Sherpas Carry a Gene From an Extinct Human Species That Lets Them Breathe Where Others Suffocate
The reason your Sherpa guide isn't gasping at 5,000 metres traces back tens of thousands of years to interbreeding with the Denisovans, an extinct human relative known only from a Siberian cave.
At a glance
At Everest Base Camp, 5,364 metres up, trekkers who have trained for months stop mid-sentence to catch their breath. Their Sherpa guide, carrying the heavier pack, keeps talking. This isn't just acclimatisation or a lifetime spent at altitude. Geneticists have traced part of it to a single gene, inherited from a human species that went extinct tens of thousands of years ago.
Key facts
- The gene is called EPAS1, and the high-altitude version carried by Sherpas and Tibetans matches DNA from the Denisovans, an extinct archaic human relative.
- Denisovans are known from a single finger bone found in Siberia's Denisova Cave in 2008, dated to roughly 60,000–80,000 years old; their genome was published in Nature in December 2010.
- Peer-reviewed research (PNAS, 2012) found Sherpas at 3,440 metres have serum erythropoietin levels matching lowlanders at just 1,300 metres — their bodies barely register the thin air that would send others into a hypoxic stress response.
- The variant works by keeping haemoglobin lower, not higher — the opposite of what most people's bodies do at altitude, and a safer adaptation than thickening the blood.
Most people's bodies respond to thin air by producing more red blood cells to carry more oxygen. It works, up to a point — but blood that's too thick raises the risk of clots, strokes and chronic mountain sickness in populations that live permanently at altitude. Sherpas and Tibetans do something different: the EPAS1 variant they carry dials the hypoxia response down rather than up, keeping haemoglobin closer to sea-level normal while their bodies extract oxygen more efficiently elsewhere in the chain. It's a genuinely different physiological strategy, not just a stronger version of everyone else's.
Where the variant came from is the more startling part. When researchers compared the Tibetan and Sherpa version of EPAS1 against the genome sequenced from the Denisova Cave finger bone, the match was too close to be coincidence. At some point, tens of thousands of years ago, the ancestors of today's high-altitude Himalayan populations interbred with Denisovans — a human relative that otherwise vanished from the record entirely, surviving today only as fragments in the DNA of people descended from that encounter. Natural selection then did the rest: on the Tibetan Plateau and in the high valleys of Nepal, carrying the variant meant a real survival advantage, and it spread.
An archaic human population, distinct from Neanderthals, lives across parts of Asia.
Ancestors of Tibetan Plateau and Himalayan populations interbreed with Denisovans, picking up the EPAS1 variant.
Denisova Cave yields the only physical evidence of the species ever found.
Nature reveals the Denisovan genome from that single fossil.
PNAS research directly links the protective EPAS1 variant to Sherpa physiology at altitude.
What this means for trekkers
It's a scientific footnote to something Himalayan trekking has always known by observation: the Sherpa people who guide, cook and carry on treks to Everest, Gokyo and the high climbing peaks aren't just experienced — a real slice of that resilience is written into their biology. It's also a practical reminder for anyone planning a high-altitude trip: your NMA-certified guide's steady pace at 5,000 metres isn't a sign you're moving too slowly, it's a different starting point entirely. Respect the mountain's pace, not theirs.
What this means for you
Altitude sickness isn't weakness — it's biology, and even Sherpas with this adaptation still take Everest seriously. Acclimatise properly, hire NMA-certified guides, and let their genetics do what training alone can't.
Trek where this adaptation matters most, guided by Nepal's own high-altitude specialists, on the Everest Base Camp Trek, the lake-studded Gokyo Ri Trek, or the technical Island Peak Climb.
Cover photo: Sajjad Hossen via Pexels (Pexels License).
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