Movie 2.

Example of elongating chimeric gastruloid in 0.8mM dextran gel. Chimeras are constituted of 129/svev cells and a small fraction of cells expressing a nuclear marker H2B-iRFP. Gastruloid contour was extracted using brightfield images and plotted in blue. Video shows fluorescence as well as tracks extracted using TrackMate. The same gastruloid was used to produce Fig. S10A.