Fig. 6. cyp26b1 mutants and morphants display precocious and increased ossification of vertebral centra in the developing vertebral column. (A-K) Alizarin Red stainings of zebrafish larvae of genotype indicated in the upper right corners and at stages indicated in the lower right corners. (A-F,I-K) Lateral views; (G,H) transverse sections. Arrows in A indicate time course of centra ossification, starting at centra 3/4. In contrast to the segmented ossification of the wild-type larva (A,D,I,K), the cyp26b1 mutant (C,J) and morphant (F) show uniform and caudally extended perichordal ossification. See text for details. bop, basioccipital articulatory process.