Molecular evidence of current and historical introgressive hybridization between bull trout (Salvelinus confluentus) and Dolly Varden (S. malma) ...

• Main Author: Redenbach, Zoë
• Format: Text
• Language: English
• Published: University of British Columbia 2009
• Subjects: Ice Sheet
• Online Access: https://dx.doi.org/10.14288/1.0089603; https://doi.library.ubc.ca/10.14288/1.0089603

Natural hybridization, once thought to be relatively rare, has been widely observed in both plants and animals. Studies of species that hybridize at low rates across wide ranges, however, are still relatively rare. Dolly Varden (Salvelinus malma) and bull trout (S. confluentus) have widely overlapping ranges and have been shown to hybridize at two localities. This thesis is a molecular analysis of Dolly Varden/bull trout hybridization over a range of spatial scales. Large-scale mtDNA phylogeography revealed that Dolly Varden survived the last glaciation in a previously unsuspected refuge south of the ice sheet, which resulted in continuous sympatry of a Dolly Varden refugial population with bull trout over the last 100,000 years. Discordant mitochondrial and nuclear phylogenies revealed historical introgression of bull trout mitochondrial DNA into Dolly Varden. Population samples revealed widespread local sympatry and current hybridization throughout the overlapping range, with hybrids consisting of 0 to 25% ...