Genetic Variability in the Yellow-Necked Field Mouse (<Emphasis Type="Italic">Sylvaemus flavicollis</Emphasis> Melch., 1834, Muridae,Rodentia) at the Eastern Border of the Range

The first characterization of the genetic variability in populations of S. flavicollis on the eastern border of the range is presented. Seven individuals from the most northeastern habitat of the species (Middle Urals) were karotyped. No deviations from the standard chromosome set, either by the chromosome number or morphology, were revealed. Analysis of the mtDNA cytochrome b gene sequences (1133 bp) in 44 individuals from five populations on the eastern border of the species range (Middle and Southern Urals) resulted in identification of 17 haplotypes. All haplotypes were new and not found earlier in other parts of the species range. The genetic diversity indices and analysis of the demographic and genetic structure indicate a relatively recent origin of the populations under study as a result of rapid expansion. Phylogenetic analysis (97 haplotypes, including the GenBank data) showed that all haplotypes described at the eastern border of the range belonged to the same phylogroup distributed in the Balkan region, Northern and Eastern Europe, and Russia (Samara oblast). Close relationships between the examined populations and the populations from the northern part of the species range in Eastern Europe was demonstrated.