Canadian researchers have found that when a particular gene—known as the FTO gene—predisposes a person toward obesity, there is an associated 8 percent drop in the probability of becoming depressed. David Meyre, who led the study for McMaster University in Hamilton, Canada, “suspects that the gene, which methylates DNA and therefore turns other genes off and on, is able to independently influence several disorders—all of which may involve ‘appetitive’ drives such as eating, and the mood that goes with them.”
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What’s the Big Idea?
Because of its modest contribution to a person’s happiness, Meyre is happy to call FTO the happiness gene. Based on its prevalence among ethnic groups, it should prevent 6.7 per cent of the cases of depression that would otherwise afflict Africans, 5.3 per cent of cases in Europeans, and 2.2 per cent in Chinese. “This varying prevalence suggests it was selected for in the past by different histories, probably involving famine, when being better at storing fat was an advantage. A tendency to have a positive attitude as well, Mayre speculates, also had survival value.”