ESTIMATION OF THE CYTOGENETIC HOMEOSTASIS IN NATURAL-POPULATIONS OF SMALL RODENTS FROM THE LOWER (ASTRAKHAN) AND MIDDLE (CHAPAEVSK) VOLGA REGIONS

Frequencies of chromosomal aberrations were estimated in the bone marr ow of two background small rodent species, the bank vole (Clethrionomy s glareolus) and the house mouse (Mus musculus) from the middle (Chapa evsk, Samarskaya oblast) and lower (Astrakhanskaya oblast) Volga regio ns. The majority of chromosomal aberrations were chromatid deletions. In the studied species, cytogenetic disturbances were most prevalent i n areas where the anthropogenic environmental pollution was maximum. T he lowest frequencies of disturbances were observed in the control are as, where the environmental pollution was insignificant. Thus, anthrop ogenic exposure caused disturbances of cytogenetic homeostasis in diff erent small rodents living in different regions.