A sequence-based approach demonstrates that balancing selection in classical human leukocyte antigen (HLA) loci is asymmetric.

ABSTRACT: Balancing selection has maintained human leukocyte antigen (HLA) allele diversity, but it is unclear whether this selection is symmetric (all heterozygotes are comparable and all homozygotes are comparable in terms of fitness) or asymmetric (distinct heterozygote genotypes display greater fitness than others). We tested the hypothesis that HLA is under asymmetric balancing selection in populations by estimating allelic branch lengths from genetic sequence data encoding peptide-binding domains. Significant deviations indicated changes in the ratio of terminal to internal branch lengths. Such deviations could arise even if no individual alleles present a strikingly altered branch length (e.g. if there is an overall distortion, with all or many terminal branches being longer than expected). D

SUBMITTER: Bronson PG 

PROVIDER: S-EPMC3526157 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature