Gene flow as a simple cause for an excess of high-frequency-derived alleles.

ABSTRACT: Most human populations exhibit an excess of high-frequency variants, leading to a U-shaped site-frequency spectrum (uSFS). This pattern has been generally interpreted as a signature of ongoing episodes of positive selection, or as evidence for a mis-assignment of ancestral/derived allelic states, but uSFS has also been observed in populations receiving gene flow from a ghost population, in structured populations, or after range expansions. In order to better explain the prevalence of high-frequency variants in humans and other populations, we describe here which patterns of gene flow and population demography can lead to uSFS by using extensive coalescent simulations. We find that uSFS can often be observed in a population if gene flow brings a few ancestral alleles from a well-differentia

SUBMITTER: Marchi N 

PROVIDER: S-EPMC7513730 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature