X-RAY-INDUCED MUTATIONS AFFECTING THE LEVEL OF THE ENZYME ALCOHOL-DEHYDROGENASE IN DROSOPHILA-MELANOGASTER - FREQUENCY AND GENETIC-ANALYSIS OF NULL-ENZYME MUTANTS

The frequency of X-ray-induced (null-enzyme) mutations at the alcohol dehydrogenase locus in Drosophila melanogaster was measured. The rate of recovery of chromosomes that fail to direct the synthesis of a functional Adh protein is 3 × 10-8 per R for chromosomes that do not include large chromosome rearrangements. However, this analysis excludes a larger number of chromosomes that are null-enzyme mutations" because they are deleted for the region of the Adh locus. The dose of X-rays required to induce a frequency of non-deletion null-enzyme mutants equal to the spontaneous frequency is about 73 rad calculated from the data reported in this communication. © 1979."