# A New Aging Clock Reads Age From the Packaging Around DNA

_Evidence Level: Preliminary · Niu Z et al., Proceedings of the National Academy of Sciences of the United States of America, DOI 10.1073/pnas.2533687123_

*Histone modification clocks for robust cross-species biological age prediction and elucidating senescence regulation.*

- **Evidence Level**: Preliminary
- **Why this grade**: Lab work using 2,428 existing tissue datasets, cell experiments and flies; the samples are snapshots, so changes within the same person were not tracked.
- **Facts**: Design: Lab study · Funding: Deutsche Forschungsgemeinschaft (DFG)
- **Population**: Cell or computational study
- **Publication Types**: Journal Article
- **Journal**: Proceedings of the National Academy of Sciences of the United States of America
- **Sample Size**: 2,428 human tissue datasets, plus fruit flies
- **Authors**: Niu Z, Liu C, Fan Y, Gu L
- **Graded and published**: 2026-03-10
- **Last edited**: 2026-10-19
- **Topics**: Epigenetics, Biomarkers, Senescence
- **DOI**: https://doi.org/10.1073/pnas.2533687123
- **Free full text**: https://pmc.ncbi.nlm.nih.gov/articles/PMC12993953/
- **Original Source**: https://pubmed.ncbi.nlm.nih.gov/41805570/

## Summary

Scientists often estimate how old a body is biologically with so-called epigenetic clocks. Most of these read chemical tags sitting directly on DNA. A new study looks somewhere else: the histones. These are proteins that DNA winds around, like thread on a spool. They carry chemical tags too, and those tags shift with age.

The team analysed 2,428 publicly available datasets from six tissues of healthy people aged 5 to 75, including blood, liver and heart. From these they built 36 clocks. On average the clocks missed a person's age by just under five years, similar to established clocks. Many tags did not change steadily but peaked in midlife. In cell cultures, the researchers dialled down one of these tags. The cells then divided more slowly and showed signs of cell aging. In fruit flies, which lack the classic DNA tags, the clock estimated age moderately well.

These clocks are a research tool, not a test for everyday use. The data come from single samples taken from different people. How the tags change within one person over the years cannot be read from this work.

## Practical Takeaway

Chemical tags on the proteins that package DNA reveal the age of tissue to within about five years.

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_Canonical: https://longevity-germany.com/en/research/a-new-aging-clock-reads-age-from-the-packaging-around-dna · Part of Longevity Cities · Updated 2026-10-19_