Fig. 2. Skeletal phenotype of the forelimb. Dorsal view of the left forelimb of wild-type, wild-type/raz and raz/raz embryos. Anterior is upwards in A-F and towards the right in G-I. (C) There are two holes in the scapula as well as a notch (arrow) at the vertebral border in raz/raz fetuses. The olecranon process of the ulna (arrow) is present in wild-type/wild-type fetuses (A,D) but not in raz/raz fetuses (C,F). Note the styloid process of radius and ulna arises from different sites, peripherally from the radius and centrally from the ulna in wild-type/wild-type (G') and wild-type/raz (H) fetuses. However, in raz/raz fetuses the styloid process of both bones originates peripherally (I), indicating both bones have characteristics of a radius. Note cartilage bar in carpus of raz/raz (red arrow in I). Nomenclature in G is according to Davis and Capecchi (Davis and Capecchi, 1994). Scale bars: in C, 1.0 mm for A-C; in F, 1.0 mm for D-F; in I, 1.0 mm for G-I.