Faʻatupu se faʻamatalaga sili atu ona faigata o lenei fuaiupu Semaphorin - neuropilin repulsive signaling galue faʻatasi ma le EphB faʻailo e taʻitaʻia neural crest sela i lalo o le rostral afa o somites i isumu.
O le mea moni, o se lomiga e sili atu ona lavelave o le fuaiupu o le "Semaphorin - Neuropilin repulsive signaling works synergistically with the forward EphB signaling to guide neural crest cells down the rostral half of somites in mice ; in chick embryos, semaphorin acts in the cephalic region to guide neural crest cells through the pharyngeal arches. "