Divergent allele advantage at MHC-DRB through direct and maternal genotypic effects and its consequences for allele pool composition and mating
2013 (English)In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 280, no 1762, 20130714- p.Article in journal (Refereed) Published
It is still debated whether main individual fitness differences in natural populations can be attributed to genome-wide effects or to particular loci of outstanding functional importance such as the major histocompatibility complex (MHC). In a long-term monitoring project on Galapagos sea lions (Zalophus wollebaeki), we collected comprehensive fitness and mating data for a total of 506 individuals. Controlling for genome-wide inbreeding, we find strong associations between the MHC locus and nearly all fitness traits. The effect was mainly attributable to MHC sequence divergence and could be decomposed into contributions of own and maternal genotypes. In consequence, the population seems to have evolved a pool of highly divergent alleles conveying near-optimal MHC divergence even by random mating. Our results demonstrate that a single locus can significantly contribute to fitness in the wild and provide conclusive evidence for the 'divergent allele advantage' hypothesis, a special form of balancing selection with interesting evolutionary implications.
Place, publisher, year, edition, pages
2013. Vol. 280, no 1762, 20130714- p.
Galapagos sea lion, major histocompatibility complex, survival, reproductive success, overdominance, sequence divergence
IdentifiersURN: urn:nbn:se:uu:diva-202888DOI: 10.1098/rspb.2013.0714ISI: 000319385100015OAI: oai:DiVA.org:uu-202888DiVA: diva2:634683