A wide hybrid zone of chromosome races of the common shrew, Sorex araneus Linnaeus, 1758 (Mammalia), between the Dnieper and Berezina Rivers (Belarus)

Abstract

Abstract. Karyological study of 75 specimens of the common shrew, Sorex araneus Linnaeus, 1758, from 8 localities in the Berezina River basin (eastern Belarus) was carried out. A wide hybrid zone (not less than 100 km) between the northern West Dvina chromosome race (XX / XYY, af, bc, gm, hk, ip, jl, no, qr, tu) and the southern Turov race (XX / XYY, af, bc, g, h/k, i, jl, m, n, o, p, q, r, tu) was revealed in this region. Frequencies of fused-unfused arms comprising four diagnostic metacentrics of the West Dvina race (g/m, h/k, n/o, q/r) were calculated in all capture sites. Taking into consideration the absence of metacentric ip in specimens from six northern localities, the Borisov (Bs) race (XX / XYY, af, bc, g/m, h/k, i, jl, n/o, p, q/r, tu) (Orlov, Borisov, 2009) was distinguished in these sites. Common shrews from two southern localities on the right and left banks of the Berezina River (Berezino vicinity) were referred to the Turov race. The presence of four metacentrics descended from the West Dvina race in the Bs race testifi es to the hypothesis expressed earlier that the polymorphic populations of the S. araneus between the Dnieper and Berezina Rivers originated as a result of the West Dvina race spreading from the north and of hybridization between this race and local populations with acrocentric chromosomes.

Karyotypic differentiation of populations of the common shrew Sorex araneus L. (Mammalia) in Belarus

“…A significant variation in the Rb translocation frequency was earlier described in populations of chromosome races West Dvina, Borisov, Kiev, and Białowieża in the Dnieper-Pripyat interfluve (Orlov and Borisov 2009, Borisov et al 2010, Borisov et al 2014. It should be noted that the West Dvina race (gm, hk, ip, no, qr;Bulatova et al 2002), like the Neroosa race, is monomorphic for five Rb translocations throughout most part of its distribution range, from the Valdai Hills to the Smolensk Upland .…”

“…Our karyological data on 290 shrews trapped in -2013(Borisov et al, 2010, 2014 and data on 252 shrews presented by other authors were used to determine the distribution range of race-specific metacentrics. In total, 603 individuals from 43 sites (an area from 51°22' to 54°55'N; from 23°10' to 34°10'E) have been analysed in this work (Suppl.…”

“…Karyotypes with ten pairs of acrocentric chromosomes (g, h, i, k, m, n, o, p, q, r) were found in some of these polymorphic populations (Borisov et al 2010(Borisov et al , 2014. Such a pattern of karyotype distribution may be associated either with the selection against heterozygotes in the interracial hybrid zone ("acrocentric peak") (term by J.…”

“…The West Dvina race (gm, hk, ip, no, qr;Bulatova et al 2002) occupies a vast territory from the Valdai Hills to the Smolensk Upland, its southern boundary passes through Vitebsk region of Belarus (Bulatova et al 2002, Orlov and Borisov 2009. The Borisov race (g/m, h/k, i, n/o, q/r, p;Orlov and Borisov 2009), which is a derivative of race West Dvina, is distributed in the middle Berezina basin (Borisov et al 2010). The Bobruysk (g, h/i, k, m, n, o, p, q, r) and Turov (g, h/k, i, m, n, o, p, q, r) races were described in the vicinities of Bobruisk and Turov towns, respectively (Mishta et al 2000).…”

Narrow hybrid zone between Moscow and Western Dvina chromosomal races and specific features of population isolation in common shrew Sorex araneus (Mammalia)

“…In unimodal hybrid zones of chromosomal races Oxford/Hermitage, Ulm/Drn holec, and Turov/West Dvina the zone width reaches 40 to 100 km [24][25][26]. Bimodal zones seem to be nar rower; however, statistically significant determination of the recombinants scattering in such zones is extremely difficult.…”