Comparative genetics of apodemus agrarius (Rodentia: Mammalia) from insular and continental eurasian populations: Cytochrome B sequence analyses

To reexamine genetic divergence of Apodemus agrarius in insular Taiwan and the Korean Jeju from other populations in continental Eurasia, we obtained 91 cytochrome b complete sequences of A. agrarius across Eurasia, and these sequences were compared to eight corresponding sequences of A. agrarius, obtained from GenBank. We first found that the two insular populations are two clades, and that each of them is divergent from continental Eurasian populations, clustered into another clade. Each of the two insular clades appeared to be isolated in spite of land connection to nearby continent during the last glacial period, and we considered the two insular forms as A. a. insulaemus and A. a. chejuensis and one continental Eurasian form as A. a. agrarius, although further analyses are needed to confirm our present findings. Additionally, the Taiwan clade seemed to be composed of two subclades (western and eastern), separated by Taiwan's central mountain range.