Major histocompatibility complex influences reproductive efficiency: evolutionary implications.

Measurements of six reproductive characteristics revealed differences in seven congenic mouse strains with genetic differences in H-2, the major histocompatibility complex (MHC). Associations between reproductive efficiency and MHC has evolutionary implications. One association explains the uneven distribution and heterozygosity of MHC alleles in wild mouse and human populations. The second is based on links between MHC and hormonal sensitivities that regulate an individual's responses to the environment. MHC may be a seat of genotypic-environmental interactions that guide natural selection.