Jim Manzi has already posted on the warranted skepticism of DRD4 being reported in the press as the “liberal gene.” Here’s the original paper. The main issue I have is not with the original research, but the inevitable confusions in the media which always arise. First, we know that complex behavioral phenotypes such as religiosity and personality seem to be heritable. That is, a set of genetic variants within the population seems to track the variation in the trait (just as with I.Q.). But, it’s been a much longer haul to actually connect a specific genetic locus to said variation, though the dopamine related genes are always brought forward as candidates. Additionally, particularly when it comes to politics there’s the norm of reaction looming. One might grant that same genetic variation which predisposes Swedes in Sweden to being on the Left or the Right is operative among ethnic Swedes in Minnesota, but most of the difference is actually between population, and a function of the differing environmental milieus of the Upper Midwest and Scandinavia (though perhaps there were strong selection effects operating upon those who chose to leave Scandinavia for the USA). Finally, as with personality, there’s the problem of characterizing the phenotype in the first place in political orientation. Not insoluble in my opinion, but far less clear than something like height, or even intelligence.
The big picture is that variation on most complex behavioral traits has some upstream genetic correlates. And, we can get some sense of the magnitude (or lack thereof) of the effect in a given environment. But like fMRI the introduction of DNA probably adds more glitz than substance at this point. We’ve long known many traits which we think as purely reflective and environmental have a partial biological basis in disposition. Clearly an area to be continued….