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Newly Invented Biological Clock Improves Accuracy in Measuring Aging

About the Initiative:

  • Dr. Steve Horvath of the department of Biostatistics has contributed to furthering our understanding of the human aging process by discovering a “biological clock”, embedded in our genomes, which might help us learn more about the process of human aging including how to slow it.
  • Dr. Horvath’s research has allowed him to invent an age-predictive tool to help scientists better understand how the aging process speeds up or slows down. While earlier research has linked saliva, hormones and telomeres to biological clocks, Dr. Horvath’s work is the first to lead to the development of an age-predictive tool.
  • The tool uses a previously unknown time-keeping mechanism in the body to gauge the age of human organs, tissues and cell types.
  • Dr. Horvath tested his tool by comparing a tissue’s biological age to its chronological age. In testing, the tool was consistently accurate in matching biological age to chronological age.
  • Dr. Horvath also looked at stem cells, finding that “all stem cells are newborns” and showing that in principle, the body’s biological clock can be reset to zero.


  • Although this research is preliminary, the possible implications are far-reaching. For example, the tool has already shown that a woman’s breast tissue ages more quickly than the rest of her body, which may explain why breast cancer is the most common type of cancer in women.
  • This research could offer valuable insights to benefit cancer and stem cell research.
  • As Dr. Horvath remarks: “"The big question is whether the underlying biological clock controls a process that leads to aging. If so, the clock will become an important biomarker for studying new therapeutic approaches to keeping us young."
  • Accurate measures of biological age (biological aging clocks) could be useful in many ways, such as predicting/prognosticating the onset of various diseases, diagnosing various age related diseases and for defining cancer subtypes, and forensic applications, for example to estimate the age of a suspect based on blood left on a crime scence.


    * Portions of this story excerpted from UCLA scientist uncovers biological clock able to measure age of most human tissues, by Elaine Schmidt.


Steve Horvath