Humans in The Andes Seem to Have Evolved a Strange Genetic Ability

Key Points:

• Researchers have identified a genetic adaptation in a population from the Argentinian Andes that helps them metabolize and tolerate high levels of naturally occurring arsenic in their drinking water, which would be toxic to most humans.
• The gene variant near AS3MT, an enzyme involved in arsenic metabolism, allows individuals to convert arsenic into less toxic forms that are more easily excreted, reducing harmful effects from long-term exposure.
• This population, living in San Antonio de los Cobres with arsenic levels about 20 times the WHO recommended limit, has inhabited the region for thousands of years, allowing natural selection to favor this protective genetic trait.
• Comparative genetic analysis showed these protective variants are more frequent in this Argentinian group than in similar populations from Peru and Colombia, suggesting a localized evolutionary adaptation.
• The findings provide rare evidence of human genetic adaptation to a toxic chemical in the environment and imply that similar adaptations may exist in other Andean populations exposed to arsenic over generations.