Betterhumans reports on research that gives more support for telomere theories of aging. These state, in short, that telomeres -- junk DNA that caps the ends of our chromosomes -- protect our DNA from damage until they are "worn away" with the passing of time. After that, our cells start to accumulate defects and damage more rapidly. A good explanation of the basics can be found over at Wikipedia. It is interesting to keep track of the different theories of aging as they move forward; it is very likely at this stage that all are correct in some sense. The overall picture is still elusive, however.