[Changes in radiosensitivity of chromosomes at the presynthetic stage of the mitotic cycle: role of single-stranded segments of DNA].

Formation of single-stranded DNA regions was investigated during the presynthetic stage of human lymphocyte cell cycle. Two peaks of single-stranded region production were found in about the middle and near the end of the G1 stage. Both the peaks appeared some hours earlier in gamma-irradiated cells than in control. Experiments showed that the periods of the peak formation coincided with the terms when time-effect dependence for gamma-induced chromosomal aberrations changed its character. The interpretation of the results supposes existence of inherent for the G1 stage process of genetic material correction.