STUDIES ON AN INTERESTING SACCHAROMYCES-CARLSBERGENSIS MUTANT .2. GENETICAL STUDIES

The genetics of a spontaneous double mutant Hla, belonging to Saccharomyces carlsbergensis, has been studied. The two mutated loci, controlling the biosyntheses of lysine and uracil are either loosely linked or they are located on separate chromosomes. Spontaneous mutations in the two genes are therefore likely to have followed from two independent mutagenic events. The mating-type locus, the methionine, the lysine and the uracil synthesising loci are not linked. Segregations for mating-type locus are Mendelian where as segregations for lysine, uracil and methionine synthesising loci are both Mendelian and Non-Mendelian. The 4:0 class of Non-Mendelian segregation is not found. The apparently Non-Mendelian segregations for mehtionine synthesis can be explained on the basis of the presence of two complementary methionine synthesising genes in Hla. © 1969 Kluwer Academic Publishers.