Figure 4. Additional simulations.

When lamellipodium action is totally disabled in the model (Case S4), the resulting NTD embryo has features very similar to those produced when microinjected mRNA is used to disrupt the PCP pathway (Wallingford and Harland, 2002). When forces in the neural ridges assumed to be produced by Shroom are turned off in the model (Case S5), it predicts a final geometry consistent with that produced in Xenopus embryos when Shroom3 is disabled using an antisense morpholino oligonucleotide (Haigo et al., 2003). Case S6 shows an embryo in which the tensions in the NNE have been doubled and Case S7 shows an embryo in which the thickness of the epidermis and mesoderm have been doubled. All of the cases shown in this figure were run for extended periods of time and all give rise to NTDs as their final configurations, illustrated here, show.