Fig. 1. Dorsal clearance of Bmp gene transcripts and concomitant formation of a dorsoventral Fgf gradient. (A-C) Expression of bmp2b at sphere stage (A), 30% epiboly (B) and at shield (C) stages. (D-F) Expression of bmp7 at sphere (D), 30% epiboly (E) and at shield (F) stages. (G) Expression of bmp2b at 30% epiboly in embryo injected with a chd morpholino (mo-chd). (H) Expression of bmp2b at 30% epiboly in an embryo injected with chd RNA. (I) Expression of dharma (dha) in wild-type embryo at 30% epiboly (inset provides a lateral view of the same embryo). Expression of dha is restricted to the yolk syncytial layer (y). Expression of (J) fgf8 at sphere stage, (K) fgf3 at 30% epiboly and (L) fgf24 at 30% epiboly. (M-O) Expression of spry4 at sphere (M), 30% epiboly (N) and late blastula (O) stages. Embryos are oriented dorsal towards the right. A-I,O are animal pole views; J-N are lateral views.