[Properties of progeny of irradiated cells]

On cells in culture (HeLa, Chinese hamster cells) examined after gamma-irradiation with different doses, properties of the progeny of cells that survived for more than 30 generations have been studied. In the progeny of irradiated cells, the induction of lethal (micronuclei-MN) and nonlethal (sister chromatid exchanges--SCEs) cytogenetic alterations, radiosensitivity, adaptive response induction, and the influence of repair of potentially lethal damages (PLD) on the appearance of MN were detected. The cytogenetic damages are considered as manifestation of genomic instability. In descendants of the irradiated cells the increase in SCE induction and the formation of cells with high SCE level were observed; besides, an enhanced frequency of cells with MN were noticed. Then in the progeny of irradiated cells the radiosensitivity was increased and no adaptive response was induced. It has been found that the PLD recovery led to a decrease in the degree of manifestation of lethal damages (MN) in the progeny of irradiated cells. It was stated that PLD repair could eliminate the damages that result in genomic instability. These effects were registered during more than 20 generations after irradiation. The degree of alterations in the progeny of irradiated cells depends on the dose of irradiation, but the alterations are seen induced when cells are irradiated by low does (0.5 Gy). We can conclude that the low level of DNA damages can induce genomic instability. Forms of genomic instability in the progeny of irradiated cells and possible ways of its induction are discussed.