DOSE-RESPONSE RELATIONSHIPS IN RADIATION INDUCED MUTATION. SATURATION EFFECTS IN STREPTOMYCES

Abstract

E R Y considerable effort has been devoted to showing that the frequencies vof X-ray induced mutations, and in particular the recessive lethal mutations of Drosophila, rise linearly with increasing dose ; and the theoretical implications of this relationship have been much discussed. Special interest therefore attaches to KELNER'S ( 1948) demonstration of a clear-cut exception to the general rule in X-irradiated spores of Streptomyces, such that at high doses the capacity for mutational response appears to be saturated and further increases in exposure fail to cause the expected rise in mutant frequency.