|dc.description.abstract||Objectives: High-altitude hypoxia, or decreased oxygen levels caused by low barometric pressure, challenges the
ability of humans to live and reproduce. Despite these challenges, human populations have lived on the Andean Altiplano and the Tibetan Plateau for millennia and exhibit unique circulatory, respiratory, and hematological adaptations
to life at high altitude. We and others have identified natural selection candidate genes and gene regions for these
adaptations using dense genome scan data. One gene previously known to be important in cellular oxygen sensing, egl
nine homolog 1 (EGLN1), shows evidence of positive selection in both Tibetans and Andeans. Interestingly, the pattern
of variation for this gene differs between the two populations. Continued research among Tibetan populations has identified statistical associations between hemoglobin concentration and single nucleotide polymorphism (SNP) genotype at
EGLN1 and a second gene, endothelial PAS domain protein 1 (EPAS1).
Methods: To measure for the effects of EGLN1 and EPAS1 altitude genotypes on hemoglobin concentration among
Andean highlanders, we performed a multiple linear regression analysis of 10 candidate SNPs in or near these two
Results: Our analysis did not identify significant associations between EPAS1 or EGLN1 SNP genotypes and hemoglobin concentration in Andeans.
Conclusions: These results contribute to our understanding of the unique set of adaptations developed in different
highland groups to the hypoxia of high altitude. Overall, the results provide key insights into the patterns of
genetic adaptation to high altitude in Andean and Tibetan populations. Am. J. Hum. Biol. 25:190–197, 2013.||es_ES