Mitochondrial DNA Variation in Great Lakes Walleye (Stizostedion vitreum) Populations

Abstract

Mitochondrial DNA variation was examined in 141 walleye (Stizostedion vitreum) from 10 populations in the Great Lakes basin. Twenty-two hexanucleotide sequence recognition endonucleases were used, of which six (Ava I, Bst EII, Cla I, Dra I, Nco I, and Sca I) revealed polymorphisms between fish. Nine mitochondrial clones were resolved which fell into two major groups that differed in their Nco I and Sca I fragment patterns. The "A" group predominates in the eastern Great Lakes, while the "B" group predominates in the west. The geographical distribution of these two groups suggests that Great Lakes walleye persisted in at least two refugia during the last glaciation. The study revealed several rare mitochondrial genotypes which may prove useful in creating genetically marked brood stocks. Since mtDNA is maternally inherited, such markers would provide information on both the survival and long-term reproductive success of stocked fish.