Microsatellite DNA analysis reveals lower than expected genetic diversity in the threatened leopard cat (<Emphasis Type="Italic">Prionailurus bengalensis</Emphasis>) in South Korea

To optimize conservation efforts, it is necessary to determine the risk of extinction by collecting reliable population information for a given species. We developed eight novel, polymorphic microsatellite markers and used these markers in conjunction with twelve existing markers to measure genetic diversity of South Korean populations of leopard cat (Prionailurus bengalensis), a species for which population size and habitat area data are unknown in the country, to assess its conservation status. The average number of alleles and the observed heterozygosity of the species were 3.8 and 0.41, respectively, and microsatellite diversity was lower than the average genetic diversity of 57 populations of 12 other felid species, and lower than that of other mammal populations occurring in South Korea, including the raccoon dog (Nyctereutes procyonoides), water deer (Hydropotes inermis), and endangered long-tailed goral (Naemorhedus caudatus). Furthermore, analysis of genetic structure in the national leopard cat population showed no clear genetic differentiation, suggesting that it is not necessary to divide the South Korean leopard cat population into multiple management units for the purposes of conservation. These results indicate that the genetic diversity of the leopard cat in South Korea is unexpectedly low, and that the risk of local extinction is, as a result, substantial. Thus, it is necessary to begin appropriate conservation efforts at a national level to conserve the leopard cat population in South Korea.     

Variation in the <Emphasis Type="Italic">COI</Emphasis> gene of the freshwater pearl mussel <Emphasis Type="Italic">Margaritifera margaritifera</Emphasis> from River Vuokkijoki

The freshwater pearl mussel Margaritifera margaritifera L. is one of the most endangered freshwater mussels in the world. Effective conservation of threatened species requires not only ecological, but also genetic information from the target species and populations. Since low genetic diversity can reduce the ability of a species to adapt to environmental changes, maintaining genetic diversity has been identified as one of the key elements in successful conservation programs. We examined genetic variation of the freshwater pearl mussel from the River Vuokkijoki, Karelia, Russia. We sequenced a fragment of the cytochrome c oxidase subunit I gene (COI) from 22 individuals and compared the data to 32 previously published COI sequences available in GenBank. We identified 10 different COI haplotypes in the sequenced samples, three of which had not been previously reported. Our results show that the River Vuokkijoki has high genetic diversity and suggest that the colonization of this northern freshwater pearl mussel population might have occurred from multiple and even distant refugia. Therefore, the freshwater pearl mussel population of the River Vuokkijoki is valuable for the conservation of the whole species.     

Genetic diversity and population structure of the northern snakehead (<Emphasis Type="Italic">Channa argus</Emphasis> Channidae: Teleostei) in central China: implications for conservation and management

Major threats to freshwater fish diversity now include loss of native genetic diversity as a consequence of translocations of fishes between sites and from hatcheries to sites, and small effective population sizes resulting from overfishing and/or habitat loss. Ten polymorphic microsatellite markers were employed to evaluate genetic diversity, population genetic structure and gene flow amongst nine populations of the ecologically and economically important fish, the northern snakehead (Channa argus), in three river systems in central China. Multiple analyses revealed evidence of high genetic diversity and pronounced subdivision based on both regional separation and on river systems. A lack of evidence of genetic bottleneck over recent generations was consistent with the long-term stability of population size and contemporary distribution. The effective population sizes for most C. argus populations were small, suggesting the need for future conservation efforts focusing on these populations. Different lines of evidence point to the local enhancement of stocks by both aquaculture-reared fish and the transfer of wild fish. This study illustrates how human activities may affect genetic diversity and population genetic structure of C. argus populations, and highlights the need for new management regimes to protect native freshwater fish genetic diversity.     

Phylogeography of the Asian lesser white-toothed shrew, <Emphasis Type="Italic">Crocidura shantungensis</Emphasis>, in East Asia: role of the Korean Peninsula as refugium for small mammals

Many peninsulas in the temperate zone played an important role as refugia of various flora and fauna, and the southern Korean Peninsula also served as a refugium for many small mammals in East Asia during the Pleistocene. The Asian lesser white-toothed shrew, Crocidura shantungensis, is a widely distributed species in East Asia, and is an appropriate model organism for exploring the role of the Korean Peninsula as a refugium of small mammals. Here, we investigated phylogenetic relationships and genetic diversity based on the entire sequence of the mitochondrial cytochrome b gene (1140 bp). A Bayesian tree for 98 haplotypes detected in 228 C. shantungensis specimens from East Asia revealed the presence of three major groups with at least 5 subgroups. Most haplotypes were distributed according to their geographic proximity. Pairwise F_ST’s and analysis of molecular variance (AMOVA) revealed a high degree of genetic differentiation and variance among regions as well as among populations within region, implying little gene flow among local populations. Genetic evidence from South Korean islands, Jeju-do Island of South Korea, and Taiwan leads us to reject the hypothesis of recent population expansion. We observed unique island-type genetic characteristics consistent with geographic isolation and resultant genetic drift. Phylogeographic inference, together with estimates of genetic differentiation and diversity, suggest that the southern most part the Korean Peninsula, including offshore islands, played an important role as a refugium for C. shantungensis during the Pleistocene. However, the presence of several refugia on the mainland of northeast Asia is also proposed.     

Mitogenomic analysis of the Australian lungfish (<Emphasis Type="Italic">Neoceratodus forsteri</Emphasis>) reveals structuring of indigenous riverine populations and late Pleistocene movement between drainage basins

Neoceratodus forsteri: is a freshwater species of Dipnoan currently listed as ‘vulnerable to extinction’ under Australian legislation. The species is restricted to at least two indigenous riverine populations in southeastern Queensland, and several other putatively translocated populations. Current understanding of genetic relationships among populations is based on studies of allozymes, microsatellites and mitochondrial DNA (mtDNA) fragments. A notable feature of all these datasets was low genetic variability. Here we sequence the complete mitogenome of 71 N. forsteri individuals from five populations to improve resolution of mtDNA diversity, examine relationships among populations, and evaluate recent demographic history. We recorded 137 variable positions forming 41 haplotypes in the 16,573 bp mitogenome alignment. Strong genetic structure was observed among riverine samples (global Φ_ST?=?0.342) in a pattern consistent with translocation history. Tinana Creek was confirmed as an isolated and genetically unique subpopulation that should be recognized as a distinct management unit. Two previously unreported mtDNA clades (0.46% mean divergence) were found and suggest that genetic exchange among coastal catchments may have been facilitated by riverine connections on the exposed continental shelf during the late Pleistocene. Extended Bayesian skyline analysis showed no evidence for recent historical change in female effective population size, and codon-based selection tests found no evidence for positive selection in coding genes. Overall, our results emphasise the utility of the full mtDNA molecule for capturing population structure in taxa with low genetic diversity. In such cases, informative variation may be scattered across disparate parts of the mitogenome. Surveying relatively short fragments of mtDNA may lead to significant underestimates of population structure when applied to threatened species with low genetic diversity.     

Genetic assessment of <Emphasis Type="Italic">Abies koreana</Emphasis> (Pinaceae), the endangered Korean fir,and conservation implications

To establish a management plan for endangered and rare species, genetic assessment must first be conducted. The genetic characteristics of plant species are affected by demographic history, reproductive strategy, and distributional range as well as anthropological effects. Abies koreana E. H. Wilson (Pinaceae), Korean fir, is endemic to Korea and found only in sub-alpine areas of the southern Korean Peninsula and Jejudo Island. This species has been designated as critically endangered by the International Union for Conservation of Nature due to a continuous decline in its range and population fragmentation. We genotyped 176 individuals from seven natural populations and two afforested populations on the Korean Peninsula using 19 microsatellite loci. STRUCTURE analysis revealed two genetic clusters in natural populations (F _st  = 0.040 and R _st  = 0.040) despite low differentiation. We did not detect a significant reduction in genetic diversity or the signature of a genetic bottleneck despite population fragmentation and small population size. We deduced that this species exhibits a metapopulation structure, with the population on Jirisan Mountain acting as a source of genetic diversity for other local small populations on the Korean Peninsula, through contemporary asymmetric gene flow. However, the majority of afforested individuals on the Korean Peninsula originated from a different gene cluster. Thus, we recommend a conservation strategy that maintains two genetically unique clusters.     

Genetic diversity and structure analyses on the natural populations of diploids and triploids of tiger lily, <Emphasis Type="Italic">Lilium lancifolium</Emphasis> Thunb., from Korea,China, and Japan

Tiger lily, Lilium lancifolium Thumb. is an endemic species in Korea. Genetic structure and diversity of diploid and triploid tiger lily accessions were analyzed using SSRP and IRAP molecular markers. All genetic indices analyzed showed that the diploids hold higher genetic variations compared to the triploids which were collected from Korea, China, and Japan. All variations found in triploids were also found in diploids to support the autotriploidy of L. lancifolium. It was also revealed that the triploid populations have experienced population regrowth from small population after population bottleneck. The population and phylogenetic analyses showed that analyzed tiger lilies were partitioned into three populations, Pop 1 from West Sea of Korean Peninsula, Pop 2 from South Sea of Korean Peninsula and Pop 3 of triploids in which many accessions of West Sea and South Sea were admixed in each partitioned group. Although the level of population differentiation is not extensive, F_ST analysis revealed some level of differentiation among the three populations. The analyses of genetic structure and phylogenetic dendrogram revealed admixture in some accessions among populations. All the results obtained in our analyses imply that autotriploid tiger lilies were originated from a small number of accessions of diploid L. lancifolium.     

Genetic evidence of recent migration among isolated-by-sea populations of the freshwater blenny (<Emphasis Type="Italic">Salaria fluviatilis</Emphasis>)

Genetic diversity is the raw material for evolutionary change, so a species’ capacity to maintain its genetic diversity is a major concern in conservation genetics. Although genetic diversity within a population is reduced through time by genetic drift, gene flow among populations can act to recover or add new genetic variants. The goal of this study was to infer potential connectivity among isolated-by-sea populations of the vulnerable freshwater blenny (Salaria fluviatilis) and to determine if gene flow could contribute to maintaining genetic diversity in connected populations. Four genetic clusters (one small at the North, one large at the South for both East and West coasts) were detected with different clustering methods (FLOCK, STUCTURE, UPGMA, AMOVA). The two larger genetic clusters with higher migration-rate estimates among localities had higher genetic diversity and allelic richness and lower relatedness between individuals, compared to isolated localities found in smaller clusters. Our results also suggest that sea currents may facilitate fish movements among neighbouring rivers. Overall, gene flow among isolated-by-sea but close rivers could maintain the evolutionary potential of freshwater blenny populations. This finding should be considered when elaborating a conservation program for this species.     

Origin and dispersal of bluegill sunfish, Lepomis macrochirus, in Japan and Korea

The bluegill sunfish, Lepomis macrochirus, is a notorious exotic species in many freshwater ecosystems, currently expanding its distribution worldwide. In 1960, a small group of bluegills captured in the Mississippi River at Guttenberg in Iowa were imported to Japan as a gift from the mayor of Chicago to the Japanese government. The offspring of these fish were released into the wild in Japan and also in Korea. Over 40 years after this first introduction, L. macrochirus now occupies all the freshwater ecosystems of both countries. We compared invading populations of L. macrochirus in Japan and Korea with native populations in the USA, using PCR-RFLP (polymerase chain reaction-restricted fragment length polymorphism) analyses of mitochondrial DNA, to estimate the origin and dispersal of L. macrochirus in Japan and Korea. Five haplotypes of mitochondrial DNA detected in Japanese and Korean populations completely coincided with the haplotypes of the Guttenberg population. Haplotype diversity of invading populations was shown to be highest in populations established in the 1960s, while genetic variability was lower in more recently established populations. Our results suggest that all L. macrochirus in Japan and Korea have originated from the 15 fish first introduced in 1960. Low haplotype diversity in newly established populations is probably due to genetic drift arising from repeated population bottlenecks, while the high similarity of haplotypes among neighbouring populations is considered to reflect the history of transplantation by humans.     

Genetic variability comparison of cultured Israeli carp (<Emphasis Type="Italic">Cyprinus carpio</Emphasis>) from Korea using microsatellites

In aquaculture, cultured fish often undergo continuous cross-fertilization without any inflow of new broodstock. This lowers genetic diversity, leading to increased disease rates and decreased survival rates. To improve the mass production and easy culture of Israeli carp, it is essential to investigate the population structure and genetic diversity of these fish. However, such a survey has not yet been performed on Korean Israeli carp. In this study, we used seven microsatellite markers to analyze the genetic diversity and association of cultured Israeli carp from Korea and China. The average numbers of alleles per locus (N _A ) for two Korean (KorA and KorB) and two Chinese (ChA and ChB) populations were as follows: KorA (10.42), KorB (14.43), ChA (20.57) and ChB (20.71). The expected heterozygosity (H _e ) ranged from 0.672 to 0.897 and from 0.827 to 0.938 in the Korean sample and Chinese sample respectively. The genetic diversity of the Korean Israeli carp was about half that of the Chinese carp. The diversity of the Korean Israeli carp was very low, suggesting that the immunity of this population could be weak, and that diversity–recovery studies are urgently needed. Therefore, our results may therefore form the foundation for future research efforts towards genetic monitoring and selective breeding, continuous research needs to be conducted in order to recover the genetic diversity of the Korean Israeli carp.     

Genetic variation of <Emphasis Type="Italic">Picea jezoensis</Emphasis> populations in South Korea revealed by chloroplast,mitochondrial and nuclear DNA markers

Genetic variation associated with Picea jezoensis populations of South Korea was investigated using chloroplast (cp), mitochondrial (mt) and nuclear DNA markers. In South Korea, P. jezoensis is distributed across a very restricted area, being found on the summits of three mountains: Mts. Jiri, Dokyu and Gyebang. Examination of five region restriction enzyme combinations for mtDNA and four for cpDNA revealed haplotypes endemic to South Korea. The Gyebang population, the most northerly and most isolated, was genetically distinct from the other populations. Nuclear microsatellite markers indicated, overall, a low level of genetic diversity (H _e = 0.406) in South Korea; this could be attributed to genetic drift and/or founder effects associated with historical events. The Wilcoxon sign-rank test did not indicate a recent bottleneck in any of the populations irrespective of the model considered (infinite allele model, two-phased model of mutation, and stepwise mutation model). Microsatellite markers also demonstrated that the Gyebang population was distinct from the others. The results of this study could be used as the basis for conservation guidelines for the management of this species in South Korea.     

Conservation genetics of rare trees restricted to subtropical montane cloud forests in southern China: a case study from <Emphasis Type="Italic">Quercus arbutifolia</Emphasis> (Fagaceae)

Montane cloud forests (MCFs), with their isolated nature, offer excellent opportunities to study the long-term effects of habitat fragmentation and the impacts of climate change. Quercus arbutifolia is a rare oak in MCFs of southern China and Vietnam. Its isolated populations, small population size and unique ecological niche make this species vulnerable to climate change and habitat loss. In this study, we used chloroplast (cpDNA) and nuclear (ITS) DNA sequences to investigate genetic divergence patterns and demographic history of five of the six known populations of Q. arbutifolia. Considering its small population size and fragmentation, Q. arbutifolia has unexpectedly high genetic diversity. The time since the most recent common ancestor of all cpDNA haplotypes was c. 10.25 Ma, and the rapid diversification of haplotypes occurred during the Quaternary. The maximum clade credibility chronogram of cpDNA haplotypes suggests that the DM population (Daming Mountain, Guangxi province) diverged early and rapidly became isolated from other populations. The Pearl River drainage system may have been the main geographic barrier between DM and other populations since the late Miocene. ITS data suggests that population expansion occurred during the last interglacial of the Quaternary. The combined effects of pre-Quaternary and Quaternary climatic and geological changes were the main drivers to the current genetic diversity and distribution pattern of Q. arbutifolia. Because of the high between-population genetic differentiation and high within-population genetic diversity of Q. arbutifolia, conservation efforts should be implemented for all populations, but if conservation resources are limited, populations DM, YZ (Mang Mountain, Hunan province) and ZZ (Daqin Mountain, Fujian province) should have priority.     

Genetic structure and diversity of the koala population in South Gippsland,Victoria: a remnant population of high conservation significance

In the Australian state of Victoria, the history of koalas and their management has resulted in the homogenisation and reduction of genetic diversity in many contemporary populations. Decreased genetic diversity may reduce a species’ ability to adapt to future environmental pressures such as climate change or disease. The South Gippsland koala population is considered to be unique in Victoria, as it is believed to be a remnant population, not originating from managed populations that have low genetic variation. This study investigated genetic structure and diversity of koalas in South Gippsland, with comparison to other populations in Victoria (French Island/Cape Otway, FI and Raymond Island, RI), New South Wales and south east Queensland. Population analyses were undertaken using both microsatellite genotype and mitochondrial DNA sequence data. Non-invasive sampling of koala scats was used to source koala DNA, allowing 222 South Gippsland koalas to be genotyped. Using nuclear data the South Gippsland koala population was found to be significantly differentiated (D_jost 95% CI SG–RI?=?0.03–0.06 and SG–FI?=?0.08–012) and more diverse (A_R 95% CI SG?=?4.7–5.6, RI?=?3.1–3.3, FI?=?3.0–3.3; p?=?0.001) than other Victorian koala populations, supporting the premise that koalas in the South Gippsland region are part of a remnant population, not derived from translocated island stock. These results were also supported by mitochondrial data where eight haplotypes (Pc4, Pc17, Pc26, Pc27, and Pc56–Pc59) were identified in South Gippsland while a single haplotype (Pc27) was found in all island koalas tested. Compared to other Victorian koala populations, greater genetic diversity found in South Gippsland koalas, may provide this population with a greater chance of survival in the face of future environmental pressures. The South Gippsland koala population is, therefore, of high conservation significance, warranting the implementation of strategies to conserve this population and its diversity into the future.     

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.     

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.     

Isolation and Characterization of Microsatellite Markers for <Emphasis Type="Italic">Viola websteri</Emphasis> (Violaceae) and Cross-Species Amplification within the Genus <Emphasis Type="Italic">Viola</Emphasis>

We isolated and characterized microsatellite loci in Viola websteri (Violaceae), an endangered species from Korea and endemic to Northeast Asia. A total of 27 microsatellite loci were developed and tested in Korean and Chinese populations. The number of alleles per locus varied from two to eight. The observed and expected heterozygosities within two populations were 0.000 to 1.000 and 0.080 to 0.816, respectively. Korean and Chinese populations were clearly distinguished by the private alleles from 16 loci. A total of 21 loci out of the 27 developed loci were successfully cross-amplified in 39 other Viola species. We believe that these microsatellite loci will be useful for future studies on genetic diversity and population structure of V. websteri, as well as other Viola species.     

Haplotype diversity of mt<Emphasis Type="Italic">COI</Emphasis> in the fall webworm <Emphasis Type="Italic">Hyphantria cunea</Emphasis> (Lepidoptera: Arctiidae) in introduced regions in China,Iran, Japan,Korea, and its homeland,the United States

Hyphantria cunea (Drury) has colonized many countries outside its native range of North America and has become a model species for studies of the colonization and subsequent adaptation of agricultural pests. Molecular genetic analyses can clarify the origin and subsequent adaptations to non-native habitats. Using the mitochondrial COI gene, we examined the genetic relationships between invasive populations (China, Iran, Japan, and Korea) and native populations (i.e., the United States). The Jilin (China) and Guilan (Iran) populations showed nine previously unknown haplotypes that differed from those found in the south–central United States, suggesting multiple colonization events and different regions of invasion. A dominant mtDNA haplotype in populations in the United States was shared by all of the populations investigated, suggesting that H. cunea with that haplotype have successfully colonized China, Iran, Japan, and Korea.     

Genetic characteristics of Y-chromosome short tandem repeat haplotypes from cigarette butt samples presumed to be smoked by North Korean men

Korea has been divided into South Korea and North Korea for over 70 years. DNA profiles of the North Korean population have never been reported in the Y-chromosome STR Haplotype Reference Database (YHRD; https://yhrd.org). To investigate genetic features of Y-chromosome STR haplotypes of the North Korean population for the first time. Genomic DNA was isolated from 838 cigarette butts assumed to have been smoked by North Korean men and amplified with PowerPlex Y23 (PPY23) kit. Statistical parameters were calculated using Nei’s formula and analysis of molecular variance (AMOVA). Multidimensional scaling (MDS) plot was constructed by the AMOVA tool and neighbor-joining (NJ) tree was constructed by MEGA 6.06. A total of 121 haplotypes were analyzed for PPY23 loci from a sample population. Haplotype diversity and discrimination capacity were 0.9992 and 0.9837, respectively. Genetic diversities ranged from 0.2981 to 0.9716. For the 16 Y-filer loci and eight minimal loci, respectively 90.9 and 82.6% of the matched haplotypes were estimated to belong to haplogroup O, representing the Southeast and East Asian type. The MDS plot and NJ tree indicated that the samples are most closely related to South Korean. In addition, p-value in the pairwise comparison to the South Korean was slightly above statistical significance (p?=?0.0534). The Y-STR haplotypes of the samples were unique and highly genetically polymorphic. Despite the separation between North and South Korea for 70 years, they can still be considered a single genetic population, based on Y-STR haplotypes.     

Invasion genetics of nutria (<Emphasis Type="Italic">Myocastor coypus</Emphasis>) in Okayama,Japan, inferred from mitochondrial and microsatellite markers

Nutria (Myocastor coypus) is a large semi-aquatic rodent native to South America, introduced worldwide for fur farming in the early twentieth century. In Japan, 150 individuals were introduced from the USA in 1939, and their feral populations are currently causing serious problems to aquatic ecosystem and agriculture. Okayama Plain is the largest habitat of nutria in Japan, established by the escapees from breeding farms around the middle of the 1940s. Here, we examined genetic structure of Okayama population and inferred gene flow among populations, using mtDNA and ten microsatellite markers (MS), to estimate eradication units for the effectiveness of population control. For mtDNA, two haplotypes (A and B) were detected in cytochrome b region. Haplotype A was widely distributed in Okayama Plain, while haplotype B was mainly observed around Yoshii River. For MS, Okayama population showed high genetic diversity, comparable to USA and Argentine populations. Genetic differentiation was recognized among drainages with a significant isolation-by-distance pattern. Multivariate analyses and Bayesian clustering method suggested two genetic clusters and radial dispersal around the coast of the Kojima Bay, while these clusters did not necessarily concord with mtDNA haplotypes in distribution. Genetic heterogeneity tended to be higher in males than in females, and females exhibited a higher relatedness than males in Asahi River. These results suggest that nutria in Okayama Plain originated from farming sites downstream in Yoshii and Takahashi Rivers and have expanded its distribution along rivers via tributaries. Mitochondrial-nuclear discordance seems to be due to male-biased dispersal in nutria.     

Genetic diversity of the dung beetle,Copris tripartitus (Coleoptera: Scarabaeidae), that is endangered in Korea

The dung beetle, Copris tripartitus (Coleoptera: Scarabaeidae), is an endangered insect in Korea. In order to establish a conservation strategy, a preliminary investigation on the genetic diversity of Korean populations was performed using mitochondrial COI (658 bp), CytB (433 bp), and nuclear ITS2 (411 nucleotide positions). Sequencing of 69 individuals collected from five localities showed substantially higher variability (5.02% for COI, 4.62% for CytB, and 8.03% for ITS2). The resulting networks for mitochondrial DNA (mtDNA) haplotypes exhibited two star‐like phylogenies, which might indicate that Korean populations have recently expended from two small populations. The ITS2 network, which was presented in the form of a star‐like phylogeny, confirmed that a recent population expansion occurred. Considering the high genetic diversity and gene flow in C. tripartitus populations, one issue regarding conservation seems to be the recovery of previous habitats.