[Multiple mutants of Saccharomyces cerevisiae. IV. Mutability of yeast cultures at different growth stages].

Mutability at different stages of culture growth in liquid media of two yeast strains, which revealed a property of "multiple mutability" and one strain of wild type for this property, was studied. One strain that possessed the property of "multiple mutability" showed at stationary phase a very high frequency of mutability, which reached 3.5%. It was found that multiple mutants arose in both strains, that possessed the property under investigation, at lag- and log-growth phases, and only in one strain -- at the stationary phase of growth. The possible reasons of "multiple mutability" display are discussed.