FIGURE 5

FIGURE 5

Complexities beyond the clock and wavefront (A). The regressing Wnt/FGF-based gradients from the posterior to anterior PSM specify the determination front, however, targets of these signaling pathways (green-Wnt; yellow-FGF) oscillate in the PSM, with changing phase relationships to Notch signaling targets (grey) (B). The period and the phase of cyclic gene oscillations change along the length of the PSM (C). The period of the segmentation clock changes temporally as somitogenesis proceeds (D). The anterior and posterior body segmentation are plausibly regulated by separate mechanisms. Illustrations adapted and modified from (Schröter et al., 2008; Lauschke et al., 2012).