“He [Horvath] has discovered an algorithm, based on the methylation status of a set of these genomic positions, that provides a remarkably accurate age estimate — not of the cells, but of the person the cells inhabit.

““Such tight correlations suggest there is something seemingly immutable going on in cells,” says Elizabeth Blackburn [Nobel prize winner for work on telomeres]…It could be a clue to undiscovered biology, she suggests. And there may be medical implications in cases in which epigenetic estimates do not match a person’s birth certificate.

“This [third] time, Horvath refused to take no for an answer. “After reading the reviewers’ comments, I spent the next 10 minutes doing three things that one should never do,” he says. “First, I went to the fridge and drank three bottles of beer as fast as I could. Second, I went back to the computer and drafted a letter to the editor. Third, I sent it off.””

Article: http://www.nature.com/news/biomarkers-and-ageing-the-clock-watcher-1.15014