Mustard Gas Mutations in Neurospora

Abstract

Asexual spores of wild-type 1A of N. crassa were exposed to [beta],[beta]''-dichlorodiethylsulfide, and applied to protoperithecia of wild-type strain E5297a. The same cross was made with untreated spores. Following fusion and development, single ascospores were isolated on "complete" medium for germination. Of 760 treated spores which germinated, 29 were mutants. In the controls, 769 spores germinated and 1 was a doubtful mutant. The 29 mutants included 17 visible and 12 biochemical mutants. The frequency of mutant spores compared favorably with that obtained after u.-v. irradiation. The actual mutation rate was close to twice the % of mutants found. One of the mutants, the "albino," appeared to be a new type and had a yellow tint. No new kinds of growth factor requirements were identified among the biochemical mutants.