A landmark paleogenomic study published in Molecular Biology and Evolution has sequenced the genomes of 8,000-year-old individuals from the Camarones valley in the Atacama Desert. The research identified a specific mutation in the AS3MT gene, which is responsible for arsenic metabolism. This represents the earliest known evidence of a human population genetically adapting to a toxic environmental factor—high arsenic levels naturally present in the local water supply.
The study found that these ancient inhabitants developed the ability to rapidly process and excrete arsenic, allowing them to thrive in an environment that would be lethal to most other human groups. This discovery provides critical insights into the evolutionary pace of human adaptation and demonstrates how localized environmental pressures have shaped the genomic diversity of South American indigenous populations over thousands of years.