Figure 5.

aldh1a2 expression in zebrafish and Mexican tetra embryos. A–H) aldh1a2 expression in embryos at 26 hpf for zebrafish and 27 hpf for Mexian tetra. Arrows indicate expression in the caudal branchial arch; arrowheads denote expression in the dorsal retina. I–P) aldh1a2 expression at 44 hpf. Arrows indicate the 2 patches of cells in the ventral posterior pharynx in zebrafish (J) and the expression in the caudal branchial arch in Astyanax (N). White lines (K, O) demarcate the midline of the embryo; black lines (O) the limit of aldh1a2 expression in the pharynx toward the midline. Asterisks (D, H, K, L, P) mark the putative location of the induction of the first tooth. Note that this location is within the aldh1a2-positive cells for the zebrafish (K) but not for the Astyanax as marked by the black arrows (O). Scale bars = 100 μm.