Population genetic structure of the tongue sole (Cynoglossus semilaevis) in Korea based on multiplex PCR assays with 12 polymorphic microsatellite markers

The tongue sole, Cynoglossus semilaevis, is an important fishery resource in Korea. About 100 tongue sole sampled from three major habitats along the western coast of Korea were assessed using multiplex assays with 12 highly polymorphic microsatellite loci to explore the population genetic structure of the species; 151 alleles and similar high levels of gene diversity (mean number of alleles (N_A) = 10.42, mean expected heterozygosity (He) = 0.78) were detected. Three populations showed significant Hardy–Weinberg equilibrium deviations at four loci. Although a significant difference in the number of unique alleles was observed among populations, genetic population subdivision was low by F-statistics (overall F _ST = 0.007, p < 0.05). However, this substructure was not supported by analysis of molecular variance or analyses of isolation by distance. The results suggest a lack of genetic structure among the tongue sole populations in Korean waters and that the populations should be managed as a single unit. The lack of genetic differentiation among samples may be due to high levels of larval dispersal in ocean currents. Alternatively, the populations may have diverged too recently for significant genetic differentiation to have become evident. Given the intensity of tongue sole aquaculture activity in China, which adjoins the western coast of Korea, the possibility that aquaculture may have partially contributed to the population genetic characteristics detected cannot be excluded. This study provides the basic information on nature population structure of C. semilaevis that may help to preserve and manage tongue soles in Korea.     

Population Genetic Structure and Demographic History of Atrina pectinata Based on Mitochondrial DNA and Microsatellite Markers

The pen shell, Atrina pectinata, is one of the commercial bivalves in East Asia and thought to be recently affected by anthropogenic pressure (habitat destruction and/or fishing pressure). Information on its population genetic structure is crucial for the conservation of A. pectinata. Considering its long pelagic larval duration and iteroparity with high fecundity, the genetic structure for A. pectinata could be expected to be weak at a fine scale. However, the unusual oceanography in the coasts of China and Korea suggests potential for restricted dispersal of pelagic larvae and geographical differentiation. In addition, environmental changes associated with Pleistocene sea level fluctuations on the East China Sea continental shelf may also have strongly influenced historical population demography and genetic diversity of marine organisms. Here, partial sequences of the mitochondrial Cytochrome c oxidase subunit I (COI) gene and seven microsatellite loci were used to estimate population genetic structure and demographic history of seven samples from Northern China coast and one sample from North Korea coast. Despite high levels of genetic diversity within samples, there was no genetic differentiation among samples from Northern China coast and low but significant genetic differentiation between some of the Chinese samples and the North Korean sample. A late Pleistocene population expansion, probably after the Last Glacial Maximum, was also demonstrated for A. pectinata samples. No recent genetic bottleneck was detected in any of the eight samples. We concluded that both historical recolonization (through population range expansion and demographic expansion in the late Pleistocene) and current gene flow (through larval dispersal) were responsible for the weak level of genetic structure detected in A. pectinata.     

Genetic Diversity and Population Structure of Alnus hirsuta (Betulaceae) in Korea

Alnus hirsuta in Korea was measured to estimate the amount and pattern of genetic diversity and population structure. The mean genetic diversity within populations was 0.166. Korean alder populations have slightly high levels of genetic diversity compared to those of two Canadian alder species. The genetic differentiation among populations accounted for 9% of the total variation. The rate of gene flow was estimated high (Nm=2.63). Analysis of inbreeding coefficient, calculated for all polymorphic loci in each population, showed a substantial heterozygote deficiency relative to Hardy-Weinberg expectations. The mean G _ST value of A. hirsuta in Korea was 0.087. The low value of G _ST in this species, reflecting little spatial genetic differentiation, may indicate extensive gene flow. A relationship between the mean heterozygosity and annual rainfall showed a positive relationship (r ²=0.54, F=4.67). Received 8 August 1998/ Accepted in revised form 7 July 1999     

Population genetic structure of the Korean threadsail filefish (Stephanolepis cirrhifer) based on microsatellite marker analysis

The threadsail filefish Stephanolepis cirrhifer is one of the most important commercial fish resources in Korea. However, its natural populations have declined drastically over the last several decades. To investigate the genetic characteristics of the threadsail filefish for conservation and management purposes, its genetic variation was analyzed in Korean fishing grounds using 11 microsatellite loci. All populations showed moderate genetic diversity (mean number of alleles (N_A) = 8.6, expected heterozygosity (He) = 0.73), representing a slightly lower level of genetic variability than other congeneric species. The presence of a weak genetic population substructure was detected (F_ST = 0.023, R_ST = 0.030, P < 0.001), but this substructure did not feature significant isolation based on the distance between populations. This differentiation may be primarily attributable to genetic differences between populations from Geomundo and other localities, based on relative low level of gene flow, a high level of pairwise F_ST and R_ST or the position of this population in a phylogenetic tree. An analysis of molecular variance (AMOVA) also revealed a greater part of the variation within the population and genetic differentiation among the samples analyzed and identified two genetic clusters. The possibility of a recent genetic bottleneck was observed in some populations of S. cirrhifer. Given the prevailing ocean currents and the intensity of threadsail filefish harvesting activities in Korea, the possibility that human harvest and stock enhancement activities may have partially contributed to our detected genetic pattern cannot be excluded. Management strategies that take these findings into account might lower the risk of harmful genetic change in the species.     

Genetic diversity and genetic structure of the endangered Manchurian trout, <Emphasis Type="Italic">Brachymystax lenok tsinlingensis</Emphasis>, at its southern range margin: conservation implications for future restoration

The Manchurian trout, Brachymystax lenok tsinlingensis (family: Salmonidae), is a cold freshwater fish endemic to Northeast Asia. South Korean populations of this species, which comprise its southern range limit, have recently decreased markedly in size and are now becoming critically endangered. We assessed the current population status of this species in South Korea by estimating the levels of genetic diversity and genetic structure of five natural and four restored populations using mitochondrial DNA (mtDNA) control region sequences and eight nuclear microsatellite loci. Levels of within-population genetic diversity were low, suggesting that past effective population sizes (N _e) have been small. Each population had one or a maximum of two mtDNA haplotypes. Microsatellite allelic richness (AR) was significantly higher for natural populations (mean AR?=?3.51; 95% confidence interval, 3.00–4.03) than for restored populations (mean AR?=?2.61; 2.38–2.98). South Korean populations were significantly genetically isolated from one another, with private mtDNA haplotypes and microsatellite alleles, suggesting that limited gene flow has been occurring among populations. A mtDNA phylogeny revealed that South Korean lineages were more closely related to those of China than to those of North Korea and Russia. Overall, we suggest that future restoration efforts aimed at South Korean populations should consider the genetic characteristics reported here, which should help to fulfil effective conservation strategies for this highly cherished species. Our results will inform other conservation efforts, including assisted migration of freshwater fish populations at the equatorial end of the geographical range limit of the species.     

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.     

Population genetic structure of endangered Mongolian racerunner (Eremias argus) from the Korean Peninsula

The Mongolian racerunner (Eremias argus) is a small lacertid lizard species, and its distribution range encompasses the Korean Peninsula, Mongolia, China and Russia. Eremias argus is widespread, but populations on the Korean Peninsula are small and declining, provoking concerns that genetic diversity is being lost. This species is currently listed under the Protection of Wild Fauna and Flora Act in South Korea. In this study, nine novel microsatellites for E. argus were developed with a biotin-enrichment method and used to understand its population genetic structure and delineate conservation units on the Korean Peninsula. Overall, low intrapopulation genetic diversity was observed (mean number of alleles per locus = 2.463; mean H _E = 0.398) from 10 populations investigated (n = 110). Two populations (among five with n≥ 10) showed an excess of heterozygosity expected under HWE relative to that expected at mutation-drift equilibrium, indicating severe reduction in population sizes. With only a few exceptions, the overall genetic differentiation among populations was substantial with the high levels of pairwise-F _ST (0.006–0.746) and -R _ST (0.034–0.940) values. The results of Bayesian STRUCTURE analysis showed that E. argus populations on the Korean Peninsula were most likely partitioned into three genetic clusters. Taken all together, such low levels of gene flow and strong genetic structuring have critical implications for the conservation of this endangered species and its management.     

Genetic diversity and differentiation of the Korean starry flounder (Platichthys stellatus) between and within cultured stocks and wild populations inferred from microsatellite DNA analysis

The Korean starry flounder, Platichthys stellatus, is economically valuable coastal resident fish species. However, the annual catch of this fish has fluctuated and suffered major declines in Korea. We examined the genetic diversity and population structure for four wild populations and three hatchery stocks of Korean starry flounder to protect its genetic integrity using nine microsatellites. A group of 339 genotypes belonging to seven populations were screened. High degrees of polymorphism at the microsatellite loci were observed within both the wild and hatchery populations. Compared to the wild populations, genetic changes, including reduced genetic diversity and highly significant differentiation, have occurred in cultured stocks. Significant population differentiation was also observed in wild starry flounder populations. Similar degrees of inbreeding and significant Hardy–Weinberg equilibrium deviations were detected in both the wild and the hatchery populations. The genetic connectivity pattern identified four distinct metapopulations of starry flounder in Korea by clustering in the phylogenetic tree, Bayesian analyses, molecular variance analysis, PCA and multidimensional scaling analysis. A pattern of isolation-by-distance was not significant. This genetic differentiation may be the result of the co-effects of various factors, such as historic dispersal, local environment or anthropogenic activities. These results provide useful information for the genetic monitoring of P. stellatus hatchery stocks, for the genetic improvement of this species by selective breeding and for designing suitable management guidelines for the conservation of this species.     

Genetic structure of the Korean black scraper Thamnaconus modestus inferred from microsatellite marker analysis

The Korean black scraper, Thamnaconus modestus, is one of the most economically important maricultural fish species in Korea. However, the annual catch of this fish has been continuously declining over the past several decades. In this study, the genetic diversity and relationships among four wild populations and two hatchery stocks of Korean black scraper were assessed based on 16 microsatellite (MS) markers. A total of 319 different alleles were detected over all loci with an average of 19.94 alleles per locus. The hatchery stocks [mean number of alleles (N _A) = 12, allelic richness (A _R) = 12, expected heterozygosity (He) = 0.834] showed a slight reduction (P > 0.05) in genetic variability in comparison with wild populations (mean N _A = 13.86, A _R = 12.35, He = 0.844), suggesting a sufficient level of genetic variation in the hatchery populations. Similarly low levels of inbreeding and significant Hardy–Weinberg equilibrium deviations were detected in both wild and hatchery populations. The genetic subdivision among all six populations was low but significant (overall F _ST = 0.008, P < 0.01). Pairwise F _ST, a phylogenetic tree, and multidimensional scaling analysis suggested the existence of three geographically structured populations based on different sea basin origins, although the isolation-by-distance model was rejected. This result was corroborated by an analysis of molecular variance. This genetic differentiation may result from the co-effects of various factors, such as historical dispersal, local environment and ocean currents. These three geographical groups can be considered as independent management units. Our results show that MS markers may be suitable not only for the genetic monitoring of hatchery stocks but also for revealing the population structure of Korean black scraper populations. These results will provide critical information for breeding programs, the management of cultured stocks and the conservation of this species.     

Genetic diversity and population structure of<Emphasis Type="Italic">Kalopanax pictus</Emphasis> (Araliaceae)

Kalopanax pictus (Araliaceae) is a long-lived woody species primarily distributed throughout East Asia. This species is regarded as medically and ecologically important in Korea. We used starch gel electrophoresis to investigate its allozyme variation and genetic structure in samples from Korean populations (both natural and cultivated). Our analysis of 10 enzymes revealed 18 loci, of which 10 were polymorphic (35.6%). Genetic diversity at the species and population levels were 0.200 and 0.149, respectively, with the mean for cultivated populations (0.124) being lower than for natural (wild) populations (0.181). Asexual and sexual reproduction modes, perennial habitat, and longevity all were possible factors contributing to such high diversity. An indirect estimate of the number of migrants per generation (N _m = 1.08) indicated that gene flow was not extensive among these Korean populations. Therefore, we suggest that geographical distance as well as reproductive isolation between wild and cultivated plants may play roles in shaping the population structure of this species.     

Population Genetic Structure of the Ark Shell <Emphasis Type="Italic">Scapharca broughtonii</Emphasis> Schrenck from Korea,China, and Russia Based on <Emphasis Type="Italic">COI</Emphasis> Gene Sequences

Haplotype distribution, gene flow, and population genetic structure of the ark shell (Scapharca broughtonii) were studied using a partial sequence of a mitochondrial COI gene. The sequence analysis of 100 specimens obtained from a total of seven localities-five in Korea, one in China, and one in Russia- revealed 29 haplotypes, ranging in sequence divergence from 0.1% to 2.1%. Among these, the most frequent haplotype, SB16, was extensively distributed over study areas, especially in all Korean localities. This extensive distribution consequently resulted in the near absence of statistically significant genetic distance. Also, a high rate of gene flow was characteristic among localities in Korea. A test of genetic population structure showed that the ark shell in Korea formed a large genetic group. Moreover, an AMOVA test to determine the allocation of the genetic variance showed that most of the variance was distributed between localities, instead of within localities. However, a significant population differentiation was found between geographic populations [i.e., Jinhae (locality 6) in Korea and Sangdong (locality 5) in China and Vladivostok (locality 7) in Russia] based on geographic distance and population structure. These distinct groups may be associated with geographic characteristics and barriers. The results suggest that most of the ark shell populations in Korea caused considerable distribution to form a genetically homogeneous and intermixing structure, whereas some of the Korean and Chinese and Russian populations had a significantly different genetic structure.     

Weak population genetic differentiation in the most numerous Arctic seabird,the little auk

Quantifying patterns of genetic diversity and differentiation among populations of Arctic birds is fundamental for understanding past and ongoing population processes in the Arctic. However, the genetic differentiation of many important Arctic species remains uninvestigated. Here, phylogeography and population genetics were examined in the worldwide population of a small seabird, the little auk (dovekie, Alle alle)—the most numerous avian species of the Arctic ecosystem. Blood samples or feathers were collected from 328 little auks (325 from the nominate subspecies and 3 from the A. a. polaris) in nine main breeding aggregations in the northern Atlantic and one location from the Pacific Ocean. The mtDNA haplotypes of the two subspecies were not segregated into separate groups. Also, no genetic structure was found within the nominate race based on microsatellite markers. The level of genetic differentiation among populations was low yet significant (mean F _ST = 0.005). Some pairwise F _ST comparisons revealed significant differences, including those involving the most distant Pacific colony as well as among some Atlantic populations. Weak population differentiation following the model of isolation by distance in the little auk is similar to the patterns reported in other high-Arctic bird species, indicating that a lack of distinct genetic structure is a common phenomenon in the Arctic avifauna.     

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.     

Isolation and characterization of 12 microsatellite loci from Korean water deer (Hydropotes inermis argyropus) for population structure analysis in South Korea

The main goals of this study were to isolate microsatellites markers of Korean water deer (Hydropotes inermis argyropus) and understand the genetic status of the species in South Korea. Twelve new microsatellite loci were isolated and characterized to establish basic population genetic parameters for 45 H. i. argyropus specimens in South Korea. There were no significant regional or genetic structure differences between the mid-eastern and southwestern populations in South Korea according to the population genetic analyses. The number of alleles per locus ranged from two to 13 with an average of 6.08. Mean expected (H _E) and observed heterozygosity (H _O) were 0.622 and 0.533, respectively. Microsatellite variability was also not significant between the two regions (F _ST=0.012). These new markers should facilitate the future population genetics studies of Korean water deer and other closely related species.     

Genetic structure of Korean populations of bumblebees Bombus ignitus (Hymenoptera: Apidae) as revealed by microsatellite markers

Bumblebee Bombus ignitus, which is indigenous to Korea, Japan, and China, has been recognized as a valuable pollinator for both crops and wild plants. Bombus ignitus has now become commercially important as a pollinator because of its use in the agricultural industry, particularly for greenhouse pollination. For long‐term management and effective conservation of B. ignitus, an understanding of the genetic structure of its naturally occurring populations is practically important. In this study, the genetic structure among the five populations of B. ignitus in South Korea was assessed using nine microsatellite loci. These markers showed high levels of genetic variability, with the number of alleles ranging from 6 to 22 (mean = 13.4) and the frequency of the most common allele ranging from 0.11 to 0.66. Only the Sabuk (SB) population showed a genetic signature of a recent bottleneck, which was further supported by the lowest level of allelic richness (AR) (mean AR = 3.944). Genetic differentiation was highly significant among all pairs of populations (P < 0.001) across the nine microsatellite markers, suggesting a lack of gene flow among those populations. Interestingly, F_ST (and R_ST and D_est) values were always greater for the Taebaek population than for the four remaining populations. The phylogenetic analysis showed evidence supporting our hypothesis that the Taebaek population is genetically more divergent than the other populations. Overall, our results suggest that the Korean populations of B. ignitus might have undergone geographic isolation and have become highly separated spatially from one another, thereby having a limited range of migration among their local habitats.     

Phylogeography of East Asian <Emphasis Type="Italic">Lespedeza buergeri</Emphasis> (Fabaceae) based on chloroplast and nuclear ribosomal DNA sequence variations

The dynamic changes in land configuration during the Quaternary that were accompanied by climatic oscillations have significantly influenced the current distribution and genetic structure of warm-temperate forests in East Asia. Although recent surveys have been conducted, the historical migration of forest species via land bridges and, especially, the origins of Korean populations remains conjectural. Here, we reveal the genetic structure of Lespedeza buergeri, a warm-temperate shrub that is disjunctively distributed around the East China Sea (ECS) at China, Korea, and Japan. Two non-coding regions (rpl32-trnL, psbA-trnH) of chloroplast DNA (cpDNA) and the internal transcribed spacer of nuclear ribosomal DNA (nrITS) were analyzed for 188 individuals from 16 populations, which covered almost all of its distribution. The nrITS data demonstrated a genetic structure that followed geographic boundaries. This examination utilized AMOVA, comparisons of genetic differentiation based on haplotype frequency/genetic mutations among haplotypes, and Mantel tests. However, the cpDNA data showed contrasting genetic pattern, implying that this difference was due to a slower mutation rate in cpDNA than in nrITS. These results indicated frequent migration by this species via an ECS land bridge during the early Pleistocene that then tapered gradually toward the late Pleistocene. A genetic isolation between western and eastern Japan coincided with broad consensus that was suggested by the presence of other warm-temperate plants in that country. For Korean populations, high genetic diversity indicated the existence of refugia during the Last Glacial Maximum on the Korean Peninsula. However, their closeness with western Japanese populations at the level of haplotype clade implied that gene flow from western Japanese refugia was possible until post-glacial processing occurred through the Korea/Tsushima Strait land bridge.     

Genetic diversity and historical migration patterns of an endemic evergreen oak,Quercus acuta,across Korea and Japan,inferred from nuclear microsatellites

Forests dominated by broad-leaved evergreen trees cover a narrow zone of the southern coast of Korea as well as warm-temperate and subtropical regions of Japan. However, little is known about their establishment history, especially in Korea. Endemic Quercus acuta grows in Korea and Japan. We evaluated its genetic diversity, population structure, and degree of lineage admixture in terms of its distribution history. Analyses utilized seven nuclear microsatellites that were genotyped from 330 individuals of 16 populations. Genetic diversity was highest for the Japanese Kyushu populations. The allelic diversity of populations was similar between Jeju Island and Kyushu, implying that they are putative refugia. Although the mean F _ST value was very low, patterns for isolation-by-distance were strong and significant. Results from Bayesian clustering and Monmonier’s algorithm indicated that populations are roughly partitioned from west (Korea and Kyushu) to east (Japanese Honshu). Therefore, the two divisions within this species are demographically independent and may have arisen due to past fragmentation. In considering the mixed genetic structure between Korea and Kyushu populations, and the higher levels of genetic diversity in mainland Korea relative to Honshu, we hypothesized that this species has been able to survive within Jeju Island and Kyushu. Consequently, mainland Korea populations might have been shaped by range expansion that kept them well mixed from a continuous and large genetic resource.     

Genetic diversity of Lilium tsingtauense in China and Korea revealed by ISSR markers and morphological characters

To study the genetic diversity and population structure of Lilium tsingtauense Gilg (Qingdao Lily), we collected 648 samples from 12 sites in China and Korea, and analyzed their Inter-Simple Sequence Repeat (ISSR) molecular markers and morphological characters. ISSR data revealed a relatively high genetic diversity at the species level, with 72.31% polymorphic loci, effective numbers of alleles of 1.437, average expected heterozygosity of 0.231 and Shannon’s information index of 0.369. Considerable genetic differentiation among the natural populations (G_ST = 0.144) and the gene flow (N_m = 1.487) were detected. AMOVA analysis and UPGMA-dendrogram suggested a hierarchical regional structure among populations, and spatial autocorrelation analysis showed a micro-scaled spatial structure. Furthermore, there was a high correlation between morphological characters and genetic parameters obtained from ISSR parameters. There was only a low genetic differentiation among the different morphological types of L. tsingtauence in China. Based on these findings, we recommend in situ and ex situ conservation strategies for the preservation of L. tsingtauense.     

Patterns of Genetic Diversity in Rare and Common Orchids Focusing on the Korean Peninsula: Implications for Conservation

To provide basic information for orchid conservation, we surveyed the plant allozyme literature to summarize genetic diversity and structure data for (i) rare orchids native to the Korean Peninsula, and (ii) their congeners irrespective of being common and rare or Korean or not. A total of 68 taxa (32 taxa in Korea and 37 outside Korea; Goodyera repens being included in both datasets) were considered in this study. Overall, rare Korean orchid species had significantly lower levels of genetic diversity than their common congeners and common orchids in general at both population and species levels. However, mean values of G _ST (or F _ST) for rare and common orchids (Korean or not) did not differ significantly from each other. We found patterns of both low and high genetic diversity in rare Korean orchids. Many rare orchids harbored a complete lack of allozyme variation or extremely low within-population variation, perhaps due to rarity associated with random genetic drift and/or, for the case of warm-temperate orchids, to founder effects during post-glacial re-colonization. In contrast, high levels of genetic variation were found for a few orchids that have become recently rare (due to over-collection during the past several decades), probably because there have not been sufficient generations for the initial diversity to be substantially eroded. In addition, several orchids occurring in the main mountain system of the Korean Peninsula (the Baekdudaegan), that served as a glacial refugium, maintained moderate to high levels of within-population genetic diversity. Based on our genetic data, conservation priority should be given to rare orchid species. Particularly, urgent measures should be implemented on Jeju Island, a popular vacation spot, because it also a hotspot for threatened orchids with low levels of genetic diversity.     

Dissecting the genetic structure of Korean population using genome-wide SNP arrays

Genome-wide SNP arrays have generated unprecedented quantities of data allow the detection of human evolutionary history and dense genome-wide data also enable the identification of distance ancestry among individuals or ethnic groups. To explain wider aspects of the genetic structure of Koreans and the East Asian population, we analyzed 79 individuals from the Korean HapMap project at 555,352 common single-nucleotide polymorphism loci, and compared this data with the worldwide population groups with the 53 ethnic groups from Human Genome Diversity Panel (HGDP-CEPH). Population differentiation (F_ST), Principal Component Analyses, STRUCTURE and ADMIXTURE are examined. In general, all the individual samples studies here were classified into subset of ethnic groups according to their geographical origins. Korean HapMap individuals were grouped together with East Asian populations from HGDP panel. Recently, a sub-population structure within Korean population has been reported. Our result, however, revealed the genetic homogeneity of Korean population. The ADMIXTURE analysis showed that, overall the Korean populations derive 79 % of their genomic ancestry from southern Asia and have relatively little northern Asian ancestry (21 %). The present work, therefore, provide the evidence that the male-biased southern-to-northern migration influenced not only for the genetic make up of the Y chromosome in the Korean population but also, its autosomal composition.