Video 2. A simulation of the morphogen-limited model corresponding to Figure 1C spans developmental stages E15.5 to P14 at 1 hr intervals.
The concentration of the diffusible morphogen is shown on a spectral scale from blue as zero to red as the maximum, 0.20 pM. The white curve bounds the region in which a concentration exceeding the threshold value = 0.04 pM inhibits cellular proliferation.