Fig. 7. QT6-Shh cells grafted in presumptive BA2 or in the post-optic region do not induce BA1 extra-skeletal pieces. (A) Graft of QT6-Shh cells in the presumptive BA2 territory in a 9 ss chick embryo (dotted circle). (B,C) At E11, the grafted embryo shows a normal beak morphology but presents a larger otic vesicle (arrow). No ectopic skeletal structure is observed. (D-G) Facial views of E3-4 BA2-grafted embryos. (D) Shh expression is reduced in BA2 grafted side (arrows), when compared with the control side. (E) Bmp4, (F) Fgf8 and (G) Pitx1 expression is not affected. (H) QT6-Shh cell graft in the presumptive post-optic region of a 5 ss chick embryo (dotted circle). (I,J) E11 operated chick embryo shows normal morphology and skeletal structures on the grafted side. (K,L) Induction of Bmp4 and Pitx1 expression in the post-optic region (arrows) where these genes are not expressed in control side (K',L').