Among high-altitude natives there is evidence of a general hypoxia tolerance leading to enhanced performance and/or increased capacity in several important domains. These domains likely include an enhanced ability (1} to do hard physical work in hypoxia, (2) to produce large and healthy babies, and (3) to resist several common pathologies of chronic high-altitude exposure. The "strength" of high-altitude natives in this regard must have both a genetic and a developmental basis. For example, early-life exposure to hypoxia results in lung growth leading to an increased 02 diffusion capacity. Other physiological Systems also show developmental plasticity in response to early-life O2 levels e.g., the ventilatory control System, Genetic research, while at an early stage, suggests genetic effects on a number of important traits in high-altitude natives. For example, our research shows higher arterial oxygen Saturation during exercise in Peruvian Quechua homozygous for the I-allele of the angiotensin converting enzyme (ACE) insertion/deletion polymorphism. The evolutionary significance of this gene in Quechua is unknown. Further, and in general, it should be noted that little is known about the effects of genome structure, gene-gene interaction (epistasis), and gene-environment interaction on the physiology of the high-altitude native. This talk will review the effects of nature and nurture, mostly on the process of gas exchange, which has been well studied in high-altitude natives. Our aforementioned study on the Quechua will also be presented as the research design allowed for some consideration of both genetic and developmental effects.
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