[Estimation of the cytogenetic homeostasis in natural populations of small murine rodents from the Lower (Astrakhan') and Middle (Chapaevsk) Volga regions].

Frequencies of chromosomal aberrations were estimated in the bone marrow of two background small rodent species, the bank vole (Clethrionomys glareolus) and the house mouse (Mus musculus) from the middle (Chapaevsk, Samarskaya oblast) and lower (Astrakhanskaya oblast) Volga regions. The majority of chromosomal aberrations were chromatid deletions. In the studied species, cytogenetic disturbances were most prevalent in areas where the anthropogenic environmental pollution was maximum. The lowest frequencies of disturbances were observed in the control areas, where the environmental pollution was insignificant. Thus, anthropogenic exposure caused disturbances of cytogenetic homeostasis in different small rodents living in different regions.