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Inter- and intraspecific mitochondrial DNA variation in North American bears (Ursus)

January 1, 1991

We assessed mitochondrial DNA variation in North American black bears (Ursus americanus), brown bears (Ursus arctos), and polar bears (Ursus maritimus). Divergent mitochondrial DNA haplotypes (0.05 base substitutions per nucleotide) were identified in populations of black bears from Montana and Oregon. In contrast, very similar haplotypes occur in black bears across North America. This discordance of haplotype phylogeny and geographic distribution indicates that there has been maintenance of polymorphism and considerable gene flow throughout the history of the species. Intraspecific mitochondrial DNA sequence divergence in brown bears and polar bears is lower than in black bears. The two morphological forms of U. arctos, grizzly and coastal brown bears, are not in distinct mtDNA lineages. Interspecific comparisons indicate that brown bears and polar bears share similar mitochondrial DNA (0.023 base substitutions per nucleotide) which is quite divergent (0.078 base substitutions per nucleotide) from that of black bears. High mitochondrial DNA divergence within black bears and paraphyletic relationships of brown and polar bear mitochondrial DNA indicate that intraspecific variation across species' ranges should be considered in phylogenetic analyses of mitochondrial DNA.

Citation Information

Publication Year 1991
Title Inter- and intraspecific mitochondrial DNA variation in North American bears (Ursus)
DOI 10.1139/z91-421
Authors Matthew A. Cronin, Steven C. Amstrup, Gerald W. Garner, Ernest R. Vyse
Publication Type Article
Publication Subtype Journal Article
Series Title Canadian Journal of Zoology
Series Number
Index ID 1013318
Record Source USGS Publications Warehouse
USGS Organization Alaska Biological Science Center