A collaboration between African and American researchers and a community living in one of the most hostile landscapes of northern Kenya has uncovered key genetic adaptations that explain how pastoralist people have been able to thrive in the region.<\/p>\n
Underlying the population\u2019s abilities to live in Turkana, a place defined by extreme heat, water scarcity and limited vegetation, has been hundreds of years of natural selection, according to a study published in Science<\/a>.<\/p>\n It shows how the activity of key human genes has changed over millennia and the findings place \u201cTurkana and sub-Saharan Africa at the forefront of genomic research, a field where Indigenous populations have historically been underrepresented\u201d, according to Charles Miano, one of the study\u2019s co-authors and a postgraduate student at the Kenya<\/a> Medical Research Institute (Kemri).<\/p>\n The research sequenced 367 whole genomes and analysed more than 7m genetic variants, identifying several regions of the genome under natural selection. It was conducted through the Turkana Health and Genomics Project<\/a> (THGP), an initiative bringing together researchers from Kenya and the US, including Kemri, the Turkana Basin Institute<\/a> (TBI), Vanderbilt University in Tennessee and the University of California, Berkeley.<\/p>\n The genomic analysis found eight regions of DNA that had undergone natural selection but one gene, STC1, expressed in the kidneys, showed exceptionally strong evidence of humans adapting to extreme environments. Evidence included the body\u2019s response to dehydration and processing purine-rich foods such as meat and blood, staples of the Turkana people\u2019s diet.<\/p>\n Turkana women give water to their goats from a shallow well. The region is characterised by extreme heat, water scarcity, and limited vegetation. Photograph: Monicah Mwangi\/Reuters<\/p>\n Turkana stretches across a large swathe of northern Kenya, one of the most arid regions in the world, where shade is scarce and water even more rare. Rainfall arrives in short, unpredictable bursts, and securing enough water for themselves and their herds of cattle, goats and camels is a daily chore. Fetching water can involve journeys of many hours each day across hot terrain devoid of vegetation.<\/p>\n About 70% to 80% of the community\u2019s diet comes from animal sources, mostly milk, blood and meat, reflecting resourcefulness and adaptation to scarcity, which is common among pastoralist societies around the world living in environments where crops cannot grow and where markets are too far away to be accessed on foot.<\/p>\n Yet, after years of documenting the Turkana people\u2019s lifestyle and studying blood and urine samples to assess their health, researchers found that, although the community consumes too much purine, which should lead to gout, the condition rarely appears among the Turkana.<\/p>\n \u201cAbout 90% of the people assessed were dehydrated but generally healthy,\u201d said Prof Julien Ayroles, from the University of California, Berkeley, one of the project\u2019s co-principal investigators. \u201cThe Turkana have maintained their traditional way of life for thousands of years, providing us with an extraordinary window into human adaptation.\u201d<\/p>\n Genetic adaptations are believed to have emerged about 5,000 years ago, coinciding with the aridification of northern Africa, the study suggesting that as the region became drier, natural selection favoured variants that enhanced survival under arid conditions.<\/p>\n A Turkana woman carries the leg of a cow as she migrates with Turkana people to find water and grazing land for cattle. Photograph: Goran Toma\u0161evi\u0107\/Reuters<\/p>\n \u201cThis research demonstrates how our ancestors adapted to dramatic climate shifts through genetic evolution,\u201d said Dr Epem Esekon, responsible for Turkana county\u2019s health and sanitation sector.<\/p>\n