Home About us Contact
|
Home About us Contact | ||
|
|
||
Population Genetic Survey (population + genetic_survey)
Selected AbstractsLow variation but strong population structure in mitochondrial control region of the plains topminnow, Fundulus sciadicusJOURNAL OF FISH BIOLOGY, Issue 5 2009C. Li The plains topminnow Fundulus sciadicus is a freshwater killifish endemic to the Great Plains of North America. Rising concerns for future viability of this species have prompted recent changes in its conservation status. In this study, the results of a range-wide population genetic survey based on the sequence of entire mitochondrial control region (CR) are presented. A total of 181 fish were collected from 11 sites in Nebraska and 10 sites in Missouri spanning the distribution range of the species. Seven polymorphic sites were found in the 966 base pairs of the CR, and only nine unique haplotypes were detected among all fish. Phylogenetic analysis and statistical parsimony networks identified two distinct clades. The first included fish in the Osage, Gasconade and Spring River drainages in Missouri, while the second included individuals from Nebraska and the Lamine River in Missouri, although the Lamine River is much closer to the other Missouri sites than to the Nebraska sites. Pair-wise FST and average population distances indicated that populations from most drainages are genetically distinct, as 93% of the total molecular variance was attributed to among-drainage effects. Four sites within the main distributions of this species and a highly disjunct site from the south-western portion of the range are suggested as potential targets for conservation. [source] Small effective population sizes in a widespread selfing species, Lymnaea truncatula (Gastropoda: Pulmonata)MOLECULAR ECOLOGY, Issue 9 2004C. MEUNIER Abstract We present here a spatial and temporal population genetic survey of a common freshwater snail, also a predominantly selfing species, Lymnaea truncatula. The rate of genetic diversity loss was quantified by estimating the effective size (Ne) of the snail populations, using two different methods. A temporal survey allowed estimation of a variance effective size of the populations, and a spatial survey allowed the estimation of an inbreeding effective size, from two-locus identity disequilibria estimates. Both methods were consistent and provided low Ne values. Drift due to (i) high amounts of selfing and (ii) fluctuations in population sizes because of temporary habitats, and also selection coupled to genome-wide linkage disequilibria, could explain such reductions in Ne. The loss of genetic diversity appears to be counterbalanced only very partially by low apparent rates of gene flow. [source] The ,New Wave' in plant demographic inference: more loci and more individualsMOLECULAR ECOLOGY, Issue 6 2010MARTIN LASCOUX Abstract Plant population genetic surveys are starting to take full advantage of technological advances in genotyping methods and of methodological advances in demographic inference. In this issue of Molecular Ecology, Keller et al. (2010) illustrate this trend with a particularly convincing study of rangewide genetic variation in a North American poplar, using both SNP and sequence data. They first investigate population genetic structure by estimating the most likely number of genetic clusters using a more formal approach than most other studies to date. They proceed by estimating gene flow among the inferred populations and by testing predictions on the distribution of low frequency alleles derived from recent work on range expansions. [source] Isolation and characterization of polymorphic microsatellite markers in Schistosoma mansoni from AfricaMOLECULAR ECOLOGY RESOURCES, Issue 1-2 2001L. Blair Abstract The ability of microsatellite loci to reveal genetic diversity between individuals of the digenean trematode Schistosoma mansoni was investigated. A total of 10 polymorphic microsatellite markers were isolated and optimized, allowing the variability at each locus amplified within 12 individuals from three African populations to be assessed. Allelic diversity and observed heterozygosity (HO) figures ranged from 2 to 6 and 0.33 to 1.00, respectively. These results indicated high variability both between individuals and populations, highlighting the suitability of these microsatellites for future population genetic surveys. [source] | ||||||||||