Andean Arsenic Tolerance: A Genetic Adaptation Near AS3MT

In San Antonio de los Cobres, Argentina, DNA from 124 women and their urine arsenic metabolites show variants near the AS3MT gene that appear to improve arsenic detoxification, shifting metabolism toward excretable forms. These variants are more common in this high-arsenic Andean population than in comparable groups, suggesting long-term natural selection has contributed to arsenic tolerance. The findings, published in Molecular Biology and Evolution, provide evidence of human adaptation to a toxic environmental chemical and hint that similar signals may exist in other Andean communities.