An anonymous reader writes "A research team at the National Heart, Lung, and Blood Institute has been experimenting with changing mouse genes and seeing how it impacts their life. In a surprising discovery, when targeting just one gene change it was found they could extend the life of a mouse by 20 percent. The gene the researchers focused on is called mTOR and is associated with metabolism. By lowering its expression (to about 25 percent of what is normal) in a batch of mice they did indeed live longer (abstract). They also displayed better memory, balance, muscle strength, and posture as they aged. However, the health of their bones deteriorated more quickly and their immune system was weakened, suggesting that extra time alive wouldn’t really be worth it in terms of overall health. Lead researcher Toren Finkel said, 'While the high extension in lifespan is noteworthy, this study reinforces an important facet of aging; it is not uniform. Rather, similar to circadian rhythms, an animal might have several organ-specific aging clocks that generally work together to govern the aging of the whole organism.'"