An examination of potential causal mechanisms linking genes and political behavior
Motivated by earlier work studying the genetic basis of political attitudes (Martin, Eaves, Heath, Jardine, Feingold & Eysenck 1986, Alford, Funk & Hibbing 2005), researchers found that political behaviors such as voter turnout (Fowler, Baker & Dawes 2008), broader participation (Fowler, Baker & Dawes 2008), and partisan attachment (Settle, Dawes & Fowler 2009, Hatemi, Hibbing, Alford, Martin & Eaves 2009) also have a significant heritable component. These findings prompted a great deal of discussion and debate and helped spawn the nascent field of "genopolitics". However, in order to push this area of research forward scholars must identify causal mechanisms linking genes to political behaviors. The goal of this dissertation, which is made up of three distinct chapters, is to explore potential causal pathways my testing potential mediators such as personality traits and cognitive ability as well as identifying new genetic variants that may be associated with political behaviors. The first chapter presents a twin study testing whether the psychological traits cognitive ability, personal control, and extraversion mediate the relationship between genes and political predisposition and acts of participation. The second chapter is a candidate gene association study that tests the hypothesis that extraversion mediates a relationship between a variant of the COMT gene and partisan attachment. The third chapter presents the results from a genome-wide association study of validated voter turnout in the 2010 election. To complete this work I have utilized four novel genetically informative data sets. Two of these data sets were constructed here at UCSD, one at the University of Minnesota, and another with a research team from Sweden. All three studies shed new light on the relationship between genes and these political behaviors. However, the mediation results from Chapter 1 and Chapter 2 suggest only a modest amount of the relationship between genes and political behaviors are mediated by personality traits and cognitive ability. In addition, the investigation of over 500,000 genetic variants presented in Chapter 3 did not turn up many new significant associations. However, all three chapters provide a template for how future work in this area should be done as well as highlight the pitfalls in this burgeoning area of research