ISSN:
0749-503X
Keywords:
Spontaneous mutagenesis
;
repression and derepression of genes
;
environmental effects
;
Life and Medical Sciences
;
Genetics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
Spontaneous mutation of some genes was studied in haploid adenine and leucine auxotrophic yeast Saccharomyces.It was shown that a decrease in the amount of adenine (from 500 to 0 mgl-1) or leucine (from 300 to 0·3 mgl-1) in the medium, simultaneously with the transition from repression to derepression of the biosynthesis of these metabolites, resulted in a 15- to 150-fold increase in the reversion rate of genes ade2 and leu2, respectively, for different strains. At the same time the mutation rate of suppressor genes varied relatively little (up to five-fold), and that of gene lys1 did not change at all. It was also demonstrated (on gene leu2) that the mutation rate is determined by the composition of the nutrient medium at the time of the S-phase of the cell cycle and it does not depend on the cultivation conditions during the presynthetic period.We discuss the hypothesis that derepressed genes mutate with a significantly higher rate than genes in the repressed state.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/yea.320070204
Permalink
