has potential to develop into forelimb limb bud forelimb bud Genes: Tbx5 specifies forelimbs. Wnt2b restricts Fgf10 in chick // In tetrapods, the position of the forelimb is associated with the anterior expression border of Hoxc6 in the paraxial mesoderm (Burke et al., 1995) pectoral appendage bud