In their efforts to conquer the aging process, researchers are zeroing in on one specific part of the cell: mitochondria, the energy-generating organelles that control our metabolism and, it seems, help regulate how long we live.
Mitochondria are the only structures outside the nucleus that contain their own DNA, a distinction that might be more important than previously realized, says Nils-Goran Larsson of Sweden’s Karolinska Institute. Nuclear DNA has an extensive system of proofreading and repair enzymes to weed out mutations. Mitochondrial DNA depends largely on a single enzyme.
Larsson wanted to see what happens when that enzyme fails to catch a glitch, so he and his collaborators engineered mice with a defective, error-prone version of the enzyme. The modified mice developed muscle and hair loss, spine curvature, and loss of fertility at a greatly accelerated pace. “People have noticed a striking correlation between mitochondrial DNA damage and aging, but ...
