A 160,000-year-old Denisovan jawbone unearthed in a cave in Xiahe, China, is the oldest hominin fossil ever found in the vast Himalayan region that has an average altitude of 4,500 metres (14,800ft).
…Modern day humans are not thought to have arrived on the Tibetan plateau until around 40,000 years ago.
…Both Denisovans and their sister human sub-species, the Neanderthals, are known to have interbred with the ancestors of people living today. Most intriguingly, modern Sherpas and Tibetans appear to have inherited Denisovan genetic variants that help them cope with high altitudes.
…Their muscles get more mileage out of less oxygen than those of the average person. S
herpas have mitochondria – tiny rod-like power plants in cells – that are extra-efficient at using oxygen.
While their red blood cell count is increased in thin mountain air, it remains below the point at which the blood thickens and strains the heart, causing altitude sickness.
…Sherpas have lived in the Himalayas for at least 6,000 years.