GENETICS AND METABOLISM IN NEUROSPORA

Abstract

That many biochemical syntheses performed by a fungus, Neurospora, are governed by specific genes has been shown by observing the deficient metabolism that ensues upon certain experimentally induced mutations. The author describes the history, life cycle, and methods of culture, of the genus Neurospora, and its genetic behavior, which is especially advantageous for such studies. Two species (N. crassa and N. sitophila) are heterothallic, i.e., strains of 2 sexes exist. The exptl. procedure is to expose one kind of sexual element from one strain to x-rays, [gamma]-rays, or neutrons, "fertilize" with it the opposite kind of sexual element from the other strain, and culture the haploid spores resulting from this zygote upon various minimal media to detect deficiencies in synthesizing ability. Defects so discovered include loss of power to synthesize arginine, tryptophane, lysine, leucine, valine, methionine, proline, certain vitamins, and other substances. Such mutant strains can be used as a means of bio-assay, highly sensitive, but limited in applicability. Possible mechanisms of gene action and the evolutionary implications are discussed.