The Tibetans and Han Chinese share several genetic traits and DNA. However the EPAS1 gene which increases the ability of red blood cells carry oxygen even in low environments, is only commonly found...

The Tibetans and Han Chinese share several genetic traits and DNA. However the EPAS1 gene which increases the ability of red blood cells carry oxygen even in low environments, is only commonly found in the Tibetan population that live in higher elevations. Explain why this gene is commonly in Tibetan populations from the perspective of competitive advantage and natural selection. Write your answer in 3-5 sentences