[Identification of structural rearrangements in the karyotype of Microtus oeconomus from Chernobyl by differential staining of chromosomes].

Karyological studies of rodents within a 30-km radius of the Chernobyl' nuclear power plant revealed one female root vole (Microtus oeconomus) with an abnormal karyotype. The use of C, G, and AgNOR banding methods allowed us to determine that morphological changes in two nonhomologous autosomes, which were accompanied by rearrangements in distribution of G bands, heterochromatin, and NOR, are the result of a reciprocal translocation. Chromosomal aberrations were probably inherited or appeared in embryogenesis, since none of the analyzed cells of the studied vole had a normal karyotype. It is important to note that this rearrangement was detected five years after the meltdown. Both breaks and reunions of the chromosomes that participate in this rearrangement are probably located in regions that are not important for functioning of these chromosomes. Thus, it can be supposed that the detected rearrangement did not influence the viability of the vole. This karyotype was compared to a standard karyotype of a root vole from another area of the species range. The heteromorphism of the first pair of chromosomes in both voles, which was detected for the first time, is probably normal for the karyotype of M. oeconomus, and is not linked with any radiation-induced intrachromosomal aberrations.