Fig. 4. Expression of sp8 and sp9 in the fin bud was downregulated in the zebrafish mutants with fin defects. (A-C) Dorsal views of the expression pattern of sp8 at 40 hpf. (D-F) Dorsal views of the expression pattern of sp9 at 40 hpf. (A) Expression of sp8 in the pectoral fin bud of a wild type embryo (black arrowheads). The expression in the pectoral fin bud was downregulated (red arrowheads) in hst (B) and dak (C) mutants, while a normal expression in the neural tube was still detected. (D) Expression of sp9 in the pectoral fin bud (black arrowhead) of a wild-type embryo. The expression in the pectoral fin bud was downregulated (red arrowheads) in hst (E) and dak (F) mutants, while a normal expression in the brain was still detected.