Fig. 6. Spatial relationship of the expression domains of mes-met genes in Otx2^hOtx1/hOtx1 embryos at E10.5. (A) The normal expression patterns of Wnt1, Fgf8, Pax2, En1 and En2 in the mid/hindbrain region at E10.5 (Joyner et al., 2000). (B-F) In situ hybridization analysis of expression of Fgf8 (B), Wnt1 (C), Pax2 (D), En1 (E) and En2 (F) on near adjacent sagittal sections of a Gbx2^–/–; Otx2^hOtx1/hOtx1 embryo. Note that the posterior limits (arrows) of the expression domains of Wnt1, Fgf8 and Pax2 are similar, whereas the expression domains of En1 and En2 encompass those of Wnt1, Fgf8 and Pax2 and their posterior limits (arrowheads) are successively extended more caudally, with a decreasing gradient.