Genetical and Biochemical Studies on the Red and Yellow Eye Pigments of Drosophila melanogaster

Abstract

Single and double or triple eye color mutants of Drosophila melanogaster were used. The relative amounts of eye pigments, extracted from heads without proboscis by a double extraction method, were photometrically estimated. Several kinds of pteridines, mainly from eyes and testes, were separated by paper chromatography and their amounts were fluorometrically measured. The eye pigments of Drosophila are composed of red, yellow, and brown. Red and yellow pigments have proved to be pteridine derivatives, and a metabolic pathway from yellow to red was suggested on the basis of experimental results. The genetic action of w and bw strains are assumed to block the supply of the common pteridine precursor. The route of supply is more or less depressed by the action of ca, ry, and Hnr-3 genes. The homozygous Hnr-3 fly was considered to have an incomplete conversion of sepiapterin to tetrahydropterin, because of reduced activity of pterine reductase. The cl and Hnr-1 genes inhibit considerably the transformation of tetrahydropterin into red pigment, but the se gene blocks it completely.