Selective pressures on MHC class II genes in the guppy (Poecilia reticulata) as inferred by hierarchical analysis of population structure.

摘要: Genes of the major histocompatibility complex, which are most polymorphic all vertebrate genes, a pre-eminent system for study selective pressures that arise from host-pathogen interactions. Balancing selection capable maintaining high polymorphism should lead to homogenization MHC allele frequencies among populations, but there is some evidence suggest diversifying also operates on MHC. However, pattern population structure observed at loci likely depend spatial and/or temporal scale examined. Here, we investigated acting genes different geographic scales using Venezuelan guppy populations inhabiting four regions. We found significant correlation between and microsatellite allelic richness across suggests role genetic drift in shaping diversity. compared microsatellites, more variation was explained by differences within larger regions less Furthermore, proximate significantly higher indicating may increase small scales. have diverged neutral markers, population-genetic signature be eradicated long term balancing selection, acts preserve rare alleles thus maintain common pool alleles.