Many new lineage tracing techniques are emerging, for example some that harness CRISPR-Cas9. These techniques are being added to the wealth of traditional methods that are used to explore the trajectories that every cell has in a developing and dynamically changing organism. Tracing lineage helps labs to assess the past, present and future of cells: stem cells, organs, the hematopoietic system and whole organisms.
To follow lineage, labs look for the descendants of a given cell by uniquely labeling it and its offspring. They might use one of many types of labels that are inserted into the genome to do so. As single-cell analysis methods have gained traction, scientists want to give lineage tracing single-cell resolution.