The Weissman Lab developed a method, dubbed "ReDeeM," for tracing the ancestry of human blood cells and mapping a cell’s lineage to its current behaviors. Researchers hope that, by monitoring changes in human blood cells in real time, ReDeeM could one day be used to predict disease risk years before symptoms show up. The lab is applying the technique, described in Nature, to learn more about blood cancers, autoimmune disorders, and the origins of certain types of blood cells.