Clocking Epigenetics

DNA methylation status can predict age in various human tissues, a study shows.

By | October 22, 2013

FLICKR, VISUAL DICHOTOMYEpigenetic modifications influence development, aging, and disease in myriad ways, some of which are just beginning to be understood. Geneticist and biostatistician Steve Horvath of the University of California, Los Angeles, has shown that DNA methylation can be used to accurately measure tissue age in samples from different individuals and tissue types. The work was published this week (October 21) in Genome Biology.

Horvath worked with 82 published DNA methylation datasets, focusing on 353 CpG methylation sites, some of which appeared and disappeared over time. He used these sites to design a predictor that accurately estimates the age of healthy tissues. The predictor showed that DNA methylation age of embryonic and stem cell tissue is near zero and that cancer tissues have an average DNA methylation age 36 years older than healthy tissue. Horvath also showed that before age 20, the changes in DNA methylation, which he called the “ticking rate of the epigenetic clock,” occur much more quickly than after that age. “I propose that DNA methylation age measures the cumulative effect of an epigenetic maintenance system,” Horvath wrote in his paper.

The predictor is freely available, and Veryan Codd of Leicester University told The Guardian that “these data could prove valuable in furthering our knowledge of the biological changes that are linked to the aging process.” But Darryl Shibata, a professor of medicine at the Keck School of Medicine at the University of Southern California, cautioned in an interview with Forbes that the accuracy of Horvath’s predictor does not imply that changes in DNA methylation cause aging. “The general idea that you can read a genome and it reflects the aging process is probably correct,” Shibata told Forbes. “But the weakness is that this study doesn’t provide a mechanism, and without a mechanism it’s just a correlation.”


Add a Comment

Avatar of: You



Sign In with your LabX Media Group Passport to leave a comment

Not a member? Register Now!

LabX Media Group Passport Logo


Avatar of: Hugh-F-61


Posts: 44

October 22, 2013

I think this is not a clock but a log-file of differentiation and development.

I think the more rapid changes up to age 20 are likely to relate to lockdown of developmental genes by proteins such as the polycomb family. Cell and organ differentiation for body growth and also neuron development are both completed at about 20.  Future changes are more by growth of existing structures (or pruning of neurons). I expect there is another burst of change around pregnancies and also the menopause in females. The slower changes after 20 may be related to repair or replacement of tissues, stochastic changes, or the onset of senescence, either  stochastic or programmed.


Follow The Scientist

icon-facebook icon-linkedin icon-twitter icon-vimeo icon-youtube

Stay Connected with The Scientist

  • icon-facebook The Scientist Magazine
  • icon-facebook The Scientist Careers
  • icon-facebook Neuroscience Research Techniques
  • icon-facebook Genetic Research Techniques
  • icon-facebook Cell Biology Research
  • icon-facebook Microbiology and Immunology
  • icon-facebook Cancer Research and Technology
  • icon-facebook Stem Cell and Regenerative Science