Scientists have zeroed in on one apparent key to long life: an inherited cellular repair mechanism that thwarts aging and perhaps helps prevent disease. Researches say the finding could lead to anti-aging drugs.

The study involves telomeres, the ends of chromosomes that have been likened to the plastic tips that prevent shoelaces from unraveling. Telomeres were already known to play a key role in aging, and their discovery led to this year's Nobel Prize in medicine.

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.