Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature currently requires accessing the site using the built-in Safari browser.
The clock shows that while many healthy tissues age at the same rate as the body as a whole, some of them age much faster or slower. The age of diseased organs varied hugely, with some many tens of years "older" than healthy tissue in the same person, according to the clock.
Researchers say that unravelling the mechanisms behind the clock will help them understand the ageing process and hopefully lead to drugs and other interventions that slow it down.
Therapies that counteract natural ageing are attracting huge interest from scientists because they target the single most important risk factor for scores of incurable diseases that strike in old age.
"Ultimately, it would be very exciting to develop therapy interventions to reset the clock and hopefully keep us young," said Steve Horvath, professor of genetics and biostatistics at the University of California in Los Angeles.
Horvath looked at the DNA of nearly 8,000 samples of 51 different healthy and cancerous cells and tissues. Specifically, he looked at how methylation, a natural process that chemically modifies DNA, varied with age.
Horvath found that the methylation of 353 DNA markers varied consistently with age and could be used as a biological clock. The clock ticked fastest in the years up to around age 20, then slowed down to a steadier rate. Whether the DNA changes cause ageing or are caused by ageing is an unknown that scientists are now keen to work out.
cience/2013/oct/21/dna-body-clock-ageing
I was amused by reading "unravelling" (unraveling) because on individual strands of DNA, much of the genetic code outside of the middle area of the helix is unnecessary and redundant. When cellular division occurs, the DNA unravels, losing some of its outside sections. In other words, let's say that a town suffers from a tsunami every day. There is a large wall that is vital to the protection of the city. Outside of the wall, there are large rows of sandbags extending outwards. Every day, the outer row of these sandbags is destroyed by the tsunami. Eventually, the sandbags are all gone, and there is only the large wall. The large wall gradually deteriorates per diem (by the day) because of the waves, and the water eventually reaches the city. Everyone dies. The end. The sandbags represent the redundancies in the DNA, the wall represents the genetic codes that keep us alive, and the death of the town represents the death of a human.
