Immunogenetic variation and tumor incidence of juvenile English sole (Parophrys vetulus) across an estuarine gradient of contaminants

Chemical contaminants in estuaries may interfere with an organism’s ability to ward against parasites and disease which can shape patterns of genetic diversity in populations, including at the Major Histocompatibility Complex (MHC) which helps recognize foreign pathogens. Here, we examine genetic variation in the MHC, in microsatellite repeats, and in mitochondrial control region (D-Loop) sequences to assess relationships between a tumor-causing pathogen known as X-cell disease, juvenile English sole (Parophrys vetulus), and contaminants in the San Francisco Estuary (SFE), CA. Functional molecular analysis was used to compare fish regionally and by infection status. Supertypes analysis showed no difference in supertype distributions regionally or by infection status, nor was there evidence of differentiation at microsatellite loci and Dloop. These results suggest contaminant distributions may be more fine-grained than patterns of English sole movement in SF Bay, possibly explaining the incidence of tumorous individuals throughout the bay.