A Plating Method for Genetic Analysis in Neurospora.

N Neurospora crassa, as in other ascomycetes with a spreading type of I growth, it has been necessary to obtain genetic data by the laborious method of isolating single ascospores in test tubes, and, in the case of biochemical mutants, transferring each of the cultures thus obtained to various media in order to characterize it (BEADLE 1945). The discovery that sorbose and certain other agents will induce a colonial rather than a spreading growth habit (TATUM, BARRATT and CUTTER 1949) suggested the possibility of obtaining large amounts of genetic data by plating ascospores on appropriate media. This approach has been used to develop simple and rapid techniques for identifying alleles, detecting linkage, and determining approximate map distances. This paper describes these methods, their limitations, and their application in the analysis of several tryptophanless strains.