Fig. 1. Expression of fgf8 (B-F) and fgf3 (G-L) during development of the zebrafish embryo forebrain. Lateral (B-D,F,G,J-L) or dorsal (E,H,I) views with anterior to the left. The eye was removed in F and L to facilitate observation of expression in the brain. (A) Diagram depicting brain subdivsions and structures relevant to this study in a 24 hpf embryo. (B-F) fgf8 expression at tailbud stage (B), during early somitogenesis (C), late somitogenesis (D,E; E, dorsal view focussed on the hypothalamic region) and 30 hpf (F). (G-L) fgf3 expression. (G) onset at 80% epiboly (arrow). (H,I) Dorsal views at 90% epiboly (H) and 2s (I), showing fgf3 transcripts in the forebrain and in presumptive rhombomere 4. Early (J) and late (K) somitogenesis, and 30 hpf (L). ac, anterior commissure; d, diencephalon; dd, dorsal diencephalon; dt, dorsal thalamus; ep, epiphysis; fb, forebrain; h, hypothalamus; hb, hindbrain; hpf, hours postfertilisation; i, isthmus; os, optic stalk; poc, post-optic commisure; pt, pretectum; r, retina; s, somites; t, posterior tuberculum; tc, tectum; tel, telencephalon; tg, tegmentum; vt, ventral thalamus. Asterisk indicates the zona limitans intrathalamica.