Fig. 5.

Summary of chevron dynamics. Time of somite formation, approximate start of muscle differentiation (including cellular rearrangements and shape changes), and chevron formation start and end time are sketched as a function of segment index. Segments 1–7 differentiate simultaneously, i.e. anterior-most segments delay differentiation by up to 3 h after segmentation. Chevron formation of segments 1 and 2 is not detectable. Segments 4–7 deform simultaneously. Segments posterior to segment 7 differentiate and deform sequentially. For any segment, chevron formation takes 2 h from onset until the final angle is reached.