The paper aims to investigate cytogenetic and apoptotic responses of γ-irradiation in a radio-resistant cell strain designated
as M5. Induced micronuclei, chromosomal aberrations, nuclear fragmentation and nucleosomal ladders by γ-irradiation were less
at equal doses in M5 cells in comparison with that obtained in the parental Chinese hamster V79 cells. However, at equal survival,
there were no differences in the end points studied. Results indicate that the residual damages that lead to reproductive
cell death also resulted in the cytogenetic and apoptotic responses. We speculate that the repair efficiency in M5 cells was
more efficient and increased DNA repair could be the cause of radiation resistance observed in M5 cells.