Extensive Genetic Variation in Mitochondrial DNA'S Among Geographic Populations of the Deer Mouse, Peromyscus maniculatus

Abstract

An extensive analysis of mitochondrial DNA (mtDNA) nucleotide sequence variation within the rodent P. maniculatus is presented. Using techniques which allow assay of mtDNA from individual animals, variable and conserved cleavage sites were mapped for 8 restriction endonucleases in mtDNA prepared from 135 animals collected throughout North America. The data provide information on 2 different but interrelated aspects of mtDNA evolution: the nature of evolutionary change in the molecule itself, and the implications of these molecular changes for estimating matriarchal relationships within P. maniculatus. Mammalian mtDNA probably evolves primarily by the accumulation of single base substitutions which occur in most of the coding regions of the genome. Sequence divergence between P. maniculatus mtDNA samples can be as high as 7%. The distributions of cleavage sites and the magnitudes of sequence divergence among samples, are strongly related to the geographic sources of collections. The data clearly distinguish 5 major genetic assemblages within P. maniculatus and as extensive clonal diversity within each of those assemblages. Convergent or parallel sequence alterations are not uncommon. Phylogenies derived from mtDNA restriction analysis are not generally concordant with those previously estimated from morphological consideration.