Scientists find genes protect against arsenic
Do genes play a role in people being more resistant to toxic substances? A new international study suggests they do. Investigating Argentinian villagers in the Andes, an area in which the water contains high levels of arsenic, researchers discovered the prevalence of a gene variant that produces efficient and less toxic metabolism of arsenic in the bodies of the locals compared to other indigenous groups in both South and Central America. Led by Lund University and Uppsala University in Sweden, the researchers investigated for the first time whether people in specific regions have protective genes against arsenic.
Presented in the journal Environmental Health Perspectives, the study was funded in part by the PHIME ('Public health impact of long-term, low-level mixed element exposure in susceptible population strata') project, which was supported under the 'Food quality and safety' Thematic area of the EU's Sixth Framework Programme (FP6) to the tune of EUR 13.4 million.
'We know that many bacteria and plants have genes that increase resistance to arsenic, a highly toxic substance that is found in soil and water in many parts of the world,' said Professor Karin Broberg from Lund University. 'There has been no previous research on whether the people in these regions also have protective genes against arsenic.'
Past studies found a connection between high levels of arsenic in potable water and health problems, such as heart disease and diabetes, as well as increased child morbidity and cancer risk. This problem recently emerged in some areas of the planet, such as in Bangladesh; but in the Andes, the potable water has contained arsenic for thousands of years, mostly due to high levels of the toxic substance in bedrock and also because of mining activity since the pre-colonial era. Researchers had previously discovered 7,000-year-old mummies from northern Chile contained high levels of arsenic in their hair and internal organs.
For the purposes of their study, the researchers examined the genes of Atacameño Indian villagers in San Antonio de los Cobres in Argentina, who have lived in the area for many generations. They compared their genes with those of various indigenous and Mestizo groups from Peru and indigenous groups from Colombia and Mexico. More than 66 % of the Argentinian villagers carry a gene variant that speeds up the metabolism of arsenic versus 50 % of the Peruvian villagers and just 14 % of the other indigenous groups, according to the researchers.
'We found that people up in the mountains in Argentina had unusually efficient metabolism of arsenic,' said Professor Broberg, a specialist in occupational and environmental medicine. 'This meant that the toxin left the body rapidly and less toxically instead of accumulating in tissue.'
Scientists from Peru, Sweden and the United States contributed to this study.
Category: Project results
Data Source Provider: Environmental Health Perspectives; Lund University
Document Reference: Schlebusch, C. M., et al., 'Possible Positive Selection for an Arsenic-Protective Haplotype in Humans', Environmental Health Perspectives, 2012.
Subject Index: Biotechnology; Coordination, Cooperation; Life Sciences; Scientific Research; Social Aspects