Carina Schlebusch and colleagues just published an article in Molecular Biology and Evolution demonstrating human adaptation to the locally high arsenic levels in groundwater in the Argentine Andes. This work is the first to show a genetic adaptation that allows the detoxification of a environmental toxin (arsenic) in humans.
Title: Human adaptation to arsenic-rich environments
Abstract: “Adaptation drives genomic changes; however, evidence of specific adaptations in humans remains limited. We found that inhabitants of the northern Argentinean Andes, an arid region where elevated arsenic concentrations in available drinking water is common, have unique arsenic metabolism, with efficient methylation and excretion of the major metabolite dimethylated arsenic and a less excretion of the highly toxic monomethylated metabolite. We genotyped women from this population for 4,301,332 single nucleotide polymorphisms (SNPs) and found a strong association between the AS3MT (arsenic [+3 oxidation state] methyltransferase) gene and mono- and dimethylated arsenic in urine, suggesting that AS3MT functions as the major gene for arsenic metabolism in humans. (more…)