Epigenetic modulation expressed as methylation changes in DNA from primary school children of two different geographical environments II

Abstract

In previous work, proportions of the phenotypic characteristics attributable to the HSR (Hand Skill Relative, OMIM 139900) gene were found modified in primary school children from one of two distinct geographical regions of La Rioja province (Argentina). HSR gene has been described subjected to epigenetic regulation, and one of the main molecular mechanisms whereby this regulation is performed is by methylation of DNA. Thus, it was of interest in the present work to analyze in these children the possibility of changes in the DNA methylation patterns. 40 children from the two regions (20 from Region 2, and 20 from Region 1, considered control) were randomly selected from the original total sample of 547 children, and blood samples were taken to analyze the DNA methylation patterns by capillary electrophoresis technique. The phenotypic characterization for HSR also was performed on the children sample. Results showed that children from Region 2 had significantly altered the writing/reading capacity with a proportion about 65% of writing disturbances over control children of Region 1. No statistical differences were found in the other two phenotypic traits linked to the HSR gene (brain asymmetry and handedness). Molecular analysis of the methylation patterns revealed a significantly higher ratio of non-methylated to methylated cytosine in DNA from children of Region 2, compared to those of Region 1 (control). The present results suggest that the altered proportions of phenotypic characteristics found in children of Region 2 are supported by altered DNA methylation patterns, suggesting an environmental epigenetic modulation of DNA expression.