Finally, given the distinctive environments of racial minorities in the U.S., more systematic attention should be given to identifying potential epigenetic effects. Epigenetics refers to changes in the patterns of gene expression in the absence of changes in the nucleotide sequences of the DNA. While variation in genotype is unlikely to play a major role in accounting for disparities, differences in gene expression linked to occupancy of different environmental contexts could play a critical role. Research on the role of genetics in social disparities in health has mistakenly emphasized gene frequency over gene expression.126 Although racial group membership and continental origin are poor predictors of genetic variation, they are strongly related to distinctive patterns of social exposures that can produce epigenetic changes in gene expression and tissue and organ function.144 Recent research has highlighted the potential of the social environment to produce epigenetic changes. For example, by analyzing the brain tissue from adults who had committed suicide one study found genetic changes in those who had been abused as a child.156 That is, hippocampal gene expression was decreased in victims
