A recent publication in the American Journal of Physical Anthropology describes how humans adapted to arsenic in Andean populations of the Atacama Desert. It is here, where the highest arsenic levels in the Americas are found (>1,000 µg/L). The local population though, the Camarones people, who live in this environment during the last 7,ooo years, have not presented any epidemiological emergencies.
So the authors of the study – Mario Apata, Bernado Arriaza, Elena Llop and Mauricio Moraga fom the Universidad de Chile in Santiago and the Universidad de Tarapacá – compared the frequencies of four protective genetic variants of the AS3MT gene associated with efficient arsenic metabolization, between the living populations of Camarones and two other populations historically exposed to lower levels of arsenic. They found higher frequencies of the protective variants in those people from Camarones than in the other two populations.
The higher frequency of protective variants in both northern Chilean populations indicates a long exposure to naturally arsenic-contaminated water sources. The data suggest that a high arsenic metabolization capacity has been selected as an adaptive mechanism in these populations in order to survive in an arsenic-laden environment.
However, one has to note that a third of the population does not have any of the protective genetic variants of the AS3MT gene and still does not show any significant signs of arsenicosis – further research is planned (or maybe they should visit Styria?).
(for further info, see the article here).