The effect of DNA replication on mutation of the Saccharomyces cerevisiae CDC8 gene

Summary Incubation in YPD medium under permissive conditions when DNA replication is going on, strongly stimulates the induction of cdc⁺ colonies of UV-irradiated cells of yeast strains HB23 (cdc8-1/cdc8-3), HB26 (cdc8-3/cdc8-3) and HB7 (cdc8-1/cdc8-1). Inhibition of DNA replication by hydroxyurea, araCMP, cycloheximide or caffeine or else by incubation in phosphate buffer pH 7.0, abolishes this stimulation. Thus the replication of DNA is strongly correlated with the high induction of cdc⁺ colonies by UV irradiation. It is postulated that these UV-induced cdc⁺ colonies arise as the result infidelity in DNA replication.