Localisation of 7-12-dimethylbenz(a)anthracene induced chromatid breaks and sister chromatid exchanges in chromosomes 1 and 2 of bone marrow cells of rat in vivo.

The frequency of chromatid breaks associated with sister chromatid exchanges at the break point was determined in rat bone marrow cells treated in vivo with 7-12 DMBA, during the late S phase of the cell cycle. The chromosomal aberrations and SCEs were scored in the same cells. Under the experimental conditions employed, more than 40% of the chromatid breaks were found to be associated with an SCE, a frequency expected according to Revell's hypothesis for the formation of chromatid breaks.