ABSTRACT
The biological signicance of apparent redundancy is a very promising area of fertile research (Ripamonti et al. 2001, 2004, 2014a; Ripamonti 2004). The bone morphogenetic proteins (BMPs), together with the three mammalian and the amphibian transforming growth factor-β isoforms (TGF-β1, -β2, -β3, and -β5, respectively), form a triad of subfamilies consisting of 40 or more homo-or heterodimeric structurally related morphogens that belong to the TGF-β supergene family (Wozney et al. 1988; Kingsley 1994; Massagué 2000). All the listed morphogens of the family play pleiotropic roles in axial patterning, tissue morphogenesis, and organogenesis in both vertebrates and invertebrates (Wozney et al. 1988; Reddi 2000; Ripamonti et al. 2005; Ripamonti 2006).
