Movie 2.

Mathematical modelling predicts that ectoderm divisions both challenge and refine the ME boundary. Simulations of mesectoderm ingression in control embryos (top left), with an acute loss of tension at the ME interface (bottom left), without ectoderm cell divisions (top right), or with simultaneous acute loss of tension at the ME interface and inhibition of ectoderm cell divisions (bottom right). Magenta, ectoderm; teal, mesectoderm. Anterior, left. Time zero corresponds to the time in which the mesectoderm width starts decreasing. Images were generated every 10 minutes.