Fig. 4

Cross section of pectoral fins stained with Alcian blue. Wild-type embryos showed well-developed apical folds and organized chondrocytes at 37 (A), 48 (C), and 72 hpf (E). The tbx5a morphant showed severe pectoral fin hypoplasia with loss of the apical fold, reduced chondrocytes, unorganized chondrogenic condensation and endoskeletal disc at 37 (B), 48 (D), and 72 hpf (F). (af, apical fold; cc, chondrogenic condensation; dm, dorsal musculature; dmm, dorsal myogenic mesenchyme; ed. endoskeleton disc; vm, ventral musculature; vmm, ventral myogenic mesenchyme; pe, peritoneal epithelium; y, yolk).