[Regularities in formation of sister chromatid exchanges (SCE) in three generations after irradiation].

Frequencies of sister chromatid exchanges (SCE) induction in 3 generations of Chinese hamster cells (clone 237-7) after gamma-irradiation with a dose of 3 Gy have been studied. It is shown that the frequency of SCE significantly increases only in the 1st postirradiation cycle; it does not differ from the control in the 2nd and 3nd cycles. Irradiation induces production of cells with levels of SCE, which have practically never been discovered in non-irradiated population. These cells are eliminated from the population during the next division. Furthermore, it is stated that SCE can be produced in the same locus of chromosome during successive cell divisions. These results permit to conclude that the mechanism of formation of radiation-induced SCE differs from that in normal non-irradiated population.