Selection and recombination drive the evolution of MHC class II DRB diversity in ungulates

Schaschl, H; Wandeler, P; Suchentrunk, F; Obexer-Ruff, Gaby; Goodman, S J (2006). Selection and recombination drive the evolution of MHC class II DRB diversity in ungulates. Heredity, 97(6), pp. 427-37. London: Oliver and Boyd 10.1038/sj.hdy.6800892

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Major histocompatibility complex (MHC) antigen-presenting genes are the most variable loci in vertebrate genomes. Host-parasite co-evolution is assumed to maintain the excessive polymorphism in the MHC loci. However, the molecular mechanisms underlying the striking diversity in the MHC remain contentious. The extent to which recombination contributes to the diversity at MHC loci in natural populations is still controversial, and there have been only few comparative studies that make quantitative estimates of recombination rates. In this study, we performed a comparative analysis for 15 different ungulates species to estimate the population recombination rate, and to quantify levels of selection. As expected for all species, we observed signatures of strong positive selection, and identified individual residues experiencing selection that were congruent with those constituting the peptide-binding region of the human DRB gene. However, in addition for each species, we also observed recombination rates that were significantly different from zero on the basis of likelihood-permutation tests, and in other non-quantitative analyses. Patterns of synonymous and non-synonymous sequence diversity were consistent with differing demographic histories between species, but recent simulation studies by other authors suggest inference of selection and recombination is likely to be robust to such deviations from standard models. If high rates of recombination are common in MHC genes of other taxa, re-evaluation of many inference-based phylogenetic analyses of MHC loci, such as estimates of the divergence time of alleles and trans-specific polymorphism, may be required.

Item Type:

Journal Article (Original Article)

Division/Institute:

05 Veterinary Medicine > Department of Clinical Research and Veterinary Public Health (DCR-VPH) > Institute of Genetics

UniBE Contributor:

Obexer, Gaby

ISSN:

0018-067X

Publisher:

Oliver and Boyd

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:45

Last Modified:

04 May 2014 23:13

Publisher DOI:

10.1038/sj.hdy.6800892

PubMed ID:

16941019

Web of Science ID:

000242244900008

URI:

https://boris.unibe.ch/id/eprint/18479 (FactScience: 623)

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