[Genome of somatic cells of animals during prolonged radiation exposure]

The genome of the thymus and bone marrow of the Wistar rat brain was investigated during daily repeated irradiation at a dose of 0.5 Gy in total doses of 0.5-20 Gy. The genome was assessed by a number of tests characterizing the high and low levels of DNA structural organization. Analysis was performed one day after the last fraction of irradiation. Stable changes in the primary DNA structure of thymocytes were shown by a decrease in the content of double-strand DNA using spectrofluorimetry. Changes in the primary DNA structure of the bone marrow were undetectable. Prolonged irradiation led to the formation of conformation changes in the nucleoid of cells of both tissues detectable by viscosimetric and spectrofluorimetric methods.