MO knockdown: pigment cell differentiation markers, in situ hybridizations. (A) Histogram of tail iridophore counts. Both MOs were injected at 2 mg/ml. The mean number of tail iridophores per embryo ± SEM are depicted for uninjected (n = 60), morpholino injected (n = 107), and mismatch morpholino injected (n = 83). (B) Presumptive iridophores expressing ednrb1 (endothelin receptor b1) are absent from Foxd3 morpholino-injected embryos. (C) Melanoblast marker dct (dopachrome tautomerase) is unaffected. (D) Xanthoblast marker xdh (xanthine dehydrogenase) is slightly reduced in the trunk.