Final answer:
The EPAS1 gene activity adaptation in Tibetans is a result of natural selection to high altitude hypoxia. It involves genetic mutations and physiological changes, such as increased erythropoietin production for improved oxygen transport.
Step-by-step explanation:
The activity of the EPAS1 gene is indeed induced by hypoxia, which is a condition of low oxygen availability typically encountered at high altitudes. The adaptation of the version of the EPAS1 gene found among Tibetans is a result of natural selection. This gene helps in improving oxygen transport by regulating the body's response to hypoxia, including influencing the concentration of hemoglobin in the blood.
Another mutation related to high-altitude adaptation is in the PPARA gene, which is associated with fatty acid production, a mechanism often seen during hibernation. Additionally, Andean populations have a variation in the PRKAA1 gene, encoding for a protein kinase that plays a role in cellular energy homeostasis and responds to oxygen levels.
Adaptations to high altitudes are not restricted to genetic mutations but also involve physiological adjustments. For example, the production of erythropoietin (EPO) by the kidneys is stimulated when oxygen levels are low, resulting in an increased production of red blood cells to improve oxygen transport within the body.