The molecular basis of genetic complementation
Three phenotypically identical white harebell mutants—$, £, and ¥—are intercrossed. Mutations in the same gene (such as $ and £) cannot complement because the Fi has one gene with two mutant alleles. The pathway is blocked and the flowers are white. When the mutations are in different genes (such as £ and ¥), there is complementation by the wild-type alleles of each gene in the Fļ heterozygote. Pigment is synthesized and the flowers are blue. (What would you predict to be the result of crossing $ and ¥ ?)