Fig. 3. Analysis of the proliferation defect of cells in dve^P1738-mutant wing pouches. (A) An overlay of a wild-type (grey) and mutant (red) wing. The double-ended arrows show the distances between wing vein 3 and the anterior wing margin (labelled a), between vein 3 and vein 4 (labelled b), and between vein 4 and the posterior margin (labelled c). Distances are counted in cell numbers. The cell density was measured in three different areas (labelled d-f). The results are summarized in the table below (d-f, n=14; a and c, n=4; b, n=14 wings counted for each genotype). In the region between vein 3 and vein 4, no differences in the distance (b) and the cell density (e) were observed. These results confirm the observation that both wings are of the same size in this region, as seen by the overlay of the wings. By contrast, anterior to vein 3 and posterior to vein 4 the distances in the mutant wings are shorter (a,c). Furthermore, the cell density is similar in the anterior area (see d) and even slightly lower in the posterior area (see e) in the mutant. This indicates that the observed reduction in size of these areas in the mutant is caused by having fewer cells. (B-F) Clonal analysis of dve^P1738. Clones were induced using hsFlp, and the wing imaginal discs were prepared 48 hours after heat shock. Discs are stained with anti-Dl and anti-ß-Gal antibodies. (B) dve^P1738-mutant clones revealed by the absence of the GFP marker. (C) The same disc as in B showing the expression of ß-Gal. The expression of ß-Gal is complementary to that of GFP, showing loss of staining in the wild-type clones and stronger staining in the dve^P1738-homozygous clones. (D) Expression of Dl (blue), GFP (green) and ß-Gal (red). The expression of Dl reveals the primordia of wing veins 3-5. The arrow indicates a wild-type clone with no obvious mutant counterpart. The arrowhead (B,D) points to a twin pair of clones in which the size of the mutant clone is dramatically reduced in comparison to its wild-type twin. (E) Expression of Dl in the disc also shown in B-D. The numbers highlight the primordia of the wing veins 3-5. A1-A3 labels the different areas in which the clones have been analysed. The results of this analysis are summarized in Table 1. (F) Another example of a dve^P1738-mutant clone bearing wing imaginal disc, showing expression of Dl (blue), ß-Gal (red) and GFP (green). The arrows indicate a pair of clones that are separated by a band of heterozygous cells. This separation has been found in a few cases. Arrowheads indicate a pair of clones that are adjacent to each other.