Variability of DNA repeats in four species of common voles

The electrophoretic DNA repeat patterns revealed by hydrolysis with differe nt restriction endonucleases of genomic DNA were compared in four species o f common voles, genus Microtus (M. arvalis, M. rossiaemeridionalis, M. tran scaspicus, and M. kirgisorum). The patterns of M. rossiaemeridionalis and M . transcaspicus were the most similar, which confirms the conclusion about the considerable genetic similarity of these species based on the cytogenet ic comparison and interspecific crosses. The similarity of the patterns bet ween other vole species is also in accord with the present concept of phylo geny of this vole group. Monomers of the tandem repeat family MSAT-160 reve aled in all four vole species by HindIII hydrolysis were cloned and sequenc ed. Basing on the similarity of nucleotide sequences, all the monomers were subdivided in four subfamilies differing in nucleotide substitutions in ce rtain positions, as compared with the consensus. Three MSAT-160 subfamilies include the monomers of at least three vole species. The monomers of M. ar valis make a separate subfamily. The occurrence of monomers belonging to di fferent subfamilies in dimeric clones suggest that MSAT-160 evolved as a hi gher-order repeat unit.