Fig. 5. Models of interactions between ZAM, Idefix and white in the different white alleles. (A), (B), (C) and (D) correspond to the w^IR6RevI, w^IR6RevIIa, w^IR6RevIIb and w^IR6RevIV alleles, respectively. The white gene is indicated by its promoter, and the beginning of its first exon is shown by a black box. DNA upstream of the gene is shown as a line. The regulatory sequences present in the different white alleles studied are represented as follows: enhancers of eyes (E) and testes (T) by boxes; Idefix insulator by a hatched rectangle; promoters by arrows; and the 5′-UTR of ZAM bearing an eye enhancer (Uz) by a dotted box. Pointed arrows indicate the activating effects of the eye enhancers. Plain lines indicate the activating effect of the testes enhancer. Names of the alleles and the eyes and testes colors of their corresponding lines are indicated on the right.