Phylogenetic Relationships among Members of the Coregoninae Inferred from Direct Sequencing of PCR-Amplified Mitochondrial DNA

Abstract

We determined the DNA sequence of a portion of the mitochondrial cytochrome b gene for eight members of the Coregoninae (Salmonidae) from North America in an effort to elucidate phylogenetic relationships in the subfamily. DNA was prepared for sequencing by the polymerase chain reaction (PCR). Direct estimates of mitochondrial DNA (mtDNA) sequence divergence among taxa ranged from 0.0% between Arctic cisco (Coregonus autumnalis) from the Mackenzie River, Canada, and cisco (C. artedi) from the Laurentian Great Lakes to 5.8% between the inconnu (Stenodus leucichthys) and the round whitefish (Prosopium cylindraceum). As has been noted in other fish species and vertebrates in general, third position silent substitutions predominated over any other type of nucleotide change. No amino acid replacement substitutions were found among any of the eight taxa examined. Comparison of mtDNA sequence divergence estimates from this and other studies suggests that the radiation of the genera within the Coregoninae occurred relatively recently (2–6 million yr B.P.). Cladistic analysis of the mtDNA sequence data yields a hypothesis of relationships that supports previous genetic and morphological classifications of coregonines.