Patterns and Processes of Genetic Diversification in Solitary and Social Subterranean Rodents

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Lacey 0128857 The PI will examine relationships among social behavior, demography, and genetic variation in two species of tuco-tucos (Rodentia: Ctenomyidae) from southwestern Argentina. The presence of both the group-living colonial tuco-tuco (Ctenomys sociabilis) and the solitary Patagonian tuco-tuco (C. haigi) in Argentina's Limay Valley provides an unusual opportunity to explore the effects of sociality on genetic variation in closely related species that occur in similar habitats. Using DNA extracted from tissue samples collected from 10 populations per species, variation at both microsatellite and Major Histocompatibility Complex (MHC) loci will be quantified. These data will be used to determine how genetic variation is apportioned within and among populations of each species. Specifically, the PI will test the hypothesis that group living is associated with enhanced selection for diversity at MHC genes, which are the genes associated with the vertebrate immune response. To determine if selection on MHC genes is influenced by presumably greater pathogen exposure among members of group-living species, the prevalence of fleas and flea-borne bacteria of the genus Bartonella will be assessed for all populations of C. sociabilis and C. haigi sampled by the PI. The proposed research is important in that it is one of the first studies of natural populations of non-human vertebrates to (1) link behavioral and demographic variables to patterns of MHC variation and (2) explore the role of behaviorally-mediated differences in pathogen exposure in generating selection on MHC genes. Both aspects of the project will significantly improve our understanding of the processes underlying observed patterns of genetic variation in vertebrates. The project will also contribute significantly to our understanding of the biology of the endangered colonial tuco-tuco, which is endemic to the western Limay Valley and surrounding hills. Specifically, by engaging Argentine university students to assist with the project, the PI will facilitate involvement of local biologists in the study and management of this little-known species.