Figure 2.

Phenotype of Ihh mutant mice. (A,C,E) Wild-type animals (Ihh ^+/+); (B,D,F) mutant animals (Ihh ^−/−). (A, B) 13.5-dpc embryos. The forelimb in the mutant embryo is significantly shorter than in the wildtype (white arrows). (C,D) Gross appearance of newborns. Note the rounded skull, shortened face and tail, and the severe dwarfism of the limbs in the mutant. (E,F) Skeletons of newborns stained with Alcian blue (cartilage) and Alizarin red (calcified tissue). General patterning of the skeleton is normal but all elements of the axial and appendicular skeletons are significantly reduced in size in the mutant.