Abstract
Ommochromes (brown pigments) and certain pteridines (red pigments), contribute to the typical reddish-brown eye color of wild-type Drosophila melanogaster. Each pigment is the end product of a seemingly unrelated metabolic pathway (Ziegler 1961; Kaufman 1967a). Mutations which alter the synthesis of these pigments are manifested as numerous variations in eye color (Lindsley and Grell 1967). Suppressed production of brown pigment results in the accumulation of ommochrome precursors which in some instances alters the production of drosopterins and their intermediates. "Pteridine mutants" accumulate pteridine intermediates and show altered ommochrome formation (Hadorn and Mitchell 1951) . Therefore, an interaction between the two biosynthetic pathways is indicated.