levels of genetic diversity. The hierarchical AMOVA revealed high levels (42.60%) of among‐population genetic differentiation, which was in congruence with the high levels of Nei's genetic differentiation index (G_ST = 0.4629) and limited gene flow (N_m = 0.5801) among the studied populations. Mantel test showed a significant isolation‐by‐distance, indicating that geographic isolation has a significant effect on genetic structure in this species. Unweighted pair‐group method with arithmetic average clustering, PCoA, and Bayesian analyses uniformly recovered groups that matched the geographical distribution of this species. In particular, our results suggest that Yangtze River has served as a natural barrier to gene flow between populations occurred on both riversides. Concerning the management of P. subaequalis, the high genetic differentiation among populations indicates that preserving all five natural populations in situ and collecting enough individuals from these populations for ex situ conservation are necessary.     

Genetic differentiation of Albizia lebbeck (L.) Benth. populations estimated by RAPD and ISSR markers

Abstract

Albizia lebbeck (L.) Benth., a popular multi‐purpose legume tree species, has a wide distribution throughout the Indian subcontinent. The species is highly valued for its quality timber, gum yield and therapeutical uses. However, the increasing social and economical pressures are devastating the natural stands of A. lebbeck forests. So, there is a need to estimate the genetic variation present in A. lebbeck populations. Both RAPD and ISSR molecular markers were used to analyse 172 individuals representing eight populations of the species in different geographical range. The within‐population genetic diversity ranged from 1.23 to 1.38. The total gene variability was 0.34 of which 0.17 (50%) accounted for within‐population gene variability. The genetic differentiation between populations (Gst = 0.49) was significantly correlated to geographical distance (r = 0.61, p < 0.001). An UPGMA clustering suggests a high level of genetic isolation due to distance. This study revealed the genetic differentiation which will provide a template for adaptation and evolution of the populations and species.     

Genetic diversity and structure of the invasive tree Miconia calvescens in Pacific islands

Aim This study investigates the amount and distribution of genetic variation within and among populations of the highly invasive tree, Miconia calvescens (Melastomataceae; hereafter miconia), in tropical island habitats that are differently impacted (distribution and spread) by this weed. Location Invasive populations were included from northern and southern Pacific islands including the Hawaiian Islands (Hawaii, Kauai and Maui), Marquesas Islands (Nuku Hiva), Society Islands (Tahiti, Tahaa, Moorea, Raiatea) and New Caledonia. Methods We used 9 codominant microsatellite and 77 highly variable dominant intersimple sequence repeat markers (ISSRs) to characterize and compare genetic diversity among and within invasive miconia populations. For the codominant microsatellite data we calculated standard population genetic estimates (heterozygosity, number of alleles, inbreeding coefficients, etc.) and described population genetic structure using AMOVA, Mantel tests (to test for isolation by distance), unweighted pair‐group method with arithmetic averages (UPGMA) cluster analysis and principal components analysis (PCA). We also tested for the presence of a population bottleneck and used a Bayesian analysis of population structure in combination with individual assignment tests. For the dominant ISSR data we used AMOVA, PCA, upgma and a Bayesian approach to investigate population genetic structure. Results Both markers types showed little to no genetic differentiation among miconia populations from northern and southern Pacific hemispheres (AMOVA: microsatellite, 3%; ISSR, 0%). Bayesian and frequency‐based analysis also failed to support geographical genetic structure, confirming considerable low genetic differentiation throughout the Pacific. Molecular data furthermore showed that highly successful miconia populations throughout the Pacific are currently undergoing severe bottlenecks and high levels of inbreeding (f = 0.91, ISSR; F_IS = 0.27, microsatellite). Main conclusions The lack of population genetic structure is indicative of similar geographical sources for both hemispheres and small founding populations. Differences in invasive spread and distribution among Pacific islands are most likely the result of differences in introduction dates to different islands and their accompanying lag phases. Miconia has been introduced to relatively few tropical islands in the Pacific, and the accidental introduction of a few or even a single seed into favourable habitats could lead to high invasive success.     

Population Genetic Study of Fagopyrum tataricum from Western Himalaya Using ISSR Markers

Inter-simple sequence repeat (ISSR) markers were used to analyze genetic diversity and relatedness of 15 germplasms of Fagopyrum tataricum. Samples representing 75 individuals were collected from a range of altitudes in the Western Himalaya. The 13 ISSR primers revealed 98.1% polymorphism among populations, whereas average polymorphism was extremely low (2.18%) within populations. The coefficient of population differentiation was 0.9750, with limited gene flow (N _m) of 0.0128. The average PIC value of the ISSR markers was high (0.812), with a marker ratio of 0.65 and marker index of 6.66. The genetic diversity of F. tataricum significantly correlated with altitude and gene diversity, Shannon’s index, and the percentage of polymorphic bands. The genetic diversity among populations showed broad genetic base and provided a developmental strategy for crop improvement.     

Genetic diversity and population structure of Butea monosperma (Lam.) Taub.- a potential medicinal legume tree

Three molecular marker systems, Random Amplified Polymorphic DNA (RAPD), Inter-Simple Sequence Repeats (ISSR) and Sequence-Related Amplified Polymorphism (SRAP) were employed to investigate the genetic structure and diversity among the 14 natural populations of Butea monosperma collected from different geographical regions of India. Detected by 17 RAPD, 15 ISSR and 11 SRAP primer combinations, the proportions of polymorphic bands were 84.2 %, 77.2 % and 91.9 %, respectively, and the mean Nei’s genetic distances among the populations were 0.13, 0.10 and 0.13, respectively. Partitioning of genetic variability by Analysis of molecular variance (AMOVA) revealed that the high genetic diversity was distributed within the populations. AMOVA also revealed that the coefficient of gene differentiation among populations based on F_ST was very high irrespective of markers used. The overall gene flow among populations (Nm) was very low. Cophenetic correlation coefficients of Nei’s distance values and clustering pattern by Mental test were statistically significant for all three marker systems used but poor fit for ISSR data than for RAPD, SRAP and combined data set of all three markers. For all markers, a high similarity in dendrogram topologies was obtained, although some differences were observed with ISSR. The dendrogram obtained by RAPD, SRAP and combined data set of all three markers reflect relationship of most of the populations according to their geographic distribution.     

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.     

Genetic diversity and differentiation of Daphnia galeata in the middle and lower reaches of the Yangtze River,China

Mitochondrial 16S rDNA and CO I gene were used as molecular markers for the analysis of the genetic diversity and differentiation of Daphnia galeata populations in nine water bodies in the middle and lower reaches of the Yangtze River. In the combined 16S rDNA and CO I gene sequences, 54 variable sites and 44 haplotypes were observed among 219 individuals belonging to nine D. galeata populations. Average haplotype diversity and nucleotide diversity were, respectively, 0.72% and 0.56%. The F‐statistics (F_ST) value of the D. galeata populations was 0.149. According to the results of the neutral test, D. galeata in the middle and lower reaches of the Yangtze River had experienced a bottleneck effect in the history. Molecular variance analysis indicated that the genetic differentiation of the D. galeata populations mainly occurred within populations (85.09%). Greater genetic differentiations of D. galeata among individuals within populations appeared in the populations from the Huaihe River basin, whereas smaller genetic differentiations occurred in the populations from the middle reaches of the Yangtze River. Strong gene flows were all observed between Group I (four populations from the middle reaches of the Yangtze River) and Group ΙΙ (three populations from the middle and lower reaches of the Yangtze River), and Group ΙΙΙ (two populations from the Huaihe River basin). The effective migration rates (M) were 851.49 from Group I to Group ΙΙ and 685.96 from Group I to Group ΙΙΙ, respectively. However, no significant relationship was observed between the genetic differentiation and geographical distance of the nine populations (r = .137, p > .05). Results suggested that the genetic differentiation of D. galeata in the water bodies in the middle and lower reaches of the Yangtze River resulted mainly from geographical isolation.     

Genetic diversity of endangered Manglietia patungensis assessed by inter simple sequence repeat and sequence-related amplified polymorphism markers

Manglietia patungensis Hu is an endangered plant native to China. Knowledge of its genetic diversity and structure would aid its conservation. This study assessed nine natural populations of M. patungensis using two methods: inter simple sequence repeat (ISSR) and sequence-related amplified polymorphism (SRAP) markers. Using 10 ISSR primer pairs, 334 bands were generated, and 10 SRAP primer pairs generated 276 bands. The percent of polymorphic bands (91.32% and 93.48%), Nei's genetic diversity (0.3448 and 0.3323), and Shannon's information index (0.5075 and 0.4935) revealed a high level of genetic diversity at the species level. Total heterozygosity was 0.3439 by ISSR and 0.3281 by SRAP. The mean heterozygosity was 0.2323 by ISSR and 0.2521 by SRAP. The coefficient of genetic differentiation among natural populations was 0.3245 by ISSR and 0.2316 by SRAP. These data indicated higher levels of genetic diversity of M. patungensis within, rather than among, populations. Estimates of gene flow among natural populations were 1.0411 and 1.0589, which implied a certain amount of gene exchange among populations. A Mantel test revealed no significant correlation between genetic and geographic distance. ISSR and SRAP markers are both effective for genetic diversity research in M. Patungensis. Based on these results, conservation of M. patungensis should be performed both in situ and ex situ.     

Global diversity and genetic contributions of chicken populations from African,Asian and European regions

Genetic diversity and population structure of 113 chicken populations from Africa, Asia and Europe were studied using 29 microsatellite markers. Among these, three populations of wild chickens and nine commercial purebreds were used as reference populations for comparison. Compared to commercial lines and chickens sampled from the European region, high mean numbers of alleles and a high degree of heterozygosity were found in Asian and African chickens as well as in Red Junglefowl. Population differentiation (F_ST) was higher among European breeds and commercial lines than among African, Asian and Red Junglefowl populations. Neighbour‐Net genetic clustering and structure analysis revealed two main groups of Asian and north‐west European breeds, whereas African populations overlap with other breeds from Eastern Europe and the Mediterranean region. Broilers and brown egg layers were situated between the Asian and north‐west European clusters. structure analysis confirmed a lower degree of population stratification in African and Asian chickens than in European breeds. High genetic differentiation and low genetic contributions to global diversity have been observed for single European breeds. Populations with low genetic variability have also shown a low genetic contribution to a core set of diversity in attaining maximum genetic variation present from the total populations. This may indicate that conservation measures in Europe should pay special attention to preserving as many single chicken breeds as possible to maintain maximum genetic diversity given that higher genetic variations come from differentiation between breeds.     

Use of RAPD and ISSR Markers in Detection of Genetic Variation and Population Structure among Fusarium oxysporum f. sp. ciceris Isolates on Chickpea in Turkey

Genetic variation among the isolates of Fusarium oxysporum f. sp. ciceris, the causal agent of chickpea wilt worldwide, was analysed using pathogenicity tests and molecular markers – random amplified polymorphic DNA (RAPD) and inter‐simple sequence repeat (ISSR) polymorphism. Hundred and eight isolates were obtained from diseased chickpea plants in 13 different provinces of Turkey, out of which 74 isolates were assessed using 30 arbitrary decamer primers and 20 ISSR primers. Unweighted pair‐grouped method by arithmetic average cluster analysis of RAPD, ISSR and RAPD + ISSR datasets provided a substantially similar discrimination among Turkish isolates and divided into three major groups. Group 1, 2 and 3 consisted of 41, 18 and 15 isolates, respectively. These methods revealed a considerable genetic variation among Turkish isolates, but no correlation with regard to the clustering of isolates from different geographic regions. Analysis of molecular variance confirmed that most genetic variability resulted from the differences among isolates within regions. Our results also indicated that the low‐genetic differentiation (F_ST) and high gene flow (Nm) among populations had a significant effect on the emergence and evolutionary development of F. oxysporum f. sp. ciceris. This is the first report on genetic diversity and population structure of F. oxysporum isolates on chickpea in Turkey.     

Patterns of Genetic Variation in Swertia przewalskii, an Endangered Endemic Species of the Qinghai-Tibet Plateau

Swertia przewalskii Pissjauk. (Gentianaceae) is a critically endangered and endemic plant of the Qinghai-Tibet Plateau in China. RAPD and ISSR analyses were carried out on a total of 63 individuals to assess the extent of genetic variation in the remaining three populations. Percentage of polymorphic bands was 94% (156 bands) for RAPD and 96% (222 bands) for ISSR. A pairwise distance measure calculated from the RAPD and ISSR data was used as input for analysis of molecular variance (AMOVA). AMOVA indicated that a high proportion of the total genetic variation (52% for RAPD and 56% for ISSR) was found among populations; pairwise Φ _ST comparisons showed that the three populations examined were significantly different (p < 0.001). Significant genetic differentiation was found based on different measures (AMOVA and Hickory θ_B) in S. przewalskii (0.52 on RAPD and 0.56 on ISSR; 0.46 on RAPD and 0.45 on ISSR). The differentiation of the populations corresponded to low average gene flow (0.28 based on RAPD and 0.31 based on ISSR), whereas genetic distance-based clustering and coalescent-based assignment analyses revealed significant genetic isolation among populations. Our results indicate that genetic diversity is independent of population size. We conclude that although sexual reproduction and gene flow between populations of S. przewalskii are very limited, they have preserved high levels of genetic diversity. The main factors responsible for the high level of difference among populations are the isolation and recent fragmentation under human disturbance.     

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.     

A morphometric analysis and taxonomic study of Panax bipinnatifidus Seem. (Araliaceae) species complex from Sikkim Himalaya, India

Cattleya elongata is a rupicolous orchid species spread throughout and endemic to outcrop islands in campo rupestre vegetation of the Chapada Diamantina, northeastern Brazil. We scored nine natural populations of C. elongata for morphological and genetic variability, covering the whole distribution area of the species, using allozymes and ISSR markers and morphometric multivariate analyses. Genetic variability in allozimes was relatively high (H _e?=?0.12?C0.25), and unexpectedly higher than the values based on ISSR (H _e?=?0.16?C0.19). The populations present moderate structuring (allozymes, ??_PT?=?0.14; ISSR, ??_PT?=?0.18) and low inbreeding (allozymes, F _IS?=?0.06). Genetic similarity among the populations was high in both markers, in spite of the discontinuity of the outcrops of the Chapada Diamantina. We found no particular biogeographical pattern to the distribution of the genetic and morphologic similarity among the populations of C. elongata. We found high morphological variability with moderate differentiation among the populations. We did not find any correlation among genetic, morphological, and geographical distances, and among the variability found in the morphological and genetic markers. The differences observed between the two genetic markers and the various morphological markers examined here indicated that the isolated use of any single parameter of these different populations for conservation planning or management would not consider all of the variability to be found in the species, as found in other Brazilian campos rupestres plants.     

A Study of Conservation Genetics in Cupressus chengiana,an Endangered Endemic of China,Using ISSR Markers

ISSR markers were used to analyze the genetic diversity and genetic structure of eight natural populations of Cupressus chengiana in China. ISSR analysis using 10 primers was carried out on 92 different samples. At the species level, 136 polymorphic loci were detected. The percentage of polymorphic bands (PPB) was 99%. Genetic diversity (H _e) was 0.3120, effective number of alleles (A _e) was 1.5236, and Shannon’s information index (I) was 0.4740. At the population level, PPB = 48%, A _e=1.2774, H _e=0.1631, and I=0.2452. Genetic differentiation (G _st) detected by Nei’s genetic diversity analysis suggested 48% occurred among populations. The partitioning of molecular variance by AMOVA analysis indicated significant genetic differentiation within populations (54%) and among populations (46%; P < 0.0003). The average number of individuals exchanged between populations per generation (N _m ) was 0.5436. Samples from the same population clustered in the same population-specific cluster, and two groups of Sichuan and Gansu populations were distinguishable. A significantly positive correlation between genetic and geographic distance was detected (r=0.6701). Human impacts were considered one of the main factors to cause the rarity of C. chengiana, and conservation strategies are suggested based on the genetic characters and field investigation, e.g., protection of wild populations, reestablishment of germplasm bank, and reintroduction of more genetic diversity.