[The clinal variability of the B-chromosome system in the East Asian mouse Apodemus peninsulae from Buryatia and Mongolia].

Karyological investigation of 22 East-Asiatic mice from different points of the North Mongolia showed the availability in all the mice from 1 to 13 B chromosomes, including from 1 to 5 middle-sized and small two-shoulder chromosomes, from 0 to 11 dot-like B chromosomes, and, seldom, 1 small acrocentric B chromosome. Nearly every mouse is characterized by its variant of B-chromosome system. Most frequent mice with 3, 4 and 8 B chromosomes were met. The comparison of the B-chromosome system variants in mice from Buryatia, Chita Province (USSR) and the North Mongolia, showed an increase in the number of B chromosomes, mainly at the expense of the number of dot-like B chromosomes, in the direction from Ulan-Ude to the south and to the east.