Fig. 11. Parallel forces in axial elongation. (A,B) In normal embryos, elongation of the posterior neural ectoderm (blue), dorsal mesoderm (red), and ventral tissues (green) all contribute to the generation of a straightened and elongate A/P axis. (C) In embryos injected dorsoanimally with Xdsh-D2, strong inhibition of neural convergent extension and mild effects on mesodermal convergent extension conspire to generate a dorsally kinked and foreshortened A/P axis. (D) In dorsovegetally injected embryos, strong inhibition of mesodermal convergent extension results in a shortened axis, while neural and ventral elongation produce a straight axis. (E) In grafted Xdsh-D2 embryos, the embryo is dorsally curved, owing to the failure of neural convergent extension, and mesodermal convergent extension elongates the axis, though not completely.