Testing for post-copulatory selection for major histocompatibility complex genotype in a semi-free-ranging primate population

Authors

  • Joanna M. Setchell,

    Corresponding author
    • Evolutionary Anthropology Research Group, Department of Anthropology, Durham University, Durham, United Kingdom
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  • Kristin M. Abbott,

    1. Division of Biological Anthropology, University of Cambridge, Cambridge, United Kingdom
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  • Jean-Paul Gonzalez,

    1. Health Ecology Unit, Centre International de Recherches Médicales de Franceville, Franceville, Gabon
    2. Institut de Recherche Pour le Développement, Chargé des Relations Bilatérales Santé et Biosécurité, France
    3. METABIOTA Senior Advisor for Emerging Diseases and Biosecurity
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  • Leslie A. Knapp

    1. Division of Biological Anthropology, University of Cambridge, Cambridge, United Kingdom
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Correspondence to: Joanna M. Setchell, Department of Anthropology, Durham University, South Road, Durham DH1 3LE, UK. E-mail: joanna.setchell@durham.ac.uk

Abstract

A large body of evidence suggests that major histocompatibility complex (MHC) genotype influences mate choice. However, few studies have investigated MHC-mediated post-copulatory mate choice under natural, or even semi-natural, conditions. We set out to explore this question in a large semi-free-ranging population of mandrills (Mandrillus sphinx) using MHC-DRB genotypes for 127 parent–offspring triads. First, we showed that offspring MHC heterozygosity correlates positively with parental MHC dissimilarity suggesting that mating among MHC dissimilar mates is efficient in increasing offspring MHC diversity. Second, we compared the haplotypes of the parental dyad with those of the offspring to test whether post-copulatory sexual selection favored offspring with two different MHC haplotypes, more diverse gamete combinations, or greater within-haplotype diversity. Limited statistical power meant that we could only detect medium or large effect sizes. Nevertheless, we found no evidence for selection for heterozygous offspring when parents share a haplotype (large effect size), genetic dissimilarity between parental haplotypes (we could detect an odds ratio of ≥1.86), or within-haplotype diversity (medium-large effect). These findings suggest that comparing parental and offspring haplotypes may be a useful approach to test for post-copulatory selection when matings cannot be observed, as is the case in many study systems. However, it will be extremely difficult to determine conclusively whether post-copulatory selection mechanisms for MHC genotype exist, particularly if the effect sizes are small, due to the difficulty in obtaining a sufficiently large sample. Am. J. Primatol. 75:1021–1031, 2013. © 2013 Wiley Periodicals, Inc.

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