MHC, mate choice and heterozygote advantage in a wild social primate

Authors

  • ELISE HUCHARD,

    1. CNRS—UMR5554, Place Eugène Bataillon, CC 065, 34 095 Montpellier Cedex 5, France
    2. Institut des Sciences de l’Evolution, Université Montpellier II, Place Eugène Bataillon, CC 065, 34 095 Montpellier cedex 5, France
    3. Department of Behavioral Ecology and Sociobiology, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
    4. Institute of Zoology, Zoological Society of London, Regent’s Park, London NW1 4RY, UK
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  • LESLIE A. KNAPP,

    1. Department of Biological Anthropology, University of Cambridge, Downing Street, Cambridge CB2 3DZ, UK
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  • JINLIANG WANG,

    1. Institute of Zoology, Zoological Society of London, Regent’s Park, London NW1 4RY, UK
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  • MICHEL RAYMOND,

    1. CNRS—UMR5554, Place Eugène Bataillon, CC 065, 34 095 Montpellier Cedex 5, France
    2. Institut des Sciences de l’Evolution, Université Montpellier II, Place Eugène Bataillon, CC 065, 34 095 Montpellier cedex 5, France
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  • GUY COWLISHAW

    1. Institute of Zoology, Zoological Society of London, Regent’s Park, London NW1 4RY, UK
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Elise Huchard, Fax: +49 551 38 51 291; E-mail: ehuchard@gmail.com

Abstract

Preferences for mates carrying dissimilar genes at the major histocompatibility complex (MHC) may help animals increase offspring pathogen resistance or avoid inbreeding. Such preferences have been reported across a range of vertebrates, but have rarely been investigated in social species other than humans. We investigated mate choice and MHC dynamics in wild baboons (Papio ursinus). MHC Class II DRB genes and 16 microsatellite loci were genotyped across six groups (199 individuals). Based on the survey of a key segment of the gene-rich MHC, we found no evidence of mate choice for MHC dissimilarity, diversity or rare MHC genotypes. First, MHC dissimilarity did not differ from random expectation either between parents of the same offspring or between immigrant males and females from the same troop. Second, female reproductive success was not influenced by MHC diversity or genotype frequency. Third, population genetic structure analysis revealed equally high genotypic differentiation among troops, and comparable excess heterozygosity within troops for juveniles, at both Mhc-DRB and neutral loci. Nevertheless, the age structure of Mhc-DRB heterozygosity suggested higher longevity for heterozygotes, which should favour preferences for MHC dissimilarity. We propose that high levels of within-group outbreeding, resulting from group-living and sex-biased dispersal, might weaken selection for MHC-disassortative mate choice.

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