Gwylim Blackburn, Postdoctoral Fellow

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My research in the Sperling lab explores the ‘landscape genetics’ (i.e., the connection between environmental and genetic variation) of several North American members of the budworm moth genus Choristoneura (Lepidoptera: Tortricidae). The larval stages of each species feed on one or more conifer tree hosts, causing substantial defoliation during periodic population outbreaks. Consequently, identifying factors that shape Choristoneura evolution is of interest from both ecological and economic perspectives.

I study several closely related forms that have abutting or overlapping ranges in western Canada. In general, when speciation between taxa is incomplete, population contact often results in hybridization and an exchange of genetic material. The widespread occurrence of this process in nature has raised several questions about the effect of gene flow on evolutionary divergence, including: Does it promote or inhibit population differentiation? How does it influence adaptation? What roles do natural selection and genetic drift play in these processes?

To address these questions, I am examining landscape-scale environmental data (GIS data layers) and genome-wide genetic variation for budworm samples collected from across Alberta and southern British Columbia. Specifically, I aim to describe the relationship between ecological variation and alleles showing different degrees of putative selection, and to assess how these alleles move across the landscape when divergent genetic lineages come into contact. This approach offers a high-resolution, landscape-scale view to divergence in the presence of gene flow in a natural setting. It will also inform management practices by exposing key environmental factors associated with genetic markers.

In related work I have explored the role of selection in promoting divergence of male mating traits in the face of gene flow among populations of jumping spiders (PhD: Maddison lab, University of British Columbia). Earlier projects have included the evolution of sex allocation in the presence sexual conflict, the influence of kleptoparasitism risk by gulls on parental behavior of tufted puffins (MSc, Ydenberg lab, Simon Fraser University), and ecological factors influencing dispersal in collared lemmings (BSc, Krebs lab, University of British Columbia).

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