In mammals, males typically have shorter lives than females. This difference is thought to be due to behavioural traits which enhance competitive abilities, and hence male reproductive success, but impair survival. Furthermore, in many species males usually show higher parasite burden than females. Consequently, the intensity of selection for genetic factors which reduce susceptibility to pathogens may differ between sexes. High variability at the major histocompatibility complex (MHC) genes is believed to be advantageous for detecting and combating the range of infectious agents present in the environment. Increased heterozygosity at these immune genes is expected to be important for individual longevity. However, whether males in natural populations benefit more from MHC heterozygosity than females has rarely been investigated. We investigated this question in a long-term study of free-living Alpine chamois (Rupicapra rupicapra), a polygynous mountain ungulate.
Animals Female Gene Frequency Genes, MHC Class II* Genetic Variation Genetics, Population Genotyping Techniques HLA-DR beta-Chains/genetics* Heterozygote Italy Longevity Major Histocompatibility Complex/genetics* Male Microsatellite Repeats Reproduction Rupicapra/genetics* Selection, Genetic* Sequence Analysis, DNA Sex Factors