Analysis of genetic diversity in the endangered Hucho taimen from China

Hucho taimen are listed as endangered in China. The population size has declined recently, prompting an increase in the level of listing from grade three in 2002 to grade five in 2006. We analyzed the genetic diversity of wild populations using 17 microsatellite markers to establish a scientific basis for conservation of this species. We collected tissue samples from four populations in the Heilongjiang River basin: Huma River (HM), Hutou (HT), Haiqing (HQ), and Zhuaji (ZJ). A total of 21 loci were amplified, 18 of which were polymorphic. The number of alleles per locus ranged from 2 to 9 (mean: 4.1905). There were 13 highly polymorphic loci and 5 moderately polymorphic loci. Analysis of five genetic diversity parameters (Na, Ne, Ho, He, and PIC) suggested moderate levels of diversity within the populations. The populations were ranked HT > HQ > ZJ > HM, but the differences in diversity were not statistically significant (P > 0.05). A comparison of variation among all four populations suggested Hardy–Weinberg disequilibrium at 20% of the loci. Genetic differentiation (Fst) was 0.0644 and the gene flow among populations was estimated at 3.36 individuals per generation. The majority of diversity (93.88%) occurred among individuals within a population. In contrast, relatively little (6.12%) of the genetic diversity was distributed between the populations. An analysis of genetic differentiation and genetic distance between pairs of populations revealed that both parameters were higher in comparisons of the HM population to the HT, HQ, and ZJ populations than among the three latter populations. This suggests that the HM population has a distinct genetic structure. We hypothesize that habitat degradation and excessive fishing, not low genetic diversity, has caused the decline in H. taimen populations. However, this species should be protected from further declines in genetic diversity.     

Characterization of genetic variance within and among five populations of Sperata seenghala (Skyes, 1839) revealed by random amplified polymorphic DNA markers

The genetic diversity among five populations (Bhadbada reservoir, Mohinisagar reservoir, Bansagar reservoir, Bargi reservoir and Gandhisagar reservoir) was revealed using random amplified polymorphic DNA markers. 10 random primers screened, 5 primers revealed various banding patterns and yielded 71 total loci as an average of which 39.60 (55.77%) were polymorphic between the population and 86.84% within the population of Sperata seenghala. Population wise the highest genetic polymorphism was obtained in Bhadbada reservoir as 67.61% whereas the lowest was in Gandhisagar reservoir as 49.30%. However, Analysis of Molecular Variance indicated low genetic diversity (H_pop = 0.0921 ± 0.1249; I = 0.1584 ± 0.1942) in Bansagar reservoir. Relative genetic differentiation (G_ST = 0.3993) and restricted gene flow (N_m = 0.7523) as an average indicated low gene diversity among the fish populations. The un-weighted pair group method with averages (UPGMA) dendrogram showed 05 major clusters, each cluster representing a population. Fish population of Mohinisagar reservoir showed high genetic distance (0.3981) with respective Bargi reservoir population and highest genetic identity (0.8846) reflected between Bansagar and Gandhisagar reservoir. Highest genetic distance between Mohinisagar and Bargi reservoir fish populations shows no significant correlation between genetic and geographical distance of the genotypes collected from different lentic and geographical isolated water bodies. This investigation indicated that lowest genetic diversity existed in different geographic populations of S. seenghala. All the five populations were found to be low in genetic variation, which is useful information for future conservation measures of S. seenghala confined in natural water bodies of Madhya Pradesh.     

Genetic variation and clonal diversity in populations of Nelumbo nucifera (Nelumbonaceae) in central China detected by ISSR markers

To obtain accurate estimates of population structure for purposes of conservation planning for wild lotus (Nelumbo nucifera Gaertn.) in central China, genetic diversity among and within six populations, and clonal diversity within another two populations of the species were analyzed. The genetic diversity was high (percentage of polymorphic bands, PPB = 90.0%; Shannon's information index, I = 0.383 ± 0.234) at the species level, but low within individual study populations (PPB = 35.8%; Shannon's information index I = 0.165 ± 0.241). The mean coefficient of gene differentiation (G_st) was 0.570, indicating that 43.0% of the genetic diversity resided within the population. Analysis of molecular variance (AMOVA) indicated that 50.47% of the genetic diversity among the study populations was attributed to geographical location while 12.3% was attributed to differences in their habitats. An overall value of mean estimated number of gene flow (N_m = 0.377) indicated that there was limited gene flow among the sampled populations. The level of clonal diversity found within the populations was considerably high (Simpson's diversity index, D = 0.985) indicating that clonal diversity contributes to a major extent to the overall genetic variation in the genetic structure of N. nucifera. On the basis of the high G_st and D values detected in this study we recommend that any future conservation plans for this species should be specifically designed to include those representative populations with the highest genetic variation for both in situ conservation and germplasm collection expeditions.     

Analysis of genetic variation in selected stocks of hatchery flounder,Paralichthys olivaceus,using AFLP markers

Amplified fragment length polymorphism (AFLP) analysis was performed in order to evaluate genetic characteristics of one common population and two selective hatchery populations of flounder Paralichthys olivaceus. A group of 60 genotypes belonging to three populations was screened using 10 different AFLP primer combinations. A total of 491 loci were produced in the three studied populations. The loci of 65.78%, 61.47% and 60.92% were polymorphic over all the genotypes tested in common, susceptible and resistant populations, respectively. The number of polymorphic loci detected by single primer combination ranged from 21 to 43. The average heterozygosity of common, susceptible and resistant populations was 0.1656, 0.1609 and 0.1586, respectively, which showed no significant difference. Compared with the common population, the two selective hatchery populations, susceptible and resistant, showed significant genetic differences including a smaller (P < 0.05) number of total loci, a smaller (P < 0.05) number of total polymorphic loci and a smaller (P < 0.05) percentage of low frequency (0–0.2) polymorphic loci. AFLP banding pattern was transformed into binary data and matrices were processed with POPGENE and TFPGA software. Similarity relationships were described graphically by a dendrogram, which clustered the three populations. The AFLP fingerprinting technique was confirmed to be a reproducible and sensitive tool for the study of population genetics of flounder. The present study confirmed that it was important to detect the genetic variability of the selective hatchery populations for the conservation of natural flounder resources.     

Population structure and genetic diversity of Dysosma versipellis (Berberidaceae), a rare endemic from China

Dysosma versipellis (Berberidaceae) is an endangered and endemic species in China. To provide scientific foundation for formulating conservation strategies, we sampled six extant populations of this species and assessed the levels and patterns of genetic diversity using ISSR markers (11 primers). Of 144 bands detected 57.64% were polymorphic, but on average only 20.72% were polymorphic within populations. Our results revealed a low level of intraspecific genetic diversity (at population level: H_pop = 0.082, H_B = 0.177, SI = 0.1194; at species level: H_pop = 0.207, H_B = 0.378, SI = 0.3069). A high level of genetic differentiations among populations was detected based on Nei's genetic diversity analysis (60%), AMOVA analysis (65%), and Bayesian analysis (53%). The low levels of heterozygosity and high genetic differentiation observed in D. versipellis may be the consequence of low rate of natural recruitment, clonal growth, gene drift, and habitat fragmentation. Based on this, we suggest that in situ conservation be an important and practical measure for maintaining the genetic diversity of this species. Ex situ conservation should sample from different populations across the distribution range of the species to conserve high genetic diversity.     

Genetic diversity and population structure of a protected species: Polygala tenuifolia Willd

Polygala tenuifolia Willd. is an important protected species used in traditional Chinese medicine. In the present study, amplified fragment length polymorphism (AFLP) markers were employed to characterize the genetic diversity in wild and cultivated P. tenuifolia populations. Twelve primer combinations of AFLP produced 310 unambiguous and repetitious bands. Among these bands, 261 (84.2%) were polymorphic. The genetic diversity was high at the species level: percentage of polymorphic loci (PPL) = 84.2%, Nei's gene diversity (h) = 0.3296 and Shannon's information index (I) = 0.4822. Between the two populations, the genetic differentiation of 0.1250 was low and the gene flow was relatively high, at 3.4989. The wild population (PPL = 81.9%, h = 0.3154, I = 0.4635) showed a higher genetic diversity level than the cultivated population (PPL = 63.9%, h = 0.2507, I = 0.3688). The results suggest that the major factors threatening the persistence of P. tenuifolia resources are ecological and human factors rather than genetic. These results will assist with the design of conservation and management programs, such as in natural habitat conservation, setting the excavation time interval for resource regeneration and the substitution of cultivated for wild plants.     

Population genetics and conservation of the Azorean tree Picconia azorica

Picconia azorica (Tutin) Knobl. (Oleaceae) is an endangered species, endemic to the Azores. Samples from 31 populations in 8 islands were genotyped using 8 newly developed nuclear microsatellite markers. From the amplified loci, 81% were polymorphic across all populations and the species showed a relatively high total genetic diversity (H_T = 0.7). Several populations were close to Hardy–Weinberg equilibrium while others presented positive F_IS values (0.02–0.2). The largest proportion of genetic variation (98%) occurred within populations and the level of differentiation between populations, was generally low, although 27% of the population pairwise comparisons showed relatively high differentiation values (0.25 ≤ R_ST ≤ 0.65). Relatively high levels of gene flow were also found among most populations. Using the Bayesian clustering method implemented in STRUCTURE we found a particular genetic pattern in Corvo samples, and also similarities between Santa Maria, São Miguel and Flores populations. Considerable levels of genetic admixture within P. azorica populations might have resulted from: (i) fruit dispersal by native birds; and/or (ii) human mediated dispersal between islands. Our results revealed the existence of some genetically depauperate populations needing specific conservation measures, and indicate that arbitrary translocation of individuals between islands should be avoided.     

Genetic structure of Himalayan marmot (Marmota himalayana) population alongside the Qinghai–Tibet Railway

In order to verify the effect of social behavior and geographical isolation on the genetic structure of the Himalayan marmot (Marmota himalayana) population, we examined the genetic diversity of Himalayan marmots alongside the Qinghai–Tibet Railway using microsatellite markers. Eight microsatellite loci were used to examine 120 animals of 4 populations: Ulan (U), Delhi (D), Tuotuohe (T) and Ando (A). The results show that: (1) Himalayan marmots alongside the Qinghai–Tibet Railway are highly genetically diversified. The allele number (Na), effective allele number (Ne), observed heterozygosity (Ho), Nei’s expected heterozygosity (He) and polymorphism information content (PIC) of the total Himalayan marmot population were 4.75, 3.0332, 0.6990, 0.6672, 0.6102, respectively. (2) Himalayan marmots may be able to avoid inbreeding by a mechanism that will prevent the genetic diversity reduction caused by their social lifestyle. Heterozygote excess was observed at most loci. The inbreeding coefficients within the subpopulation (F_IS), in the total population (F_IT), the differentiation index of population (F_ST), and the gene flow (Nm) were ?0.2265, ?0.0477, 0.1458, and 1.4646, respectively. (3) The genetic differentiation of the Himalayan marmot population was in accordance with Wright’s “isolation by distance” theory. The Mantel test indicates that the correlation between genetic distance and geographic distance was significant (P < 0.05, r = 0.698). (4) Each of the four geographical populations had moderate differentiation. Both geographic distance and isolation could affect the population genetic structure of the Himalayan marmot. The maximum gene flow (3.5915), the smallest genetic differentiation index (0.0651), the lowest genetic distance (0.0700) and the highest genetic identity (0.9526) were all between the Ulan population and Delhi populations. (5) The cluster analysis, based on Nei’s standard genetic distance, showed that the populations of Delhi and Ulan were first merged in a cluster, and then Tuotuohe population was merged in the clustering. The Ando population was the last element in the clustering.     

Evaluation of genetic diversity of Panicum turgidum Forssk from Saudi Arabia

The genetic diversity of 177 accessions of Panicum turgidum Forssk, representing ten populations collected from four geographical regions in Saudi Arabia, was analyzed using amplified fragment length polymorphism (AFLP) markers. A set of four primer-pairs with two/three selective nucleotides scored 836 AFLP amplified fragments (putative loci/genome landmarks), all of which were polymorphic. Populations collected from the southern region of the country showed the highest genetic diversity parameters, whereas those collected from the central regions showed the lowest values. Analysis of molecular variance (AMOVA) revealed that 78% of the genetic variability was attributable to differences within populations. Pairwise values for population differentiation and genetic structure were statistically significant for all variances. The UPGMA dendrogram, validated by principal coordinate analysis-grouped accessions, corresponded to the geographical origin of the accessions. Mantel’s test showed that there was a significant correlation between the genetic and geographical distances (r = 0.35, P < 0.04). In summary, the AFLP assay demonstrated the existence of substantial genetic variation in P. turgidum. The relationship between the genetic diversity and geographical source of P. turgidum populations of Saudi Arabia, as revealed through this comprehensive study, will enable effective resource management and restoration of new areas without compromising adaptation and genetic diversity.     

Effect of cliff connectivity on the genetic population structure of a rock-dwelling land snail species with frequent self-fertilization

To examine the effect of habitat connectivity on the genetic differentiation in the frequently selfing gastropod Chondrina avenacea we assessed RAPD profiles in 12 subpopulations from continuous cliffs and in 12 subpopulations from small, naturally fragmented cliffs in the Swiss Jura mountains. Subpopulations of C. avenacea on continuous cliffs showed a smaller number of polymorphic RAPD loci and a lower gene diversity (Nei's h = 0.049) than subpopulations on fragmented cliffs (h = 0.078). Genetic distance was not correlated with geographical distance between subpopulations. G_ST analysis indicated strong isolation effects. Neither the number of polymorphic loci nor Nei's h was correlated with local population density. Our analysis indicates that the local population structure of C. avenacea is a combined result of frequent self-fertilization, genetic drift and low dispersal. Similar findings have been reported in studies on spatial population structure of plants. We suggest that future management actions (selective tree cutting, and controlled access of sport climbers) should also consider small, isolated limestone cliffs to preserve the genetic diversity of C. avenacea.     

Genetic diversity and population structure in Vallisneria spinulosa (Hydrocharitaceae)

Vallisneria spinulosa is a dominant submerged macrophyte in lakes of the middle–lower reaches of the Yangtze River. Allozyme variation, clonal diversity and population genetic structure were investigated for a total of 396 individuals sampled from 10 extant populations. V. spinulosa maintained high levels of genetic variation both at the species (P = 46.2, A = 1.69, H_e = 0.23) and at the population level (P = 46.2, A = 1.58, H_e = 0.21). Although aquatic macrophytes commonly exhibit low genetic variation within populations, the obligately outcrossing mating system of V. spinulosa and pervasive gene flow likely account for the high levels of diversity maintained within populations. All V. spinulosa populations contained high clonal diversity with a mean proportion of distinguishable genotypes of 0.57 and a mean Simpson's diversity index of 0.95, indicating that populations were founded sexually or that successful seedling recruitment occurred after initial colonization. Partitioning of genetic diversity revealed a surprisingly low population differentiation (G_ST = 0.06) as compared to other hydrophilous angiosperms. No evidence of isolation-by-distance was found (r = 0.056, P = 0.312), suggesting that gene flow was not restricted geographically. The UPGMA cluster analysis revealed that several widely separated populations grouped together, suggesting long-distance gene flow among populations. The high vagility of V. spinulosa and extensive hydrologic connectivity among populations have facilitated long-distance gene flow and resulted in the pattern of population genetic structure in V. spinulosa.     

Analysis of the genetic diversity of Bemisia tabaci populations in Shanxi province, China☆

Five different primer combinations were used for the analysis of 152 B biotype Bemisia tabaci (Gennadius) individuals and five Trialeurodes vaporairiorum individuals collected from 19 counties and seven host plants in Shanxi province in China, respectively. The main objective of the present study was to use AFLP markers to determine the genetic diversity of B. tabaci populations collected from Shanxi Province. The use of these primer combinations allowed the identification of 127 polymorphic bands (52.26%) from 60 to 500 bp. The average number of polymorphic bands per primer was 25.4 while the range for the five primers was 20–32. The average degree of heterozygosity was 0.251, while the range for the five primers was 0.204–0.289. The results suggested definite genetic diversity among different B. tabaci populations. Cluster analysis showed that B. tabaci populations were firstly scattered to three genetic groups according to the regions, then every genetic group was scattered to several subgroups according to the host plants, which revealed the genetic variability of B biotype B. tabaci populations has been not only among different regions, but also among different host plants in Shanxi Province.     

High genetic diversity in fragmented Iris pumila L. populations in Ukrainian steppe enclaves

Habitat fragmentation can prevent gene flow between plant populations and lead to a loss of genetic diversity. However, such impact of fragmentation has not always been consistently confirmed by previous studies and the issue still needs further research. Particularly little is known about the impact of fragmentation on steppe plants. Steppe once covered vast, continuous areas, and nowadays is among the most fragmented biomes. In Ukraine, remnants of this habitat survived in large but few nature reserves and loess ravines as well as on kurgans (burial mounds of ancient nomadic people), which, despite their small size, are still numerous and scattered throughout the landscape.We studied the impact of fragmentation on the genetic diversity and structure of Iris pumila, a typical species of European steppes. Our main focus was to compare the genetic characteristics between kurgan populations (n = 8), and populations from larger refugia (n = 6). We assessed the genetic diversity of the studied populations with Universal Rice Primers.Our analyses revealed high genetic diversity across all investigated populations (mean He: 0.233; mean PPB: 58.57). However in kurgan populations genetic diversity was significantly higher than in larger refugia. Genetic diversity (He) was negatively correlated with population size. Most of the molecular variance (82%) was represented within populations, whereas genetic differentiation among populations was moderate (Φ_ST = 0.160), and low among refugia types (Φ_RT = 0.026).The maintenance of high genetic diversity despite two centuries of fragmentation may be related to the moderate disturbance occurring on kurgans, which enhances the sexual reproduction of the species. Moreover, we assume that species traits such as longevity and polyploidy might counterbalance genetic drift, while its self-incompatibility and presence of a soil seed bank allows for the replenishment of the gene pool. Overall, our results suggest that kurgans can protect genetic diversity of steppe species.     

High genetic differentiation revealed by RAPD analysis of narrowly endemic Sinocalycanthus chinensis Cheng et S.Y. Chang,an endangered species of China

Genetic diversity and genetic differentiation of narrowly endemic Sinocalycanthus chinensis Cheng et S.Y. Chang, an endangered species of China, were analyzed using random amplified polymorphic DNA (RAPD) markers. Totally, 165 stable and clearly scored RAPD bands were achieved from 12 primers. The genetic diversity of S. chinensis was high (P% = 68.84; h = 0.2421 ± 0.1978; I = 0.3615 ± 0.2789), whereas that at the population level was relatively low (P% = 14.49; h = 0.0578 ± 0.0167; I = 0.0843 ± 0.0236). High genetic differentiation among populations was detected based on Shannon's information index (0.7668), Nei's gene diversity (0.7613) and AMOVA (0.8183). This might be explained by its survival in refugia during the last glaciation in southeastern China with origin from a widespread continental progenitor. The 10 populations from different geographical sites could be clustered into two groups. Low gene flow due to mixed mating system and anthropogenic activities likely played important roles in shaping the population genetic structure of the species.     

High allozymic diversity in natural populations of Mycoheterotrophic Orchid Gastrodia elata,an endangered medicinal plant in China

Gastrodia elata Blume, a mycoheterotrophic orchid native to the Far East, is an endangered medicinal plant in China. Genetic variation among 19 natural populations of G. elata was examined in central China by using allozyme polymorphism (16 loci in six enzymatic systems). The species exhibited high level of genetic diversity (P = 56.3%, A = 2.2 and H_E = 0.221), which was mainly attributed to its perennial habit and mixed reproduction system (both sexual and asexual). Evident genetic differentiation in G. elata natural populations was suggested by F_ST = 0.241. AMOVA analysis showed 31.3% of the total molecular variation was attributed to inter-population differentiation. Obvious genetic structure and genetic depauperation of some populations indicate forest fragmentation and over-collection have affected genetic variation of G. elata. A conservation strategy, which is conserving populations with great genetic distinction or high level of genetic variation from four management units, is recommended.     

Micro-geographic landscape features demarcate seedling genetic structure in the stream lily,Helmholtzia glaberrima

In this study, 169 stream lily (Helmholtzia glaberrima) seedlings from six micro-drainages were genotyped with AFLP markers to quantify the impact that topographic landscape features and altitude may have in shaping patterns of genetic diversity within individual populations. A global analysis of genetic diversity detected significant genetic differentiation among micro-drainages (F_ST = 0.22, P < 0.01). The observed genetic structure of sampled sites conformed to a hierarchical model of gene flow. Assignment tests also supported a hierarchical model of gene flow as only one dispersal event among the sampled micro-drainages was detected. This suggests that opportunities for seed dispersal in H. glaberrima are highly constrained by patterns of hydrographic networks even at a local scale. In contrast, altitude had little impact on partitioning of genetic diversity as no increase in genetic diversity was evident among individuals in the upper (0.18 ± 0.02), and lower (0.17 ± 0.02) areas of micro-drainages. Overall these results suggest that the influence of freshwater landscape features can vary widely the effect on the patterns of genetic diversity of seedlings in stream lily populations.     

Patent Reports

We synthesized a hydroquinone glucoside (HG) as a potential skin-whitening agent using Leuconostoc mesenteroides (B-1299CB BF563) dextransucrase with hydroquinone (HQ) as an acceptor and sucrose as a donor. The product was purified using butanol partitioning and silica gel column chromatography. The structure of the purified HG was determined by nuclear magnetic resonance and the ionic product was observed at m/z 295 (C12, H16, O7 Na)⁺. HG was identified as 4-hydroxyphenyl-α-d-glucopyranoside. The optimum condition of HG synthesis, determined using a response surface methodology, was 450 mM HQ, 215 mM sucrose, and 0.55 U/mL dextransucrase; the final HG produced was 544 mg/L. The IC₅₀ of diphenylpicryl-hydrazyl scavenging activity was 3.85 mM indicating a higher antioxidant activity compared to β-arbutin (IC₅₀ = 6.04 mM). HG-mediated inhibition of lipid peroxidation was 3.51% that of HQ (100%) and much higher than that of β-arbutin (0.81% of HQ). In addition the IC₅₀ value of nitrite-scavenging activity was 14.76 mM showing a superior scavenging activity to that of β-arbutin (IC₅₀ = 27.09 mM).     

Genetic structure of Podocarpus nubigena (Podocarpaceae) provides evidence of Quaternary and ancient historical events

Evolution of ancient lineages inhabiting austral latitudes of the southern Andes has taken place in response to historical processes occurring at distinct spatial and temporal scales. We tested the hypothesis that distribution patterns of genetic polymorphisms within Podocarpus nubigena Lindl. (Podocarpaceae) were shaped by contemporary events acting at local scales such as Quaternary glaciations as well as pre-Quaternary palaeogeographical features of the landscape. We predict that such cold hardy species was able to survive locally in refugia during ice ages. As a result of local long-lasting persistence, its gene pool may also reflect the pre-Quaternary palaeogeography of southern South America. We collected fresh leaves from 30 randomly selected individuals at 14 populations. Leaf tissue was analyzed by isozyme electrophoresis using 12 putative loci most of which (92%) were polymorphic in at least one population. Elevated total genetic diversity was recorded H_T = 0.275 which was similarly high throughout populations with an overall significant mean among-population isolation (F_ST = 18%). Multivariate cluster and Bayesian analyses yielded significant latitudinal divergence at 43°S associated to a palaeobasin that produced a barrier for gene flow. Populations south of 43°S and those growing in lowland areas on Quaternary substrates of the North Patagonian Massif (Q NPM) present the highest genetic diversity suggesting long-lasting persistence. In contrast, northern mountain populations on pre-Quaternary substrates (pre-Q NPM) hold reduced genetic variation due to altitudinal movements in response to climate shifts. We suggest that palaeogeography of southern South America in addition to Neogene glaciations have shaped the genetic makeup of such ancient lineage as Podocarpus.     

Amplified fragment length polymorphism analysis to identify the genetic structure of the Gymnocypris przewalskii (Kessler, 1876) population from the Qinghai Basin, China

Amplified fragment length polymorphism (AFLP) was used to analyse the genetic structure of 45 individuals of Gymnocypris przewalskii (Kessler, 1876), an endangered and state‐protected rare fish species, from three areas [the Heima (HM), Buha (BH) and Shaliu rivers (SL), all draining into Qinghai Lake]. A total of 563 polymorphic loci were detected. The HM, BH and SL populations have 435, 433 and 391 loci, respectively ( Zhu and Wu, 1975 ), which account for 77.26%, 76.91% and 69.45% of the total number of polymorphic loci of each population, respectively. The Nei indices of genetic diversities (H) of the three populations were calculated to be 0.2869 (HM), 0.2884 (BH) and 0.2663 (SL), respectively. Their Shannon informative indices are 0.4244, 0.4251 and 0.3915, respectively. Research results show that the mean genetic distance between HM and BH is the smallest (0.0511), between BH and SL is the second shortest (0.0608), and between HM and SL is the largest (0.0713), with the mean genetic distance among the three populations being over 0.05. Data mentioned above indicate that the three populations have a certain genetic differentiation. The total genetic diversity (H_t = 0.3045) and the mean value of genetic diversity within the population (H_s = 0.2786) indicate that the variations have mainly come from within the population.     

Mitochondrial DNA sequence variation of the bumblebee,Bombus ardens (Hymenoptera: Apidae)

The bumblebee, Bombus ardens, is a valuable natural resource, and is most notably utilized for greenhouse pollination. In order to gain a greater understanding of the population genetic structure and the genetic diversity of this species, we sequenced a portion of the mitochondrial COI gene corresponding to the “DNA Barcode” region (658 bp) from 160 individuals collected over 15 Korean localities. Uncorrected pairwise distances among the eight haplotypes suggested low intraspecific genetic diversity, with a maximum sequence divergence of 0.3%. Such a low level of intraspecific genetic diversity was further reflected in local populations, particularly to islet populations, such as those of Youngheungdo, Jakyakdo, and Ulleugdo, which had zero genetic diversity. Geographically, one haplotype (BARBA01) was widespread and dominant, with a frequency of 90.6% (145 among 160 individuals). Other haplotypes were restricted to one to three localities and had low frequency. Overall, a very high rate of per generation female migration ratio (Nm = 4.6 to infinite) and a very low level of genetic fixation (F_ST = 0 to 0.099) were detected between pairs of localities, suggesting that the B. ardens populations on the Korean peninsula are panmictic, which is consistent with our understanding of their dispersal capability.