Cytogenetic analysis of a hybrid zone between the Moscow and Neroosa races of the common shrew (Sorex araneus) differing by a single wart-like chromosome rearrangement.

Three karyotypic variants were revealed in the Moscow-Neroosa chromosomal hybrid zone by comparative cytogenetic analysis: homozygotes of the pure parental races and complex heterozygotes (F1 hybrids). As expected, a ring-of-four configuration (RIV) was observed in diakinesis spreads of hybrids. No disturbances in the structure of the RIV were found. Distribution of telomeric repeats and rDNA on the chromosomes of an individual of the Neroosa race were studied using dual-colour FISH.