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Microsatellite DNA Analysis (microsatellite + dna_analysis)
Selected AbstractsCombining genetic and ecological data to assess the conservation status of the endangered Ethiopian walia ibexANIMAL CONSERVATION, Issue 2 2009B. Gebremedhin Abstract Knowledge about the phylogenetic history, genetic variation and ecological requirements of a species is important for its conservation and management. Unfortunately, for many species this information is lacking. Here we use multiple approaches (phylogenetics, population genetics and ecological modelling) to evaluate the evolutionary history and conservation status of Capra walie, an endangered flagship species of wild goat endemic to Ethiopia. The analysis of mitochondrial cytochrome b and Y-chromosome DNA sequences suggests that C. walie forms a monophyletic clade with Capra nubiana, but potentially has been isolated for up to 0.8 million years from this closely related species. Microsatellite DNA analyses show that C. walie has very low genetic variation (mean heterozygosity=0.35) compared with other endangered mammals. This reduced variation likely derives from a prolonged demographic decline and small effective population size. Ecological niche modelling using the bioclimatic features of habitats occupied by C. walie, suggests ecological differences between C. walie and C. nubiana, and identifies the areas most suitable for future reintroductions of C. walie. The genetic and bioclimatic data suggest that C. walie is distinct and requires immediate conservation actions including genetic monitoring and reintroductions to establish independent populations. This study illustrates how combining noninvasive sampling along with genetic and ecological (bioclimatic) approaches can help assess conservation status of poorly known species. [source] Microsatellite DNA analysis of success in conserving genetic diversity after 33 years of refuge management for the desert pupfish complexANIMAL CONSERVATION, Issue 4 2008H. Koike Abstract Refuge populations of Cyprinodon macularius and Cyprinodon eremus, the extant members of the endangered desert pupfish complex, have been maintained for up to 33 years in semi-natural refuges. We examined the success of the refuge program in maintaining diversity at four microsatellite DNA loci in 24 refuge populations of C. macularius and six of C. eremus that include, respectively, seven and four lineages representing original translocations from the wild. These lineages have been maintained with essentially no inoculations of genetic material from the wild and, except for one refuge, no intermixing of lineages. Comparison with wild-source populations showed marked declines in diversity within local refuges and within lineages, but relatively minor declines for the composite of all refuge populations for each species. In genetic makeup, the refuge populations generally clustered by lineage, indicating significant genetic drift early in lineage history. The results indicate that, with relatively minor adjustments in management, the refuge program can successfully preserve a large portion of the wild genetic diversity in the desert pupfish complex. [source] Low gene flow but high genetic diversity in the threatened Mallorcan midwife toad Alytes muletensisMOLECULAR ECOLOGY, Issue 11 2005F. J. L. KRAAIJEVELD-SMIT Abstract We investigated fine-scale genetic structuring in the rare and vulnerable Mallorcan midwife toad Alytes muletensis using eight polymorphic microsatellite markers. The current range of this amphibian is restricted to some 19 sites of which six are derived from reintroductions, all located in the mountain ranges of Mallorca. We sampled tadpoles from 14 pools covering 10 natural sites and two reintroduction sites for microsatellite DNA analyses. Relatively high levels of genetic variation were found in most pools (HE = 0.38,0.71, allelic richness = 2.6,6.2). Only at one pool has the population recently gone through a bottleneck. Dispersal between pools in different torrents does not occur whereas downstream dispersal between pools within the same torrent does happen at low frequencies. This occasional exchange of individuals does not lead to neighbouring pools in the same torrent being panmictic. This can be concluded because all FST values (0.12,0.53) differ significantly from zero and structure analyses identified neighbouring pools as separate populations. Furthermore, assignment and migration tests showed little exchange between neighbouring pools. If upstream locations or complete torrents go extinct, they are unlikely to be recolonized naturally. For conservation purposes, reintroductions of tadpoles to sites where local extinctions have occurred may therefore be advisable. [source] Genome size evolution and polyploidy in the Daphnia pulex complex (Cladocera: Daphniidae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009ROLAND VERGILINO Genome size was estimated in 49 clones of the Daphnia pulex complex from temperate and subarctic locations using flow cytometry and microsatellite DNA analyses. Significant genome size differences were found in diploid species belonging to the two genetically distinct groups (the pulicaria and the tenebrosa groups), with clones from the tenebrosa group having genome sizes 22% larger than those in the pulicaria group. Combined flow cytometry and microsatellite DNA analyses revealed that nearly all polyploid clones in the D. pulex complex are triploid and not tetraploid, as was previously suggested. Sequencing analyses of the ND5 gene to position clones in their respective clades within the D. pulex complex have uncovered three triploid clones of Daphnia middendorffiana with a D. pulex maternal parent. This result was unexpected because Daphnia pulicaria has always been identified as the maternal parent of these hybrid polyploid clones. Triploid clones likely owe their origins to interactions between sexual and asexual populations. Further interactions in the tenebrosa group have generated tetraploid clones but these events have been rare. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 68,79. [source] Genetic restoration of a stocked brown trout Salmo trutta population using microsatellite DNA analysis of historical and contemporary samplesJOURNAL OF APPLIED ECOLOGY, Issue 4 2006MICHAEL M. HANSEN Summary 1Gene flow from domesticated to wild populations is a major threat to wild salmonid fish. However, few studies have addressed how populations could be restored after admixture has occurred. We analysed the prospects for restoring the previously intensively stocked brown trout population of the Skjern River, Denmark, by identifying remaining non-admixed individuals to be used for supportive breeding. 2We analysed microsatellite DNA markers in historical (1940,50s) and contemporary (1992,2004) samples from the Skjern River system, from the strain of domesticated trout previously used for stocking, and from the neighbouring Storå River. We analysed admixture proportions to estimate the genetic contribution by domesticated trout. We identified non-admixed trout using assignment tests, and further analysed the possible sources of indigenous trout by estimating contemporary migration among populations. 3Genetic differentiation between the historical Storå and Skjern river populations was low (,ST = 0·004), suggesting considerable gene flow in the past. The contemporary Skjern and Storå river populations and a supportive breeding brood stock were strongly admixed, but some non-admixed individuals nevertheless remained in the wild-caught samples. In addition, two resident populations in isolated tributaries were found to be indigenous. The indigenous anadromous individuals from the Skjern River were unlikely to have been recruited from either the isolated tributary populations or the neighbouring Storå River and were presumably derived from unidentified spawning sites in the river system. 4All but one non-admixed anadromous Skjern River trout were females, which we ascribed to sampling bias. Moreover, all non-admixed fish were late-spawning (January,February) whereas the majority of all trout caught for the study were ripe by November,December. The difference in spawning time could be an important factor delaying complete admixture of domesticated and indigenous trout. 5Synthesis and applications. This study demonstrates the feasibility of restoring populations that have been admixed with exogenous individuals, by identifying non-admixed individuals using genetic markers. However, the results also highlight the problem that numbers of identified non-admixed individuals may be small, necessitating identification of nearby, closely related populations that can be incorporated into breeding programmes. [source] Microsatellite DNA variation in Bornean orangutans (Pongo pygmaeus)JOURNAL OF MEDICAL PRIMATOLOGY, Issue 2 2000K.S. Warren Orangutans (Pongo pygmaeus) on the islands of Borneo and Sumatra are considered two separate subspecies. However, the genetic relationships between isolated populations on Borneo are not clear. This study determined the extent of variation within the Bornean subspecies of orangutan, using microsatellite DNA analysis. Blood samples were collected from 96 individuals of known origin from East, West and Central Kalimantan. Human microsatellite primer pairs located at human map position D2S141, D4S431, D11S925, D16S420 and D17S791 were suitable for use in primates. D4S431 appeared monomorphic for all orangutans. In three cases (D2S141 East and West and D16S420 West), a highly significant excess of homozygous allele frequencies was detected, but with other primer pairs no significant difference in allele frequencies occurred. We conclude that the divergence between the different populations on Borneo is less than the variation within the populations. There was also evidence that inbreeding occurred within the populations. [source] Genetic structure of Anopheles gambiae (Diptera: Culicidae) in São Tomé and Príncipe (West Africa): implications for malaria controlMOLECULAR ECOLOGY, Issue 10 2002J. Pinto Abstract The impact of a vector eradication programme, conducted in the 1980s, on Anopheles gambiae populations from the islands of São Tomé and Príncipe, was evaluated by microsatellite DNA analysis. Significant genetic differentiation was observed within and between the two islands and between the islands and a population from Gabon, suggesting a degree of isolation between them. Large estimates of long-term Ne suggested that the control programme did not affect the effective population size of the vector. Heterozygosity tests were also not consistent with a recent bottleneck. [source] | ||||||||||