Time adds a wrinkle to nature and nurture

Nature and nurture have found a new companion - historical context. A new study has produced the best evidence yet that the role of genetics in complex traits, including obesity, varies over time. Both the era in which scientific research is conducted and the era in which subjects were born may have an impact on the degree to which genetic factors are present in scientific data. "I liken it to a kind of uncertainty principle, or 'observer effect,' for genetics," said Nicholas Christakis, a Yale professor of sociology, ecology & evolutionary biology, and medicine, and co-author of the study. "In principle, any study of how DNA affects bodily outcomes may thus be finding effects that are not ever-enduring, or may be missing effects that - but for the timing of the research - are enduring." The research appears online in the Dec. 29 edition of the Proceedings of the National Academy of Sciences. Christakis and his colleagues focused on a specific genetic variant in the FTO gene that is widely known to be associated with obesity.