Phylogeography and post-glacial dispersal of Brook trout (Salvelinus fontinalis) in Labrador, Canada, inferred from microsatellite and mitochondrial DNA variation

Abstract

Understanding how contemporary and historical factors have shaped genetic structure of populations is important for making management decisions, in order to characterise and preserve diversity. Genetic structure of brook trout (Salvelinus fontinalis) in Labrador and eastern Canada was investigated utilizing microsatellite and mitochondrial DNA (mtDNA) variation to collect baseline data so future impacts of the Trans-Labrador Highway may be monitored, and to investigate post-glacial recolonization. Genetic variation was moderate (Hₑ=0.622) to low (overall pairwise sequence diversity = 0.00094) based on microsatellite and mtDNA variation, respectively. Investigation of mtDNA diversity provided evidence that the mitochondrial genome of brook trout (GenBank AF15480) may have recombined with Artic charr mtDNA. Microsatellite variation was able to detect structure, which revealed limited ongoing gene flow at the level of the watershed. Finally, both microsatellite and mtDNA variation revealed dual routes of colonization in Labrador. Overall, my results emphasize the strong influence of both contemporary and historical events on shaping population genetic structure of brook trout in Labrador.