The Production of Mutations by Chemical Substances

Abstract

The production of mutations by the action of chemical substances on germ cells has often been reported. However, the variability of the spontaneous mutation rate and its dependence not only on environmental conditions and physiological factors, but also on the genotype, make it extremely difficult to assess the value of tests in which only small increases over the spontaneous mutation rate have been found. For this reason, Muller was still able to conclude in 1941 that there was no definite proof that chemical substances could exert an effect on the mutation rate. Since then, Thomas and Chevais (1943) have reported results with sulphonamides which, if they can be confirmed, would indicate a real, though slight, action of these substances on the chromosomes, at least as far as gene mutations are concerned. Stubbe (1940), working on plant material, observed a significant increase in mutation rate with phenol and potassium thiocyanate. It is of interest that Auerbach and Robson (1943) independently observed a similar effect with allyl isothiocyanate in experiments on Drosophila. Even these definite effects are, however, very slight.During the last four years we have been testing a number of chemical substances. Among these a certain group has been found which increases the rate of occurrence of mutations and chromosome rearrangements to a similar extent as that brought about by X-rays and similar physical agencies. The best known representative of this group is mustard gas, and the present report deals only with the effects produced by this substance. Results obtained with other effective substances will be published later.