Specificity of Dnd1 knockdown. (A) Morphology of uninjected control (brown), AS-oligo-injected (blue), and AS-oligo- and tropicalis dnd1-injected (red) embryos at stage 25. (B) Summary of experiments shown in A. (C) RT-PCR results showing the expression of noggin, chordin, Xnr3, siamois and dnd1 in control, AS-oligo-injected, and AS-oligo- and tropicalis dnd1-injected (rescued) embryos at stage 10.5.