Evidence For Selection Acting On Immune-Related Iron Transport Genes In Wild Rodents

Every organism requires certain resources that they cannot endogenously produce; one such dietary component, iron, is essential for many basic cellular functions and the host-immune response. By studying patterns of genetic diversity within the genes involved in immune-related iron transport we can achieve a greater understanding of the evolutionary mechanisms which drive these processes, including those underlying host-pathogen interactions. This thesis describes further evidence of patterns indicative of positive selection within apical regions of the transferrin receptor complex (Tfr1), sites known to be involved in an evolutionary arms race with pathogens, within two rodent species endemic to Europe and Asia, the bank vole, Myodes glareolus, and the field vole, Microtus agrestis. Other immune-related iron transport genes, including lipocalin-2 (Lcn2), haptoglobin, (Hp), solute carrier family 11 member 1 (Slc11a1), lactotransferrin (Ltf), lipocalin-12 (Lcn12), and mitochondrial ferritin (Ftmt) were sequenced and analyzed in the hopes of identifying regions under positive selection. This is the first study to date describing the genetic variation and site-specific non-neutral selection pressures for several immune-related iron transport proteins in natural populations of bank vole and field vole. We identified 7 SNPs in Lcn2 across both species and identified two sites displaying patterns indicative of positive selection within the functional loci of the lipocalin-2 siderophore binding calyx. This work contributes to the growing body of literature describing the diversity and the non-neutral selection pressures acting on immune-related iron transport proteins in natural populations