Iwasa M.A., Utsumi Y., Nakata K., Kartavtseva I.V., Nevedomskaya I.A., Kondoh N., Suzuki H.
В журнале Zoological Science
Год: 2000 Том: 12 Страницы: 477-484
The gray red-backed vole, Clethrionomys rufocanus, from Far East Asia including Sakhalin and Hokkaido is known to harbor intraspecific morphological and cytogenetic variations. Here we analyzed geographic variation in the mitochondrial cytochrome b (Cytb) gene and Y chromosome specific Sry gene by a PCR direct sequencing technique. Determination of sequences in the Cytb gene (1140 bp) in 29 individuals provided 28 haplotypes and construction of a neighbor joining tree clearly indicated that they were grouped into four major lineages, which predominated in Primorskyi territory, Kamchatska-Magadan, Sakhalin, and Hokkaido-Kuril, with 0.02-0.04 sequence divergence (Kimura's distance, all substitutions, all codon positions). The sequences for the Sry region (336-366 bp) included a variable repetitious region of microsatellites such as TG(TC)(2). In total five sequences were recognized which can be grouped into two forms, continental and insular (Sakhalin and Hokkaido) based on the presence or absence of a segment of TG(TC)(3)TG(TC)(4). It was revealed that, therefore, the population of Sakhalin possessed their own type of mitochondrial DNA but the same Sry gene as Hokkaido. A similar trend can be seen in the continental populations. Our results suggested that the population of C. rufocanus in each of the geographic domains accumulated own genetic elements in part but genetic exchanges between neighboring populations occurred during the course of evolution. It is noteworthy that the insular domains, Sakhalin and Hokkaido, have played an important role in raising the amount of genetic diversity in small rodent species.
