A Multi-cell, Multi-scale Model of Vertebrate Segmentation and Somite Formation
(A–D)The number of in silico Lfng stripes in the PSM is independent of the PSM growth rate for fixed segmentation-clock period and minimum (anterior) concentration of FGF8. Faster/slower PSM growth stretches/compresses the Wnt3a profile, stretching/compressing the Lfng concentration stripes. (A) Slow PSM growth rate ( = 0.82 µm/min). (B) Reference simulation (PSM growth rate = 1.63 µm/min). (C) Fast PSM growth rate ( = 3.27 µm/min). (D) Rescaling the length of the PSM in (A) and (C) to match the reference simulation in (B) demonstrates that the three cases are equivalent after accounting for the expansion or compression of the Wnt3a gradient. (E–G) The number of in silico Lfng concentration stripes in the PSM depends on the PSM growth rate for a fixed segmentation-clock period and PSM length. When the PSM length, rather than the minimum (anterior) FGF8 concentration, is fixed, faster/slower PSM growth decreases/increases the change in Wnt3a concentration between the posterior and anterior ends, decreasing/increasing the number of Lfng concentration stripes in the PSM. (E) Slow PSM growth rate ( = 0.82 µm/min). (F) Reference simulation (PSM growth rate = 1.63 µm/min). (G) Fast PSM growth rate ( = 3.27 µm/min). Anterior to the left. Scale bar 80 µm. The color scale is the same as that in Figure 5 (red indicates high concentration of Lfng and blue low concentrations of Lfng). Parameters, when not otherwise noted, are equal to those in the reference simulation (Figure 7). For more information see RESULTS: The number of high Lfng concentration stripes in the simulated PSM depends on the segmentation-clock period.