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1.
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
2.
Genetic variability in random amplified polymorphic DNA (RAPD) was studied in 90 individuals of Caragana microphylla, an outcrossing perennial shrub species, from five natural populations sampled in Inner Mongolia steppe of China on a small
scale. Nineteen selected primers were used to amplify DNA samples, and totally 225 bands were detected. The percentage of
polymorphic bands within populations ranged form 58.22% to 63.56%, with an average of 60% at the population level and 71.11%
at the species level, indicating relatively high genetic variations in C. microphylla species. Shannon’s information index (l) and Nei’s gene diversity (h) showed the similar trend with each other. According to the analysis of Nei’s gene diversity, the percentage of genetic variation
among populations was 7.13%, indicating a low level of genetic differentiation among populations. There existed a strong gene
flow (N
m
= 3.26) among populations. Although AMOVA analysis also revealed most variation was within populations (ΦST = 4.1%), a significant proportion was observed among populations (P < 0.001) in the present study, suggesting genetic differentiation occurred among populations at a certain extent. Based on
Mantel’s tests and the results of previous studies, the genetic structure pattern of C. microphylla accorded with the isolation-by-distance model on a very large scale, however, on a small scale, the significant genetic differentiation
among populations might be enhanced by the micro-environmental divergence among the sampling sites, rather than by geographic
factors. Analysis of the genetic variations of C. microphylla populations provided useful information for the adaptive strategy of Caragana species. 相似文献
3.
K. L. Ciborowski S. Consuegra C. García de Leániz J. Wang M. A. Beaumont W. C. Jordan 《Conservation Genetics》2007,8(6):1355-1367
Over the last 50 years, Spanish Atlantic salmon (Salmo salar) populations have been in decline. In order to bolster these populations, rivers were stocked with fish of northern European
origin during the period 1974–1996, probably also introducing the furunculosis-inducing pathogen, Aeromonas salmonicida. Here we assess the relative importance of processes influencing mitochondrial (mt)DNA variability in these populations from
1948 to 2002. Genetic material collected over this period from four rivers in northern Spain (Cantabria) was used to detect
variability at the mtDNA ND1 gene. Before stocking, a single haplotype was found at high frequency (0.980). Following stocking,
haplotype diversity (h) increased in all rivers (mean h before stocking was 0.041, and 0.245 afterwards). These increases were due principally to the dramatic increase in frequency
of a previously very low frequency haplotype, reported at higher frequencies in northern European populations proximate to
those used to stock Cantabrian rivers. Genetic structuring increased after stocking: among-river differentiation was low before
stocking (1950s/1960s Φ
ST = –0.00296–0.00284), increasing considerably at the height of stocking (1980s Φ
ST = 0.18932) and decreasing post-stocking (1990s/2002 Φ
ST = 0.04934–0.03852). Gene flow from stocked fish therefore seems to have had a substantial role in increasing mtDNA variability.
Additionally, we found significant differentiation between individuals that had probably died from infectious disease and
apparently healthy, angled fish, suggesting a possible role for pathogen-driven selection of mtDNA variation. Our results
suggest that stocking with non-native fish may increase genetic diversity in the short term, but may not reverse population
declines. 相似文献
4.
Genetic diversity and differentiation within and among nine G. morsitans morsitans populations from East and southern Africa was assessed by examining variation at seven microsatellite loci and a mitochondrial
locus, cytochrome oxidase (COI). Mean COI diversity within populations was 0.63 ± 0.33 and 0.81 taken over all populations. Diversities averaged over microsatellite
loci were high (mean number of alleles/locus ≥7.4; mean H
E ≥ 65%) in all populations. Diversities averaged across populations were greater in East Africa (mean number of alleles = 22 ± 2.6;
mean h
e = 0.773 ± 0.033) than in southern Africa (mean number of alleles = 18.7 ± 4.0; mean h
e = 0.713 ± 0.072). Differentiation among all populations was highly significant (R
ST = 0.25, F
ST = 0.132). Nei’s G
ij
statistics were 0.09 and 0.19 within regions for microsatellites and mitochondria, respectively; between regions, G
ij
was 0.14 for microsatellites and 0.23 for mitochondria. G
ST among populations was 0.23 for microsatellite loci and 0.40 for mitochondria. The F, G and R statistics indicate highly restricted gene flow among G. m. morsitans populations separated over geographic scales of 12–917 km. 相似文献
5.
We used random amplified polymorphic DNA markers (RAPDs) to assess genetic variation between- and within-populations of Anisodus tanguticus (Solanaceae), an endangered perennial endemic to the Qinghai-Tibetan Plateau with important medicinal value. We recorded
a total of 92 amplified bands, using 12 RAPD primers, 76 of which (P = 82.61%) were polymorphic, and calculated values of Ht and Hsp of 0.3015 and 0.4459, respectively, suggesting a remarkably high rate of genetic variation at the species level. The average
within-population diversity also appeared to be high, with P, He and Hpop values of 55.11%, 0.1948 and 0.2918, respectively. Analyses of molecular variance (AMOVA) showed that among- and between-population
genetic variation accounted for 67.02% and 32.98% of the total genetic variation, respectively. In addition, Nei’s coefficient
of differentiation (GST) was found to be high (0.35), confirming the relatively high level of genetic differentiation among the populations. These
differentiation coefficients are higher than mean corresponding coefficients for outbreeding species, but lower than reported
coefficients for some rare species from this region. The genetic structure of A. tanguticus has probably been shaped by its breeding attributes, biogeographic history and human impact due to collection for medicinal
purposes. The observed genetic variations suggest that as many populations as possible should be considered in any planned
in situ or ex situ conservation programs for this species. 相似文献
6.
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
7.
Cymbidium goeringii is a diploid and nonrewarding, bumblebee-pollinated species, which is distributed in China, Japan and Korea Peninsula. This
species is now highly endangered due to the mass collection and forest clearance in China. In the present study, we investigated
the distribution of genetic variation within and between eleven populations of Cymbidium goeringii in central China by using Inter-simple sequence repeats (ISSR) markers. Eleven primers produced a total of 127 clear and
reproducible bands of which 112 were polymorphic. High genetic diversity was detected in Cymbidium goeringii for both population level (P = 63.1%; He = 0.194 5) and species level (P = 88.2%; He = 0.262 8). A higher level of genetic differentiation was detected among populations (G
ST = 0.244 0, F
ST = 0.220 7) with Nei’s G
ST analysis and analysis of molecular variance (AMOVA), and no correlation was found between geographical and genetic distance.
Genetic drift rather than gene flow played an important role in forming the present population structure of Cymbidium goeringii. Limited gene flow among populations and gene drift increase the extinction risk of local populations. Some conservation
concerns are therefore discussed together with possible strategies for implementing in situ and ex situ conservation.
__________
Translated from Biodiversity Science, 2006, 14(3): 250–257 [译自: 生物多样性]
Equally contributed authors 相似文献
8.
Melinda D. Peters Qiu-Yun Xiang David T. Thomas Jon Stucky Noah K. Whiteman 《Conservation Genetics》2009,10(1):1-14
Echinacea laevigata (Boynton and Beadle) Blake is a federally endangered flowering plant species restricted to four states in the southeastern
United States. To determine the population structure and outcrossing rate across the range of the species, we conducted AFLP
analysis using four primer combinations for 22 populations. The genetic diversity of this species was high based on the level
of polymorphic loci (200 of 210 loci; 95.24%) and Nei’s gene diversity (ranging from 0.1398 to 0.2606; overall 0.2611). There
was significant population genetic differentiation (GST = 0.294; ӨII = 0.218 from the Bayesian f = 0 model). Results from the AMOVA analysis suggest that a majority of the genetic variance is attributed to variation within
populations (70.26%), which is also evident from the PCoA. However, 82% of individuals were assigned back to the original
population based on the results of the assignment test. An isolation by distance analysis indicated that genetic differentiation
among populations was a function of geographic distance, although long-distance gene dispersal between some populations was
suggested from an analysis of relatedness between populations using the neighbor-joining method. An estimate of the outcrossing
rate based on genotypes of progenies from six of the 22 populations using the multilocus method from the program MLTR ranged
from 0.780 to 0.912, suggesting that the species is predominantly outcrossing. These results are encouraging for conservation,
signifying that populations may persist due to continued genetic exchange sustained by the outcrossing mating system of the
species. 相似文献
9.
Abies ziyuanensis is a highly endangered fir species endemic to South China. Unlike other Abies species that are distributed in areas with cold climates, A. ziyuanensis is restricted to several isolated island-like localities at subtropical mountains. In this study, we used dominant amplified
fragment length polymorphism (AFLP) and co-dominant simple sequence repeats (SSR) markers to infer the genetic structure of
A. ziyuanensis. Seven populations consisting of 139 individuals were sampled across their whole distribution. A. ziyuanenesis has a relatively low level of genetic variation, with a mean genetic diversity per population (He) of 0.136 (AFLP) and 0.337 (SSR), which is lower than that of other reported endemic species based on the same kind of marker.
We observed high population differentiation, with Gst = 0.482 (AFLP) and Fst = 0.250 (SSR), among the seven populations. AMOVA also detected significant differentiation among populations (Φst (AFLP) = 0.550
and Φst (SSR) = 0.289) and among regions (Φct (AFLP) = 0.139 and Φct (SSR) = 0.135) in both marker types. Both ongoing evolutionary
forces (e.g., genetic drift resulting from small population size) and historical events (e.g., population contraction and
fragmentation during and after the Quaternary glacial cycles) may have contributed to the genetic structure in A. ziyuanensis. 相似文献
10.
Jorge C. Pereira Raquel Chaves Alexandra Leitão Domitilia Matias Henrique Guedes-Pinto 《Helgoland Marine Research》2011,65(3):361-367
The clam Ruditapes decussatus is commercially important in the south of Portugal. The random amplified polymorphic DNA (RAPD) technique was applied to
assess the genetic diversity and population structure of two Portuguese populations occurring in the Ria Formosa (Faro) and
the Ria de Alvor, respectively. Twenty-five individuals of each population were investigated by RAPD profiles. Genetic diversity
within populations, measured by the percentage of polymorphic loci (%P), varied between 68.57% (Alvor) and 73.88% (Faro). Shannon’s information index (H) and Nei’s gene diversity (h) were 0.281 and 0.176, respectively, for the Alvor population and 0.356 and 0.234 for the Faro population. Overall, genetic
variation within R. decussatus populations was high. The total genetic diversity (H
T) was explained by a low variation between populations (G
ST = 0.145), which is consistent with high gene flow (N
m = 2.9). The analysis of molecular variance (AMOVA) showed that 65% of variability is within populations and 35% between populations
(ΦPT = 0.345; P ≥ 0.001). The value of Nei’s genetic distance was 0.0881, showing a low degree of population genetic distance, despite the
different geographic origin. This is the first study on the population genetics of R. decussatus by RAPD technique. The results may be useful for restocking programs and aquaculture. 相似文献
11.
RAPD analysis of genetic diversity and population genetic structure of Stipa krylovii reshov. in Inner Mongolia steppe 总被引:1,自引:0,他引:1
J. L. Wang N. X. Zhao Y. B. Gai F. Lin A. Z. Ren W. B. Ruan L. Chen 《Russian Journal of Genetics》2006,42(5):468-475
Random amplified polymorphic DNA (RAPD) analysis was used to characterize the genetic diversity and population genetic structure
of Stipa krylovii populations in Inner Mongolia steppe of North China. Thirteen 10-bp oligonucleotide primers, which generated 237 RAPD bands,
were used to analyze 90 plants of five populations from three regions, meadow steppe, typical steppe and desert steppe, from
the east to the west. The genetic diversity of Stipa krylovii that was revealed by observed number of alleles (na), expected number of alleles (ne), Nei’s diversity index (h), Shannon’s diversity index (H), amplificated loci, polymorphic loci and the percentage of polymorphic loci (PPB) increased from the east to the west. The Pearson’s correlation analysis between genetic diversity parameters and ecological
parameters indicated that the genetic diversity of Stipa krylovii was associated with precipitation and cumulative temperature variations along the longitude (humidity were calculated by
precipitation and cumulative temperature). Dendrogram based on Jaccard’s genetic distance showed that the individuals from
the same population formed a single subgroup. Although most variation (56.85%) was within populations, there was high genetic
differentiation among populations of Stipa krylovii, high differentiation within and between regions by AMOVA analysis. Either Nei’s unbiased genetic distance (G
ST) or gene flow (Nm) among pairwise populations was not correlated with geographical distance by Mantel’s test (P > 0.05), suggesting that there was no consistency with the isolation by distance model in these populations. Natural selection
may have played a role in affecting the genetic diversity and population structure, but habitat destruction and degradation
in northem grassland in China may be the main factor responsible for high genetic differentiation among populations, within
and among regions.
The text was submitted by the authors in English. 相似文献
12.
Studies about the organization of the genetic variability and population structure in natural populations are used either
to understand microevolutionary processes or the effects of isolation by human-inducted landscape modifications. In this paper,
we analyzed patterns of genetic population structure using 126 RAPD loci scored for 214 individuals of Physalaemus cuvieri, sampled from 18 local populations. Around 97% of these loci were polymorphic. The among-population variation component (ΦST) obtained by AMOVA was equal to 0.101 and θ
B obtained using a Bayesian approach for dominant markers was 0.103. Genetic divergence, analyzed by Mantel spatial correlogram,
revealed only a short-distance significant correlation between genetic and geographic distances. This is expected if low levels
of population differentiation, due to high abundance buffering the effect of stochastic processes, are combined with low spatially
restricted gene flow. Although this may be consistent with the current knowledge of species’ biology, the spatial distribution
of local populations observed in this study also suggest that, at least in part, recent human occupation and habitat fragmentation
may also explain part of the interpopulational component of the genetic variation. 相似文献
13.
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
14.
Xianyun Zheng Yang Zhong Yihao Duan Chunxuan Li Li Dang Yaping Guo Enbo Ma 《Biochemical genetics》2006,44(7-8):332-346
Allozyme analysis, microsatellite primer PCR (SSRP-PCR), and amplified fragment length polymorphism (AFLP) techniques were
used to assess genetic diversity and population structure of the Chinese oriental migratory locust, Locusta migratoria manilensis. A total of 299 PCR markers (67 SSRPs and 232 AFLPs) were detected in eight populations, of which 98.7% were polymorphic markers.
The proportion of polymorphic loci (95.5–98.8%) by SSRP+AFLP markers indicated no significant differences between populations,
and all populations exhibited a similar level of variability; results of the allozyme analysis demonstrated that 19 loci gave
rise to a lower level of polymorphism (55.6–66.7%). The genetic distances between the populations were relatively low. Shannon’s
index and Nei’s gene diversity showed low differentiation among the populations. Allozyme analysis, however, reflected greater
similarity and smaller differentiation between the populations than those shown by SSRP and AFLP markers. Neighbor-joining
dendrograms derived from both the allozyme and SSRP+AFLP markers showed that the genetic distances among Chinese oriental
migratory locust populations were not greatly influenced by geographic distance and breeding habitats. 相似文献
15.
Elizabeth S. MacAvoy Lorna M. McGibbon James P. Sainsbury Hayley Lawrence Carol A. Wilson Charles H. Daugherty Geoffrey K. Chambers 《Conservation Genetics》2007,8(2):305-318
Tuatara (Sphenodon spp) populations are restricted to 35 offshore islands in the Hauraki Gulf, Bay of Plenty and Cook Strait of New Zealand.
Low levels of genetic variation have previously been revealed by allozyme and mtDNA analyses. In this new study, we show that
six polymorphic microsatellite loci display high levels of genetic variation in 14 populations across the geographic range
of tuatara. These populations are characterised by disjunct allele frequency spectra with high numbers of private alleles.
High F
ST (0.26) values indicate marked population structure and assignment tests allocate 96% of all individuals to their source populations.
These genetic data confirm that islands support genetically distinct populations. Principal component analysis and allelic
sequence data supplied information about genetic relationships between populations. Low numbers of rare alleles and low allelic
richness identified populations with reduced genetic diversity. Little Barrier Island has very low numbers of old tuatara
which have retained some relictual diversity. North Brother Island’s tuatara population is inbred with fixed alleles at 5
of the 6 loci. 相似文献
16.
Emma L. Burns Mark D. B. Eldridge Darren M. Crayn Bronwyn A. Houlden 《Conservation Genetics》2007,8(1):17-32
The green and golden bell frog (Litoria aurea) has a widespread distribution along the south-east coast of Australia. The species range, however, is highly fragmented
and remaining populations are predominately isolated and restricted to the coastline. Previously, the range extended further
inland and the species was considered common. Here we report a study designed to identify the phylogeographic and conservation
genetic parameters of L. aurea. Mitochondrial DNA sequences were examined from 263 individuals sampled from 26 locations using both phylogenetic and population
analyses. Despite a general consensus that amphibians are highly structured we found no phylogeographic divisions within the
species, however, there was significant structure amongst extant populations (F
ST=0.385). Patterns of haplotype relatedness, high haplotypic diversity (mean h=0.547) relative to low nucleotide diversity (mean π=0.003) and mismatch distribution analysis supported a Pleistocene expansion
hypothesis with continued restricted dispersal and gene flow. We conclude that the genetic structure of the species may permit
‘well managed’ intervention to mediate gene flow amongst isolated populations and provide some guidelines for the implementation
of such conservation strategies. 相似文献
17.
Lan Q Shen M Garcia-Rossi D Chanock S Zheng T Berndt SI Puri V Li G He X Welch R Zahm SH Zhang L Zhang Y Smith M Wang SS Chiu BC Linet M Hayes R Rothman N Yeager M 《Immunogenetics》2007,59(11):839-852
Selection and genetic drift can create genetic differences between populations. Cytokines and chemokines play an important
role in both hematopoietic development and the inflammatory response. We compared the genotype frequencies of 45 SNPs in 30
cytokine and chemokine genes in two healthy Chinese populations and one Caucasian population. Several SNPs in IL4 had substantial genetic differentiation between the Chinese and Caucasian populations (F
ST ~0.40), and displayed a strikingly different haplotype distribution. To further characterize common genetic variation in
worldwide populations at the IL4 locus, we genotyped 9 SNPs at the IL4 gene in the Human Diversity Panel’s (N = 1056) individuals from 52 world geographic regions. We observed low haplotype diversity, yet strikingly different haplotype
frequencies between non-African populations, which may indicate different selective pressures on the IL4 gene in different parts of the world. SNPs in CSF2, IL6, IL10, CTLA4, and CX3CR1 showed moderate genetic differentiation between the Chinese and Caucasian populations (0.15 < F
ST < 0.25). These results suggest that there is substantial genetic diversity in immune genes and exploration of SNP associations
with immune-related diseases that vary in incidence across these two populations may be warranted. 相似文献
18.
Random amplified polymorphic DNA (RAPD) markers were used to estimate the population structure and phylogenetic relationships
among samples of the Salmo trutta complex that inhabit the Balkan Peninsula. Five random oligodecamers were selected to amplify DNA from 140 fish from seven
populations. Using these primers, 55 discernible DNA fragments were generated, of which 50 (90.91%) were polymorphic. The
statistical results indicated that there was low genetic diversity within populations (with an average percentage of polymorphic
bands (P) of 11.69% and a Nei’s genetic diversity index (h) of 0.035), but at the same time high genetic differentiation among populations (F
ST = 0.89). The distribution of genetic diversity among Balkan trout may result from their evolutionary history and reflects
genetic drift coupled with bottleneck phenomena. Overall, RAPDs proved valuable tools for quick and reliable stock discrimination
and provided information that might be useful regarding conservation and management of trout. 相似文献
19.
Vítor Sousa Filipa Penha Maria J. Collares-Pereira Lounès Chikhi Maria M. Coelho 《Conservation Genetics》2008,9(4):791-805
The endemic and critically endangered cyprinid Chondrostoma lusitanicum has a very restricted distribution range. In order to estimate genetic diversity, characterize population structure and infer
the demographic history, we examined six microsatellite loci and cytochrome b (mtDNA) sequences from samples taken throughout C. lusitanicum’s geographical range. Estimates of genetic diversity were low in all samples (average He < 0.35). The microsatellite data
pointed to a major difference between northern (Samarra and Tejo drainages) and southern (Sado and Sines drainages) samples.
This separation was not so clear with mtDNA, since one sample from the Tejo drainage grouped with the southern samples. This
could be related with ancestral polymorphism or with admixture events between northern and southern sites during the late
Pleistocene. Nevertheless, both markers indicate high levels of population differentiation in the north (for microsatellites
F
ST > 0.23; and for mtDNA ΦST > 0.74) and lower levels in the south (F
ST < 0.05; ΦST < 0.40). With microsatellites we detected strong signals of a recent population decrease in effective size, by more than
one order of magnitude, starting in the last centuries. This is consistent with field observations reporting a severe anthropogenic-driven
population decline in the last decades. On the contrary mtDNA suggested a much older expansion. Overall, these results suggest
that the distribution of genetic diversity in C. lusitanicum is the result of both ancient events related with drainage system formation, and recent human activities. The potential effect
of population substructure generating genetic patterns similar to a population decrease is discussed, as well as the implications
of these results for the conservation of C. lusitanicum.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
20.
Bingqing Hao Wang Li Mu Linchun Yao Li Zhang Rui Tang Mingxia Bao Weikai 《Biochemical genetics》2006,44(1-2):29-43
ISSR markers were used to analyze the genetic diversity and genetic structure of eight natural populations of Cupressus chengiana in China. ISSR analysis using 10 primers was carried out on 92 different samples. At the species level, 136 polymorphic loci were detected. The percentage of polymorphic bands (PPB) was 99%. Genetic diversity (H e) was 0.3120, effective number of alleles (A e) was 1.5236, and Shannon’s information index (I) was 0.4740. At the population level, PPB = 48%, A e=1.2774, H e=0.1631, and I=0.2452. Genetic differentiation (G st) detected by Nei’s genetic diversity analysis suggested 48% occurred among populations. The partitioning of molecular variance by AMOVA analysis indicated significant genetic differentiation within populations (54%) and among populations (46%; P < 0.0003). The average number of individuals exchanged between populations per generation (N
m
) was 0.5436. Samples from the same population clustered in the same population-specific cluster, and two groups of Sichuan and Gansu populations were distinguishable. A significantly positive correlation between genetic and geographic distance was detected (r=0.6701). Human impacts were considered one of the main factors to cause the rarity of C. chengiana, and conservation strategies are suggested based on the genetic characters and field investigation, e.g., protection of wild populations, reestablishment of germplasm bank, and reintroduction of more genetic diversity. 相似文献