Fig. 2. Expression of TId6 in trout embryos. The expression was identical using Id6a or Id6b riboprobe. (A) Stage 12 embryo (approximately 20 somites), dorsal view. The label is observed in the tail bud, the neural keel (white arrow), the rostral presomitic mesoderm (arrowhead) and the somites (arrow). (B) Stage 15 embryo (35 somites), lateral view. The label progresses caudally as somites form and is higher in the ventral and dorsal domains of the somites. (C) Stage 20 embryo (the segmentation is complete), lateral view. Axial structures as well as ventral (arrowheads) and dorsal domains of the somites are labelled. Scale bars: A, 230 µm; B, 400 µm; C, 600 µm.