Genetic features and the putative sources of formation of isolated populations of the striped field mouse Apodemus agrarius Pallas, 1771 in Magadan oblast

The striped field mouse Apodemus agrarius is an invasive species new for Magadan oblast; however, the adaptation of the animals to the conditions of the habitats north of the Sea of Okhotsk has been successful. The full nucleotide sequence of the cytochrome b (cytb) gene from the mtDNA has been determined for mice from four local populations in the region (settlements of Snezhnaya Dolina, Snezhnyi, Solnechnyi, and Talon), and five cytb-haplotypes have been detected. Phylogenetic analysis revealed the similarity of cytb nucleotide sequences in the mice from the habitats north of the Sea of Okhotsk and the conspecifics from the Far East-Chinese part of the range. The invasion of A. agrarius into Talon is likely to have started from Primorsky krai, whereas the animals captured in Snezhnaya Dolina had ancestors from both Primorsky krai and from China, and the animals captured in Snezhnyi and Solnechnyi were exclusively of Chinese ancestry. The striped field mice from Snezhnyi and Solnechnyi were of a single monophyletic origin. The origin of mice captured in Snezhnaya Dolina was apparently polyphyletic, and the origin of the animals from Talon was monophyletic and different from the origin of other populations of the enclave located north of the Sea of Okhotsk. Investigation of 16 allozyme loci revealed highly significant differences between the samples of striped field mice of Snezhnyi, Solnechnyi, and Talon. The variability parameters in the set of biochemical gene markers used for the analysis showed a trend to a decrease in striped field mouse samples from the habitats north of the Sea of Okhotsk. Genetic analysis revealed that the local settlements of A. agrarius in Magadan oblast are currently represented by small isolated populations.