“…Furthermore, genetic mutations of SCF and SCF receptor in Steel (SI) and Dominant white spotting (WW) loci, respectively, were associated with severe anemia (Broudy, 1997). Other factors such as basic ®broblast growth factor (bFGF, FGF-2), transforming growth factor a (TGFa) and members of the TGFb family, including TGFb, bone morphogenic proteins (BMPs) and activin A, are also involved (Krystal et al, 1994;Dickson et al, 1995;Huber et al, 1998;Mead and Zon, 1998;Gandrillon et al, 1999;Koritschoner et al, 1999).…”