Rapid detection of allelic recombination at thegalllocus in yeast by assay of the recombinant gene product

Abstract

SummaryA diploid heteroallelic at thegal1locus and producing little residual galactokinase activity was chosen. Following either γ- or UV-irradiation, recombination occurred leading to the formation of wild-typeGAL1 genes and an increase in detectable galactokinase. An enhanced level of enzyme was first detectable 2 h after irradiation and reached a maximum within 12–14 h. With increasing doses of irradiation, more enzyme was produced and this increase superficially resembled that obtained for plated recombinants. However, far more enzyme was actually synthesized than expected from the number of viable recombinants in the cells assayed. This suggests that recombination must have occurred in cells without colony-forming ability, indeed it may have occurred more frequently in these cells than in viable cells.