Cynthia M Beall

Learn More
By impairing both function and survival, the severe reduction in oxygen availability associated with high-altitude environments is likely to act as an agent of natural selection. We used genomic and candidate gene approaches to search for evidence of such genetic selection. First, a genome-wide allelic differentiation scan (GWADS) comparing indigenous(More)
Newcomers acclimatizing to high altitude and adult male Tibetan high altitude natives have increased ventilation relative to sea level natives at sea level. However, Andean and Rocky Mountain high altitude natives have an intermediate level of ventilation lower than that of newcomers and Tibetan high altitude natives although generally higher than that of(More)
Human populations use a variety of subsistence strategies to exploit an exceptionally broad range of ecoregions and dietary components. These aspects of human environments have changed dramatically during human evolution, giving rise to new selective pressures. To understand the genetic basis of human adaptations, we combine population genetics data with(More)
Blood group variants are characteristic of population groups, and can show conspicuous geographic patterns. Interest in the global prevalence of the Duffy blood group variants is multidisciplinary, but of particular importance to malariologists due to the resistance generally conferred by the Duffy-negative phenotype against Plasmodium vivax infection. Here(More)
Populations native to the Tibetan and Andean Plateaus are descended from colonizers who arrived perhaps 25,000 and 11,000 years ago, respectively. Both have been exposed to the opportunity for natural selection for traits that offset the unavoidable environmental stress of severe lifelong high-altitude hypoxia. This paper presents evidence that Tibetan and(More)
Research on humans at high-altitudes contributes to understanding the processes of human adaptation to the environment and evolution. The unique stress at high altitude is hypobaric hypoxia caused by the fall in barometric pressure with increasing altitude and the consequently fewer oxygen molecules in a breath of air, as compared with sea level. The(More)
Humans inhabit a remarkably diverse range of environments, and adaptation through natural selection has likely played a central role in the capacity to survive and thrive in extreme climates. Unlike numerous studies that used only population genetic data to search for evidence of selection, here we scan the human genome for selection signals by identifying(More)
Although hypoxia is a major stress on physiological processes, several human populations have survived for millennia at high altitudes, suggesting that they have adapted to hypoxic conditions. This hypothesis was recently corroborated by studies of Tibetan highlanders, which showed that polymorphisms in candidate genes show signatures of natural selection(More)
Admixture is recognized as a widespread feature of human populations, renewing interest in the possibility that genetic exchange can facilitate adaptations to new environments. Studies of Tibetans revealed candidates for high-altitude adaptations in the EGLN1 and EPAS1 genes, associated with lower haemoglobin concentration. However, the history of these(More)
The low barometric pressure at high altitude causes lower arterial oxygen content among Tibetan highlanders, who maintain normal levels of oxygen use as indicated by basal and maximal oxygen consumption levels that are consistent with sea level predictions. This study tested the hypothesis that Tibetans resident at 4,200 m offset physiological hypoxia and(More)