Extended Data Fig. 8: Stress maps and hole opening locations near topological defects.

(a, b) Sketches of the two mechanisms of hole initiation at a tri-cellular vertex: (a) stress-dependent mechanism (model 1) where a large tension at cell-cell junctions favours hole initiation, and (b) strain rate-dependent mechanism (model 2), where a junctional elongation rate favours hole initiation. (c-f) Average isotropic stress comparisons of hole opening locations near half-integer topological defects: (c, e) model 1 and (d, f) model 2. (c, e) Average isotropic stress (c) and 95 th percentile of isotropic stress (e) overlaid with the location of holes in the frame of reference of the closest (left) -1/2 defect (n = 8555 defect and n = 55 holes) or a (right) +1/2 defect (n = 8553 defects and n = 30 holes). (d, f) Average isotropic stress (d) and 95 th percentile of elongation rate (f) overlaid with the location of holes in the frame of reference of the closest (left) -1/2 defect (n = 8555 defect and n = 69 holes) or a (right) +1/2 defect (n = 8553 defects and n = 90 holes). White symbols represent the centre and orientation of the defects. The black spots indicate the locations of opening holes. The 95th percentile is the value above which lies 5% of the field distribution. Domain size = 200 µm. The initial state of the simulations is under tension (soft gel case, see Supplementary Information Sec. I. G. for more details).