Single gene mutation helped our ancestors become long-distance runners*

The loss of a single gene millions of years ago may have helped human ancestors make the change from a forest environment to life as hunter-gatherers on the African savannah, according to a new study. And this, in turn, may have contributed to modern humans' unmatched abilities as long-distance runners.

A mutation linked to the lack of a gene called CMAH lines up with the emergence of several key changes in early hominids' bodies, such as long legs and more powerful gluteal muscles, all of which helped to drive our species' physical endurance. In the new study, researchers from the University of California, San Diego examined mice who were engineered to lack this gene.

The loss of CMAH has previously been tied to modern humans' fertility rates and even cancer risk from red meat. And, it sets humans apart from our closest living ancestors, who have this gene. 'We discovered this first clear genetic difference between humans and our closest living evolutionary relatives, the chimpanzees, more than 20 years ago,' said senior author Ajit Varki, MD.