Normal eye colour in Drosophila is red. White eyed Drosophila was one of the first mutations known in Drosophila. Red eye and white eye showed simple dominant recessive relationship.

Subsequently, different shades between red and white were recovered. About a dozen different allelomorphs, some of them shown in Table 5.5, are known now at this locus. Red eye was dominant over all others. When any two recessive alleles were brought together, intermediate type was obtained. That these different members of the series may not be allelic in a strict sense but are pseudoallelic, would be discussed in Fine Structure of Gene-at the Genetic Level (A New Concept of Allelomorphism).