A genetic and functional characterization of adenine mutants induced in yeast by 1-nitroso-imidazolidone-2 and nitrous acid

Summary The mutational activity of NIL and HNO₂ is compared in a forward mutation system of Saccharomyces cerevisiae involving ad₁ and ad₂ loci. The comparison includes the distribution of ad₁ to ad₂ mutations as well as certain functional aspects, namely, the frequency of KCl remedials and intragenic complementation with the tester strains. The results show that NIL and HNO₂ mutants are similar both in the distribution of ad₁ to ad₂ and in their functional aspects. Our findings suggest, furthermore, that in a certain group of mutants—mutants complementing with the tester strains—complementation is incompatible with KCl repair.