Modeling Gastrulation in the Chick Embryo: Formation of the Primitive Streak
Figure 5
Formation of the primitive streak for different chemotactic mechanisms.
(A) Typical concentration of a chemotactic agent produced by ST cells (mechanisms M2, M2b and M4). Gray-scale indicates concentration from 0 (black) to 1.5 (white). (B) Typical pattern at 7000 time steps beginning from Fig. 3D, when ST cells produce a repellent for AP cells (βk = −60 for AP cells) (mechanism M2). See Supplementary Materials Movie S5 for a movie of this process. (C) Typical pattern at 7000 time steps beginning from Fig. 3D, when ST cells produce a repellent for AP and AO cells (βk = −60 for AP cells and βk = −15 for AO cells) (mechanism M2b). (D) Typical concentration of a chemotactic agent produced by S cells (mechanisms M1, M3). Gray-scale indicates concentration from 0 (black) to 1.5 (white). (E) Typical pattern at 7000 time steps beginning from Fig. 3D, when S cells produce a repellent for ST cells (βk = −40 for ST cells) (mechanism M3). See Supplementary Materials Movie S7 for a movie of this process. (F) Typical pattern at 7000 time steps beginning from Fig. 3D, when ST cells produce an attractant for S cells (βk = 40 for S cells)(mechanism M4). Chemotaxis follows Eq. 4. with βk = 0 if a cell does not respond chemotactically. In (A)–(F) J3,3 = J4,4 = 2, J3,4 = 4, other values as in Eq. 2. In (E) and (F) J2,4 = 9, other values as in Eq. 2. See Simulation Details for other parameter values. Simulations generated using the code in Supplementary Materials, Code S1.