By UTMB’s David Niesel and Norbert Herzog: Those traveling to the Himalayas have a tough time adjusting to the harsh altitude. But for those native to Tibet, called the Roof of the World due to its location 14,700 feet up, it’s not a problem. Studies have linked the Tibetan’s adaptation to high altitude with several genes, including a unique form of the EXPAS1 gene. We know that the ancestors of Nepal’s Sherpa people carried a Tibetan EXPAS1 gene variant about 30,000 years ago. Today, only Tibetans carry this version of the gene, and no other modern humans have it. That’s because Tibetans have adapted to this extreme environment partly due to a gene they inherited from an extinct species of prehumans called the Denisovans