[Experimental hybridization of voies of the genus Microtus s.l. M. socialis with species of the group arvalis (Mammalia, Rodentia)].

The results of interspecific crosses of the social vole Microtus socialis with the Altai vole M. obscurus, the East European vole M. rossiaemeridionalis, and the Transcaspian vole M. transcaspicus are presented. The role of the sperm head structure in the reproductive isolation of this species was studied. Hybrids were obtained in five of the six crossing combinations. It is established that significant differences in the sperm head shape in the social vole and in arvalis group species do not prevent fertilization. The sterility of hybrids indicates the existence of postcopulative mechanisms of reproductive isolation.

[Cytogenetic study of the parapatric contact zone between two 46-chromosomal forms of the common vole in European Russia].

Since the first description of sympatric sibling species and allopatric chromosomal forms of the common vole (Microtus arvalis group) in 1969, the search of their range boundaries has been Continually going on up to the present time. Based on the cytogenetic material presented in the present study, the geographical distribution of two karyoforms (2n = 46: NF = 84 and NF = 72) was examined in 20 geographic localities of European Russia (within the interval between the longitude 34 degrees-56 degrees East and 51 degrees-61 degrees). The places of findings of two karyoforms, "arvalis" and "obscurus", in Russia have been supplemented and were shown to be significantly closer; whereas the well-known distribution boundaries for the "obscurus" form were specified in the northern and southern parts of Russia.A direct evidence of parapatric distribution and hybrid zone formation between the "arvalis" and "obscurus" karyoforms was obtained, which suggests the possibility of studying the evolutionary relations ships between two genomes in the Russian part of the group range under the natural experimental conditions-the hybrid zone at the boundary between the "arvalis" and "obscurus".

[Genetic differentiation of voles of the tribe Arvicolini (Cricetidae, Rodentia) using taxonprint analysis and polymerase chain reaction with random primers]. / Geneticheskaia differentsiatsiia polevok triby Arvicolini (Cricetidae, Rodentia) metodami taksonoprintnogo analiza i polimeraznoi tsepnoi reaktsii so sluchainymi praimerami.

The variability of the genomes of ten vole species was analyzed by means of taxonomic DNA fingerprinting and polymerase chain reaction using random primers (RAPD-PCR). The dendrograms of genetic similarity between the representatives of the tribe Arvicolinae (Gray, 1821) were constructed, based on the data obtained by means of both methods. The topology of the genetic similarity dendrogram that is based on the RAPD-PCR data generally correlates with the genetic distances estimated from biochemical and karyological data. The results did not confirm the genus status of Terricola. On the other hand, the data from taxonprint analysis suggest the recognition of Lasiopodomys as a separate genus.