Chromosomal polymorphism of populations of the common shrew, Sorex araneus L., in Belarus

The present paper reports karyotypic data for 76 individuals of the common shrew, Sorex araneus L., collected from 10 geographic sites in Belarus. We revealed two vast areas of polymorphism for diagnostic chromosomes of karyotypic races BiaowieA1/4a (gr, hn, ik, mp) and Kiev (gm, hi, ko) with low frequency of metacentrics. The frequencies of the BiaowieA1/4a diagnostic metacentrics decreased towards the east and the frequency of the Kiev metacentrics decreased towards the north. A high level of chromosomal variability was observed in the River Ptich basin. The contact zone of races BiaowieA1/4a and Kiev was observed along the Ptich and Pripyat Rivers. The polymorphism and a low metacentric frequencies in the studied populations of the BiaowieA1/4a and Kiev races from the Pripyat and Ptich basin may be associated either with selection against heterozygotes in the hybrid zone of these two races ("acrocentric peak") or with the spread of the diagnostic metacentrics of the BiaowieA1/4a and Kiev races in populations characterized by 10 pairs of acrocentric diagnostic chromosomes (g, h, i, k, m, n, o, p, q, r). Individuals with single diagnostic metacentric hk (such karyotype was previously attributed to new race Turov, Mishta et al. Acta Theriol 45 (Suppl 1):47-58, 2000) occurred in sites where the BiaowieA1/4a and Kiev races cohabited. In accordance with these data, the previous description of the Turov race (Mishta et al. Acta Theriol 45 (Suppl 1):47-58, 2000) needs a revision.