DNA recording system reveals how a single cell becomes a body
Scientists have traced the development of a mouse embryo from its first two cells to the formation of organs, using a remarkable DNA recording system that reveals the family history of individual cells. Their findings uncover how different cell types emerge on their own schedules and could help explain what goes wrong in birth defects, genetic disorders, and cancer.
Key points
- Scientists used a DNA recording system to trace cell ancestry in a developing mouse embryo.
- The record covered the first 13.5 days of development in mice.
- The two first cells produced similar ratios of diverse cell types.
Scientists have reconstructed a detailed family tree of cells in a developing mouse embryo, tracing their origins to the first division of a fertilized egg. The work used a DNA recording technology to follow how early cells multiplied and took on specialized roles, according to findings published on October 8, 2026, in the journal Science.
The recording covered the first 13.5 days of embryonic development. Full gestation in mice is 19 to 21 days. The research was led by Dr. Jay Shendure of the University of Washington School of Medicine in Seattle and Dr. Chengxiang Qiu of Dartmouth College in New Hampshire, who served as senior authors.
How the DNA Typewriter works
The technology, called DNA Typewriter, was developed by Shendure and Junhong Choi, now at Sloan Kettering Cancer Center. The researchers inserted a redesigned recording sequence, called a tape, into the genome of a fertilized mouse egg.
Haedong Kim, a co-first author, said the system types onto a cell's own DNA instead of paper. Each cell division adds one new character in order without overwriting earlier ones, so the sequence spells out the cell's division history. Kim said the tape was redesigned to make reading the record easier.
Every time a cell divides, it strikes one new character onto the next blank line -- always in order, never overwriting what's already there.
— Haedong Kim
What the recordings showed
The researchers began with 100 fertilized mouse eggs, and 10 embryos were ultimately available for examination. One specimen, Embryo No. 3, preserved the most extensive history and received detailed analysis.
A recording made right after the first cell division showed a clear mark distinguishing the two founding cells. Kim said one produced more descendants than the other, but both produced diverse cell types at almost equal ratios. The recordings also indicated blood cells and the retina committed relatively early, while the skin's outer layer committed noticeably later.
Possible medical implications
The findings could help scientists understand normal development and what happens when it goes wrong. Shendure said the work gives a map of how one cell becomes a whole body, which helps explain organ formation, birth defects and cancer, and could guide stem cell engineering for therapeutic use.
The study was conducted in mouse embryos and does not yet represent a direct medical treatment. Additional co-first authors included Qi Yu and Sophie Seidel. The research received support from several institutions, including the Seattle Hub for Synthetic Biology and the National Institutes of Health.
