共查询到20条相似文献,搜索用时 703 毫秒
1.
Mitochondrial DNA (mtDNA) control region sequences and microsatellite loci length polymorphisms were used to investigate genetic
differentiation in spotted dolphins (Stenella attenuata) in the Eastern Tropical Pacific and to examine the intraspecific structure of the coastal subspecies (Stenella attenuata graffmani). One-hundred and thirty-five animals from several coastal areas and 90 offshore animals were sequenced for 455 bp of the
mitochondrial control region, resulting in 112 mtDNA haplotypes. Phylogenetic analyses and the existence of shared haplotypes
between the two subspecies suggest recent and/or current gene flow. Analyses using χ2, F
ST (based on haplotype frequencies) and ΦST values (based on frequencies and genetic distances between haplotypes) yielded statistically significant separation (randomized
permutation values P<0.05) among four different coastal populations and between all but one of these and the offshore subspecies (overall F
ST=0.0691). Ninety-one coastal animals from these four geographic populations and 50 offshore animals were genotyped for seven
nuclear microsatellite loci. Analysis using F
ST values (based on allelic frequencies) yielded statistically significant separation between most coastal populations and offshore
animals, although no coastal populations were distinguished. These results argue for the existence of some genetic isolation
between offshore and inshore populations and among some inshore populations, suggesting that these should be treated as separate
units for management purposes. 相似文献
2.
Population structure of nuclear and mitochondrial DNA variation among humpback whales in the North Pacific 总被引:5,自引:0,他引:5
C. S. BAKER L. MEDRANO-GONZALEZ J. CALAMBOKIDIS A. PERRY F. PICHLER H. ROSENBAUM J. M. STRALEY J. URBAN-RAMIREZ M. YAMAGUCHI & O. VON ZIEGESAR 《Molecular ecology》1998,7(6):695-707
The population structure of variation in a nuclear actin intron and the control region of mitochondrial DNA is described for humpback whales from eight regions in the North Pacific Ocean: central California, Baja Peninsula, nearshore Mexico (Bahia Banderas), offshore Mexico (Socorro Island), southeastern Alaska, central Alaska (Prince Williams Sound), Hawaii and Japan (Ogasawara Islands). Primary mtDNA haplotypes and intron alleles were identified using selected restriction fragment length polymorphisms of target sequences amplified by the polymerase chain reaction (PCR–RFLP). There was little evidence of heterogeneity in the frequencies of mtDNA haplotypes or actin intron alleles due to the year or sex composition of the sample. However, frequencies of four mtDNA haplotypes showed marked regional differences in their distributions (ΦST = 0.277; P < 0.001; n = 205 individuals) while the two alleles showed significant, but less marked, regional differences (ΦST = 0.033; P < 0.013; n = 400 chromosomes). An hierarchical analysis of variance in frequencies of haplotypes and alleles supported the grouping of six regions into a central and eastern stock with further partitioning of variance among regions within stocks for haplotypes but not for alleles. Based on available genetic and demographic evidence, the southeastern Alaska and central California feeding grounds were selected for additional analyses of nuclear differentiation using allelic variation at four microsatellite loci. All four loci showed significant differences in allele frequencies (overall FST = 0.043; P < 0.001; average n = 139 chromosomes per locus), indicating at least partial reproductive isolation between the two regions as well as the segregation of mtDNA lineages. Although the two feeding grounds were not panmictic for nuclear or mitochondrial loci, estimates of long-term migration rates suggested that male-mediated gene flow was several-fold greater than female gene flow. These results include and extend the range and sample size of previously published work, providing additional evidence for the significance of genetic management units within oceanic populations of humpback whales. 相似文献
3.
Christopher J. Durrant Trevor J. C. Beebee Frank Greenaway David A. Hill 《Conservation Genetics》2009,10(2):489-496
We investigated the population genetics of seven maternity roosts of Bechstein’s bats widely distributed across the south
of England. Across all of the populations sampled, two mitochondrial DNA microsatellite loci were fixed for single haplotypes.
Genetic diversity across eight nuclear microsatellite loci was similar in all seven populations, with a mean He of 0.727. However, six of the populations showed substantial homozygote excess, with F
IS estimates greater than zero, indicative of recent inbreeding. Bottleneck tests also implied that six of the populations have
experienced recent declines. Genetic differentiation among the populations was low, with a mean intersite F
ST estimate of 0.041. There was no significant isolation by distance using allele frequency-based criteria (F
ST and genetic distances), however, a weak correlation was found using the allele size-based R
ST criterion. Assignment tests were unable to distinguish the seven sampling sites as distinct clusters. Mean intra-roost relatedness
(r) was 0.079, indicative of recent inbreeding relative to German populations. All but one of the bats had one or more half
or full siblings in its maternity roost. In addition, family relationships of individuals within a colony were significantly
commoner than family relationships among four proximal roosts <8 km apart. The results are discussed in the context of conservation
requirements for this rare British bat. 相似文献
4.
Nonamplified (null) alleles are a common feature of microsatellite genotyping and can bias estimates of allele and genotype frequencies, thereby hindering population genetic analyses. The frequency of microsatellite null alleles in diploid populations can be estimated for populations that are in Hardy–Weinberg equilibrium. However, many microsatellite data sets are from nonequilibrium populations, often with known inbreeding coefficients (F) or fixation indices (FIS or FST). Here, we propose a novel null allele estimator that can be used to estimate the null allele frequency and adjust visible allele frequencies in populations for which independent estimates of F, FIS or FST are available. The algorithm is currently available as an Excel macro that can be downloaded at no cost from http://www.microchecker.hull.ac.uk/ and will be incorporated into the software micro ‐checker . 相似文献
5.
J.P. Grobler D.M. Pretorius Karen Botha Antoinette Kotze E.M. Hallerman Bettine Jansen Van Vuuren 《Mammalian Biology》2005,70(5):291-299
We report patterns of genetic variation based on microsatellite, allozyme and mitochondrial control region markers in nyala from geographic locations sampled in South Africa, Mozambique, Malawi and Zimbabwe. Highly significant differences were observed among allele frequencies at three microsatellite loci between populations from KwaZulu-Natal, Limpopo and Malawi, with the Malawi and KwaZulu-Natal groupings showing the highest differentiation (RST=0.377). Allozyme frequencies showed minor, non-statistically significant regional differences among the South African populations, with maximum FST values of 0.048–0.067. Mitochondrial DNA analyses indicated a unique haplotype in each location sampled. Since none of these indices of population differentiation showed significant correlation to absolute geographic distance, we conclude that geographic variation in this species is probably a function of a distribution pattern stemming from habitat specificity. It is suggested that translocations among geographically distant regional populations be discouraged at present, pending a more elaborate investigation. Transfer of native individuals among local populations may, however, be required for minimizing the likelihood of inbreeding depression developing in small captive populations. 相似文献
6.
Vincent B. Muwanika Silvester Nyakaana Hans R. Siegismund Peter Arctander 《African Journal of Ecology》2007,45(1):22-30
Fine‐scale genetic structure of large mammals is rarely analysed. Yet it is potentially important in estimating gene flow between the now fragmented wildlife habitats and in predicting re‐colonization following local extinction events. In this study, we examined the extent to which warthog populations from five localities in Uganda are genetically structured using both mitochondrial control region sequence and microsatellite allele length variation. Four of the localities (Queen Elizabeth, Murchison Falls, Lake Mburo and Kidepo Valley) are national parks with relatively good wildlife protection practices and the other (Luwero), not a protected area, is characterized by a great deal of hunting. In the total sample, significant genetic differentiation was observed at both the mtDNA locus (FST = 0.68; P < 0.001) and the microsatellite loci (FST = 0.14; P < 0.001). Despite the relatively short geographical distances between populations, significant genetic differentiation was observed in all pair‐wise population comparisons at the two marker sets (mtDNA FST = 0.21–0.79, P < 0.001; microsatellite FST = 0.074–0.191, P < 0.001). Significant heterozygote deficiency was observed at most loci within protected areas while no significant deviation from Hardy–Weinberg expectation was observed in the unprotected Luwero population. We explain these results in terms of: (i) a strong philopatry among warthogs, (ii) a Wahlund effect resulting from the sampling regime and (iii) break down of social structure in the disturbed Luwero population. 相似文献
7.
Genetic variation and population structure of wild white shrimp (Litopenaeus vannamei) from 4 geographic locations from Mexico to Panama were investigated using 5 microsatellite DNA loci. The genetic diversity between populations was indicated by the mean number of alleles per locus and mean observed heterozygosity, which ranged from 7.4 to 8.6 and from 0.241 to 0.388, respectively. Significant departures from Hardy-Weinberg equilibrium were found at most locations at each locus, with the exception Guatemala at Pvan0013, and were caused by high heterozygote deficiencies. Genetic differences between localities were detected by pairwise comparison based on allelic and genotypic frequencies, with the exception of locus Pvan1003. Significant pairwise F
ST values between locations and total F
ST showed that the white shrimp population is structured into subpopulations. However, population differentiation does not follow an isolation-by-distance model. Knowledge of the genetic diversity and structure of L.vannamei populations will be of interest for aquaculture and fisheries management to utilize and preserve aquatic biodiversity. 相似文献
8.
Seven novel tetranucleotide microsatellite loci were identified from a partial genomic DNA library, enriched for GATA‐motif microsatellites, from the rough‐skinned newt (Taricha granulosa). All loci were polymorphic, and one displayed a high frequency null allele. A related species, T. rivularis, displays strong site fidelity and detectable population structure over small spatial scales, so we assessed genetic variation in two samples of T. granulosa separated by 16 km. Distributions of allele frequencies differ significantly between our two sites, but small values of FST and RhoST suggest that the populations are linked by a large amount of gene flow. 相似文献
9.
Jacob F. Degner I. Jack Stout James D. Roth Christopher L. Parkinson 《Conservation Genetics》2007,8(6):1441-1452
We investigated genetic diversity within the southeastern beach mouse (SEBM-Peromyscus polionotus niveiventris) and also tested the hypothesis that the subspecies recognition of P.p. niveiventris, based on size and color differences, is congruent with this taxon representing a discrete evolutionary lineage. We used
ten polymorphic microsatellite loci and mitochondrial cytochrome-b gene DNA sequences to investigate genetic diversity and population structure within the SEBM, and to determine the level
of divergence between the SEBM and the nearest known inland subspecies of the oldfield mouse (Peromyscus polionotus rhoadsi). Moderate genetic distances were observed between the SEBM and the inland oldfield mouse based on microsatellite data, with
F
ST values ranging from 0.11 to 0.22 between these taxa. Additionally, mitochondrial DNA haplotypes of the SEBM formed a distinct
monophyletic group relative to haplotypes sampled from P. p. rhoadsi. Based on previous estimates of rates of mitochondrial DNA evolution in rodents, we inferred that Pleistocene sea-level fluctuations
are likely responsible for the historical isolation of the SEBM lineage from mainland P. polionotus. Our data demonstrate the genetic distinctiveness of the SEBM, justifying the current subspecies designation for the SEBM
and its continued protection under the United States Endangered Species Act. We classify the Cape Canaveral and Smyrna Dunes
Park populations of SEBM as a single evolutionary significant unit. The two known extant allopatric populations of the SEBM
showed some differentiation in microsatellite frequencies and were moderately reciprocally distinguishable based on assignment
to distinct genetic clusters by a Bayesian admixture procedure. These results justify the classification of these two extant
SEBM populations as distinct management units that should be independent targets of management and conservation attention. 相似文献
10.
Dispersal triggers gene flow, which in turn strongly affects the ensuing genetic population structure of a species. Using
nuclear microsatellite loci and mitochondrial DNA (mtDNA), we estimated the genetic population structure of the wasp Polistes olivaceus throughout Bangladesh. The level of population differentiation using nuclear markers (F
ST) appeared to be much lower than that estimated using mtDNA haplotype sequences (ФST), even after correcting for effective population size differences between the two markers. These results suggest a philopatric
tendency, in which gynes disperse less than males. We observed no isolation by distance among the study populations at either
the nuclear or mtDNA level, suggesting nonequilibrium between gene flow and drift as a result of very frequent interpopulation
movement. For the nuclear markers, an individual assignment test showed no genetically and geographically distinct groups.
Instead, phylogenetic analyses as well as a minimum spanning network using mtDNA haplotypes consistently revealed two distinct
lineages. The distribution of haplotypes indicated western populations with a single lineage and offered clear evidence for
restricted gene flow across the Jamuna–Padma–Upper Meghna river system. Mismatch distributions exhibited a unimodal distribution,
which along with a starlike haplotype network, suggested a population expansion in lineage I but not in lineage II. Overall,
these results suggest that gene flow among populations of P. olivaceus was affected by both female philopatry and a major river system across Bangladesh. 相似文献
11.
Using mitochondrial and microsatellite DNA data and a population genetic approach, we tested male‐mediated gene flow in the toad‐headed lizards Phrynocephalus przewalskii. The mitochondrial DNA (ND2 gene), on the one hand, revealed two major lineages and a strong population genetic structure (FST = 0.692; FST′ = 0.995). The pairwise differences between the two lineages ranged from 2.1% to 6.4% and the geographical division of the two lineages coincided with a mountain chain consisting of the Helan and Yin Mountains, suggesting a historical vicariant pattern. On the other hand, the nuclear microsatellite DNA revealed a significant but small population genetic structure (FST = 0.017; FST′ = 0.372). The pairwise FST among the nine populations examined with seven microsatellite DNA loci ranged from 0.0062 to 0.0266; the assignment test failed to detect any naturally occurring population clusters. Furthermore, the populations demonstrated a weak isolation by distance and a northeast to southwest clinal variation, rather than a vicariant pattern. A historical vicariant event followed by male‐mediated gene flow appears to be the best explanation for the data. Approximately 2–5 Ma, climatic change may have created an uninhabitable zone along the Helan‐Yin mountain chain and initiated the divergence between the two mitochondrial lineages. With further climatic changes, males were able to disperse across the mountain chain, causing sufficient gene flow that eventually erased the vicariant pattern and drastically reduced the population genetic structure, while females remained philopatric and maintained the mitochondrial DNA (mtDNA) divergence. Although polygyny mating system and female philopatry may partially contribute to the reduced movement of females, other hypotheses, such as female intrasexual aggression, should also be explored. 相似文献
12.
Microsatellite DNA Polymorphism in Intensely Enhanced Populations of Sea Trout (Salmo trutta) in the Southern Baltic 总被引:1,自引:0,他引:1
Sea trout (Salmo trutta) is an anadromous form of brown trout, a commercially important salmonid species in Europe. Stocking has been used to compensate for the decrease of natural populations and maintenance of fishery and angling catches. Over 1.5 million smolts and 4.5 million alevins are released to Polish coastal rivers each year. Variation at 7 microsatellite loci (Ssa197, Ssa171, Ssa85, Str15, Str73, Str591, and Str543) was used to study genetic polymorphism of spawners returning to 6 rivers. Application of distance method for comparison of pairs of populations based on number of different alleles (F
ST) revealed significant differences between Vistula and Wieprza, and Parseta as well as between Drweca and Wieprza, and Slupia. The level of heterozygosity was similar between most of the studied sea trout populations; considerable differences were found only for Str591. Differences in frequencies of a few alleles between populations were observed. An exact test of sample differentiation based on allele frequencies confirmed lack of significance of differentiation between the 6 pairs of populations (F
ST and R
ST). No admixture was observed in the studied populations. Possible effects of stocking on the genetic polymorphism of the sea trout populations in wild with implications for biotechnology are discussed. 相似文献
13.
Mounawer Badri Adel Zitoun Houcine Ilahi Thierry Huguet Mohamed Elarbi Aouani 《Journal of genetics》2008,87(3):241-255
Genetic variability in 10 natural Tunisian populations of Medicago laciniata were analysed using 19 quantitative traits and 12 polymorphic microsatellite loci. A large degree of genetic variability
within-populations and among-populations was detected for both quantitative characters and molecular markers. High genetic
differentiation among populations for quantitative traits was seen, with Q
ST
= 0.47, and F
ST
= 0.47 for microsatellite markers. Several quantitative traits displayed no statistical difference in the levels of Q
ST
and F
ST
. Further, significant correlations between quantitative traits and eco-geographical factors suggest that divergence in the
traits among populations may track environmental differences. There was no significant correlation between genetic variability
at quantitative traits and microsatellite markers within populations. The site-of-origin of eco-geographical factors explain
between 18.13% and 23.40% of genetic variance among populations at quantitative traits and microsatellite markers, respectively.
The environmental factors that most influence variation in measured traits among populations are assimilated phosphorus (P205) and mean annual rainfall, followed by climate and soil texture, altitude and organic matter. Significant associations between
eco-geographical factors and gene diversity, H
e
, were established in five-microsatellite loci suggesting that these simple sequence repeats (SSRs) are not necessarily biologically
neutral. 相似文献
14.
John D. Perrine John P. Pollinger Benjamin N. Sacks Reginald H. Barrett Robert K. Wayne 《Conservation Genetics》2007,8(5):1083-1095
California is home to both the native state-threatened Sierra Nevada red fox (Vulpes vulpes necator), which historically inhabited high elevations of the Sierra Nevada and Cascade mountains, and to multiple low-elevation
red fox populations thought to be of exotic origin. During the past few decades the lowland populations have dramatically
expanded their distribution, and possibly moved into the historic range of the native high-elevation fox. To determine whether
the native red fox persists in its historic range in California, we compared mitochondrial cytochrome-b haplotypes of the only currently-known high-elevation population (n = 9 individuals) to samples from 3 modern lowland populations (n = 35) and historic (1911–1941) high-elevation (n = 22) and lowland (n = 7) populations. We found no significant population differentiation among the modern and historic high-elevation populations
(average pairwise F
ST = 0.06), but these populations differed substantially from all modern and historic lowland populations (average pairwise
F
ST = 0.52). Among lowland populations, the historic and modern Sacramento Valley populations were not significantly differentiated
from one another (F
ST = −0.06), but differed significantly from recently founded populations in the San Francisco Bay region and in southern California
(average pairwise F
ST = 0.42). Analysis of molecular variance indicated that 3 population groupings (mountain, Sacramento Valley, and other lowland
regions) explained 45% of molecular variance (F
CT = 0.45) whereas only 4.5% of the variance was partitioned among populations within these groupings (F
SC = 0.08). These findings provide strong evidence that the native Sierra Nevada red fox has persisted in northern California.
However, all nine samples from this population had the same haplotype, suggesting that several historic haplotypes may have
become lost. Unidentified barriers have apparently prevented gene flow from the Sacramento Valley population to other eastern
or southern populations in California. Future studies involving nuclear markers are needed to assess the origin of the Sierra
Nevada red fox and to quantify levels of nuclear gene flow. 相似文献
15.
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
16.
As a consequence of persecution and habitat fragmentation, wildcats (Felis silvestris silvestris) in Western Europe have experienced a severe reduction in population numbers and sizes. The remaining wildcat populations are considered to be endangered by losses of genetic variability and by hybridisation with free-ranging domestic cats. To investigate genetic diversity within and among wild and domestic cat populations in Germany and to estimate the extent of gene flow between both forms, we analysed a total of 266 individuals. PCR-amplification and sequencing of 322 base pairs of a highly variable part of the mitochondrial control region (HV1) of 244 specimens resulted in 41 haplotypes with 31 polymorphic sites. Additionally, eight microsatellite loci were examined for those 244 cats. Moreover, a total of 46 wildcats and 22 domestic cats could be genotyped for 13 polymorphic out of 31 enzyme loci. Genetic variability in both groups was generally high. Variability in domestic cat populations was higher than in wildcat populations. Almost no differentiation between domestic cat populations could be found (FST for microsatellites=3%). In contrast, wildcat populations differed significantly from one another (FST for microsatellites=9.55%) Within the smaller wildcat populations, a reduction of genetic diversity was detectable with regard to the nuclear DNA. Wildcat and domestic cat mitochondrial haplotypes were separated, suggesting a very low level of maternal gene flow between both forms. In microsatellites and to a somewhat lesser extent in allozymes, wildcats and domestic cats showed distinct differentiation, suggesting an only low extent of past hybridisation in certain populations. The microsatellite data set indicated a significantly reduced effective population size (bottleneck) in the recent past for one German wildcat population. 相似文献
17.
D. St. George S. M. Witte T. R. Turner M. L. Weiss J. Phillips-Conroy E. O. Smith J. Rogers 《International journal of primatology》1998,19(2):273-285
We investigated genetic variation at six microsatellite (simple sequence repeat) loci in yellow baboons (Papio hamadryas cynocephalus) at two localities: the Tana River Primate Reserve in eastern Kenya and Mikumi National Park, central Tanzania. The six loci (D1S158, D2S144, D4S243, D5S1466, D16S508, and D17S804) were all originally cloned from and characterized in the human genome. These microsatellites are polymorphic in both baboon populations, with the average heterozygosity across loci equal to 0.731 in the Tana River sample and 0.787 in the Mikumi sample. The genetic differentiation between the two populations is substantial. Kolmogornov–Smirnov tests indicate that five of the six loci are significantly different in allele frequencies in the two populations. The mean F
ST
across loci is 0.069, and Shriver's measure of genetic distance, which was developed for microsatellite loci (Shriver et al., 1995), is 0.255. This genetic distance is larger than corresponding distances among human populations residing in different continents. We conclude that (a) the arrays of alleles present at these six microsatellite loci in two geographically separated populations of yellow baboons are quite similar, but (b) the two populations exhibit significant differences in allele frequencies. This study illustrates the potential value of human microsatellite loci for analyses of population genetic structure in baboons and suggests that this approach will be useful in studies of other Old World monkeys. 相似文献
18.
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
19.
Microgeographic structure of Anopheles gambiae in western Kenya based on mtDNA and microsatellite loci 总被引:3,自引:0,他引:3
T. Lehmann N. J. Besansky W. A. Hawley T. G. Fahey L. Kamau & F. H. Collins 《Molecular ecology》1997,6(3):243-253
The population genetic structure of the Anopheles gambiae in western Kenya was studied using length variation at five microsatellite loci and sequence variation in a 648-nt mtDNA fragment. Mosquitoes were collected from houses in villages spanning up to 50 km distance, The following questions were answered, (i) Are mosquitoes in a house more related genetically to each other than mosquitoes between houses? (ii) What degree of genetic differentiation occurs on these geographical scales? (iii) How consistent are the results obtained with both types of genetic markers? At the house level, no differentiation was detected by FST and RST, and the band sharing index test revealed no significant associations of alleles across loci. Likewise, indices of kinship based on mtDNA haplotypes in houses were even lower than in the pooled sample. Therefore, the hypothesis that mosquitoes in a house are more related genetically was rejected. At increasing geographical scales, microsatellite allele distributions were similar among all population samples and no subdivision of the gene pool was detected by FST or RST. Likewise, estimates of haplotype divergence of mtDNA between populations were not higher than the within population estimates, and mtDNA-based FST values were not significantly different from zero. That sequence variation in mtDNA provided matching results with microsatellite loci (while high genetic variation was observed in all loci), suggested that this pattern represents the whole genome. The minimum area associated with a deme of A. gambiae in western Kenya is therefore larger than 50 km in diameter. 相似文献
20.
Md Sajedul Islam Chunlan Lian Norikazu Kameyama Taizo Hogetsu 《Tree Genetics & Genomes》2012,8(6):1247-1260
We analyzed nuclear and chloroplast microsatellite makers to assess genetic diversity and examine genetic structure of two mangrove tree species, Bruguiera gymnorrhiza and Kandelia obovata recovered from nine major river basins of Iriomote Island of the Ryukyu Archipelago, Japan. The average number of alleles per nuclear locus per population was 2.6 in B. gymnorrhiza and 1.7 in K. obovata. Bayesian clustering analysis using InStruct identified two genetic clusters in B. gymnorrhiza and three clusters in K. obovata. Chloroplast microsatellites revealed two dominant haplotypes from B. gymnorrhiza and three haplotypes from K. obovata. The overall result suggests low genetic diversity for both species. AMOVA for nuclear microsatellites showed 9.3?% of population variation in B. gymnorrhiza. Although genetic differentiation between several populations was significant in this species, F ST suggested low to moderate level of differentiations between most of the populations. Distribution of genetic clusters and chloroplast haplotypes also suggested weak differentiations among B. gymnorrhiza populations. In K. obovata, population variation was, however, relatively high (27.8?%). The high differentiation between K. obovata populations was also suggested from the F ST and genetic clusters from nuclear microsatellites, and chloroplast haplotypes. A significant correlation between chloroplast genetic distances and coastline distances as well as haplotype distributions for both species suggest that propagules from each species mostly disperse to the neighboring river basins. While significant F IS and higher percentage of admixed clusters from nuclear microsatellites suggested inbreeding, continual gene exchange by propagule dispersal among populations especially among neighboring populations was suggested for both species from maternally inherited chloroplast microsatellites analyses. 相似文献