Fig. 5. Comparison of Dlx5^-/- and Dlx6^-/- head skeletal phenotypes and branchial arch gene expression changes. (A) Structure of the Dlx6-lacZ (Dlx6-) allele. Black boxes, exon coding region; white boxes, untranslated region; red boxes, homeodomain; blue bars, PCR primers for genotyping. (B-J) Head skeleton and skeletal elements of E18.5-P0 mice stained with Alcian Blue (cartilage) and Alizarin Red (bone). (B-D) Lateral views of the whole head. (E-G) Dentaries. (H-J) Otic capsules and associated skeletal elements. Arrows and arrowheads indicate the skeletal abnormalities of the mutants; see text for details. (K-V) Lateral views of E10.5 mouse embryos processed by whole-mount in situ hybridization. Arrows and arrowheads, downregulation (K-P) or upregulation (Q-V) of expression in the mutant mdBA1 and BA2, respectively. agp, angular process; cdp, condylar process; crp, coronoid process; GN, gonial; IP, interparietal; MC, Meckel's cartilage; NA, nasal bone; OC, otic capsule; OP, os paradoxicum; TY, ectotympanic; for remainder, see legend to Fig. 4. Scale bar: 1 mm.