Science & Technology

By T.K. Randall
June 25, 2026

Image: Driving to El Chalten, Argentinian Patagonia
Credit: Evelyn Proimos / CC BY 2.0 (adapted)

The people who live in a remote part of the Andes seem to have the unique ability to safely drink water that would kill anyone else.

The mountainous region of Northern Argentina has thrown up a genetic surprise - one that has enabled the local people to drink the water without becoming unwell.

There, naturally occurring arsenic typically makes its way into the groundwater - something that would normally make the water hazardous to human health and generally undrinkable.

Nonetheless, the local people in the Andes seem to be able to drink it without any issues.

As it turns out, natural selection has provided them with a genetic adaptation enabling their bodies to more safely metabolize arsenic.

The discovery has been hailed as an example of evolution in action and demonstrates how life - and even humans - can adapt to environments and conditions that would otherwise prove unsafe.

"Adaptation drives genomic changes; however, evidence of specific adaptations in humans remains limited," researchers from Uppsala University wrote.

"Our data show that adaptation to tolerate the environmental stressor arsenic has likely driven an increase in the frequencies of protective variants of AS3MT, providing the first evidence of human adaptation to a toxic chemical."

Source: Science Alert

Tags: Genetics