How much do our genes influence our political beliefs?

One of MindBlog’s subject threads has been noting articles that examine the correlation between our genetic constitution and our political behaviors. Thus I point to a recent article by Thomas Edsall that notes work in this controversial field by Ludeke et al. who:

...write that “authoritarianism, religiousness and conservatism,” which they call the “traditional moral values triad,” are “substantially influenced by genetic factors.” — all three traits are reflections of “a single, underlying tendency,” previously described in one word by Bouchard in a 2006 paper as “traditionalism.” Traditionalists in this sense are defined as “having strict moral standards and child-rearing practices, valuing conventional propriety and reputation, opposing rebelliousness and selfish disregard of others, and valuing religious institutions and practices.”

From this perspective, the Democratic Party — supportive of abortion rights, same-sex marriage and the primacy of self-expressive individualism over obligation to family — is irreconcilably alien to a segment of the electorate. And the same is true from the opposite viewpoint: a Republican Party committed to right-to-life policies, to a belief that marriage must be between a man and a woman, and to family obligation over self-actualization, is profoundly unacceptable to many on the left.

Ludeke et al. studied a sample of identical (monozygotic) and fraternal (dizygotic) twins who were separated from each other early in life. They assessed their adult social, political, and social attitudes, finding that they represented a single construct that was heritable and similar to a traditionalism measure. Their abstract:

Social attitudes, political attitudes and religiousness are highly inter-correlated. Furthermore, each is substantially influenced by genetic factors. Koenig and Bouchard (2006) hypothesized that these three areas (which they termed the Traditional Moral Values Triad) each derive from an underlying latent trait concerning the tendency to obey traditional authorities. We tested this hypothesis with data from a sample of twins raised in different homes. We assessed social attitudes with Altemeyer’s (1988) Right-Wing Authoritarianism scale, political attitudes with Wilson and Patterson’s (1968) Conservatism scale, and religiousness with Wiggins’ (1966) Religious Fundamentalism scale. The best-fitting model identified the three TMVT domains as different manifestations of a single latent and significantly heritable factor. Further, the genetic and environmental bases for this factor overlapped heavily with those for the Multidimensional Personality Questionnaire Traditionalism scale, supporting the conception of traditionalism as the latent factor represented by the three scales in contemporary Western societies.