English: Simulation of normal chick gastrulation. Different views of videos showing simulations of normal embryo development (the videos are synchronised with each other). Left column: all cells in the embryonic epiblast are shown in white, confined by the marginal zone (green). In the upper panel, the lower layers are displayed in the background, the hypoblast in pale brown and the endoblast in pale green; in the lower panel, only the epiblast cells are shown. The epiblast cells performing oriented intercalation in the posterior crescent are shown in orange and the early ingressing cells in blue. Cells ingressing by a community effect are displayed in pink. See also Figures 6, 7, Tables 2 and 3, and ‘Materials and methods—Description of the Model for details and colour codes. Middle column: cell movements in the epiblast. In the upper panel, horizontal bands of cells are coloured differently, to allow comparisons with the results in Gräper 1929; in the lower panel, cells in the posterior domain were coloured green and groups of cells in other epiblast locations in red, allowing comparisons with the experimental observations presented here (Video 8). Lower right panel: global movements in the epiblast. A uniform grid of individual objects were tracked over time, and their trajectories are time-coded in rainbow colours. Top right: pattern of ingression in the epiblast. The apical aspect of the epiblast is shown at the top, and its basal side in the lower side of the panel. Cells engaged in EMT are shown in blue, and the locations of completed EMTs in turquoise. Time indicated as hh:mm before (negative values) and after primitive streak formation, as for the experimental observations in Video 8. See also Figure 7F–H,K–J.

DOI:

https://dx.doi.org/10.7554/eLife.01817.027