Quantitation of induced mutation in Dictyostelium discoideum: characterization and use of a methanol-resistance mutation assay.

An assay based on forward mutation of Dictyostelium discoideum to 3% methanol resistance allows quantitation of induced mutation following treatment with physical and chemical agents. Properties of this assay are: uniform recovery of methanol-resistant (MeOHr) cells over a wide range of plated cell densities, equal growth rates of methanol-sensitive and methanol-resistant cells in the absence of methanol during the expression period and the attainment of plateau in the number of mutants as a function of expression time. When 4 mutagens were tested with this system and compared at the 10% survival level, N-methyl-N'-nitrosoguanidine was the most effective for mutation induction, followed by 60Co-gamma-rays, ultraviolet light, and methyl methanesulfonate.