Adaptive Divergence Versus Gene Flow in the Wild: Evaluation in Trinidadian Guppy Populations

This research investigates the impact of gene flow (genetic exchange among populations) on the evolution of biological diversity. The investigators will first document background patterns of diversity in adaptive traits (e.g., morphology, color pattern, life history) and gene flow for wild populations of Trinidadian guppies that face different environmental conditions (high vs. low predation). The investigators will then perform an experimental manipulation of the rate of gene flow between selected populations in order to evaluate theoretical predictions about the impact of gene flow on variation in adaptive traits. Gene flow is pervasive in the wild, but the activities of humans have extensively altered natural patterns of gene flow and adaptation. A growing body of theory suggests that gene flow may have substantial implications for the persistence of adaptation and hence for the evolution and preservation of biological diversity. Unfortunately, most current theory relating gene flow to adaptive trait variation remains largely untested in natural populations (particularly for the traits most closely related to fitness). The proposed research will test this theory and thus help develop robust strategies for managing gene flow in disturbed systems. It will also build on an increasingly popular case study for teaching evolution in classrooms