In house mice (Mus domesticus), immunity-related protein domains comprise 75% of the most rapidly evolving protein domain classes in the genome, a pattern that has been documented in diverse animals and plants. Such rapid evolution is consistent with natural selection, but does not tell us how selection acted within populations to produce this between-species pattern. This project will explore both (i) the mode of selection which best explains rapid immunity gene evolution and (ii) how specific pathogens affect these genes. Specifically, DNA sequences will be determined for ten innate immunity genes and ten non-immunity control genes in a population of wild house mice. Prevalence of selected pathogens will be quantified, and these infection phenotypes will be compared with resistance alleles to test for a statistical association.
Few studies have focused on the evolution of innate immunity, the first and fastest response to infections, in mammals. In particular, it remains unclear whether rapid evolution of immunity genes is due to recurrent selection for novel variants or selection to maintain multiple variants. This work will improve our understanding of immune system evolution in an important model of human health, and provide a useful contrast to studies of immunity in invertebrates and plants. This work will also help train a female Native American Ph.D. student.
