Homo- and heterothallic sexual types inSchizosaccharomyces pombe var. malidevorans

摘要

Although some differences are remarkable, the sexual system ofSchizosaccharomyces pombe var. malidevoransis, in principle, compatible with that ofSchizosaccharomyces pombe var. pombe. It has two heterothallic types analogous to Leupold'sh+h−, and a homothallic type, calledspotty, which resemblesh90. In addition, pseudoheterothallic types (pseudo-h−andpseudo-h+) similar to certain mutants ofS.p.v. pombedefective in conjugation were also found, as well as a homothallic type (grey) which has not been described inS. p. v. pombe. Genetic analysis of various hybrids constructed by mating and protoplast fusion revealed the probable genetic determination of the sexual types. Assuming a mating-type region similar to that ofS.p.v. pombe, a five-gene-system can be supposed. Themat-locus is the residence of the expressible mating type information (either plus or minus), one gene determines whether the clone is homo- or heterothallic, another one regulates the intensity of mating and sporulation, and two are responsible for accomplishing certain mating-type dependent conjugation functi