Mitochondrial and microsatellite DNA diversity throughout the range of a cold adapted freshwater salmonid : phylogeography, local population structure and conservation genetics of Arctic grayling (Thymallus arcticus) in North America ...

• Main Author: Stamford, Michael D.
• Format: Text
• Language: English
• Published: University of British Columbia 2009
• Subjects: Arctic grayling; Arctic; Thymallus arcticus; Alaska; Beringia
• Online Access: https://dx.doi.org/10.14288/1.0090290; https://doi.library.ubc.ca/10.14288/1.0090290

The distributions of most Holarctic freshwater fish species were severely altered and restricted during the many glaciation events that have occurred throughout the Pleistocene. Isolation of groups of fish into distinct glacial refugia provided the opportunity for genetic divergence during these periods of allopatry through genetic drift and novel selection pressures. In this thesis, I examined the signature of such isolation and postglacial range expansion in the Arctic grayling (Thymallus arcticus) by assaying mitochondrial and microsatellite (nuclear) DNA variation throughout the species' range in North America. I also examined local population structure in the Peace River, British Columbia, because local demographics are integral to a species' phylogeographic structure. I found a dramatic decline in genetic diversity from Alaska to the southeast, which suggests Arctic grayling survived the last ice age in Beringia then bottlenecks and founder events reduced diversity during southward postglacial range ...