Plays a crucial role in pectoral fin bud outgrowth. Not clearly detected before 12 and 14 hpf. At 18 and 24 hpf, detected in the otic vesicle, telencephalon, and caudal fin. At 30 and 36 hpf, expressed in the otic vesicle, caudal fin, branchial arch, pectoral fin bud, and pituitary gland. Fishes shown a severe reduction in the size of the pectoral fins. Belongs to the heparin-binding growth factors family.