A study from the lab of MIT professor Jonathan Weissman, reported in the journal Cell on Oct. 8, 2026, and described in an MIT report published Oct. 28, 2026, traced the family history of over a million cells during mouse embryo development. The researchers combined cell lineage trees, produced by a tool called PEtracer that makes heritable DNA changes as cells divide, with gene activity and cell location data from embryos collected at closely spaced developmental stages. Collaborators included Zachary Smith's group at Yale University and the Max Planck Institute for Molecular Genetics.

The authors describe the work as a detailed developmental map of a mammal, assembled from snapshots into a continuous view of how cells divide and take on tissue and organ roles. Weissman said the map shows how genomic information plays out over space and time. The researchers suggest such maps could help clarify when cells diverge during birth defects, when cancer cells acquire traits such as the ability to spread or resist treatment, and which cell states precede mature cell types in stem cell research.

The study is preclinical mouse research, not a clinical result or medical guidance. Its claims concern a research resource and its potential uses.