共查询到20条相似文献,搜索用时 31 毫秒
1.
This study tests population genetic patterns across the Eurasian dreissenid mussel invasions of North America—encompassing
the zebra mussel Dreissena polymorpha (1986 detection) and the quagga mussel D. rostriformis
bugensis (detected in 1990, which now has largely displaced the former in the Great Lakes). We evaluate their source-spread relationships
and invasion genetics using 9–11 nuclear microsatellite loci for 583 zebra mussels (21 sites) and 269 quagga mussels (12 sites)
from Eurasian and North American range locations, with the latter including the Great Lakes, Mississippi River basin, Atlantic
coastal waterways, Colorado River system, and California reservoirs. Additionally, mtDNA cytochrome b gene sequences are used to verify species identity. Our results indicate that North American zebra mussels originate from
multiple non-native northern European populations, whereas North American quagga mussels trace to native estuaries in the
Southern Bug and Dnieper Rivers. Invasive populations of both species show considerable genetic diversity and structure (zebra
F
ST = 0.006–0.263, quagga F
ST = 0.008–0.267), without founder effects. Most newer zebra mussel populations have appreciable genetic diversity, whereas
quagga mussel populations from the Colorado River and California show some founder effects. The population genetic composition
of both species changed over time at given sites; with some adding alleles from adjacent populations, some losing them, and
all retaining closest similarity to their original composition. Zebra mussels from Kansas and California appear genetically
similar and assign to a possible origin from the St. Lawrence River, whereas quagga mussels from Nevada and California assign
to a possible origin from Lake Ontario. These assignments suggest that overland colonization pathways via recreational boats
do not necessarily reflect the most proximate connections. In conclusion, our microsatellite results comprise a valuable baseline
for resolving present and future dreissenid mussel invasion pathways. 相似文献
2.
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
3.
Dustin G. Loftis Anthony A. Echelle Haruko Koike Ronald A. Van Den Bussche C. O. Minckley 《Conservation Genetics》2009,10(2):453-463
Data from 10 microsatellite DNA loci were used to describe the genetic structure of the two extant species (Cyprinodon macularius and C. eremus) of the endangered Desert Pupfish complex of southwestern United States and northwestern Mexico. Variation at microsatellite
loci was significantly correlated (Mantel test) with that of previous mtDNA results, both for the complex and for the relatively
wide-ranging C. macularius alone. Both species showed unusually high levels of microsatellite diversity for non-marine fish (H
e = 0.84–0.93; AR = 11.9–17.0). There was evidence (R
ST > F
ST) that the two extant populations of C. eremus have been isolated sufficiently long for mutation to contribute significantly to genetic divergence, whereas divergence among
the nine assayed populations of C. macularius could be attributed to genetic drift alone. Correspondingly, 10% of the diversity in C. eremus was attributable to differences between the two populations, whereas, for C. macularius, only 2.7% was attributable to among-population variation. Within C. macularius, a small (0.8%), but statistically significant, portion was attributable to differences between populations in the Salton
Sea area and those on the lower Colorado River delta. The two populations of C. eremus and five groups of populations of C. macularius are recommended as management units for conservation genetics management of the two species. 相似文献
4.
Warangkana Prakoon Suriyan Tunkijjanukij Thuy T. T. Nguyen Uthairat Na-Nakorn 《Marine biotechnology (New York, N.Y.)》2010,12(5):506-515
The culture of green mussel (Perna viridis) in the Gulf of Thailand depends on natural spat which are believed to come from spawning grounds adjacent to major river
mouths. In the present paper, genetic diversity of spatial and temporal populations of green mussel in the Gulf of Thailand
was investigated using five microsatellite loci. The results showed moderate genetic variation of all 11 populations (averaged
number of alleles per locus, A = 10.4–12.2; effective number of alleles per locus, A
e = 5.36–6.59; mean allelic richness, A
r = 10.23–12.06; observed heterozygosity, H
o = 0.52–0.63, and expected heterozygosity, H
e = 0.66–0.73) without significant differences among populations. No sign of bottleneck or genetic disequilibrium was observed.
Genetic differentiation among spatial populations was low (F
ST = 0.0046, CI0.95 = 0.0020–0.0083 for the samples collected in January, 2007, and F
ST = 0.0088, CI0.95 = 0.0010–0.0162 for the samples collected in July, 2007) while temporal variation was significant as revealed by the analysis
of molecular variance. Multidimensional scaling separated temporal population groups with minor exception. The assignment
test revealed that most of the recruits were from other populations. 相似文献
5.
Saša Marić Belma Kalamujić Aleš Snoj Andrej Razpet Lada Lukić-Bilela Naris Pojskić Simona Sušnik Bajec 《Hydrobiologia》2012,691(1):225-237
In order to elucidate genetic composition of European grayling (Thymallus thymallus) populations in the Western Balkans, the partial mitochondrial DNA (mtDNA) control region was sequenced and 12 microsatellite loci genotyped in 14 populations originating from tributaries of the Adriatic and Danube drainages. Eleven mtDNA haplotypes were found, one confined to the Adriatic clade, one to the Alpine group and the rest to the ‘Balkan’ grayling phylogenetic clade. Haplotypes from the Balkan clade were confined to the Danube drainage and constituted two groups: northern group with haplotypes found in the Slovenian part of the Danube drainage, and southern group, consisting from Bosnia–Herzegovina and Montenegro. Substantial genetic distance between northern and southern groups of haplotypes (0.75–1.8%) and well supported divisions within the northern group indicate very structured grayling population within the studied Danube basin that most probably did not evolve due to vicariance but rather as a consequence of multiple colonization waves that might have occurred during the Pleistocene. Furthermore, genetic distance of ~4% between Adriatic and Danube populations’ haplotypes, suggest that their separation occurred in mid-Pliocene. These findings imply a complex colonization pattern of the Western Balkans drainages. Microsatellite data also confirm high genetic diversity in Western Balkans populations of grayling (on average 7.5 alleles per microsatellite locus and H exp 0.58). Limited stocking activities were detected based on microsatellites and mtDNA data. Regarding current knowledge of grayling phylogeography appropriate management strategies were proposed to preserve unique, autochthonous grayling populations in Western Balkan. 相似文献
6.
Conservation and management implications of fine-scale genetic structure of Gulf sturgeon in the Pascagoula River, Mississippi 总被引:1,自引:0,他引:1
M. A. Dugo B. R. Kreiser S. T. Ross W. T. Slack R. J. Heise B. R. Bowen 《Zeitschrift fur angewandte Ichthyologie》2004,20(4):243-251
The anadromous Gulf sturgeon occurs along the north central coast of the Gulf of Mexico and is federally listed as threatened. We analyzed fine‐scale patterns of Gulf sturgeon population structure, focusing on the Pascagoula River drainage of Mississippi, in reference to movement patterns as determined via telemetry and capture data. We genotyped 361 Gulf sturgeon using eight microsatellite loci including samples from the Pascagoula, Pearl, Escambia, Yellow, Choctawhatchee, and Apalachicola river drainages. Pairwise FST estimates indicated that genetic structure occurs at least at the drainage level. The Pascagoula and Pearl rivers form a western group, demonstrating 100% bootstrap support for a division with drainages to the east. Assignment tests detected non‐natal genotypes occurring in all drainages. According to assignment tests, the Pascagoula supports an admixture of individuals, containing minimal influence from drainages to the east (2%) and substantial interaction with the Pearl River (14.1%). The occurrence of Pascagoula River fish in the Pearl was non‐reciprocal, observed at 1.1%. After accounting for non‐natal genetic diversity within the Pascagoula, there remained a disparity between a pooled Pascagoula group and the only documented spawning site within the drainage located in the Bouie River. We interpret this as an indication of a second genetic stock within the Pascagoula River drainage. Radio telemetry data suggest that spawning likely occurs in the Chickasawhay River, in areas isolated from the Bouie River spawning site by about 350 river kilometers. We emphasize the utility of integrating field and molecular approaches when delineating fine‐scale patterns of population structure in anadromous fishes. 相似文献
7.
Samantha M. Wisely Rachel M. Santymire Travis M. Livieri Sara A. Mueting JoGayle Howard 《Conservation Genetics》2008,9(2):389-399
Population augmentation with translocated individuals has been shown to alleviate the effects of bottlenecks and drift. The
first step to determine whether restoration for genetic considerations is warranted is to genetically monitor reintroduced
populations and compare results to those from the source. To assess the need for genetic restoration, we evaluated genetic
diversity and structure of reintroduced (n = 3) and captive populations of the endangered black-footed ferret (Mustela nigripes). We measured genotypic changes among populations using seven microsatellite markers and compared phenotypic changes with
eight morphometric characters. Results indicated that for the population which rapidly grew post-reintroduction, genetic diversity
was equivalent to the captive, source population. When growth languished, only the population that was augmented yearly maintained
diversity. Without augmentation, allelic diversity declined precipitously and phenotypic changes were apparent. Ferrets from
the genetically depaupertate population had smaller limbs and smaller overall body size than ferrets from the two populations
with greater diversity. Population divergence (F
ST = 0.10 ± 0.01) was surprisingly high given the common source of populations. Thus, it appears that 5–10 years of isolation
resulted in both genotypic divergence and phenotypic changes to populations. We recommend translocation of 30–40 captive individuals
per annum to reintroduction sites which have not become established quickly. This approach will maximize the retention of
genetic diversity, yet maintain the beneficial effects of local adaptation without being swamped by immigration. 相似文献
8.
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
9.
Pacific halibut collected in the Aleutian Islands, Bering Sea and Gulf of Alaska were used to test the hypothesis of genetic
panmixia for this species in Alaskan marine waters. Nine microsatellite loci and sequence data from the mitochondrial (mtDNA)
control region were analyzed. Eighteen unique mtDNA haplotypes were found with no evidence of geographic population structure.
Using nine microsatellite loci, significant heterogeneity was detected between Aleutian Island Pacific halibut and fish from
the other two regions (F
ST range = 0.007–0.008). Significant F
ST values represent the first genetic evidence of divergent groups of halibut in the central and western Aleutian Archipelago.
No significant genetic differences were found between Pacific halibut in the Gulf of Alaska and the Bering Sea leading to
questions about factors contributing to separation of Aleutian halibut. Previous studies have reported Aleutian oceanographic
conditions at deep inter-island passes leading to ecological discontinuity and unique community structure east and west of
Aleutian passes. Aleutian Pacific halibut genetic structure may result from oceanographic transport mechanisms acting as partial
barriers to gene flow with fish from other Alaskan waters. 相似文献
10.
Genetic variability and population structure of the Chinese longsnout catfish Leiocassis longirostris Günther in the Yangtze River was examined with mitochondrial control region sequences and nuclear microsatellite markers.
A 705-bp segment of the mitochondrial DNA control region was sequenced from 132 samples, which identified a total of 61 haplotypes.
The Chinese longsnout catfish in the Yangtze River was characterized with high haplotype diversity (h = 0.9770 ± 0.0041) but low nucleotide diversity (π = 0.0081 ± 0.0043). Median-joining network analysis revealed a star-shaped
pattern and mismatch distribution analysis found a smooth unimodal distribution, which suggested that this species in the
Yangtze River underwent a population expansion following bottlenecks and/or they originated from a small size of founding
population. It was estimated that the possible time of population expansion was 139,000–435,000 years before present, a time
period in the middle Pleistocene. The analysis of molecular variance and phylogenetic reconstructions did not detect significant
geographic structure between different river sections. This pattern of genetic variation was further evidenced with nuclear
microsatellite markers. The genetic differentiation between above and below the Gezhouba Dam and Three Gorges Dam is very
small at mitochondrial and nuclear levels, which suggested that these recently developed dams might have not significantly
resulted in population genetic fragmentation in the Chinese longsnout catfish. However, the potential exacerbation of genetic
structuring by the dams should not be overlooked in the future. 相似文献
11.
Insuan S Deowanish S Klinbunga S Sittipraneed S Sylvester HA Wongsiri S 《Biochemical genetics》2007,45(3-4):345-361
Genetic diversity and population differentiation of the giant honey bee (Apis dorsata) in Thailand were examined. Six PCR-RFLP mitotypes were generated from digestion of the COI-COII, Cytb-tRNAser, ATPase6-8, and lrRNA genes with Dra
I and Hin
fI. Low genetic diversity (h=0.074, π=0.032%) and a lack of genetic population differentiation between A. dorsata originating from geographically different
regions were observed from mtDNA polymorphisms (P > 0.05). In contrast, microsatellite (A14, A24, and A88) polymorphisms revealed a relatively high level of genetic diversity in A. dorsata (H
o=0.68–0.74, average number of alleles per locus=6.0–9.0). Both A24 and A88 indicated significant population differentiation between bees from the north-to-central region (north, northeast, and central
regions), peninsular Thailand, and Samui Island. 相似文献
12.
Chaturvedi A Mohindra V Singh RK Lal KK Punia P Bhaskar R Mandal A Narain L Lakra WS 《Molecular biology reports》2011,38(5):3513-3529
We examined population structure of Labeo dero (Hamilton, 1822) from different riverine locations in India using 10 polymorphic allozyme and eight microsatellite loci.
For analysis, 591 different tissue samples were obtained from commercial catches covering a wide geographic range. Allozyme
variability (An = 1.28–1.43, Ho = 0.029–0.071) was much lower than for microsatellites (An = 4.625–6.125, Ho = 0.538–0.633).
Existence of rare alleles was found at three allozyme (MDH-2*, GPI* and PGDH*) and at two microsatellite loci (R-3* and MFW-15*). Deviation from Hardy–Weinberg equilibrium (P < 0.05, after the critical probability levels were adjusted for sequential Bonferroni adjustment) could be detected at three
loci (EST-1*, -2* and XDH*) whereas, after correction for null alleles, two microsatellite loci (MFW-1*,-15*) deviated from HWE in the river Yamuna. Fst for all the samples combined over all allozyme loci was found to be 0.059 suggesting
that 5.9% of the total variation was due to genetic differentiation while microsatellite analysis yielded 0.019 which was
concordant to mean Rst (0.02). Hierarchical partition of genetic diversity (AMOVA) showed that greater variability (approx.
95%) was due to within population component than between geographical regions. Based on distribution of genetic differentiation
detected by both markers, at least five different genetic stocks of L. dero across its natural distribution could be identified. These results are useful for the evaluation and conservation of L. dero in natural water bodies. 相似文献
13.
Erika A. Alacs Peter B. S. Spencer Paul J. de Tores Siegfried L. Krauss 《Conservation Genetics》2011,12(1):297-309
Translocation and reintroduction are important tools for the conservation or recovery of species threatened with extinction
in the wild. However, an understanding of the potential genetic consequences of mixing populations requires an understanding
of the genetic variation within, and similarities among, donor and recipient populations. Genetic diversity was measured using
two independent marker systems (microsatellites and AFLPs) for one island and four small remnant mainland populations of Setonix brachyurus, a threatened medium sized macropod restricted to fragmented habitat remnants and two off-shore islands in southwest Australia.
Microsatellite diversity in the island population (R
s = 3.2, H
e = 71%) was similar to, or greater than, all mainland populations (R
s = 2.1–3.9, H
e = 34-71%). In contrast, AFLP diversity was significantly lower in the island population (PPL = 20.5; H
j = 0.118) compared to all mainland populations (mean PPL = 79.5–89.7; mean H
j = 0.23–0.29). Microsatellites differentiated all (mainland and island) populations from each other. However, AFLP only differentiated
the island population from the mainland populations—all mainland populations were not significantly differentiated from each
other for this marker. Given a known time since isolation of the island population from the mainland (6,000 years ago), and
an overall more conservative rate of evolution of AFLP markers, our results are consistent with mainland populations fragmenting
thousands of years ago (but <6,000 years), probably as a consequence of reduced rainfall and the constriction of the preferred
mesic habitat of quokkas. Our results also support a recent history of severe population bottlenecks in mainland populations,
and a long history of bottlenecks of the island population, but reflect a recent explosion in numbers since European occupation
of the island. Our results indicate that translocation of island populations to supplement mainland populations would introduce
genetically markedly differentiated, and possibly maladapted, individuals. 相似文献
14.
Kouichi Kawamura Masashi Kubota Miki Furukawa Yasushi Harada 《Conservation Genetics》2007,8(5):1163-1176
The amago salmon, Oncorhynchus masou ishikawae, is an endemic subspecies of O. masou in Japan. Owing to the extensive stocking of hatchery fish throughout Japan, indigenous populations of O. m. ishikawae are now on the verge of extinction. We examined the genetic effects of stocking hatchery fish on wild populations in the
River Koza, Japan, using microsatellite and mitochondrial DNA (mtDNA) markers. For mtDNA, haplotype mt1, which is common in
wild populations, was present exclusively in isolated wild populations assumed to be unaffected by previous stocking, while
it was never observed in hatchery fish. Genetic diversity was much higher in wild populations in the stocked area, which shared
many mtDNA haplotypes with hatchery fish, than in isolated wild populations with haplotype mt1. Pairwise F
ST estimates based on microsatellites showed significant differentiation among the isolated populations with many microsatellite
loci monomorphic. Significant deviation from Hardy–Weinberg equilibrium was observed in wild populations in the area subject
to stocking, where a Bayesian-based assignment test showed a high level of introgression with hatchery fish. These results
suggest that wild populations with haplotype mt1, which became isolated through anthropogenic environmental change in the
1950–1960s, represent indigenous populations of O. m. ishikawae in the River Koza. They have low genetic diversity, most likely caused by genetic bottlenecks following damming and environmental
deterioration, while stocking of hatchery fish over the past 30 years apparently had a large impact on the genetic structure
of wild populations in the main channel of the River Koza. 相似文献
15.
Population subdivision due to habitat loss and modification, exploitation of wild populations and altered spatial population
dynamics is of increasing concern in nature. Detecting population fragmentation is therefore crucial for conservation management.
Using computer simulations, we show that a single sample estimator of N
e based on linkage disequilibrium is a highly sensitive and promising indicator of recent population fragmentation and bottlenecks,
even with some continued gene flow. For example, fragmentation of a panmictic population of N
e = 1,000 into demes of N
e = 100 can be detected with high probability after a single generation when estimates from this method are compared to prefragmentation
estimates, given data for ~20 microsatellite loci in samples of 50 individuals. We consider a range of loci (10–40) and individuals
(25–100) typical of current studies of natural populations and show that increasing the number of loci gives nearly the same
increase in precision as increasing the number of individuals sampled. We also evaluated effects of incomplete fragmentation
and found this N
e-reduction signal is still apparent in the presence of considerable migration (m ~ 0.10–0.25). Single-sample genetic estimates of N
e thus show considerable promise for early detection of population fragmentation and decline. 相似文献
16.
Peter O. Aikpokpodion Juan C. Motamayor Victor O. Adetimirin Yaw Adu-Ampomah Ivan Ingelbrecht Albertus B. Eskes Raymond J. Schnell Maria Kolesnikova-Allen 《Tree Genetics & Genomes》2009,5(4):699-711
Knowledge of genebank and on-farm genetic diversity, particularly in an introduced crop species, is crucial to the management
and utilization of the genetic resources available. Microsatellite markers were used to determine genetic diversity in 574
accessions of cacao, Theobroma cacao L., representing eight groups covering parental populations in West Africa, genebank, and farmers’ populations in Nigeria.
From the 12 microsatellite markers used, a total of 144 alleles were detected with a mean allelic richness of 4.39 alleles/locus.
The largest genetic diversity was found in the Upper Amazon parent population (H
nb
= 0.730), followed by the 1944 Posnette’s Introduction (H
nb
= 0.704), and was lowest in the Local parent population (H
nb
= 0.471). Gene diversity was appreciably high in the farmers’ populations (H
nb
= 0.563–0.624); however, the effective number of alleles was lower than that found in the genebank’s Posnette’s population.
Fixation index estimates indicated deficiency of heterozygotes in the Upper Amazon and the Local parent populations (F
is
= 0.209 and 0.160, respectively), and excess of heterozygotes in the Trinitario parent population (F
is
= −0.341). The presence of inbreeding in the Local parent populations and substructure (Wahlund effect) in the Upper Amazon
were suggested for the deficiency of heterozygotes observed. Non-significant genetic differentiation observed between the
genebank’s and farmers’ populations indicated significant impact of national breeding programs on varieties grown in farmers’
plantations. From this study, we showed that appreciable genetic diversity was present in on-farm and field genebank collections
of cacao that can be exploited for crop improvement in West Africa. Suggestions for future conservation of on-farm genetic
diversity and local landraces are further discussed. 相似文献
17.
Human activities such as fragmentation and selective logging of forests can threaten population viability by modification
of ecological and genetic processes. Using six microsatellite markers, we examined the effects of forest fragmentation and
local disturbance on the genetic diversity and structure of adult trees (N = 110) and seedlings (N = 110) of Prunus africana in Kakamega Forest, western Kenya. Taking samples of adults and seedlings allowed for study of changes in genetic diversity
and structure between generations. Thereby, adults reflect the pattern before and seedlings after intensive human impact.
Overall, we found 105 different alleles in the six loci examined, 97 in adults and 88 in seedlings. Allelic richness and heterozygosity
were significantly lower in seedlings than in adults. Inbreeding increased from adult tree to seedling populations. Genetic
differentiation of adult trees was low (overall F
ST = 0.032), reflecting large population sizes and extensive gene flow in the past. Genetic differentiation of seedlings was
slightly higher (overall F
ST = 0.044) with all of the 28 pairwise F
ST-values being significantly different from zero. These results suggest that human disturbance in Kakamega Forest has significantly
reduced allelic richness and heterozygosity, increased inbreeding and slightly reduced gene flow in P. africana in the past 80–100 years. 相似文献
18.
Wouter F. D. van Dongen Gopi K. Munimanda Jakob Augustin Donald Blomqvist Tibor Szép Richard H. Wagner 《Journal of Ornithology》2010,151(3):761-764
We isolated and characterised six novel microsatellite loci for paternity analysis in the sand martin Riparia riparia, by screening an enriched genomic library. In addition, we tested 16 already published microsatellite markers, five of which
were also polymorphic in the sand martin. Only one of these 11 loci exhibited evidence of null alleles, and all were polymorphic
(mean H
o = 0.68, range of number of alleles per locus = 4–24), making them suitable for individual heterozygosity quantification and
paternity assessment in this species (exclusion probability of 11 unlinked loci = 0.999997). 相似文献
19.
Deborah A. Randall John P. Pollinger Kifle Argaw David W. Macdonald Robert K. Wayne 《Conservation Genetics》2010,11(1):89-101
We used demographic, spatial, and microsatellite data to assess fine-scale genetic structure in Ethiopian wolves found in
the Bale Mountains and evaluated the impact of historical versus recent demographic processes on genetic variation. We applied
several analytical methods, assuming equilibrium and nonequilibrium conditions, to assess demography and genetic structure.
Genetic variation (H
E = 0.584–0.607, allelic richness = 4.2–4.3) was higher than previously reported for this species and genetic structure was
influenced by geography and social structure. Statistically significant F
ST values (0.06–0.08) implied differentiation among subpopulations. STRUCTURE analyses showed that neighbouring packs often
have shared co-ancestry and spatial autocorrelation showed higher genetic similarity between individuals within packs and
between individuals in neighbouring packs compared to random pairs of individuals. Recent effective population sizes were
lower than 2n (where n is the number of packs) and lower than the number of breeding individuals with N
e
/N ratios near 0.20. All subpopulations have experienced bottlenecks, one occurring due to a rabies outbreak in 2003. Nevertheless,
differentiation among these subpopulations is consistent with long-term migration rates and fragmentation at the end of the
Pleistocene. Enhanced drift due to population bottlenecks may be countered by higher migration into disease-affected subpopulations.
Contemporary factors such as social structure and population bottlenecks are clearly influencing the level and distribution
of genetic variation in this population, which has implications for its conservation. 相似文献
20.
Genetic diversity and population structure of 9 populations of Bufo gargarizans with total 111 samples in China were assessed using seven microsatellite loci. The analysed microsatellite markers produced
161 alleles, varied from 9 to 38 alleles each locus. The number of alleles per population per locus ranged from 4.43 to 10.29.
Polymorphic information content showed that all seven loci were highly informative (mean = 0.810 ± 0.071). The average observed
heterozygosity was less than the expected (0.353 ± 0.051 and 0.828 ± 0.067, respectively). All tested populations gave significant
departures from Hardy–Weinberg equilibrium. Genetic differentiation among the populations was considerably high with the overall
and pairwise F
ST values (mean = 0.160 ± 0.039), and showed fairly high level of inbreeding (indicated by a mean F
IS value of 0.504 ± 0.051) and global heterozygote deficit. In comparison to other amphibian studies; however, our results suggested
that the level of genetic structuring in B. gargarizans was relatively low in the geographical scale of the study area. Interestingly, the speculated population bottleneck was found
to be absent and the analyses provide only weak evidence for a recent contraction in size even though there was severe inbreeding
(indicated by the F
IS value) in the Chinese toad populations. 相似文献