What’s the News: By knocking out a single gene, scientists at the University of Pennsylvania have significantly increased the physical endurance of lab mice, as explained in their recent paper in the Journal of Clinical Investigation. The researchers also found that certain variants of the same gene may be linked to greater endurance in humans.

How the Heck:

Past in vitro studies showed that a gene called IL-15R? is involved in controlling muscle contractions, which play a role in both muscle strength and endurance. But the gene has never been studied in a living animal, so physiologist Tejvir Khurana and his research team decided to engineer lab mice that lack IL-15R?.
They noticed that at night the altered mice ran six times farther than normal mice. When the team dissected the engineered mice, they found that their muscles had more fibers than normal mice, as well as a higher number of mitochondria, the power plants of cells. ...