Fig. 7. Clonal relationship between the wing disc epithelial layers. PE-specific cell clones induced during the second larval instar (48-72 hours AED) using UAS-flp-EBD, Ubx-Gal4 and act5C>stop>nuclacZ. Analysis of clone distribution and frequency was performed in 110 hours AED larvae. (A) Clones with 1-3 cells are present and also a clone with 30+ cells limited to the sPE (yellow asterisks). Cuboidal cell clones are also present at the disc margins in either the PE or DP (arrows), as is a clone that includes squamous and margin cells of both epithelial layers (yellow arrowhead). Scale bar: 50 µm. (B-B'') A z-series of confocal images of the boxed region in A. Teashirt labels squamous PE cells and margin cells in both PE and DP, ß-gal labels clones. Images in the PE (B,B') and the DP (B'') showing a clone that consists of both squamous PE cells and margin cells present in both the disc epithelia. (C) Distribution and frequency of clones born in the wing disc PE during the second (48-72 hours AED) and third (72-96 hours AED) larval instars. sPE, clones of squamous cells in the PE; mPE, clones of margin cells in the PE; mDP, clones of margin cells in the DP; sPE+mPE+mDP clones of squamous PE cells and margin cells in both the PE and DP.