Tandemly repeated sequences in the mitochondrial DNA control region and phylogeography of the pike-perches Stizostedion

DNA sequences from the mitochondrial DNA control region are used to test th e phylogeographic relationships among the pike-perches, Stizostedion (Teleo stei: Percidae) and to examine patterns of variation. Sequences reveal two types of variability: single nucleotide polymorphisms and 6 to 14 copies of 10- to Il-basepair tandemly repeated sequences. Numbers of copies of the t andem repeats are found to evolve too rapidly to detect phylogenetic signal at any taxonomic level, even among populations. Sequence similarities of t he tandem repeats among Stizostedion and other percids suggest concerted ev olutionary processes. Predicted folding of the tandem repeats and their pro ximity to termination-associated sequences indicate that secondary structur e mediates slipped-strand mispairing among the d-loop, heavy, and light str ands. Neighbor-joining and maximum parsimony analyses of sequences indicate that the genus is divided into clades on the continents of North America a nd Eurasia. Calibrating genetic distances with divergence times supports th e hypothesis that Stizostedion dispersed from Eurasia to North America acro ss a North Pacific Beringial land bridge approximately 4 million years befo re present, near the beginning of the Pliocene Epoch. The North American S, vitreum and S. canadense appear separated by about 2.75 million years, and the Eurasian S. lucioperca and S. volgensis are diverged by about 1.8 mill ion years, suggesting that speciation occurred during the late Pliocene Epo ch. (C) Press Academic Press.