Fig. 7

Morphology of wild-type and syu pectoral fin buds. Cross sections through fin buds performed perpendicular to the P/D axis of the fin bud. (A,B) Pectoral fin buds at 32 hours; (C,D) pectoral fin buds at 38 hours; (E,F) pectoral fin buds at 72 hours. (A,C,E) Wildtype fin buds; (B,D,F) syu fin buds. An apical fold (af) is not present in syu buds at 38 hours (D), but is present in some syu buds at 72 hours (F). Note the reduced size of syu buds compared to wild-type buds. The syu apical fold does not develop into a fin fold, which is well developed in wild-type fins at 72 hours (E,F). Note the absence of differentiated tissues in syu buds at 72 hours. ae, apical epicermis; af, apical fold; dm, dorsal musculature; en, endoskeletal disc; ff, fin fold; mbv, marginal blood vessel; mes, mesenchyme; vm, ventral musculature.