LACK OF SPECIFICITY OF CHROMOSOME BREAKS RESULTING FROM RADIATION-INDUCED GENOMIC INSTABILITY IN CHINESE-HAMSTER CELLS

In V79 Chinese hamster cells, radiation-induced genomic instability re sults in a persistently increased frequency of micronuclei, dicentric chromosomes and apoptosis and in decreased colony-forming ability. The se manifestations of radiation-induced genomic instability may be attr ibuted to an increased rate of chromosome breakage events many generat ions after irradiation This chromosomal instability does not seem to b e a property which has been inflicted on individual chromosomes at the time of irradiation. Rather, it appears to be secondary to an increas ed level of non-specific clastogenic factors in the progeny of most if not all irradiated cells. This conclusion is drawn from the observati ons presented here, that all the chromosomes in surviving V79 cells ar e involved in the formation of dicentric chromosome aberrations 1 or 2 weeks after irradiation with about equal probability if corrections a re made for chromosome length.