Gene-editing recorders map mouse embryo cell lineages

Nature reports that two teams used gene-editing cell recorders to reconstruct mouse embryo development at unprecedented scale. One traced relationships among 1.3 million edited cells, about 10% of the embryo; a separate Cell study recovered nearly 75% of divisions during a defined growth window. The methods could help study how development proceeds and fails, but they are research tools rather than a complete lineage map of every cell.