Conserved basic CNS genoarchitecture in bilaterians. (A) Expression of Fezf and Gbx2 in Xenopus neurula showing a gap between the expression of both genes (left) at the neural plate and expression of Fezf (blue) and Irx1 (purple) showing (right) abutting expression domains. (B) Expression of Fezf and Gbx in (left) the amphioxus neurula and expression of Fezf (purple) and IrxB (red) showing (right) abutting expression domains. (C) Schematic representation of Drosophila CNS (protocerebrum (P), deutocerebrum (D) and tritocerebrum (T) correspond in vertebrates with the forebrain, midbrain and hindbrain, respectively) showing the expression of (left) the dFezf (earmuff/CG31670), Irx (mirr) and Otx (otd) (Gbx (unpg) is expressed latter abutting Otx , and lateral view of the expression patterns of Fezf (purple) and mirr (orange). Anterior is to the left, dorsal views unless otherwise specified. Insets in (A) Xenopus and (B) amphioxus correspond to single in situ hybridization of Fezf.