Fig. 3. Abd-B misregulation in A7 of F8F7 hemizygous females. Although F8F7 homozygotes look essentially wild type, the hemiyzgous females F8F7/Df(3R)P9 harbor occasionally features reminiscent of Fab-8 homozygotes. (A) +/Df(3R)P9 hemizygous female. Note the narrow shape of the sternite on A7 with bristles pointing towards the posterior. (B,C) Two examples of F8F7/Df(3R)P9 females harboring opposite homeotic transformations. The cuticle in B has a wider seventh sternite with bristles oriented towards the lateral side similar to the sternite found on A6 (an iab-7 loss-of-function phenotype). The cuticle shown in C has spots of naked cuticle on the seventh tergite. Careful examination reveals the absence of trichomes in those spots, indicating a transformation towards A8. These opposing phenotypes are reminiscent of Fab-8 mutations in which A7 can be a mixture of A6 and A8 identity (Barges et al., 2000), suggesting that boundary function is slightly impaired in F8F7.