Overview
- Two companion papers published on Thursday used prime‑editing DNA recorders to reconstruct cellular family trees at unprecedented scale in mouse embryogenesis.
- Jay Shendure’s DNA Typewriter was inserted into a fertilized egg in an experiment started with 100 eggs that produced 10 embryos, and one highly informative embryo yielded lineage traces for about 1.3 million edited cells, roughly 10% of that embryo.
- Jonathan Weissman’s PEtracer system produced lineage maps covering more than 1.4 million cells aggregated from 16 embryos, giving a complementary, multi‑embryo view of development.
- Both teams used prime editing to write ordered, indelible marks that avoid the cell damage and unordered edits linked to earlier CRISPR‑cutting recorders, and those ordered marks let the groups estimate when lineages diverged—for example, blood and retinal lineages showed earlier commitment than the skin’s outer layer.
- The studies are framed as proof‑of‑principle that mammalian lineage maps can be built at scale and the next steps are scaling across more embryos, improving reproducibility, and applying the maps to study congenital disorders, cancer, regenerative medicine, and predictive models of development.