共查询到20条相似文献,搜索用时 15 毫秒
1.
Man Kyu Huh Hak Young Lee Shambhu Nath Mishra Hong Wook Huh 《Journal of Plant Biology》2000,43(3):136-142
We determined the genetic diversity and population structures ofCarex breviculmis (Cyperaceae) populations in Korea, using genetic variations at 23 allozyme loci.C. breviculmis is a long-lived herbaceous species that is widely distributed in eastern Asia. A high level of genetic variation was found
in 15 populations. Twelve enzymes revealed 23 loci, of which 11 were polymorphic (47.8%). Genetic diversity at the speciesand
population levels were 0.174 and 0.146, respectively. Total genetic diversity (HT = 0.363) and within-population genetic diversity (Hs = 0.346) were high, whereas the extent of the population divergence was relatively low (GST = 0.063). Deviation from random mating (Fis) within the 15 populations was 0.206. An indirect estimate of the number of migrants
per generation(Nm = 3.69) indicated that gene flow was extensive among Korean populations of this species. Analysis of fixation indices revealed
a substantial heterozygote deficiency in some populations and at some loci. Genetic identity between popu-lations was high,
exceeding 0.956. 相似文献
2.
根据 2 2个等位酶位点遗传变异 ,探讨了韩国境内委陵菜 (PotentillafragarioidesL .var.sprengeliana)的遗传多样性和种群结构。酶位点的多态位点百分比为 5 9 1%。种和种群水平上的遗传多样性比较高 ,分别为Hes=0 .2 10 ,Hep=0 .199;而种群的分化水平则相对较低 (GST=0 .0 74)。 19个种群中随机交配的偏差为FIS=0 .331。每代迁移数的间接估计 (Nm=3.15 )表明该种在韩国的种群间基因流较高。另外 ,固定指数分析显示在一些种群和位点有轻微的杂合子缺乏。种群间平均遗传一致度为 0 985。这些韩国委陵菜种群存在于较为均一的生境 ,这很有可能是造成其种群遗传一致性较高的原因。 相似文献
3.
The genetic diversity and population structure of Potentilla fragarioides var. sprengeliana(Rosaceae) in Korea were investigated using genetic variation at 22 allozyme loci. The percent of polymorphic loci within the enzymes was 59.1%. The genetic diversity at the species level and at the population level was high (Hes=0.210; Hep=0.199, respectively), whereas the extent of the population divergence was relatively low (GST=0.074). FIS, a measure of the deviation from random mating within the 19 populations, was 0.331. An indirect estimate of the number of migrants per generation (Nm=3.15) indicates that gene flow is high among Korean populations of the species. In addition, analysis of fixation indices revealed a slight heterozygote deficiency in some populations and at some loci. The mean genetic identity between populations was 0.985. It is highly probable that the trend of genetic uniformity in a relatively homogeneous habitat is thought to be operated among Korean populations of P. fragarioides var.sprengeliana. 相似文献
4.
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. 相似文献
5.
Xiao-Li Peng Chang-Ming Zhao Gui-Li Wu Jian-Quan Liu 《Trees - Structure and Function》2007,21(4):457-464
Repeated cycles of retreat and recolonization during the Quaternary ice ages are thought to have greatly influenced current
species distributions and their genetic diversity. It remains unclear how this climatic oscillation has affected the distribution
of genetic diversity between populations of wind-pollinated conifers in the Qinghai-Tibetan region. In this study, we investigated
the within-species genetic diversity and phylogenetic relationships of Picea likiangensis, a dominant forest species in this region using polymorphic DNA (RAPD) markers. Our results suggest that this species has
high overall genetic diversity, with 85.42% of loci being polymorphic and an average expected heterozygosity (H
E) of 0.239. However, there were relatively low levels of polymorphism at population levels and the differences between populations
were not significant, with percentages of polymorphic bands (PPB) ranging from 46.88 to 69.76%, Nei’s gene diversity (H
E) from 0.179 to 0.289 and Shannon’s indices (Hpop) from 0.267 to 0.421. In accordance with our proposed hypothesis, a high level of genetic differentiation among populations
was detected based on Nei’s genetic diversity (G
ST = 0.256) and AMOVA analysis (Phi
st = 0.236). Gene flow between populations was found to be limited (Nm = 1.4532) and far lower than reported for other conifer species with wide distribution ranges from other regions. No clusters
corresponding to three morphological varieties found in the south, north and west, respectively, were detected in either UPGMA
or PCO analyses. Our results suggest that this species may have had different refugia during the glacial stages in the southern
region and that the northern variety may have multiple origins from these different refugia. 相似文献
6.
Myong Gi Chung 《Journal of plant research》1994,107(4):377-383
Hosta minor, an insect-pollinated and rhizomatous herbaceous perennial, occurs in eastern and southern Korean Peninsula. AlthoughH. minor is a Korean endemic species and most populations of the species are scattered, the species maintains considerably high levels
of genetic variation within the species, with a moderate level of variation (14%) found among populations. Nineteen of the
29 putative loci resolved (66%) were polymorphic within the species, the mean number of alleles per locus was 2.10 across
all populations and averaged 1.68 within populations. In addition, genetic diversity was a considerably higher (for species
and population level, mean estimates of genetic diversity were 0.275 and 0.230, respectively) than the average for other long-lived
herbaceous perennials. Indirect estimate of the number of migrants per generation (Nm=1.03, calculated from mean GST) was moderate. Factors contributing to the high levels of genetic diversity found within populations ofH. minor include population maintenance via sexual and asexual modes of reproduction, primarily outcrossing breeding system, long
generation time, probable ancient polyploid origin of the species, and moderate levels of seed dispersal by wind. Human disturbance
in South Korea such as road and apartment constructions appears to be the major threat to this genetically diverse species. 相似文献
7.
Liatris helleri (Asteraceae) is an insect-pollinated herbaceous perennial endemic to several high-elevation sites in the Blue Ridge Mountains of North Carolina. Allozymes were used to describe the genetic diversity and population structure in nine populations of this rare, federally listed species. Differences in leaf morphology were also examined for greenhouse-grown plants representing several populations. The proportion of the total genetic diversity found among populations, as indicated by the allozyme data, was 16%. Higher levels of population differentiation were found for differences in leaf shape; population of origin accounted for 37% of the variation in maximum leaf width, while families within populations accounted for 7%. In contrast to many endemic species, L. helleri maintains fairly high levels of genetic diversity. For the species, the percent polymorphic loci was 87.5, the average number of alleles at variable loci was 3.00 and the gene diversity was 0.276. Mean population values were percent polymorphic loci =58.4, mean number of alleles per polymorphic locus =2.59 and gene diversity =0.219. The estimated gene flow was low (Nm=0.85–1.32) and a relatively high correlation (r=0.55; p<0.005) was found between linear geographic and genetic distance. This suggests that the populations are partially isolated by distance, despite the limited range (<60 km) of the species. We recommend that population distinetiveness be maintained in restoration efforts. 相似文献
8.
Allozyme variation at eleven loci encoding seven enzyme systems were examined in 20 populations of diploid (genome AA, 2n = 16)Scilla scilloides in China. In comparison with the average species of seed plants studied, populations of this species display a high amount of genetic variation (A = 2.0, P = 58.6%, Ho = 0.172, and He = 0.185). Allozyme variation pattern revealed predominant outcrossing within populations and considerable differentiation (FST = 0.314) among populations as well as between the subtropic and temperate regions. The wide distribution, long existence and outcrossing are presumably the main factors responsible for the high genetic diversity within populations. But the gravity dispersal of seeds and pollination by small insects set limits to the increase of genetic variation within populations and promote differentiation between populations and regions. In addition, allozyme variation does not distinguishS. scilloides var.albo-viridis and suggests that subtropic populations may be considered as a genetic entity. 相似文献
9.
Berchemiella wilsonii var. pubipetiolata (Rhamnaceae) is an endangered plant with only four remnant populations in eastern China. Population genetic information is
essential for understanding population history and formulating conservation strategies for this species. Thirteen microsatellite
loci were used to investigate genetic variation and population structure of the four remnant populations. Moderate levels
of expected heterozygosity (H
E = 0.466–0.543) and low allelic diversity (A = 3.1–3.6 and A
R = 2.2–2.4, respectively) were observed within populations. Bottleneck tests found three out of four populations to deviate
from mutation-drift equilibrium under the two-phase model (TPM), suggesting a recent population decline, which is congruent
with known demographic history. The evolutionary history of the species seems dominated by genetic drift rather than gene
flow. Low historical gene flow was inferred from several different approaches and N
m ranged from 0.582 by the private allele method to 0.783 by the coalescent method. Contemporary gene flow was also found to
be even lower for only one first generation migrant was detected with individual-based assignment analysis. Restricted pollen
and seed dispersal as well as a recent decline in population size associated with habitat fragmentation may have contributed
to low levels of historical and contemporary gene flow, and resulted in a high genetic differentiation. Under this scenario,
Berchemiella wilsonii var. pubipetiolata populations are expected to display more pronounced population genetic structure in the future as a result of increased inbreeding
and genetic drift. 相似文献
10.
大明松是广西和贵州特有的高山松类,具有很高的经济价值和生态价值,其自然种群长期没有得到充分的保护和利用,不利于该树种长期稳定发展。为了合理保护和开发利用大明松天然遗传资源,该文利用12个SSR分子标记对大明松3个天然群体进行遗传多样性研究,分析其群体间的遗传分化和基因流,为该物种的保护策略提供参考。研究结果表明:(1)12对引物共检测到37 个等位基因,多态位点百分率为100%。每个位点平均观察等位基因数(Na)为3.08,平均有效等位基因数(Ne)为1.68, 不同位点间有效等位基因数差异较大; 每个位点平均观察杂合度(Ho)为0.35,平均期望杂合度(He)为0.40,平均多态信息含量(PIC)为0.31。(2)3 个群体的Shannon''s多样性指数变化范围为0.48~0.65,Nei''s基因多样度的变化范围为0.27~0.39,与其他近缘种松类相比遗传多样性偏低。群体平均观察杂合度为0.40,平均期望杂合度为0.33,平均有效等位基因数为1.58。群体间基因分化系数(Gst)为0.10,群体间的遗传分化水平较低,大部分变异均存在群体内。群体间的基因流(Nm)为2.74,说明大明松群体间的基因交流比较充分。该研究可为大明松生物多样性保护提供重要参考依据,为科学利用大明松资源打下基础。 相似文献
11.
Salsola komarovi lljin is a herbaceous annual native to the sand dunes and beaches of Japan, northern China, Sakhalln and Korea. Starch-gel
electrophoresis was conducted on leaves and stems collected from 300 plants in eight Korean populations. The mean number of
alleles per locus (A
p=1.51), mean expected heterozygosity (He
p=0.116), and total genetic diversity (H
T=0.279) were comparable with those for species with similar life history and ecological traits. A general conformance of genotype
frequencies to Hardy-Weinberg expectations (meanF
IS=−0.030) indicates thatS. komarovi is an outcrossing species. Slightly more than 20% of the genetic variation was found among populations (F
ST=0.204). In addition, significant differences in allele frequency were detected between populations at all 11 polymorphic
loci (P<0.001). Nei's genetic identities range from 0.885 to 0.985 with a mean of 0.942. However, indirect estimates of the number
of migrant per generation (0.97, calculated fromF
ST and 0.31, calculated from seven private alleles) indicate that the levels of gene flow is low among Korean populations. Although
the species maintains a moderate level of genetic variation within populations, the small, isolated natural populations of
the species have been severely destructed by human activities, particularly in summer season. If this is true, conservation
efforts should be focused on those populations that currently maintain the most genetic diversity (e.g., populations of Cheju
Island and coast of the southwestern Korean Peninsula). 相似文献
12.
Ai-Lian Zhao Xiao-Yong Chen Xin Zhang Dong Zhang 《Biodiversity and Conservation》2006,15(4):1339-1351
Due to the long generation times and high densities, dominant tree species usually did not respond consistently with theoretical
predictions to the recent fragmentation. Genetic structures of shrubs and herbs, especially those with low densities, may
be more sensitive to forest fragmentation. We studied the genetic structure of a self-compatible subshrub, Ardisia crenata var. bicolor (Myrsinaceae) in a recently fragmented landscape. Ten RAPD primers used for analysis generated a total of 76 bands. We found
that A. c. var. bicolor had relatively low species-level (P95 = 63.2%; H = 0.106; Shannon diversity index (SI) = 0.246) and within-population diversity (P95 = 5.3−46.1%; H = 0.026−0.175; SI = 0.032−0.253), and significant population differentiation (GST = 0.445). Significantly positive relationships were found between measures of diversity (P95, H and SI) and the log of estimated population size. No significant relationship was observed between Nei's genetic distance
and spatial distance of pairwise populations, indicating no isolation-by-distance. Given most species of forests are shrubs
and herbs with short generation times, our observation indicated that distinct genetic consequences of recent fragmentation
may be expected for quite a number of plant species. 相似文献
13.
应用ISSR分子标记技术,对云南南部7个地区的野生大叶千斤拔( Flemingia macrophylla)居群进行了遗传多样性分析。结果表明:云南野生大叶千斤拔具有较高的遗传多样性。在物种水平上,平均每个位点的多态位点百分率(PPL)为94.85%,有效等位基因数(Ne)为1.4627,Nei’s基因多样性指数(He)为0.2815, Shannon’s多样性信息指数(Ho)为0.4337;在居群水平上,PPL =43.44%,Ne =1.2981,He =0.1704,Ho =0.2499。基于Nei’ s遗传多样性分析可得出,居群间的遗传分化系数( Gst)为0.3975,表明居群内的遗传变异为60.25%,居群间的遗传变异为39.75%,这说明居群间的遗传分化要低于居群内的遗传分化。根据遗传多样性分析和聚类结果,应在大叶千金拔遗传多样性较高的勐腊易武( MY)、丘北( QB)和宁洱( NE)地区,设立保护点对其进行就地保护。 相似文献
14.
为揭示我国东部归化水仙(Narcissus tazetta var. chinensis)的群体遗传多样性,利用2个叶绿体基因mat K和trn H-psb A片段对采自沪、浙、闽的5个代表群体的49株水仙进行了评估。结果表明,双基因联合序列的总长为1443bp,共定义6个单倍型,各归化群体的遗传多样性水平为DLSYPTDNJD=ZZCMD。AMOVA分析表明,群体内变异为遗传变异的主要来源(91.98%),群体间的遗传分化较低(Fst=0.080 22)。群体物种水平上的谱系结构不显著(Nst=0.020Gst=0.031;P0.05)。Mantel检验表明水仙群体间的遗传距离与地理距离呈显著的线性相关(r=0.929,P=0.02 0.05)。中性检验和错配分布分析结果均暗示水仙群体背离了快速扩张模型的假设。单倍型分布的中介网络图结合系统发育NJ树均将所有群体划分为2大分支。因此,我国东部沿海水仙归化群体整体遗传多样性水平较低,各群体间遗传分化较弱,遗传变异主要来自群体内,物种近期未经历扩张事件,可能是基因流受海岛隔离、自身生物学特征、生境异质性与及人为干扰的综合作用影响。 相似文献
15.
Genetic diversity and genetic structure within and among ten populations of Stephania yunnanensis H. S. Lo and three populations of S. epigaea H. S. Lo from Yunnan province were evaluated by direct amplification of length polymorphism (DALP) markers. Five primer groups
were screened, and a total of 287 DNA fragments were amplified, among which 266 were polymorphic, averaging 53.2 polymorphic
bands per primer group in S. yunnanensis. The percentage of polymorphic bands of S. yunnanensis was 92.68% at the species level and 61.92% within the ten populations sampled. At the species level, the observed number
of alleles (N
a) was 1.9268 and the effective number of alleles (N
e) was 1.5933; Nei’s gene diversity (H) was 0.3414; Shannon’s information index (I) was 0.5057. At the population level, N
a = 1.6192, N
e = 1.4001, H = 0.2298, and I = 0.3401. Total gene diversity of S. yunnanensis was 0.3419. Gene diversity within population was 0.2298, coefficient of gene differentiation was 0.3278, and estimated gene
flow was 1.0254. The results indicated that the genetic differentiation was relatively higher among populations of S. yunnanensis. DALP markers were an informative and useful method for assaying genetic diversity and authenticating species of Stephania. These data could provide basic molecular evidence for establishing a reasonable strategy for protecting and exploiting the
resource of S. yunnanensis. 相似文献
16.
We investigated levels of genetic diversity, population genetic structure, and gene flow in Eurya japonica, a widespread and broad-leaved evergreen dioecious tree native to Japan, China, Taiwan, and the southern and southwestern coast of the Korean Peninsula. Starch-gel electrophoresis was conducted on leaves collected from 1,000 plants in 20 Korean populations. All 12 loci examined were polymorphic in at least one population, and the mean number of alleles per locus was 3.79. In addition, mean observed population heterozygosity (Hop = 0.425), expected heterozygosity (Hep = 0.462), and total genetic diversity (HT = 0.496) were substantially higher than average values for species with similar life history traits. Although significant differences in allele frequency were detected between populations at all loci (P < 0.001), <7% of the genetic variation was found among populations (FST = 0.069). There was a significant negative correlation between genetic identity and distance between populations (r = -0.341; P < 0.05), but this explained only a small amount of the diversity among populations. Indirect estimates of the number of migrants per generation (Nm) (3.37, calculated from FST; 3.74, calculated from the mean frequency of eight private alleles) indicate that gene flow is extensive among Korean populations of E. japonica. Factors contributing to the high levels of genetic diversity found within populations of E. japonica include large and contiguous populations, obligating outcrossing (dioecious plant), high fecundity, and long generation time. Occasional seed dispersal by humans and pollen movement by domesticated honey bees may further enhance gene flow within the species. 相似文献
17.
Dysosma pleiantha, an important threatened medicinal plant species, is restricted in distribution to southeastern China. The species is capable
of reproducing both sexually and asexually. In this study, inter-simple sequence repeat marker data were obtained and analyzed
with respect to genetic variation and genetic structure. The extent of clonality, together with the clonal and sexual reproductive
strategies, varied among sites, and the populations under harsh ecological conditions tended to have large clones with relatively
low clonal diversity caused by vegetative reproduction. The ramets sharing the same genotype show a clumped distribution.
Across all populations surveyed, average within-population diversity was remarkably low (e.g., 0.111 for Nei’s gene diversity),
with populations from the nature reserves maintaining relatively high amounts of genetic diversity. Among all populations,
high genetic differentiation (AMOVA: ΦST = 0.500; Nei’s genetic diversity: G
ST = 0.465, Bayesian analysis: ΦB = 0.436) was detected, together with an isolation-by-distance pattern. Low seedling recruitment due to inbreeding, restricted
gene flow, and genetic drift are proposed as determinant factors responsible for the low genetic diversity and high genetic
differentiation observed. 相似文献
18.
Shuguang Jian Yang Zhong Nian Liu Zezheng Gao Qiang Wei Zhenhua Xie Hai Ren 《Biodiversity and Conservation》2006,15(5):1681-1694
Cycas fairylakea is an endangered endemic species in China. Genetic diversity within and among four natural populations of this species in
China was investigated using amplified fragments length polymorphism (AFLP). A moderate to low level of intraspecific genetic
diversity was detected in this species (at population level: P = 39.57 %, H0 = 0.244; at species level: P = 60.22%, H0 = 0.356). The among-population component accounted for, respectively, 25.7 and 31.5% of the genetic variation, according
to AMOVA and Shannon’s index, indicating most of the genetic variation was found between individuals within populations. All
four populations have opposite pyramid age structure, and few coning individuals, which is still decreasing. Possibly because
of habitat degradation and environmental pollution, plant diseases and insect pests in the populations were extremely serious,
suggesting that the main factors threatening the survival of C. fairylakea populations were not genetic variation, but human activities and the breeding system of this species. 相似文献
19.
MYONG GI CHUNG 《Plant Species Biology》1994,9(3):177-182
Abstract Genetic diversity of Korean populations in Hosta clausa was investigated using starch gel electrophoresis. Hosta clausa is widespread, grows only along streamsides, and has both sexual and asexual reproduction. Populations of the species are small and isolated. Thirty-two percent of the loci examined were polymorphic, and mean genetic diversity within populations (Hep=0.082) was lower than mean estimates for species with very similar life history characteristics (0.131), particularly for its congener H. yingeri (0.250). The mean number of multilocus genotypes per population was 8.7, and genotypic diversity index (DG) was 0.84. Significant differences in allele frequencies among populations were found in all seven polymorphic loci (P < 0.001). About one-fifth of the total allozyme variation was among populations (GST=0.192). Indirect estimate of the number of migrants per generation (Nm=0.48, calculated from mean GST) and nine private alleles found indicate that gene movement among populations was low. The low levels of genetic diversity within populations and the relatively high levels of genetic diversity among populations suggest that strong moist habitat preferences, clonal reproduction, low level of gene flow among populations, genetic drift, and historical events may have played roles in the genetic structuring of the species. 相似文献
20.
Berchemiella wilsonii var. pubipetiolata (Rhamnaceae) is an endangered tree in eastern China. Habitat destruction has resulted in fragmentation of remnant populations
and extinction of local populations. AFLP and cpDNA markers were used to determine the population structure of remnant populations
of B. wilsonii var. pubipetiolata. Moderate nuclear genomic diversity was found within each of the four remnant populations (H
S = 0.141–0.172), while the cpDNA haplotype diversity in each population ranged from 0.356 to 0.681. Six haplotypes were identified
by a combined cpRFLP and cpSSR analysis in a total of 89 individuals. AMOVA revealed significantly AFLP genetic differentiation
within and between regions (ΦSC = 0.196, ΦCT = 0.396, respectively), and a high cpDNA haplotype differentiation between regions (ΦCT = 0.849). The results suggest low gene flow between populations of B. wilsonii var. pubipetiolata. Strong genetic divergence between two regional populations as revealed by both AFLP and cpDNA markers provided convincing
evidence that two distinct evolutionary lineages existed, and should be recognized as ‘evolutionary significant units’ (ESUs)
for conservation concerns. 相似文献