How Ethiopian highlanders adapted to breathe thin air
![Ethiopian highlands](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/08/EthiopianHighlands_EDIT.jpg?fit=860%2C460&ssl=1)
Over millenia, humans have adapted to the high altitude of Ethiopia's highlands. Researchers have now pinpointed one adaptation — lower levels of cardiac signaling protein — that may make the high life possible.
Sightings of the Subtle/Flickr (CC BY-NC-ND 2.0)