The Genetics of Voting

This past weekend was Canadian Thanksgiving and with my family all together and elections on both side of the border, the conversation naturally turned to politics. One person almost proudly claimed that they had never voted (and not for lack of opportunity). It's not uncommon to see families with similar political views, but what about similar political participation? Again, I wouldn't be surprised if there were familial trends in voter engagement but my first inclination would be to chalk it up to nurture over nature. According to Wikipedia parental turnout is a strong predictor of youth turnout, and recently published twin studies of voting trends in Los Angeles showed that while the choice of a particular candidate don't appear to be heritable, "genes account for a significant proportion of the variation in voter turnout." A follow-up paper published in the Journal of Politics attempts to identify genes involved, though they stress that they work shows association, but nothing about causality. From the abstract:

Using data from the National Longitudinal Study of Adolescent Health, we show that a polymorphism of the MAOA gene significantly increases the likelihood of voting. We also find evidence of a gene-environment interaction between religious attendance and a polymorphism of the 5HTT gene that significantly increases voter turnout.

Both of those genes are involved in serotonin pathways. I haven't looked at the paper in detail, so I don't know if their methods are valid (they use a mixed-effects logistic regression model) or their conclusions are sound - or how reliable the Journal of Politics is as a source of genetic knowledge so take it with a grain of salt until you check it out for yourself.