Fig. 4. Antenna duplication by DLL induction. (A-F) Eye discs stained with an -DLL antibody (B,D,F) expressing UAS-P35 under the control of ey-Gal4 in an ey² mutant background. (A,C,E) Brightfield microscopy pictures of eye discs shown in B,D and F, respectively. (A,B) Late second instar, (C,D) early third and (E,F) late third instar eye discs. DLL is gradually induced (D), independently of endogenous DLL expression in the antenna, and leads to a transformation of the eye disc into an antennal disc (F). (G,H) The duplication of the antennal disc leads to a duplication of the adult antenna with all segments present, and the duplicated antenna in the location of the missing eye (arrows in G,H).