Meeting Abstract
Pathogens are thought to be important evolutionary forces driving the diversification of immune genes. Genes of the Major Histocompatibility Complex (MHC) are involved in activating the adaptive immune response to pathogens and it is the most polymorphic coding region in the vertebrate genome. MHC diversity has been associated with resistance to a wide variety of pathogens in studies across taxa, including many species of birds. Migratory birds are exposed to a greater diversity of diseases, including blood parasites, than resident birds because migrants visit a variety of different habitats and geographic locations during their annual cycle. As a result, migrant species harbor a greater diversity of parasites compared to non-migrant species. Thus, we might also expect migrants to have greater MHC diversity than residents. Few studies have tested this hypothesis within one species. In this study we examined blood parasite infection and MHC diversity in migratory and resident populations of common yellowthroats (Geothylpis trichas). We found that individuals in the migratory populations had higher prevalence, intensity and diversity of blood parasites and greater allelic diversity at MHC class I than individuals in the resident population. Allelic diversity at MHC class II was similar in all three populations. However, few alleles were shared among populations and as a result there was strong population differentiation at the MHC.
