Genetic Basis of Mating Preferences in Wild House Mice

Abstract

Synopsis. This paper reviews work conducted over the last several years on the effect of genetic differences within the t-complex of wild house mice on female mating preference. Wild mice are polymorphic for a mutation within the t complex on chromosome 17. About 25% of wild mice are heterozygous (+/t) for a t-haplotype and the remainder are +/+. These t-haplotypes have a number of deleterious effects when homozygous and hence t/t individuals are rarely found in wild populations. We have examined preferences of +/+ and +/t females for males of both genotypes. We have found that +/t, but not +/+ females have strong preferences for +/+ males. These preferences can be modified by a variety of factors including estrous condition ofthe female (the preferences are stronger among estrous than diestrous females) and the dominance status ofthe male (when forced to choose, females give priority to male dominance status over t complex genotype in choosing males). The restiction of preference to +/t females indicates that genes on t haplotypes modulate these preferences. Because t haplotypes include the major histocompatibility complex (MHC) of the mouse we designed a study to ascertain whether the preferences of +/t females were associated with the MHC. Results ofthe study indicate that the preferences are independent ofthe MHC. Further work testing females carrying a partial t-haplotype (twl8) indicates that the genes for mating preference are localized in the region of the t complex distal to the MHC. A large number of t haplotypes are found in wild mouse populations. Females that are themselves +/t when forced to choose between 2 +/t males (one carrying a haplotype that is the same as their own and one carrying a haplotype that is different) prefer males carrying t-haplotypes that differ from their own. Finally, we conclude that mating preference may only be a weak force regulating the frequency of t-mutations in wild mouse populations. The impact of mating preference on population genetics of genes within this region is muted because of the great importance of male dominance rank in determining mating patterns within interacting social groups.