"Balancing" balancing selection? Assortative mating at the major histocompatibility complex despite molecular signatures of balancing selection.

ABSTRACT: In vertebrate animals, genes of the major histocompatibility complex (MHC) determine the set of pathogens to which an individual's adaptive immune system can respond. MHC genes are extraordinarily polymorphic, often showing elevated nonsynonymous relative to synonymous sequence variation and sharing presumably ancient polymorphisms between lineages. These patterns likely reflect pathogen-mediated balancing selection, for example, rare-allele or heterozygote advantage. Such selection is often reinforced by disassortative mating at MHC. We characterized exon 2 of MHC class II, corresponding to the hypervariable peptide-binding region, in song sparrows (Melospiza melodia). We compared nonsynonymous to synonymous sequence variation in order to identify positively selected sites; assesse

SUBMITTER: Slade JWG 

PROVIDER: S-EPMC6509439 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature