Homozygosity at a class II MHC locus depresses female reproductive ability in European brown hares

Authors

  • STEVE SMITH,

    1. Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Savoyenstr. 1, 1160 Vienna, Austria
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  • THOMAS MANG,

    1. Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Savoyenstr. 1, 1160 Vienna, Austria
    2. Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
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  • JOELLE GOÜY DE BELLOCQ,

    1. Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Savoyenstr. 1, 1160 Vienna, Austria
    2. Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
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  • HELMUT SCHASCHL,

    1. Konrad Lorenz Institute for Ethology, Savoyenstr. 1A, 1160 Vienna, Austria
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  • CLAUDIA ZEITLHOFER,

    1. Institute of Wildlife Biology and Game Management, University of Natural Resources and Applied Life Sciences, Gregor-Mendel-Str. 33, 1180 Vienna, Austria
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  • KLAUS HACKLÄNDER,

    1. Institute of Wildlife Biology and Game Management, University of Natural Resources and Applied Life Sciences, Gregor-Mendel-Str. 33, 1180 Vienna, Austria
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  • FRANZ SUCHENTRUNK

    1. Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Savoyenstr. 1, 1160 Vienna, Austria
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Steve Smith, Fax: +431 448 909 1537; E-mail: steve.smith@fiwi.at

Abstract

The link between adaptive genetic variation, individual fitness and wildlife population dynamics is fundamental to the study of ecology and evolutionary biology. In this study, a Bayesian modelling approach was employed to examine whether individual variability at two major histocompatibility complex (MHC) class II loci (DQA and DRB) and eight neutral microsatellite loci explained variation in female reproductive success for wild populations of European brown hare (Lepus europaeus). We examined two aspects of reproduction: the ability to reproduce (sterility) and the number of offspring produced (fecundity). Samples were collected from eastern Austria, experiencing a sub-continental climatic regime, and from Belgium with a more Atlantic-influenced climate. As expected, reproductive success (both sterility and fecundity) was significantly influenced by age regardless of sampling locality. For Belgium, there was also a significant effect of DQA heterozygosity in determining whether females were able to reproduce (95% highest posterior density interval of the regression parameter [−3.64, −0.52]), but no corresponding effect was found for Austria. In neither region was reproduction significantly associated with heterozygosity at the DRB locus. DQA heterozygotes from both regions also showed a clear tendency, but not significantly so, to produce a larger number of offspring. Predictive simulations showed that, in Belgium, sub-populations of homozygotes will have higher rates of sterile individuals and lower average offspring numbers than heterozygotes. No similar effect is predicted for Austria. The mechanism for the spatial MHC effect is likely to be connected to mate choice for increased heterozygosity or to the linkage of certain MHC alleles with lethal recessives at other loci.

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