Fig. 4. Wing phenotypes in mutant flies. (A) Wild type. Homozygous dally mutant flies survive and sometimes (5%) display notches in the margin, which are symptomatic of reduced Wingless signalling (B). Distal truncation of vein 5 is also frequent but we have not attempted to characterise this further. The few homozygous dlp mutants that survive to adulthood (around 1%) have wings characterised by two fully penetrant phenotypes: a narrowing of the space between veins 3 and 4 (C), which suggests reduced hedgehog signalling (Crozatier et al., 2002) and (D) the formation of ectopic bristles on either side of the margin (arrowheads, compare with wild type shown in E), an indication of excess Wingless signalling. The same phenotypes are seen in surviving flies carrying the mutation (dlp^MH20 and dally^MH32) over a large deficiency (Df(3L) ED4543 dlp and Df(3L) ED4413 dally, respectively).