Fig. 2. Large how^stru mutant clones exhibit broadening of the Spalt, the DPP direct target, domain. Wild-type wing imaginal discs (A-D) or wing imaginal disc with large how^stru mutant clones (E-H) stained for HOW (red; A,E), Spalt (green; B,F) and Engrailed (blue; C,G). (D,H) Merged images of HOW (red) and Spalt (green) expression. Arrowheads indicate the anteroposterior boundary. (I) Quantification of the Spalt (Sal) domain width in wild-type (WT) or in mutant (CLONES) discs is given as the ratio between a cumulative value representing Spalt width (in upper, lower and middle regions) and the wing imaginal disc width (Sal/disc).