نتایج جستجو برای: population variation
تعداد نتایج: 951806 فیلتر نتایج به سال:
The cave bear spread from Western Europe to the Near East during the Riss glaciation (250 KYA) before becoming extinct approximately 12 KYA. During that period, the climatic conditions were highly dynamic, oscillating between glacial and temperate episodes. Such events have constrained the geographic repartition of species, the movements of populations and shaped their genetic diversity. We ret...
A central focus of population genetics has been examining the contribution of selective and neutral processes in shaping patterns of intraspecies diversity. In terms of selection specifically, surveys of higher organisms have shown considerable variation in the relative contributions of background selection and genetic hitchhiking in shaping the distribution of polymorphisms, although these ana...
Next-generation sequencing technologies are making a substantial impact on many areas of biology, including the analysis of genetic diversity in populations. However, genome-scale population genetic studies have been accessible only to well-funded model systems. Restriction-site associated DNA sequencing, a method that samples at reduced complexity across target genomes, promises to deliver hig...
Much thought has been given to the individual-level traits that may make a species a successful colonizer. However, these traits have proven to be weak predictors of colonization success. Here, we test whether population-level characteristics, specifically genetic diversity and population density, can influence colonization ability on a short-term ecological timescale, independent of longer-ter...
This study was performed to determine the genetic diversity of HLA class I and II alleles among two ethnic groups in Southeastern Iran. HLA profiles were determined in 71 Iranian populations (41 Zaboli and 30 Baloch). The frequencies of HLA-A02 (p=0.017), -Cw4 (p=0.003), and -DR8 (p=0.025) in the Zaboli populations were significantly higher than that in Baloch ethnic group. In contrast, the fre...
The European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), is a widely distributed and serious economic pest to corn production in the U.S. Genetic variability of O. nubilalis was studied in 18 sub-populations in the upper Midwestern United States using amplified fragment length polymorphism. The relatively low GST values indicate that more variation exists within population...
The consequences of variable rates of clonal reproduction on the population genetics of neutral markers are explored in diploid organisms within a subdivided population (island model). We use both analytical and stochastic simulation approaches. High rates of clonal reproduction will positively affect heterozygosity. As a consequence, nearly twice as many alleles per locus can be maintained and...
Commercial whaling decimated many whale populations, including the eastern Pacific gray whale, but little is known about how population dynamics or ecology differed prior to these removals. Of particular interest is the possibility of a large population decline prior to whaling, as such a decline could explain the ~5-fold difference between genetic estimates of prior abundance and estimates bas...
Many questions about human genetic history can be addressed by examining the patterns of shared genetic variation between sets of populations. A useful methodological framework for this purpose isF-statistics that measure shared genetic drift between sets of two, three, and four populations and can be used to test simple and complex hypotheses about admixture between populations. This article p...
The maintenance of genetic variation is investigated in a finite population where selection at an autosomal locus with two alleles varies temporally between two environments and the heterozygote has an intermediate fitness value. When there is additive gene action and equal selection in both environments, the autocorrelation between subsequent environments must be negative for more maintenance ...
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