Phylogenetic relationships of pocket gophers (Cratogeomys and Pappogeomys) based on mitochondrial DNA cytochrome b sequences.

Phylogenetic relationships among 7 of the 10 species of pocket gophers in the genera Pappogeomys and Cratogeomys were addressed using nucleotide sequence data from the entire cytochrome b gene of the mitochondrial genome (1140 base pairs). Results of parsimony analysis were concordant with the results of morphological analysis (R. J. Russell, Univ. Kans. Pub. Mus. Nat. Hist. 16: 581-776, 1968), but differed somewhat from the conclusions drawn from an allozymic study of these species (R. L. Honeycutt and S. L. Williams, J. Mammal. 63: 208-217, 1982). Phylogenetic analysis indicated that Cratogeomys is monophyletic, as are the two species groups within this genus. Estimates of levels of nucleotide sequence divergence between species of these genera indicated that the cytochrome b gene of pocket gophers may have evolved at a dramatically higher rate than in organisms examined previously (D. M. Irwin, T. D. Kocher, and A. C. Wilson, J. Mol. Evol. 32: 128-144, 1991).