Interchromosomal distribution of gamma ray-induced chromatid aberrations in Chinese hamster ovary cells

Interchromosomal distributions of breakpoints from chromatid-type aberratio ns induced by gamma rays in Chinese hamster ovary (CHO) cells were analyzed . In most chromosomes the distribution was as expected from chromosome leng ths for simple breaks or the respective relative corrected length in case o f exchanges. There were deviations from expectation in a few chromosomes fo r chromatid breaks, interchanges, inra-arm intrachanges and inter-arm intra changes. Especially interesting are the results concerning chromosomes 2 an d 8, which were more often involved in exchanges than expected. An "exchang e phenotype" for these chromosomes is proposed and possible explanations fo r the nonrandom distribution of chromosome breakpoints are presented.