The influence of culture history on genetic variation in cultured Arctic charr (Salvelinus alpinus) of eastern Canada.

摘要

The relative influence of culture history on decreased gene flow, increased genetic drift and/or artificial selection were investigated in two strains of aquaculture Arctic charr cultured in Eastern Canada. Using data from 6 microsatellite loci, I measured and contrasted levels of genetic variation, tested for evidence of bottlenecks, discerned differentiation patterns within and between strains, and determined population relationships within strains. Little evidence was found to suggest that bottlenecks had occurred in the creation of subsequent broodstock populations. However, observed heterozygosity showed significant decline in populations that were further removed from the wild. Heterozygote deficits were responsible for the majority of the deviations from Hardy-Weinberg proportions. Global FST estimates showed that those populations further removed from the wild were similarly differentiated to populations that were closer to the wild. Analyses of molecular variance (AMOVA) revealed that twice the variation was preserved among populations in one of the strains yet most of the variation was maintained within populations for each strain. Phenograms generated using Nei's genetic distances (D A) corroborated the differentiation findings. Taken collectively, my data suggests that drift, selection and non-random mating are acting to reduce genetic variation and promote structure in these closed hatchery systems.