BEALL, C.M.; Case Western Reserve University: Andean, Tibetan and Ethiopian patterns of human adaptation to high-altitude hypoxia.

High altitude environments have been particularly informative natural laboratories for investigating human adaptation because the stress of high-altitude hypoxia is severe and constant. Traditional people had and have no ability to create non-hypoxic microclimates. As a result, everyone at a given altitude, regardless of age, sex, socioeconomic or nutritional status, or other biological or sociocultural characteristic, is exposed to the same environmental stress to which biological adaptations must be made. People migrated to high-altitude environments on the Andean, Tibetan, and East African Plateaus, thus there are three natural experiments to evaluate. From the 1980s through the 1970s nearly all research was conducted with Andean highlanders. The distinctive morphology and physiology of �Andean man� was thought to represent the human pattern of adaptation. Since then, however, studies of Tibetan and Ethiopian highlanders have found qualitative and quantitative differences in the patterns of adaptation among the three indigenous populations. Human biology did not constrain people to a single successful adaptation to high-altitude hypoxia. This presentation compares and contrasts the different patterns of adaptation to high-altitude hypoxia, discusses models to explain how the different patterns came about, and presents an example of ongoing natural selection in the Tibetan population.