DISSERTATION RESEARCH: Immunogene Mediated Mate Choice in Populations of Peromyscus spp. Rodents with Different Mating Systems

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

The fundamental question of how animals choose mates has fascinated and intrigued biologists for centuries. Today, technological and scientific developments make it possible to push the limits of our knowledge in the field of mate choice. Recent research has generated support for a particular group of genes, the Major Histocompatibility Complex, or MHC genes, as key players during mate selection. MHC genes are ubiquitous in vertebrates and play a major role in the adaptive immune system. In mammals, MHC-genotypes, or "profiles," are communicated via urine. This allows conspecifics to identify and choose individuals based on their immunogenetic makeup. Theory predicts that if individuals are selecting mates based on MHC, they should prefer those who complement their own MHC profile. In this way, their offspring will have higher MHC diversity and/or improved immunocompetence. This project explores how differences in two factors thought to affect exposure to pathogens -- mating behavior (e.g., monogamy versus promiscuity) and population density -- influence how animals use MHC during mate choice. Studies on MHC and mate choice have important applications to conservation and captive breeding programs, where they may help determine the best strategies for maintaining diversity and improving survival. Improved understanding of the function and evolution of MHC variation also has important implications for human health, since these are the genes that underlie our adaptive response to pathogens. Traditionally, MHC-based mate choice studies have used inbred lab animals, and while a few have examined wild populations, they have been limited to the study of only a few MHC-loci. These constraints are in large part due to MHC complexity and previously available molecular techniques. As a consequence, studies on different loci and/or species have yielded contradictory results. This project aims to generate a comprehensive understanding of the relationships between immunogenetic variation and patterns of reproductive behavior by using Next Generation Sequencing techniques to study all transcribed MHC and non-MHC immunogenes in free-living peromyscine rodents with different mating systems. Special emphasis is directed towards understanding how immunogenetic variation and selection on immunogenes differ with mating system. Further, this project will explore how changes in ecology, particularly density, influence mate choice decisions based on immunogenes. Understanding how individual-level decisions interact with population level dynamics should facilitate understanding of the selective pressures acting on the immune system in natural settings. The molecular methods proposed are novel and can be applied to a wide range of studies interested in minimizing invasive sampling. Field notes, behavioral observations, trapping data, photographic and GPS data, and biological samples will be contributed to the MVZ collections, thus accessible in an online database and available to interested researchers. All DNA sequence data resulting from this project will be made publicly available after publication through GenBank.