Mitochondrial DNA Variation and Distribution in Cutthroat Trout of the Snake River and Bear River Basins: Implications for Management, Conservation, and Subspecies Classification

In this talk, I present results from studies we have completed on the diversity, biogeography and phylogeny of mitochondrial DNA in Yellowstone cutthroat trout and Bonneville cutthroat trout of the Snake River and Bear River basins. These data indicate significant geographic structuring of the genetic variation between drainages and varying levels of reproductive isolation among populations within drainages. Much of this genetic structuring is clearly the product of long-term historical processes (basaltic volcanism and glaciations) that have isolated populations for substantial periods and then, in many cases, allowed secondary contact and subsequent admixture of divergent populations. Comparisons of cutthroat trout between the two basins were consistent with the results of previous allozyme and mtDNA investigations indicating that cutthroat trout in the Bear River basin in Utah have a more recent common ancestor with Yellowstone cutthroat trout than with the populations of Bonneville cutthroat trout in the central and southern portions of their range in Utah.