CAREER: The Influence of Gene Flow on Inbreeding Depression and Local Adaptation: Replicated Experiments in Isolated Wild Populations

University Of Montana, Missoula MT

Investigators

Abstract

Most species are comprised of multiple populations that exchange genes to some extent. Whether this exchange of genetic material has positive or negative effects on population persistence is a longstanding but still unresolved issue in evolutionary biology. This issue has conservation relevance in the context of habitat fragmentation. Habitat fragmentation is a major threat to natural populations of many species because it prevents genetic exchange and isolates populations. Small and isolated populations often suffer from a loss of genetic diversity, increased inbreeding, and a reduced ability to adapt to new environmental conditions. The goal of this project is to experimentally induce genetic exchange in isolated natural trout populations as a window into understanding the effects of gene flow. This work will help resolve longstanding questions in evolutionary biology and will help to inform conservation and management. There is substantial interest in using strategic translocations of animals or plants to help save isolated populations from extinction. However, concerns about the possible negative consequences of genetic exchange have limited the application of this management approach. The educational components of this research will teach management professionals and Montana students, at all educational levels, about the application of genetic principles to conservation. This project will test the costs and benefits of experimental pulses of gene flow into isolated populations of trout in both the eastern and western United States. In the first study system, experimental gene flow from outbred immigrants into inbred recipient populations is predicted to have a positive fitness effect through the alleviation of inbreeding. In the second study system, experimental gene flow from inbred immigrants into inbred recipient populations is predicted to have negligible fitness effects because inbred immigrants will not mask deleterious alleles in inbred recipient populations. The work will examine the possible negative effects of gene flow at organismal and genome levels in both study systems. The project will also use innovative educational approaches to increase knowledge of genetic principles in current wildlife professionals, future professionals currently enrolled as undergraduates in the nation's leading Wildlife Biology program, and rural Montana middle school children.