Heterogeneity of Clones of Saccharomyces Derived from Haploid Ascospores

Abstract

In the heterothallic strains of Saccharomyces under investigation, diploidization occurs in clones derived from haploid cells. The diploid cells are of 2 types, either homozygous or heterozygous, at the mating locus. The heterozygotes differ from the homozygotes in growth habit, mating reaction, and in the capacity to sporulate. The heterozygotes, which are capable of sporulation, are incapable of fusing with other cells. The homozygotes do not sporulate; they will fuse, however, with haploid cells and diploid cells of opposite mating type to produce triploid and tetraploid zygotes.