The Rôle of Organic Peroxides in the Induction of Mutations

Abstract

The hypothesis that organic peroxides play an essential role in the mutagenic action of u.-v. light was tested on an adenineless colonial strain of Neurospora crassa which is known to have a low spontaneous rate of reversion to adenine independence. The method used was essentially that descr. by Giles and Lederberg and by Westergaard and Mitchell. Mutants formed distinct colonies that could be counted. Mutation rates were calculated on the basis of no. of spores treated and a correction made for spontaneous mutation. Many expts. were made with 6 different peroxides. The results with tert-butyl hydroperoxide show increased mutation rates, fairly reproducible at constant concns. Other agents giving similar effects were hydroxymethyl tert-butyl peroxide, peroxide derived from di-isopropyl ether, hydrogen peroxide and formaldehyde, hydrogen peroxide and acetone. The authors assume from their results that the independent colonies are the result of true mutations. The action of the peroxides produced a heritable change shown by the persistence of adenine independence through repeated subcultures on an adenine-free medium. Known mutagenic agents produced a similar effect. However, the authors recognize that genetic crosses are necessary to establish proof that genetic mutations are involved.