The role of lethal sectoring in the origin of complete mutations in Schizosaccharomyces pombe

Three cellular generations of Schizosaccharomyces pombe cells, after treatment with nitrous acid, were studied by means of a micromanipulatory pedigree analysis.Lethal sectors induced at different levels of survival were evaluated. The incidence of lethal sectors in the first cellular generation after mutagenic treatment has been used for calculating the proportions of complete mutant clones expected on the assumption that induced mutations are potential mosaics and that they are changed into complete mutants by the delayed lethality induced in the unmutated clones. The expected values can fully explain the origin of complete mutants which had been previously found in the ad₆ and ad₇ loci of the same yeast.