Amazing stuff! This research was first published in January 2023. Not fresh, but not stale! 😊
"The Turkana communities of northern Kenya live in one of the most arid regions on Earth. Perhaps unsurprisingly, when researchers tested blood and urine samples, they discovered that about 90% of the people are dehydrated. What was surprising, however, was that they were generally healthy in spite of this. Their secret? Genetic adaptations that help them fare well with less water. ...
The researchers also looked at gene expression profiles in Turkana people who now live in cities and compared them to the expression patterns of Turkana pastoralists. There was more evidence of selection in the genes that differed between the two groups than in genes that didn’t ..."
From the abstract of the Perspective:
"Despite being genetically homogeneous compared with other animals, humans are geographically diverse and have evolved to meet the demands of local environments, pathogens, and diets.
In 1962, James Neel proposed that genes that predispose people to metabolic diseases may have been advantageous in the evolutionary past.
Yet empirical support for his hypothesis remains limited. ... Lea et al. report genomic analyses of samples from the Turkana people in northwest Kenya that reveal a more nuanced narrative. The Turkana have practiced nomadic pastoralism (raising and herding of livestock) in extreme arid environments for ~5000 to 8000 years.
The authors analyzed 367 genomes and discovered adaptations to ecological pressures, particularly chronic water scarcity. They identified physiological compromises in kidney function that improved water retention but mildly increased the amounts of urea in the blood. This context-specific trade-off may become pathological as Turkana populations urbanize."
From the editor's summary and abstract:
"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 ... 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. ...
Abstract
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."
Trade-offs and human adaptation at the extremes (Perspective, no public access) "Genomic analyses of Turkana pastoralists identify variants that increase water retention"
Adaptations to water stress and pastoralism in the Turkana of northwest Kenya (preprint, possibly outdated, open access)
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