The highly conserved receptors and pathways can be organized into four major families based on similar structures: fibroblast growth factor (FGF) family, Hedgehog family, Wnt family, and TGF-β superfamily.
Estes receptores e vías moi conservados poden estar organizados en catro familias principais baseadas en estruturas similares: familia do factor de crecemento de fibroblastos (FGF), familia de Hedgehog, familia Wnt, e superfamilia do TGF-β.