Whole mount images of embryos unilaterally co-electroporated with FoxD3MO and either ContMO (A,C) or TS18MO (B,D) at late gastrula, incubated to 5–6 somites (s), and processed by in situ hybridization for Sox10 (A,B) or Snail2 (C,D). (A-D) Co-electroporation of FoxD3MO with either ContMO or TS18MO disrupts Sox10 (A,B) and Snail2 (C,D) expression on the targeted side of the neural tube (asterisks; green in A’-D’). (E,F) Bar graphs representing the frequency of electroporated embryos that exhibit a severe, moderate, mild, or no reduction in Sox10 (E) or Snail2 (F) expression, indicating that Tspan18 knockdown has no impact on the severity of FoxD3-dependent specification defects.