Biomathematician Steve Horvath has discovered a strikingly accurate way to measure human ageing through epigenetic signatures.
Horvath's clock emerges from epigenetics, the study of chemical and structural modifications made to the genome that do not alter the DNA sequence but that are passed along as cells divide and can influence how genes are expressed. As cells age, the pattern of epigenetic alterations shifts, and some of the changes seem to mark time. To determine a person's age, Horvath explores data for hundreds of far-flung positions on DNA from a sample of cells and notes how often those positions are methylated — that is, have a methyl group attached.
He 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. Read more.