Evolutionary and ecological genetics of fitness-related variation in wild animals

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Wildlife populations are increasingly challenged by new and strong selective pressures resulting from rapid and intense anthropogenic environmental change, including the spread of infectious diseases, introduction of exotic and invasive species, and global warming. Simultaneously, human activity is rapidly removing or fragmenting habitat, leading to population declines and restricting genetic exchange among populations. Together, these factors can limit the ability of populations to adapt, decrease individual fitness, and ultimately compromise the persistence of populations and species. Understanding the ecological and evolutionary processes modulating variation in fitness and adaptive evolution in natural populations is therefore critical for maintaining biodiversity. Here, I suggest using a long-term, individual-based study of feral horses at Sable Island National Park Reserve, Nova Scotia, as a model to test a variety of emerging hypotheses related to the genetic basis and evolutionary dynamics of fitness-related traits in wild animals. The Sable Island horse project, modelled on other highly successful individual-based studies such as those at Ram Mountain in Alberta (bighorn sheep) and St-Kilda in Scotland (Soay sheep), is remarkable in a number of ways. In particular, the system allows for the study of a large and diverse array of phenotypic traits putatively linked to fitness; the isolated but large population (current population size ~500) provides statistical power needed to rapidly test new ideas; and readily available equine genomic tools makes for an outstanding platform to conduct genomic-based research under natural conditions. With almost 1,150 known individuals measured at a variety of fitness-related traits each summer since 2008, the study is already one of the world's largest of its kind for a large vertebrate. My proposed research is divided into four short-term objectives contributing to my principal career goal of improving our understanding of the ecological and evolutionary processes modulating variation in fitness and adaptive evolution in wildlife populations. Using an integrative, multi-disciplinary approach combining field biology, molecular ecology, parasitology, quantitative genetics, and genomics, I will: I) Conduct a large-scale investigation of the causes and consequences of variation in gut bacterial microbiome structure and function; II) Study the ecology and evolution of complex mixed parasitic infections; III) Characterize the genomic architecture of fitness-related traits and adaptive evolution; and IV) Quantify inbreeding depression and understand the factors modulating its intensity and genetic architecture. The proposed research will contribute to developing an internationally recognized research program in evolutionary and ecological genetics of wild animals, and provide tools and knowledge needed for conserving and managing wildlife and endangered species in Canada and internationally.