Fig. 1. Light field (A,E,I) and corresponding dark field micrographs comparing the expression of Wnt5b (B,F,J) and Wnt11 (D,H,L) with Ihh (C,G,K) in the skeletal elements of the developing wing at stages 28 (A-D), 34 (E-H) and 37 (I-L). Bars, 500 µm. h, humerus; r, radius; u, ulna. HE, haematoxylin and eosin-stained sections. In H and L, arrowheads point to Wnt11 expression in a subset of the prehypertrophic chondrocytes.