Fig. S3

Fig. S3

Division Orientations and Geometry Models of Cell Shape Distribution, Related to Figure 3

(A) Centrioles and spindles highlighted by tg(actb2:EMTB-3GFP) embryos (Wühr et al., 2010). Arrows: centrioles. Scale Bar: 10µm.

(B) Division orientation angle distribution. n = 128. Angles between the straight line through anaphase daughter nuclei and the surface are measured.

(C) Changed division orientation by squishing. Dashed lines showing the agarose canyon walls pressing on the edge cells of a 16-cell stage embryo. The blastomere (Arrow) becomes flattened and divided twice along the canyon wall, while it normally divides perpendicularly at the 2nd division. Scale Bars: 100µm.

(D) Changed division orientation by oil drop injection. Dashed white circle highlights the injected oil drop inside one of the 8 early blastomeres. This blastomere (Arrow) bulges at the top surface. Consequentially it divides perpendicularly to the surface generating an aberrant S-D division. Dashed lines highlight division orientation. Scale Bars: 100µm.

(E) Morphogenesis predicted by a pure geometry-division model (no mechanical coupling), applying the division rule Th = 1.3 and using 128-cell stage cell shape distribution as initial input. The result is oscillating < L/R > instead of observed gradual flattening.

(F) Spatial distribution of shapes. Cells were randomly sampled from different distances of the animal pole (projected distance ignores the surface curvature). Cells of different L/R ratios are found at different locations therefore spatially correlated heterogeneity of shapes is unlikely underlying the shape distribution.

(G) Correlation between V_C and L/R at all time points. V_C does not predict L/R ratio of the cell therefore the volume distribution is unlikely underlying the shape distribution.