Chromosome painting of radiation-induced micronuclei

Abstract. In this report, in situ hybridization with whole chromosome painting probes was used to paint radiationinduced micronuclei (MN) in three lymphoblastoid cells lines to investigate the frequency of radiation-induced MN. The results obtained for four different chromosomes showed that there was a significant deviation of the numbers of signalpositive MN from that expected on the basis of DNA proportionality. Restriction of the analysis to three chromosomes showed that the deviations arose primarily from chromosome 7, which was underrepresented in the numbers of signalpositive MN in the group of chromosomes studied.