How one cell gives rise to an entire body

One of biology's great mysteries is how a single fertilized egg gives rise to the multitude of cell types, tissues, and organs that fit together to make a body. Now, a combination of single-cell sequencing technologies and computational tools is providing the most detailed picture yet of this process. In three papers online in Science this week, researchers report taking multiple snapshots of gene activity in most of the cells in developing zebrafish or frog embryos. They then assembled those data, taken at intervals of just minutes to hours, into coherent, cell-by-cell histories of how those embryos take shape.