The relation between induced mutation frequency and cell survival--a theoretical approach and an examination of experimental data for eukaryotes.

Many mutagens are known to induce a variety of different types of lesions in DNA. Cellular repair systems may eliminate some of these; some unrepaired lesions may lead to loss of reproductive capacity and others to viable mutations. Simple considerations of these three alternative fates of an exposed cell show that there should be a linear relation between the logarithm of the surviving fraction (log S/SO) and log (1-M) where M is the mutant frequency. For low frequencies the relation assumes the simpler form M=-m log S/SO. The published literature on experimental mutagenesis in eukaryotes confirms these expectations. Observed differences in the slope m when different mutagens induce the same mutation in a given kind of cell (or a given mutagen induces the same mutation in different kinds of cell) imply that mutation and cellular inactivation do not arise from one type of DNA lesion only.