We are all mosaics: vast genetic diversity found between cells in a single person
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Article Date: 25 November 2025
Article URL: https://www.nature.com/articles/d41586-025-03768-0
Article Image: https://media.nature.com/lw767/magazine-assets/d41586-025-03768-0/d41586-025-03768-0_51720294.jpg
Summary
Researchers performed whole-genome sequencing on more than 100 individual cells from a single 74-year-old man and uncovered extensive genetic mosaicism: large chromosome-arm gains and losses, smaller deletions and duplications, and frequent loss of the Y chromosome in some cells. The results, reported as a preprint, act as a pilot for a US$140-million consortium that will catalogue somatic mutations across many tissues and donors.
The study highlights advances in single-cell DNA-sequencing technologies and illustrates why bulk sequencing misses rare, cell-specific variants. It links accumulated somatic mutations to ageing and disease risks — notably the association between loss of the Y chromosome in blood cells and increased cardiovascular risk — and sets the stage for a systematic atlas of mosaicism across the body.
Key Points
- Whole-genome sequencing of over 100 single cells from one donor revealed widespread genetic differences between cells (mosaicism).
- Detected changes include missing or extra chromosome arms, small deletions and duplications, and complete loss of the Y chromosome in some cells.
- The work is a preprint and serves as a pilot for a large, well-funded consortium aiming to map somatic mutations across tissues and 150 donors.
- Somatic mutations accumulate with age and can drive diseases such as cancer; loss of the Y chromosome in blood has been linked to higher cardiovascular risk.
- Single-cell DNA sequencing is technically challenging because each cell contains only two genome copies, making rare-variant detection harder than in bulk or RNA sequencing.
Context and relevance
This study deepens our view of how somatic mutations accumulate within individuals and how cellular genetic diversity — mosaicism — might influence ageing, cancer onset and tissue-specific disease vulnerability. The forthcoming consortium catalogue will be a valuable resource for researchers seeking to connect cell-level mutations with clinical outcomes, and could inform early-detection and risk-assessment strategies.
Why should I read this?
Short version: your body is a genetic patchwork. If you care about ageing, cancer biology or why a few rogue cells can change health outcomes, this is worth a skim — and the full study is worth a proper read because it kicks off a major effort to map these changes across tissues.
Author style
Punchy reporting that frames the work as a technical tour-de-force and the opening move in a large consortium effort. For genomics and clinical researchers the study is highly relevant — it’s the sort of result that will shape follow-up studies and clinical thinking.