Abstract
In the lower eukaryote Saccharomyces cerevisiae, 4,5,6-trichloro-2-(dichlorophenoxy)phenol and acridine orange cause different specific genetic alterations, either gene mutations or recombinations. These specific effects were used to characterize the mechanism of sister chromatid exchange (SCE) formation in human lymphocytes. Assuming that genetically active substances have comparable effects in lower and higher eukaryotes, the observations provide indirect evidence for a connection between induced mitotic recombination in yeast and SCEs in human lymphocytes and suggest that SCEs may be the consequence of a repair process.