Abstract
Morgan (1910) described the first eye-color mutation (white) in Drosophila melanogaster. Since that time, at least 60 eye-color mutants resulting from both spontaneous and induced mutations have been reported (for index, see Lindsley and Grell 1967). | Mutations involving eye color in Eh melanogaster may be characterized by the relative amounts of pigments that constitute eye color. These pigments result from two distinct metabolic pathways (Ziegler 1961 ; Kaufman 1967). Mutations that suppress the formation of red eye pigments (drosopterins) accumulate metabolic intermediates, as well as alter production of brown eye pigment (ommochrome). In addition, mutations which suppress the formation of ommochromes accumulate metabolic intermediates and alter amounts of drosopterin intermediates (Hadorn and Mitchell 1951). Hence, mutant genes that primarily affect the amount of end-product pigments of one metabolic pathway may alter the amount of end-product pigment of the other pathway, as well as the amounts of metabolic intermediates.