This reconstruction, produced by researchers from the European Molecular Biology Laboratory in Heidelberg, Germany using a technique called digital scanned laser light sheet fluorescence microscopy, shows the movements of all 16,000 cells in an 18-hour-old zebrafish embryo.
To make the film, the researchers injected a fluorescent protein into an embryo at the one cell stage. They began imaging at the 64-cell stage and recorded 370 images, each less than 3 thousandths of a millimeter apart, in multiple directions at 1,226 time points separated by 90 second intervals. The recording was performed at a continuous speed of 10 million voxels (or volume elements) per second, to generate more than 430,000 images totalling 3.5 terabytes of data.
When this enormous data set was used to analyse the three-dimensional pattern of cell division, a symmetry-breaking event was revealed. Before this event, the embryo has no left or right side and is said to be radially symmetrical. When this is broken, the bilaterally symmetrical body plan begins to emerge and the orientation of the future body axes can be accurately predicted.