Can there be a genetic difference between progressives and conservatives?   Certainly we have had the discussion many times about studies, both sociological and biological, seeking to make the case that politics might be nature as well as nurture.

New research from U.C. San Diego and Harvard adds some fuel to the fire, stating in the Journal of Politics that a dopamine receptor gene called DRD4 may influence the sociological factors that determine a political mindset. The study's authors say this is the first research to identify a specific gene that predisposes people to certain political views.

The research focused on 2,000 subjects from The National Longitudinal Study of Adolescent Health. By matching genetic information with maps of the subjects' social networks, the researchers were able to show that people with a specific variant of the DRD4 gene were more likely to be progressives as adults (they use the term 'liberal' but, since this is a science site and 'liberal' means freedom, which both progressives and conservatives claim to espouse(1), we use progressive, which is the mindset they are discussing) but only if they had an active social life in adolescence.

Dopamine is a neurotransmitter affecting brain processes that control movement, emotional response, and ability to experience pleasure and pain. Previous research has identified a connection between a variant of this gene and novelty-seeking behavior, and this behavior has previously been associated with personality traits related to being politically progressive. 

They hypothesized that people with the novelty-seeking gene variant would be more interested in learning about their friends' points of view. 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 progressive than average.

They reported that "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." The research team also showed that this held true independent of ethnicity, culture, sex or age.

Lead researcher James H. Fowler, professor of political science and medical genetics(!) at UC San Diego, concludes that the social and institutional environment cannot entirely explain a person's political attitudes and beliefs and that the role of genes must be taken into account; "These findings suggest that political affiliation is not based solely on the kind of social environment people experience.   It is our hope that more scholars will begin to explore the potential interaction of biology and environment. The way forward is to look for replication in different populations and age groups."

These stories tend to get kicked around rather quickly, even in places where you might not expect it.  The last spate of 'liberals are genetically awesome' research got hammered in Slate, for example.

(1) Except when it comes to freedom of marriage for conservatives and freedom of speech for progressives.   Neither side is liberal on its hot button issues.

The Journal of Politics is edited by Jan Leighley and Bill Mishler and located in the Department of Political Science at the University of Arizona.  It is published by Cambridge University Press for the Southern Political Science Association.