Abstract
By using subcritical temperature and ultraviolet light as DNA-attacking agents, the duplex nature of gene mutation of ad locus in yeast cells has been studied at molecular level.
The relative frequencies of whole-colony mutation and fractional-colony (sectored) mutation induced by these two agents are strikingly different: 59% whole, 23% fractional and 18% undefined for subcritical temperature; 14% whole, 72% fractional and 13% undefined for ultraviolet light. The results are interpreted to indicate a genetic multiplicity of two of the gene, based on the assumption that subcritical temperature causes changes in both strands of a gene-DNA molecule and ultraviolet in one of the two strands by a single event.
