People in the Andes Evolved Genetic Resistance to Arsenic in Drinking Water

Researchers studied Andean highland residents exposed to high arsenic in drinking water.

Local water in San Antonio de los Cobres contained about 200 µg/L arsenic before 2012 filtration.

Genome scans of 124 women found a cluster of variants near AS3MT linked to efficient arsenic methylation.

The local population shows a high frequency of a protective haplotype and signs of recent positive selection.

The genetic changes likely reduced arsenic-related health risks by promoting faster conversion to less toxic DMA.