Genetic diversity,effective population size,and structure among black bear populations in the Lower Mississippi Alluvial Valley,USA

Multiple small populations of American black bears Ursus americanus, including the recently delisted Louisiana black bear subspecies U. a. luteolus, occupy a fragmented landscape in the Lower Mississippi Alluvial Valley, USA (LMAV). Populations include bears native to the LMAV, bears translocated from Minnesota during the 1960s, and recently reintroduced and colonizing populations sourced from within the LMAV. We estimated population structure, gene flow, and genetic parameters important to conservation of small populations using genotypes at 23 microsatellite markers for 265 bears from seven populations. We inferred five genetic clusters corresponding to the following populations: White River and western Mississippi, Tensas River and Three Rivers, Upper Atchafalaya, Lower Atchafalaya, and Minnesota. Upper Atchafalaya was suggested as the product of Minnesota-sourced translocations, but those populations have since diverged, likely because of a founder effect followed by genetic drift and isolation. An admixture zone recently developed in northeastern Louisiana and western Mississippi between migrants from White River and Tensas River, resulting in a Wahlund effect. However, gene flow among most populations has been limited and considerable genetic differentiation accumulated (global F_ST?=?0.22), particularly among the three Louisiana black bear populations that existed when federal listing occurred. Consistent with previous bottlenecks, founder effects, and persisting isolation, all LMAV bear populations had low genetic diversity (A_R?=?2.08–4.81; H_E?=?0.36–0.63) or small effective population size (N_E?=?3–49). Translocating bears among populations as part of a regional genetic restoration program may help improve genetic diversity and increase effective population sizes.     

Genetic diversity and structure of the globally invasive tree, <Emphasis Type="Italic">Paraserianthes lophantha</Emphasis> subspecies <Emphasis Type="Italic">lophantha</Emphasis>, suggest an introduction history characterised by varying propagule pressure

An emerging insight in invasion biology is that intra-specific genetic variation, human usage, and introduction histories interact to shape genetic diversity and its distribution in populations of invasive species. We explore these aspects for the tree species Paraserianthes lophantha subsp. lophantha, a close relative of Australian wattles (genus Acacia). This species is native to Western Australia and is invasive in a number of regions globally. Using microsatellite genotype and DNA sequencing data, we show that native Western Australian populations of P. lophantha subsp. lophantha are geographically structured and are more diverse than introduced populations in Australia (New South Wales, South Australia, and Victoria), the Hawaiian Islands, Portugal, and South Africa. Introduced populations varied greatly in the amount of genetic diversity contained within them, from being low (e.g. Portugal) to high (e.g. Maui, Hawaiian Islands). Irrespective of provenance (native or introduced), all populations appeared to be highly inbred (F _IS ranging from 0.55 to 0.8), probably due to selfing. Although introduced populations generally had lower genetic diversity than native populations, Bayesian clustering of microsatellites and phylogenetic diversity indicated that introduced populations comprise a diverse array of genotypes, most of which were also identified in Western Australia. The dissimilarity in the distribution and number of genotypes in introduced regions suggests that non-native populations originated from different native sources and that introduction events differed in propagule pressure.     

Genetic diversity and population structure of Chinese <Emphasis Type="Italic">Lentinula edodes</Emphasis> revealed by InDel and SSR markers

Genetic diversity and population structure of 88 Chinese Lentinula edodes strains belonging to four geographic populations were inferred from 68 Insertion-Deletion (InDel) and two simple sequence repeat (SSR) markers. The overall values of Shannon’s information index and gene diversity were 0.836 and 0.435, respectively, demonstrating a high genetic diversity in Chinese L. edodes strains. Among the four geographic populations, the Central China population displayed a lower genetic diversity. Multiple analyses resolved two unambiguous genetic groups that corresponded to two regions from which the samples were collected—one was a high-altitude region (region 1) and the other was a low-altitude region (region 2). Results from analysis of molecular variance suggested that the majority of genetic variation was contained within populations (74.8 %). Although there was a strong genetic differentiation between populations (F _ST ?=?0.252), the variability of ITS sequences from representative strains of the two regions (<3 %) could not support the existence of cryptic species. Pairwise F _ST values and Nei’s genetic distances showed that there were relatively lower genetic differentiations and genetic distances between populations from the same region. Geographic distribution could play a vital role in the formation of the observed population structure. Mycelium growth rate and precocity of L. edodes strains displayed significant differences between the two regions. Strains from region 2 grew faster and fructified earlier, which could be a result of adaptation to local environmental factors. To the best of our knowledge, this was the first study on the genetic structure and differentiation between populations, as well as the relationship between genetic structure and phenotypic traits in L. edodes.     

A mountain range is a strong genetic barrier between populations of <Emphasis Type="Italic">Afzelia quanzensis</Emphasis> (pod mahogany) with low genetic diversity

Understanding patterns of genetic diversity of plants is important in guiding conservation programs. The aim of our study was to characterize genetic diversity in Afzelia quanzensis, an economically important African tree species. We genotyped 192 individuals at 10 nuclear microsatellite loci. Samples were collected from nine sites in Zimbabwe, five in the north and four in the south, separated by a mountain range, the Kalahari-Zimbabwe axis. Overall, genetic diversity was relatively low across all sites (expected heterozygosity (H _E)?=?0.452, mean number of alleles (A)?=?4.367, allelic richness (A _R)?=?2.917, effective number of alleles (A _E)?=?2.208, and private allelic richness (PA_R)?=?0.197). Genetic diversity estimates, H _E, A, A _R, and PA_R, were not significantly different between northern and southern sites. Allelic richness was significantly higher in southern sites. Significant population differentiation was observed among all sites (F _ST ?=?0.0936, G′ _ST ?=?0.1982, G _ST ?=?0.1001, D _JOST?=?0.0598). STRUCTURE analysis and principal components analysis identified two gene pools, one predominantly made up of southern individuals, and the other of northern individuals. A Monmonier’s function detected a genetic barrier that coincided with the Kalahari-Zimbabwe axis. The relatively low level of genetic diversity in A. quanzensis may reduce adaptability and limit future evolutionary responses. All sites should be monitored for deleterious effects of low genetic diversity, and genetic resource management should take into consideration the existence of the distinct gene pools to capture the entire extant genetic variation.     

Pelagic larval dispersal habits influence the population genetic structure of clam <Emphasis Type="Italic">Gomphina aequilatera</Emphasis> in China

Pelagic larval dispersal habits influence the population genetic structure of marine mollusk organisms via gene flow. The genetic information of the clam Gomphina aequilatera (short larval stage, 10 days) which is ecologically and economically important in the China coast is unknown. To determine the influence of planktonic larval duration on the genetic structure of G. aequilatera. Mitochondrial markers, cytochrome oxidase subunit i (COI) and 12S ribosomal RNA (12S rRNA), were used to investigate the population structure of wild G. aequilatera specimens from four China Sea coastal locations (Zhoushan, Nanji Island, Zhangpu and Beihai). Partial COI (685 bp) and 12S rRNA (350 bp) sequences were determined. High level and significant F_ST values were obtained among the different localities, based on either COI (F_ST?=?0.100–0.444, P?<?0.05) or 12S rRNA (F_ST?=?0.193–0.742, P?<?0.05), indicating a high degree of genetic differentiation among the populations. The pairwise N_m between Beihai and Zhoushan for COI was 0.626 and the other four pairwise N_m values were >?1, indicating extensive gene flow among them. The 12S rRNA showed the same pattern. AMOVA test results for COI and 12S rRNA indicated major genetic variation within the populations: 77.96% within and 22.04% among the populations for COI, 55.73% within and 44.27% among the populations for 12S rRNA. A median-joining network suggested obvious genetic differentiation between the Zhoushan and Beihai populations. This study revealed the extant population genetic structure of G. aequilatera and showed a strong population structure in a species with a short planktonic larval stage.     

High genetic diversity in an endangered medicinal plant, <Emphasis Type="Italic">Saussurea involucrata</Emphasis> (<Emphasis Type="Italic">Saussurea</Emphasis>, Asteraceae), in western Tianshan Mountains,China

Saussurea involucrata (Asteraceae) is a medicinal and second-degree national priority endangered plant that is mainly distributed in the high latitude region of the western Tianshan Mountains. The population is fragmented and isolated, and extensive human impact merits a suitable and specific conservation strategy, which can be compiled based on the genetic diversity, population structure, and demographic history. Phylogeographic studies were conducted on a total of five natural populations and 150 individuals were sampled. Data from three cpDNA intergenic spacer regions (trnL-F, matK, and ndhF-rpl32) and nrDNA ITS sequences showed that twelve haplotypes in cpDNA and five haplotypes in nrDNA indicated high genetic diversity among populations sampled (H _T?=?0.820 and 0.756) and within populations sampled (H _S?=?0.792 and 0.721). Additionally, the high genetic diversity did not mirror genetic structure in either cpDNA (F _ST?=?0.03153, G _ST?>?N _ST, p?<?0.05) or nrDNA (F _ST?=?0.03666, meaningless G _ST and N _ST). Two groups (north and south) were determined for a SAMOVA analysis. Based on this analysis, the demographic history was conducted with a Bayesian Skyline Plot and Isolation with Migration analysis, which showed sustainable and stable extension without a marked bottleneck. Divergence time was indicated at c. 6.25 Mya (90%HPD: 15.30–0.22 Mya) in the Miocene, which is consistent with the formation of the Kelasu section of Tianshan. The southern populations in the Bayanbulak and Gonglu regions require additional attention and transplanting would be an effective way to restore rare cpDNA haplotypes, increase effective population size, and migration rate. Our results suggested that in situ conservation of S. involucrata in western Tianshan should be the main strategy for protection and recovery of the species.     

Mitochondrial and Nuclear DNA Based Genetic Assessment Indicated Distinct Variation and Low Genetic Exchange Among the Three Subspecies of Swamp Deer (<Emphasis Type="Italic">Rucervus</Emphasis> <Emphasis Type="Italic">duvaucelii</Emphasis>)

The swamp deer (Rucervus duvaucelii) occurs, primarily, in the wet grasslands of the Himalayan foothills as well as the dry grasslands of central India. Three subspecies have been identified, namely R. duvaucelii duvaucelii, R. duvaucelii branderi and R. duvaucelii ranjitsinhi. Degradation of grassland habitats led to a drastic decline in the total swamp deer population in the early 19th century. Even though the species has recently shown signs of recovery, it is still vulnerable to the small-population paradigm. Effective management plans need to be put in place to increase the population through scientific intervention. The current genetic variation within the three subspecies of R. duvaucelii is unclear, and this is hindering effective conservation planning. We examined the genetic variability, population structure and demography of the three subspecies of swamp deer using the mtDNA control region and microsatellite analysis. Despite the spatial isolation of the populations, we found a high level of variation and weak divergence among the subspecies. The genetic differentiation (F _ST ) between the subspecies and the mismatch distribution of haplotypes indicated recent colonization by these subspecies. Population bottleneck analysis indicated that the existing subspecies and their populations are at demographic equilibrium and are stable. The study highlights the need for effective conservation management intervention to maintain the population size and genetic diversity. It also indicates that all the subspecies need to be managed as separate conservation units.     

Characterizing genetic integrity of rear-edge trout populations in the southern Appalachians

Vertebrate populations at the periphery of their range can show pronounced genetic drift and isolation, and therefore offer unique challenges for conservation and management. These populations are often candidates for management actions such as translocations that are designed to improve demographic and genetic integrity. This is particularly true of coldwater species like brook trout (Salvelinus fontinalis), whose numbers have declined greatly across its historic range. At the southern margin, remnant wild populations persist in isolated headwater streams, and many have a history of receiving translocated individuals through either stocking of hatchery reared fish, relocation of wild fish, or both during restoration attempts. To determine current genetic integrity and resolve the genetic effects of past management actions for brook trout populations in SC, USA, we genetically assessed all 18 documented remaining brook trout populations along with individuals acquired from six hatcheries with recorded stocking events in SC. Our results indicated that six of the 18 streams showed signs of hatchery admixture (range 57–97%) and restored patches retained genetic signatures from multiple source populations. Populations had among the lowest genetic diversity (min average H_E?=?0.147) and effective number of breeders (mean N_b?=?31.2) estimates observed throughout the native brook trout range. Populations were highly differentiated (mean pair-wise F_ST?=?0.396), and substantial genetic divergence was evident across major river drainages (max pair-wise F_ST?=?0.773). The lowest local genetic diversity and highest genetic differentiation ever reported for this species make its conservation a challenging task, particularly when combined with other threats such as climate change and non-native species. We offer recommendations on managing peripheral populations with depleted genetic characteristics and provide a reference for determining which existing populations will best serve as sources for future translocation efforts aimed at enhancing or restoring wild brook trout genetic integrity.     

Genetic analysis assessed by microsatellites for a diallel mating design of two geographical stocks of the blood clam <Emphasis Type="Italic">Tegillarca granosa</Emphasis>

To determine the potential for productive efficiency and genetic improvement in the blood clam Tegillarca granosa, four offspring populations (ZZ, ZK, KZ and KK) were produced from a diallel mating of two different geographical stocks (Z and K). The levels of genetic diversity and population structures of four populations were analyzed using 14 polymorphic microsatellites. The results showed that the mean observed heterozygosities (Ho) of reciprocal cross populations (ZK and KZ) was higher than those of pure populations(ZZ and KK). The largest values of genetic differentiation coefficient (F_st?=?0.067) and Nei’s unbiased genetic distance (Dc?=?0.263) were between ZK and KZ, and the smallest (F_st?=?0.020, Dc?=?0.116) were between ZZ and KK, which revealed that the largest genetic divergence was between the two reciprocal cross populations and the smallest was between two pure populations. This study demonstrated that the reciprocal cross populations of T. granosa had an extensive genetic difference and improvement, which may be advantageous for future breeding studies.     

Genetic diversity of the house mouse <Emphasis Type="Italic">Mus musculus</Emphasis> and geographic distribution of its subspecies-specific RAPD markers on the territory of Russia

Genetic diversity and geographic distribution of taxon-specific RAPD markers was examined in ten local populations of the house mouse Mus musculus (n = 42). The house mice were generally characterized by moderate genetic variation: polymorphism P ₉₉ = 60%, P ₉₅ = 32.57%; heterozygosity H = 0.12; the observed allele number n _a = 1.6; the effective allele number n _e = 1.18; the within-population differentiation ?_s = 0.388; and Shannon index I = 0.19. The degree of genetic isolation of individual local populations was greatly variable. The genetic subdivision index G _st varied from 0.162 to 0.770 at the gene flow of Nm = 2.58?0.149, while the among-population distances D _N varied from 0.026 to 0.178. The largest part of the genetic diversity was found among the populations (H _T = 0.125), while the within-population diversity was twice lower (H _S = 0.06). The samples examined were well discriminated relative to the sets of RAPD markers. The character distribution pattern provided conditional subdivision of the mice into the “western” and the “eastern” groups with the putative boarder along the Baikal Lake. The first group was characterized by the prevalence of the markers typical of M. m. musculus and M. m. domesticus. The second group was characterized by the prevalence of the markers typical of M. m. musculus, M. m. gansuensis, M. m. castaneus, M. m. domesticus, and M. m. wagneri. The genotype of the nominative subspecies M. m. musculus was background for all populations. In the populations examined some of earlier described subspecies-specific molecular markers were found at different frequencies, pointing to the involvement of several subspecies of M. musculus in the process of hybridization.     

Patterns of population genetic structure and diversity across bumble bee communities in the Pacific Northwest

Patterns of genetic structure and diversity are largely mediated by a species’ ecological niche and sensitivity to climate variation. Some species with narrow ecological niches have been found to exhibit increased population differentiation, limited gene flow across populations, and reduced population genetic diversity. In this study, we examine patterns of population genetic structure and diversity of four bumble bee species that are broadly sympatric, but do not necessarily inhabit the same ecological niche in the Pacific Northwest of the United States. Testing for the effect of isolation by geographic distance (IBD) with linearized F _st and D _est found that Bombus sylvicola and B. mixtus exhibited significant IBD across populations. In contrast, both B. melanopygus and B. flavifrons, two species that are distributed across a broad elevation gradient, exhibited no IBD, a result further corroborated by Bayesian a priori population assignment tests. Furthermore, we discovered that B. sylvicola populations distributed on the Olympic Peninsula have significantly less average allelic diversity than populations distributed in the Cascade Mountains. Our results suggest that populations distributed in the Olympic Mountains represent a distinct genetic cluster relative to the Cascade Mountains, with B. sylvicola and B. mixtus likely experiencing the greatest degree of population genetic differentiation relative to B. flavifrons and B. melanopygus. While bumble bees are known to co-exist across a diversity of habitats, our results demonstrate that underlying population genetic structure and diversity may not necessarily be similar across species, and are largely governed by their respective niches.     

Investigating the genetic diversity and differentiation patterns in the <Emphasis Type="Italic">Penstemon scariosus</Emphasis> species complex under different sample sizes using AFLPs and SSRs

Habitat fragmentation due to anthropogenic activities is the major cause of biodiversity loss. Endemic and narrowly distributed species are the most susceptible to habitat degradation. Penstemon scariosus is one of many species whose natural habitat is vulnerable to industrialization. All varieties of P. scariosus (P. scariosus var. albifluvis, P. scariosus var. cyanomontanus, P. scariosus var. garrettii, P. scariosus var. scariosus) have small distribution ranges, but only P. scariosus var. albifluvis is being considered for listing under the Endangered Species Act. We used eight microsatellites or simple sequence repeats (SSRs) loci and two amplified fragment length polymorphism (AFLP) primer combinations to investigate the population genetic structure and diversity of P. scariosus varieties. Moreover, we compared the utility of the two marker systems in conservation genetics and estimated an appropriate sample size in population genetic studies. Genetic differentiation among populations based on F_st ranged from low to moderate (F_st?=?0.056–0.157) and from moderate to high when estimated with D_es (D_es?=?0.15–0.32). Also, AMOVA analysis shows that most of the genetic variation is within populations. Inbreeding coefficients (F_is) were high in all varieties (0.20–0.56). The Bayesian analysis, STRUCTURE, identified three clusters from SSR data and four clusters from AFLPs. Clusters were not consistent between marker systems and did not represent the current taxonomy. MEMGENE revealed that a high proportion of the genetic variation is due to geographic distance (R²?=?0.38, P?=?0.001). Comparing the genetic measurements from AFLPs and SSRs, we found that AFLP results were more accurate than SSR results across sample size when populations were larger than 25 individuals. As sample size decreases, the estimates become less stable in both AFLP and SSR datasets. Finally, this study provides insight into the population genetic structure of these varieties, which could be used in conservation efforts.     

Genetic population diversity of European eel <Emphasis Type="Italic">Anguilla anguilla</Emphasis> elvers in two Egyptian water bodies,Rosetta (Rachid) estuary and Burullus Lake

The European eel Anguilla anguilla is a species of great economic importance for Egypt. Its long trans-Atlantic migrations for semelparous spawning then larval homing provides a possible way for worldwide mixing of populations. Its natural habitats in Egypt, as in other Mediterranean countries, are under heavy load of pollution due to anthropogenic activities. Hence, a major priority should be given to assess the genetic diversity within/among eels’ populations as a step towards revealing populations’ status, identification of possible conservation units, and, subsequently, implementation of proper conservation and management strategies for them. For this, A. anguilla elvers were collected from Rosetta estuary and Burullus coastal lagoon in the North of Egypt. Sequencing of the barcode region of the cytochrome c oxidase subunit 1 gene (COI) was carried out for all collected elvers. The sequences were analyzed using various genetic, phylogenetic, and population analyses to assess their variability. A total of 33 haplotypes were identified, 14 of which were unique to Burullus Lake, and 11 to Rosetta estuary. Very low fixation (F _st ?=?0–0.04) was found for A. anguilla populations in Egypt and worldwide, except for the Turkish and Czech ones (F _st ?=?0.47–0.62 and 0.18–0.41, respectively). Both Egyptian populations showed signs of recent populations’ expansion, besides low, non-significant raggedness values. The results suggested Burullus Lake and Rosetta estuary as separate conservation units for A. anguilla in Egypt. These units require special attention for proper protection and management of the existing eel diversity and permitting sustainability in the activities dealing with eel’s fishing and aquaculture.     

Molecular genetic diversification of the lizard complex <Emphasis Type="Italic">Darevskia raddei</Emphasis> (Sauria: Lacertidae): Early stages of speciation

To characterize the molecular genetic diversity of the genus Darevskia, several populations were examined by the inter-SINE-PCR method, reporting the number and sizes of the spacers between individual copies of SINE-like interspersed repeats. Examination of 17 D. raddei geographical populations and several reference species revealed unequal genetic differences, measured as Nei and Li’s genetic distances (D_NL), for different groups of samples. The highest homogeneity was observed for the apparently panmictic D. raddei nairensis population from the basin of the Hrazdan River: genetic differences within each of the five samples and between them were similarly low (less than 0.1). The difference between ten samples of D. raddei raddei from Armenia and Karabakh (0.2–0.3) was somewhat higher than the interindividual difference within each sample (0.1–0.2), indicating that the samples belonged to different populations. The assumption was supported by the phylogenetic tree topology and multidimensional scaling. The differences between samples from the morphological subspecies D. raddei raddei and D. raddei nairensis ranged 0.3–0.4. The difference of two D. raddei raddei samples of Talysh (Azerbaijan) from other samples of the same subspecies corresponded to the subspecific level. The genetic distances between the good species D. raddei and D. rudis was 0.6–0.7. In terms of D_NL, a questionable population from northwestern Turkey (“D. tristis”) was closer to D. rudis (D_NL = 0.45), probably representing its subspecies. The phylogeography of D. raddei is discussed.     

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.     

Analysis of the mitochondrial DNA diversity in Yukaghirs in the evolutionary context

Based on the mtDNA first hypervariable segment sequence variation data, statistical analysis of the diversity in Yukaghirs in comparison with the other indigenous populations of Siberia, was carried out. The level of the Yukaghir mtDNA gene diversity (GD) constituted 0.920, which was only slightly different from the corresponding estimate for the other Siberian populations. Integral estimates of the genetic structure of Siberian populations (k, S, θ _S , and π) are presented. Phylogenetic analysis, performed using the neighbor-joining method, showed that the Siberian populations clustered irrespectively to their language affiliation. Negative F _s values found in Yukaghirs pointed to the possible influence of adaptive selection.     

Elucidating the multiple genetic lineages and population genetic structure of the brooding coral <Emphasis Type="Italic">Seriatopora</Emphasis> (Scleractinia: Pocilloporidae) in the Ryukyu Archipelago

The elucidation of species diversity and connectivity is essential for conserving coral reef communities and for understanding the characteristics of coral populations. To assess the species diversity, intraspecific genetic diversity, and genetic differentiation among populations of the brooding coral Seriatopora spp., we conducted phylogenetic and population genetic analyses using a mitochondrial DNA control region and microsatellites at ten sites in the Ryukyu Archipelago, Japan. At least three genetic lineages of Seriatopora (Seriatopora-A, -B, and -C) were detected in our specimens. We collected colonies morphologically similar to Seriatopora hystrix, but these may have included multiple, genetically distinct species. Although sexual reproduction maintains the populations of all the genetic lineages, Seriatopora-A and Seriatopora-C had lower genetic diversity than Seriatopora-B. We detected significant genetic differentiation in Seriatopora-B among the three populations as follows: pairwise F _ST = 0.064–0.116 (all P = 0.001), pairwise G′′_ST = 0.107–0.209 (all P = 0.001). Additionally, only one migrant from an unsampled population was genetically identified within Seriatopora-B. Because the peak of the settlement of Seriatopora larvae is within 1 d and almost all larvae are settled within 5 d of spawning, our observations may be related to low dispersal ability. Populations of Seriatopora in the Ryukyu Archipelago will probably not recover unless there is substantial new recruitment from distant populations.     

Genetic structure of the Russian populations of <Emphasis Type="Italic">Pyrenophora tritici-repentis</Emphasis>, determined by using microsatellite markers

The population genetic structure of plant pathogenic fungus Pyrenophora tritici-repentis was examined using microsatellite (SSR) markers. According to the geographical origin of the pathogen populations, they were designated as North Caucasian (S, 33 isolates), northwest (Nw, 39), and Omsk (Om, 43). The populations were analyzed at the nine most polymorphic SSR loci, at which 75 alleles were identified. To characterize the genetic variation within and between populations, the AMOVA algorithm as implemented in the Arlequin v. 3.5 software program was used. The number of alleles per locus ranged from 5 to 12 and their sizes varied within the range from 180 to 400 bp. The mean gene diversity at SSR loci was high for all populations (H = 0.58–0.75). The populations were considerably different in the frequencies of individual alleles of the SSR loci. Most isolates in the populations were represented by unique haplotypes. The within-population variation of the isolates at molecular markers was 86.4%; among the populations, 13.6%. Substantial interpopulation differences were found between the Om and S (F_st = 0.16) and between the Om and Nw (F_st = 0.20) populations, whereas between the S and Nw populations, these differences were small (F_st = 0.05). Thus, it was demonstrated that the population of P. tritici-repentis from Omsk oblast had the independent status of the geographical population; northwest and North Caucasian populations differed in the allelic diversity of SSR loci, and despite the low F_st value (0.05), they also belonged to independent geographical populations.     

Genetic differentiation among natural populations of the lizard complex <Emphasis Type="Italic">Darevskia raddei</Emphasis> as inferred from genome microsatellite marking

The article presents the genetic parameters of the populations of lizards of the Darevskia raddei complex (D. raddei nairensis and D. raddei raddei) and the populations of D. valentini calculated on the basis of the analysis of variability of 50 allelic variants of the three nuclear genome microsatellite-containing loci of 83 individuals. It was demonstrated that the F_st genetic distances between the populations of D. raddei nairensis and D. raddei raddei were not statistically significantly different from the F_st genetic distances between the populations of different species, D. raddei and D. valentini. At the same time, these distances were statistically significantly higher than the F_st distances between the populations belonging to one species within the genus Darevskia. These data suggest deep divergence between the populations of D. raddei raddei and D. raddei nairensis of the D. raddei complex and there arises the question on considering them as separate species.     

Conservation genetics of the annual hemiparasitic plant <Emphasis Type="Italic">Melampyrum sylvaticum</Emphasis> (Orobanchaceae) in the UK and Scandinavia

Melampyrum sylvaticum is an endangered annual hemiparasitic plant that is found in only 19 small and isolated populations in the United Kingdom (UK). To evaluate the genetic consequences of this patchy distribution we compared levels of diversity, inbreeding and differentiation from ten populations from the UK with eight relatively large populations from Sweden and Norway where the species is more continuously distributed. We demonstrate that in both the UK and Scandinavia, the species is highly inbreeding (global F _IS = 0.899). Levels of population differentiation were high (F’_ST = 0.892) and significantly higher amongst UK populations (F’_ST = 0.949) than Scandinavian populations (F’_ST = 0.762; P < 0.01). The isolated populations in the UK have, on average, lower genetic diversity (allelic richness, proportion of loci that are polymorphic, gene diversity) than Scandinavian populations, and this diversity difference is associated with the smaller census size and population area of UK populations. From a conservation perspective, the naturally inbreeding nature of the species may buffer the species against immediate effects of inbreeding depression, but the markedly lower levels of genetic diversity in UK populations may represent a genetic constraint to evolutionary change. In addition, the high levels of population differentiation suggest that gene flow among populations will not be effective at replenishing lost variation. We thus recommend supporting in situ conservation management with ex situ populations and human-mediated seed dispersal among selected populations in the UK.