Fig. 7. Mis-expression of Dup is sufficient to induce polyploidy of wing disc cells. Larvae were subjected to three heat pulses over 30 hours and wing discs were labeled with DAPI and examined by fluorescence microscopy (A,C,E,G) or by Hoechst 33342 staining and analyzed by FACS (B,D,F). Arrows indicate giant polyploid cells and arrowheads, cell death. (A,B) Wild-type. (C,D) Myc:FL-Dup. (E,F) Myc:Dup 10(A). (G) High magnification of one polytene nucleus from a wing disc over-expressing FL-Dup. Polytene chromosome arms can be seen radiating from a heterochromatic chromocenter that labels brightly with DAPI. Scale bar: 10 µm.