Molecular phylogeny and speciation in a regional fauna

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The central goal of my research program is to understand the origins and persistence of biodiversity at multiple spatial and temporal scales - from allelic variation at specific genetic loci to the assemblage of species at a biogeographic scale, and divergences spanning a few generations to millions of years. The long-term themes of my research program are to: (i) document the patterns of evolutionary divergence within and among species, (ii) test hypotheses concerning the origins and persistence of this variation and the relevance of processes such natural selection, hybridization, and vicariance, and (iii) to apply this knowledge to the conservation of biodiversity. I study freshwater and marine fishes in northwestern North America and the Arctic and integrate methods in ecology and genetics to address these central inquiries in organismal and evolutionary biology that also have important conservation applications. My research poses questions such as: what are the interrelationships amongst species within a clade and what biogeographic processes (e.g., tectonics, sea level changes, climate change) have shaped extant diversity? When species come into contact, do they hybridize and if so, what can the frequency and fate of hybrids tell us about the geographic, ecological and genetic processes driving speciation? What habitat features influence the extent and patterns of adaptive and neutral variation among conspecific populations? The key theme of this proposal examines species that come into contact to test hypotheses concerning the genome-wide extent of hybridization and the genetic basis of reproductive isolation. I exploit the occurrence of multiple areas of contact between two species of Salvelinus, S. alpinus (Arctic char) and S. malma (Dolly Varden) in western Alaska. I will build on our detailed nuclear DNA microsatellite analyses demonstrating contact and hybridization between these species by using genomic sequencing approaches to better pinpoint the extent and specific regions of the genome that distinguish these species in the face of gene flow. This work will also explore the hypothesis of life history character displacement by exploiting the occurrence of multiple allopatric and sympatric populations of both species which express the full range of freshwater resident and anadromous (searun) life histories. The significance and novelty of my research includes:(1) understanding a fundamental unknown in evolution (the origins and persistence of biodiversity),(ii) providing much needed training in biodiversity research in Canada, (iii) illustrating the intimate connection between habitat and biodiversity persistence critical for conservation assessment and action, and (iv) providing some emphasis for (i)-(iii) in northern areas which are relatively understudied and at increasing risk in Canada from environmental change.