A NEW TYPE OF MUTATION IN SCHIZOSACCHAROMYCES POMBE: VEGETATIVE IODINE REACTION

James H. Meade 1 and Herbert Gutz 1

1 Institute for Molecular Biology, The University of Texas at Dallas, Richardson, Texas 75080

Colonies of Schizosaccharomyces pombe that contain ascospores (e.g., colonies of homothallic strains) turn black after treatment with iodine vapors. Heterothallic strains of S. pombe normally do not show this reaction. In experiments with the latter strains we found mutants which exhibit a positive iodine reaction though they do not contain ascospores. This phenotype is due to mutations in a new gene, vir1 (vegetative iodine reaction). The vir1 locus is not linked with the mating-type genes.—Strains of mating-type h-s are known not to give any spontaneous mating-type mutations. Mating-type mutations were also not found after treatment with nitrous acid.

Submitted on August 7, 1974
Revised on March 26, 1975