Competition of isogenic haploid and diploid cells of the yeast Saccharomyces cerevisiae and Pichia pinus growing in mixed populations]

During "quasi-continuous" cultivation in rich and minimal media diploid yeast cells of Saccharomyces cerevisiae completely displace isogenic haploid ones. When Pichia pinus are cultivated in the minimal medium, the diploids also have an advantage over isogenic haploids. The results are discussed within the framework of the hypothesis of fixation of diploid phase in the course of biological evolution.