Phenocopies of the ma-l and ry Mutants of Drosophila melanogaster: Inhibition in vivo of Xanthine Dehydrogenase by 4-Hydroxypyrazolo(3,4-d)pyrimidine

Abstract

PHENOCOPIES are environmentally induced abnormalities which mimic the phenotype resulting from mutant genes. Pomales et al.¹ have shown that 4-hydroxypyrazolo(3,4-d)pyrimidine (HPP) is an inhibitor in vivo of xanthine oxidase in mice, and we have attempted to produce phenocopies of the maroon-like (ma-l) and rosy (ry) eye colour mutants of Drosophila melanogaster with it. Xanthine dehydrogenase is undetectable in these mutants (see Glassman² for a discussion of these loci), and as a result, there is a partial loss of the red pteridines of the eye, the eyes being a dark red-brown rather than red. In addition, the products of this enzyme's activity, isoxanthopterin and uric acid, cannot be detected, and its substrates, 2-amino-4-hydroxypteridine and hypoxanthine, accumulate. In this communication we describe the production of phenocopies of ma-l and ry by HPP in various strains of D. melanogaster.