CHROMOSOME COUNTS IN A POLYPLOID SERIES OF SACCHAROMYCES

Abstract

Diploid, triploid, and tetraploid strains of Saccharomyces inoculated onto agar slants containing yeast extract and sodium acetate underwent typical meiosis. During late prophase of meiosis I, discrete countable chromosomes were observed. When average chromosome counts of 20 to 30 cells of each strain were divided by their respective degrees of ploidy, the number was approximately 4. This is probably the haploid number of chromosomes in Saccharomyces.