Arsenic is a potent killer but up in the high Andes mountains of Argentina, researchers have identified the first-ever evidence of a population uniquely adapted to tolerate the toxic chemical. The authors speculate that the local adaptation may have occurred as a result of the severe health effects of arsenic and the need for faster metabolising arsenic which may have been a matter of life or death in ancient times.
For the study, a Swedish research team led by Karolinska Institutet and Uppsala University professor Karin Broberg performed a genome-wide survey from a group of 124 Andean women screened for the ability to metabolise arsenic (measured by levels in the urine). The study pinpointed a key set of nucleotide variants in a gene called AS3MT which were at much lower frequencies in control populations from Columbia and Peru.
The researchers estimate that the increase in frequency of these variants occurred recently, between 10,000-7,000 years ago, based on the age of a recently excavated mummy that was found to have high arsenic levels in its hair. “Thus, this Andean population has adapted to their environment through increased frequencies in protective variants against a toxicant,” the authors wrote.
For thousands of years, in some regions of the Andes, people have been exposed to high levels of arsenic, a naturally occurring phenomenon that happens when arsenic in the volcanic bedrock is released into the groundwater. The study was published in the journal Molecular Biology and Evolution. (IANS)