From LiveScience: "The new study, which focused on Ashkenazi Jews, finds those who lived the longest had inherited a hyperactive version of an enzyme called telomerase that rebuilds telomeres. In effect, centenarians tend to have a top-notch body mechanic at work 24/7 repairing the hardware that runs the body, versus a normal person whose body's cellular control center is left to wear out with time. ... Humans of exceptional longevity are better able to maintain the length of their telomeres. And we found that they owe their longevity, at least in part, to advantageous variants of genes involved in telomere maintenance ... [Researchers] studied Ashkenazi Jews, a homogeneous population whose genetics are well-studied. Three groups were part of the research: A very old (average age 97) but healthy group of 86 people; 175 of their offspring; and a control group of 93 offspring of parents who lived a normal lifespan. ... Our research was meant to answer two questions. Do people who live long lives tend to have long telomeres? And if so, could variations in their genes that code for telomerase account for their long telomeres?... 'Yes' on both accounts, the scientists conclude."