US researchers have claimed that having a particular gene variant and a sociable time in your teens may mean you are more likely to be politically liberal. In what is claimed to be the first link between a gene and a political viewpoint, four authors from Harvard University and the University of California, San Diego, took a sample of 2,000 people from The National Longitudinal Study of Adolescent Health and asked each participant to name five male and five female friendships made during their time at high school. The number of non-familial individuals they named was used to judge how social they were.
The participants were then asked to describe themselves as 'very conservative, 'conservative', 'middle-of-the-road', 'liberal' or 'very liberal'. The information obtained was compared with whether or not the participants possessed the 7R variant of the DRD4 gene - previously associated with novelty-seeking behaviour. The researchers theorised that the variant might be related to openness - a psychological trait that has been linked with political liberalism.
'People with the novelty-seeking gene variant would be more interested in learning about their friends' points of views', said lead author Professor James Fowler, from the University of California. 'As a consequence, people with this genetic predisposition who have a greater-than-average number of friends would be exposed to a wider variety of social norms and lifestyles, which might make them more liberal than average'.
The authors reported both environmental and genetic factors were decisive. 'It is the crucial interaction of two factors - the genetic predisposition and the environmental condition of having many friends in adolescence - that is associated with being more liberal', they said.
Some commentators have been critical. In his Scientific American blog, John Horgan writes that as yet no scientific claim which links a particular gene to a complex behavioural trait has been upheld. He also points out the timing of the paper - 'just before Election Day'. The findings were published in the Journal of Politics.