Mitochondrial DNA and Evolution in Peromyscus: A Preliminary Report

Abstract

Restriction endonucleases have made it possible to demonstrate extensive intraspecific mtDNA sequence heterogeneity in a variety of mammals. Mammalian mtDNA appears to evolve rapidly (Brown et al. 1979) and to be strictly maternally inherited (Avise et al. 1979a,c). We have been analyzing and quantitating mtDNA sequence divergence as a way to establish maternal phylogenies for closely related animals. Here we report the initial results of an extensive survey of over 200 field mice from two sibling species, Peromyscus maniculatus and Peromyscus polionotus. These results further establish the utility of mtDNA restriction analysis as a tool in population genetics and also yield significant information concerning the nature of evolutionary change in the mtDNA molecule. P. maniculatus is an abundant and diverse species found throughout the North American continent. P. polionotus, limited in range to the southeastern United States, is thought to have arisen relatively recently from a maniculatus- like ancestor. The animals used in this survey were collected from locales widely distributed throughout the ranges of both species. Most of the samples analyzed consisted of crude “cytoplasmic nucleic acid” fractions (Lansman et al. 1981) prepared from the hearts and livers of individual animals. These were digested with the nine endonucleases indicated in Figure 1, labeled with DNA polymerase as described by Brown (1980), electrophoresed in agarose gels, and detected by autoradiography. Larger samples of purified mtDNA were also prepared using several animals, always progeny of a single female. Three of these samples were used to construct recombinant plasmids or phage containing the...