Variants of the Y‐chromosome in sympatric taxa ofMusin southern USSR

Abstract

Abstract Karyotypes of males of house mice were studied in European and Asiatic areas of USSR. They are differentiated according to Y‐chromosome morphology, two variants of which are discussed with respect to species‐diagnostic differences. A ≪large≫ variant regards the 19th pair of autosomes, most common in indoor as well as outdoor samples, including biochemically tested Mus musculus and M. m. domesticus. A substantially ≪small≫ variant was found , in wild short‐tailed mice only. The miniature Y‐chromosome was also detected during analysis of karyograms of M. spretus from the western Mediterranean. The three taxa with unique miniature Y‐chromosome seem to correspond to three subspecies, which were considered to be united in a separate species, Mus spicilegus. The possibility of using the new simple cytogenetic marker for diagnosis of. sympatric mice populations of two presumably distinct species, M. musculus and M. spialegus, and for historic reconstructions of their man‐related distribution is discussed.