Abstract
A screen for allelic variants of the enzyme catalase indicated that the Cat(+) locus is essentially monomorphic in D. melanogaster. Segmental aneuploidy was used to screen the genome for a dosage-sensitive region for catalase activity. One region, 75D-78A on the polytene chromosome map of 3L, exhibited a hyperploid/euploid ratio of enzyme activity of 1.5. Further dissection localized the region to 75D-76A. We suggest that this region contains the structural locus for catalase in D. melanogaster.Simple methods have been developed using the specific inhibitor, 3-amino-1,2,4-triazole, for the direct analysis of rates of synthesis and degradation of the Cat(+) gene product. Based on kinetic studies of catalase synthesis in flies aneuploid and euploid for region 75D-76B, we suggest that these techniques can be readily applied to an examination of mutants that control the expression of the structural gene for catalase in Drosophila.