UAS regulatory sequences drive expression of an Tag:HA-tagged Dfd::Scr chimaera. The entire N-terminus of Dfd extending to and including the specificity module (SM) is replaced with the analogous region from Scr in the encoded gene product. The region of the Dfd and Scr polypeptides from their YPWM motif through the N-terminal arm of their homeodomain, together with the intervening linker region, is referred to as the SM.
Denticle types usually limited to the first thoracic segment (T1) in the embryo are seen in T2 and T3 as a result of Dfd::ScrN.SM.Scer\UAS.T:Ivir\HA1 expression under the control of Scer\GAL4arm.PS. Ectopic cirri are also observed in these segments.