Extinct species 'gave Tibetans altitude gene'
Tibetans acquired their ability to survive the Himalayan high life from another human species, US scientists believe.
They picked up a gene that limits the effects of high altitude from the Denisovans, who became extinct between 40,000 and 50,000 years ago, research suggests.
Like the better known Neanderthals, the Denisovans are thought to have interbred with ancestors of people living today who migrated out of Africa into Eurasia.
The gene, called EPAS1, regulates the body's production of haemoglobin, the molecule carried by red blood cells that transports oxygen in the blood.