Hard palate defect in β-Catenin cKOs. (A–F) Shox2 in situ at stages indicated. Note comparable Shox2 expression in E12.5 (B), altered expression domain in E13.5 (D) and reduced expression in E14.5 (F). (I, J) Tbx22 in situ showing comparable posterior expression in both genotypes. (K–N) Barx1 in situ showing comparable expression in the cKO, note that the Barx1-negative region in the cKOs (L, N) is smaller than the controls (K, M). The A–P expansion of the hard palate was indicated by double-headed arrows in C–F and I–N. (G–H, and O) Skeletal preparation of E17.5 embryonic heads showing a smaller palatine bone (Pl, highlighted in O) and reduced A–P expansion of palatine bone and maxillary processes (Mp) (distance between two colored vertical lines in the scaled schematic representations) in the mutant (n=4 for each experiment, p<0.001 for the size of Pl, p=0.014 for A–P expansion of Pl and Mp). Scale bars: 0.5mm.