SEQUENCING OF THE MTDNA CYTOCHROME-B GENE AND RECONSTRUCTION OF THE MATERNAL RELATIONSHIPS OF WOOD AND FIELD MICE OF THE GENUS APODEMUS (MURIDAE, RODENTIA)

The primary sequence of a 402-bp part of the cytochrome b gene was det ermined in nine species of wood and field mice of the genus Apodemus. The majority of mutations were synonymous. The total number of transit ions exceeded than of transversions. Among all substitutions, C-T tran sitions prevailed (51%); the most common substitution type in genus-sp ecific sites was C-A transversions (42%). In interpopulation analysis, only transitions were recorded. A phylogenetic tree, constructed with the use of the neighbor-joining method, showed that the genus Apodemu s is divided into three highly divergent groups: south Asian (Apodemus argenteus, A. semotus), east Asian (A. speciosus, A. agrarius), and E urocaucasian (A. sylvaticus, A. flavicollis, A. uralenrsis, A. ponticu s, A. flavipectis). The mean genetic distances within each group were 12.6, 11.2, and 8.8%, respectively. The species of the first group are more remote genetically and ancestrally with regard to the other grou ps. The interspecies divergence estimated for A. speciosus ranged from 0.25 to 3.75%. Thus, the evolutionary age of the genus Apodemus is ab out 6 Myr, and time of divergence of A. speciosus populations is 0.1-1 .5 Myr. The phylogeny inferred from the data on the sequence of the cy tochrome b gene in Apodemus mtDNA is somewhat different from similar p hylogenies based on other genetic data and from the zoological taxonom y of wood and field mice. However, the above classification of species is confirmed by features of their karyotypes and segmentation of satD NA, and by the RFLP of total nDNA and isozyme polymorphism. Our result s are in good agreement with the new classification of wood and field mice recently proposed by Russian zoologists.