No Genetic Vertigo Peoples living in high altitudes have adapted to their situation (see the Perspective by Storz ). To identify gene regions that might have contributed to high-altitude adaptation in Tibetans, Simonson et al. (p. 72 , published online 13 May) conducted a genome scan of nucleotide polymorphism comparing Tibetans, Han Chinese, and Japanese, while Yi et al. (p. 75 ) performed comparable analyses on the coding regions of all genes—their exomes. Both studies converged on a gene, endothelial Per-Arnt-Sim domain protein 1 (also known as hypoxia-inducible factor 2 α), which has been linked to the regulation of red blood cell production. Other genes identified that were potentially under selection included adult and fetal hemoglobin and two functional candidate loci that were correlated with low hemoglobin concentration in Tibetans. Future detailed functional studies will now be required to examine the mechanistic underpinnings of physiological adaptation to high altitudes.