Fig. 6. Estimated doubling times of squamous PE and columnar DP cells in wing, eye and leg (T2) imaginal discs during larval development. (A) Cell clones were induced (act5C<Gal4, UAS GFP) by heat-shocking larvae for 10-20 minutes at 37°C at the following times: first (42 hours AED), second (48, 52, 60 hours AED) and third instar (72, 84, 90, 96 hours AED). Below the timeline are eight horizontal lines, the left end of the horizontal lines indicate the time of clone induction the right end indicate time of fixation for clone analysis of each experimental set. W (wing), E (eye) and L (leg) indicate the discs analyzed for each clone induction. A vertical mark in each horizontal line represents the mid-point between clone induction and fixation (=average clone age). Estimated cell doubling times are plotted at this mid-point. At each time interval more than 100 clones were scored in over 50 discs. Data represent median cell doubling times±s.d. Cell doubling times of squamous PE cells (blue circles) and columnar DP cells (red squares) in the wing (B), leg (C) and eye (D) imaginal discs.