Adaptations to water stress and pastoralism in the Turkana of northwest Kenya.

The Turkana pastoralists of Kenya inhabit arid, water-limited environments and rely largely on livestock for subsistence. Working with Turkana communities, we sequenced 367 whole genomes and identified eight regions with evidence for recent positive selection. One of these regions includes a putative regulatory element for STC1—a kidney-expressed gene involved in metabolism and the response to dehydration. We show that STC1 is induced by antidiuretic hormone in human cells, is associated with urea levels in the Turkana themselves, and is under strong and recent selection in this population as well as a second East African population, the Daasanach. This work highlights how integrating anthropological and genomic approaches can lead to a new understanding of human physiology with biomedical relevance. Editor's summary: Humans have adapted to many environments, dietary shifts, and conditions. Lea et al. analyzed blood markers and genomes from 367 Turkana individuals in northwest Kenya (see the Perspective by McVay and Goldberg). This group has primarily practiced nomadic pastoralism in an extremely arid environment for the past 5000 to 8000 years, with as much as 80% of their traditional diet being composed of animal products. The authors identified several regions of the genome that appear to be under recent selection, including one near the gene STC1, which is involved in the kidneys' response to dehydration. The authors also shared the results with these groups, which may help them be more aware of possible medical complications as some individuals move to urban centers. —Corinne Simonti [ABSTRACT FROM AUTHOR]