Dynamics of cytogenetic injuries in natural populations of bank vole in the Republic of Belarus

The frequencies of different types of mutation as well as radionuclide content in bank vole populations in regions of Belarus with various densities of radiocontamination were studied. There were approximately 12-18 generations of animals over the period 1986-1991. The frequency of chromosome aberrations in bone marrow cells of animals in the most contaminated stations (90 and 1524 kBq.m(-2) for Cs-137) remained at a high level during this period. The frequencies of genomic mutations (polyploid cells) gradually rose until 1991. Since the radiation load on vole populations was reduced by 1991, it can be stated that there is higher sensitivity of the hereditary apparatus of somatic cells of subsequent animal generations in comparison with ones prior to the Chernobyl fallout. In other words, there is no genetic adaptation to the mutagenic effect of low level radioisotope radiation for the whole investigation period in natural populations of bank vole.