Epigenetic changes as biological clock

[deltasigma]

Although it may seem like something that should be self-evident, one of the things that medical science has wanted to understand for a while is the biological roots of aging. This doesn’t necessarily answer the question but it may be a clue.

The age of many human tissues and cells is reflected in chemical changes to DNA. The finding provides insights for cancer, aging, and stem cell research.

We may gauge how we’re aging based on visible changes, such as wrinkles. For years, scientists have been trying to gauge aging based on changes inside our cells.

      Many  alterations occur to our DNA as we age. Some of these  changes are epigenetic—they modify DNA without altering the genetic  sequence itself. These changes  affect how cells in different parts of  the body use the same genetic code. By  controlling when specific genes  are turned on and off, or “expressed,” they  tell cells what to do,  where to do it, and when to do it.

        One such type  of modification occurs when chemical tags  known as methyl groups attach to DNA  in specific places. This process,  known as methylation, affects interactions  between DNA and  protein-making machinery. Changes in DNA methylation—both  increases and  decreases—occur with aging.

It seems that we gradually accumulate more of these methylation tags at a fairly constant rate from the age of 20 on. Full article at link.