Figure 4D. Copyright: Reprinted with permission from Elsevier from [doi:10.1016/j.mod.2008.04.006] Mech Dev 125: 687-99, Heanue TA; Pachnis V, "Ret isoform function and marker gene expression in the enteric nervous system is conserved across diverse vertebrate species."Copyright 2008. [PMID:18565740]