[Evaluation of the degree of genetic divergence in the twin species of the common vole Microtus arvalis and Microtus subarvalis (Rodentia)].

By means of starch electrophoresis, 52 proteins and enzymes of Microtus arvalis and M. subarvalis were studied to establish the extent of their similarity. Out of 52 markers studied, 7 proteins and enzymes had different electrophoretic mobility: glucose-6-phosphate dehydrogenase (G6PD), phosphogluconate dehydrogenase (PGD), diaphorase (DP), adenylate kinase (AK), lactate dehydrogenase B (LDHB), alpha-galactosidase (GAL) and hemoglobin (Hb), which make up to 13% of all the enzymes and proteins studied. The differences found between the two species studied by electrophoretic mobility of G6PD, AK, GAL and Hb, as well as the absence of intraspecific polymorphism for the above proteins permit to consider these proteins as species-specific markers, with the help of which M. arvalis and M. subarvalis can be distinguished. It should be emphasized that intraspecific polymorphism was found for PGD, LDHB and DP in M. arvalis, while in M. subarvalis these proteins were monomorphic and identical, in their electrophoretic mobility, to one of electrophoretic variants of M. arvalis. Therefore, only one of allelic variants of PGD, LDHB and DP is species-specific. Estimation of the extent of genetic similarity based on analysis of distribution of gene frequencies for polymorphic loci of M. arvalis and M. subarvalis by means of Nei's method gave the value of 0.312, the genetic distance being 1.164. The data obtained, together with the known cytogenetic data, point to a species rank of the species studied. Moreover, in spite of the morphological similarity between M. arvalis and M. subarvalis, the estimation of genetic similarity proved to be close to that for morphologically contrasting species.