Recessive and dominant genes controlling inducible sexual agglutinability in Saccharomyces cerevisiae.

We have characterized the two dominant genes, IND 1 and IND 2, responsible for inducible sexual agglutinability. The strains carrying these genes differ from the inducible strains carrying the recessive gene, saa 1 in the following points. The former strains produce agglutination substance at 22 degree, 28 degree, and 37 degree C only response to sex pheromone of the opposite mating type, but the latter strains produce the substance constitutively without the pheromone at 22 degree C, only in response to the pheromone at 28 degree C, and do not produce the substance, even in the presence of the pheromone, at 37 degree C. We suggest that strains carrying one of the dominant, inducible genes are wild type and have a pheromone-controlled regulatory system of sexual agglutinability.