Sister chromatid exchanges in human cells and Chinese hamster cells. Evidence that the rate of sister chromatid exchanges is a function of ploidy.

Abstract The frequency of sister chromatid exchanges (SCE) in the chromosomes of the diploidy and polyploidy of Chinese hamster cells and human cells has been studied using BUdR-DAPI (bromodeoxyuridine, 4′-6-diamidino-2-phenylindol) fluorescence. The rate of SCEs per cell under constant control conditions is in proportion to the ploidy levels. In addition, the frequency of SCEs observed in a given human chromosome (nos. 1) is also directly proportional to the number of such chromosomes presented in the cells. The mean of SCEs in human chromosome numbers 1 is very similar (0.46–0.48) for diploid, triploid, and tetraploid cells. The results suggest that the rate of SCEs is a function of cellular ploidy levels.