(A) Wing disc with ykiB5 mutant clones (marked by absence of lacZ, green) and homozygous wild-type clones (twin spots, bright green). In anterior cells, where Yki:V5 (red) is expressed under ci-Gal4 control these occur at similar size and frequency, but in posterior cells ykiB5 clones are rare and small. (B–G) Adult female wings from flies with sd-Gal4 driving expression of B) UAS-yki:V5, C) no UAS transgene, D) UAS-ykiS111A:V5, E) UAS-ykiS169A,S172A:V5, F) UAS-ykiS250A:V5 G) UAS-ykiS169DS172D:V5, H) UAS-yki-WW:V5 G) UAS-ykiS111A S168A S250A -WW:V5.