The a and a mating types of the yeast Saccharomyces cerevisiae are controlled by the mating-type locus (MAT), which can harbor one of two genetic blocks (cassettes), a or c~. Homothallic strains of yeast, those carrying the HO allele and appropriate accessory genes, are able to interconvert mating types by replacing one MAT allele with the other MAT allele (Fig. 1) (Hicks et al. 1977a; Herskowitz et al. 1980; Herskowitz and Oshima 1981). Cryptic a and a cassettes reside at HMR and HML; standard laboratory strains have a informa-tion at HMR (=HMRa) and c ~ information at HML (=HMLa). In addition, variants have been isolated that have an a cassette at HML (=HMLa) and an a cassette at HMR (=HMRa). Mating-type interconversion ccurs by transposition of a copy of the mating-type informa-
No takes yet. Share an insight, caveat, or question.
Rine et al. (1981) studied this question.