Genic Differences and Rate of Growth in Yeasts

Abstract

A BREWERY diploid strain of yeast kept under constant observation for the past two years showed a seasonal variation in the characteristics of its giant colonies. On the basis of normal¹ and induced reverse mutations², it was surmised that different mutants get established during the various seasons of the year, and hence strains having diverse genic constitutions should differ not only in their viability but also in their growth-rate under particular environmental conditions. It was shown in a previous contribution³ that the growth-curves of the diploid and autotetraploid are widely different. Since strains having different genic constitutions were available in this Laboratory, it was considered that a study of the growth-rates of two strains assumed to be homo-and heterozygous for the rough allele would be interesting.