Gene expression analysis of the pharyngeal arches in EdnraEdn1/+ embryos. (A–T) Whole-mount in situ hybridization for Dlx2 (A and B), Fgf8 (C and D), Dlx5 (E and F), Dlx6 (G and H), Dlx3 (I and J), Pitx1 (K and L), Goosecoid (M–P), and Hand2 (Q–T) in E10.5 wild-type (A, C, E, G, I, K, M, O, Q, and S) and EdnraEdn1/+ (B, D, F, H, J, L, N, P, R, and T) embryos. Arrows indicate the junction of maxillary and mandibular arches. Yellow arrowheads indicate ectopic gene expression in the maxillary arch. hy, hyoid arch; md, mandibular arch; mx, maxillary arch.