Figure 1

Oc-Ubx(RNAi) and Oc-abd-A(RNAi) lead to homeotic transformation of Orchesella abdominal appendages. All panels show first instar Orchesella larvae, whose mothers were injected with dsRNAs. (A-C) lateral views, head on the left; (D-F) ventral views, anterior to the top. (A, D) Control RNAi. The larvae look normal. They have three pairs of thoracic legs, which are all visible in (A), a collophore on A1, a retinaculum on A3, and a furca on A4; the retinaculum is hidden in (A), but visible and enlarged in the inset in (D). In both (A) and (D) the collophore is false coloured in magenta, the retinaculum in yellow and the furca in green. (B, E) Oc-Ubx(RNAi) larvae are abnormal in that the collophore is replaced by a pair of walking legs on A1 and the retinaculum is replaced by a furca on A3; the homeotic furca is hidden in (B), but visible in (E). (C, F) Oc-abd-A(RNAi) larvae are abnormal in that they have a collophore on A3 and legs on A4. The homeotically transformed appendages are labeled in yellow in all pictures. T3, A1, A3 and A4 in (A-C) mark the third thoracic, the first, the third and the fourth abdominal segments, respectively; in (D-F) their appendages. The white arrowhead in (E) points to the ventral groove. c, collophore; f, furca; r, retinaculum; wl, walking leg. Scale bars: in (A), 200 μm for (A-C); in (D), 200 μm for (D-F); inset, 10 μm.