Presence of the 54-chromosome common vole (Mammalia) on Olkhon Island (Lake Baikal, East Siberia, Russia), and the occurrence of an unusual X-chromosome variant

• Published in: Comparative Cytogenetics
• Main Authors: Svetlana Pavlova, A.V. Tchabovsky
• Format: Article in Journal/Newspaper
• Language: English
• Published: Pensoft Publishers 2011
• Subjects: Genetics; QH426-470; Arctic; Arctic Island; Island Lake; Lake Island; Svalbard; Common vole; Siberia
• Online Access: https://doi.org/10.3897/compcytogen.v5i5.1720; https://doaj.org/article/e906720141b24993b8f5bd2e9e6ac5d1

We report a new finding of the 54-chromosome sibling species of the common vole in East Siberia - the first description from Olkhon Island (Lake Baikal). The karyotype of a male specimen revealed by routine staining and C-banding demonstrates the unambiguous presence of Microtus rossiaemeridionalis Ognev, 1924 (recently often regarded as as junior synonym of M. levis Miller, 1908). Comparison with conspecific specimens from the European part of the species range (from the left bank of the river Volga) shows that the vole of the island population has a smaller X-chromosome due to a reduced quantity of C-positive heterochromatin. This is just the third example of this type of X-chromosome variant with previous cases on an Arctic island (Svalbard) and the West Siberian lowland (Novosibirsk) and the only one on a lake island. Although M. rossiaemeridionalis is largely monomorphic in its karyotype, our data show that one specific type of X-chromosome variant is remarkably widespread, though rare.