Molecular phylogeny of forest and field mice of the genus Apodemus (Muridae, Rodentia) based on the data on restriction analysis of total nuclear DNA

Based on restriction-fragment length polymorphism (RFLP) of total nuclear D NA (nDNA), analyses of phylogenetic relations and genetic similarity were p erformed in nine species of forest and field mice of the genus Apodemus. Ge netic distances calculated for different species pairs ranged from 0.24 to 12.53%; i.e., they differences were 50-fold. The estimated evolutionary age of the genus Apodemus is approximately 12 million years. In general, the o btained data on genetic similarity and phylogenetic relationship allow us t o differentiate at least three groups of species: (1) southern Paleoarctic (A. argenteus), (2) eastern (A, peninsulae, A. speciosus, and A. agrarius), and (3) western (A. sylvaticus, A. flavicollis, A. ponticus, A. uralensis, and A. fulvipectus) ones. The latter two groups are related to the norther n Paleoarctic. Such a division into groups corresponds to characteristic fe atures of karyotype organization and segmentation of satellite DNA (satDNA) of these species, as well as the nature of variation in isozymes and in a fragment of the enzyme-encoding sequence of cytochrome b gene isolated from the mitochondrial genome. Species groups (1) and (3) exhibited a high prob ability of a monophyletic origin (70 and 99%, respectively). Group (2) is u nlikely to be monophyletic, and the genetic distances in it are significant ly greater than those in group 3. A. argenteus is the most diverged, both p henogenetically and phylogenetically. The data are consistent with a new zo ological classification, which assumes the division of the unified genus Ap odemus into two taxa of generic rank and suggests that the southern Paleoar ctic forest mouse should be regarded as a separate taxon of at least subgen eric rank.