Variability of the Mitochondrial Genome (d-Loop) in Red squirrel, Japanese squirrel and Persian squirrel

Squirrels of the genus Sciurus are tree squirrels adapted to subarctic climatic conditions. They inhabit temperate forests and are widely distributed in the Northern hemisphere. Red squirrel, Japanese squirrel and Persian squirrel are the specific species from Sciurusin Europe and Asia. Of the Palearctic species, the red squirrel (Sciurus vulgaris) has the broadest distribution, ranging from Europe to China. In contrast, the other two Palearctic species have much narrower ranges; the Persian squirrel (Sciurus anomalus) is limited to the Iranian - Anatolian region while the Japanese squirrel (Sciurus lis) is limited to the Japanese Islands. The evolutionary history and phylogenetic status of the Persian squirrel are ambiguous and genetic information about this species is currently limited. Furthermore, although there are only three species of tree squirrel in the Palearctic region, it remains unclear whether they are monophyletic or polyphyletic. Mitochondrial genes are frequently used for taxonomic and phylogenetic studies, and the mitochondrial control region (d-loop) has sufficient variability for assessing relationships among congeneric species. Here, we describe for the first time the variability in mitochondrial d-loop sequences within and among the three Palearctic Sciurus species. Result of d-loop and Cyt b compared for phylogeny and they have similar result. Our results show that the Persian squirrel has higher variability than the other two species, while the red squirrel has lowest variability. The red squirrel and Japanese squirrel are genetically similar to each other and form a single clade, while the Persian squirrel is more genetically distant from these other two species and is placed in a separate clade.