The left-wing genes

Paul Raven @ 13-10-2010

Which genes are left-wing? All of them! At least that’s the interpretation Oliver James puts forward in this piece at The Guardian, as he points out that the mapping of the human genome hasn’t delivered evidence for the genetic determinism of mental health and social status that conservative politics – not to mention the pharmacology industries – hoped it would:

This result had been predicted by Craig Venter, one of the key researchers on the project. When the map was published, he said that because we only have about 25,000 genes psychological differences could not be much determined by them. “Our environments are critical,” he concluded. And, after only a few years of extensive genome searching, even the most convinced geneticists began to publicly admit that there are no individual genes for the vast majority of mental health problems. In 2009 Professor Robert Plomin, a leading behavioural geneticist, wrote that the evidence had proved that “genetic effects are much smaller than previously considered: the largest effects account for only 1% of quantitative traits”. However, he believed that all was not lost. Complex combinations of genes might hold the key. So far, this has not been shown, nor is it likely to be.


Another theory was that genes create vulnerabilities. For example, it was thought that people with a particular gene variant were more likely to become depressed if they were maltreated as children. This also now looks unlikely. An analysis of 14,250 people showed that those with the variant were not at greater risk of depression. Nor were they more likely to be depressed when the variant was combined with childhood maltreatment.

In developed nations, women and those on a low income are twice as likely to be depressed as men and the wealthy. When DNA is tested in large samples, neither women nor the poor are more likely to have the variant. Worldwide, depression is least common in south-east Asia. Yet a study of 29 nations found the variant to be commonest there – the degree to which a society is collectivist rather than individualistic partly explains depression rates, not genes.

Politics may be the reason why the media has so far failed to report the small role of genes. The political right believes that genes largely explain why the poor are poor, as well as twice as likely as the rich to be mentally ill. To them, the poor are genetic mud, sinking to the bottom of the genetic pool.

It’s a rather generalised and sweeping statement, but I think there’s a core of truth to it. Is this why there’s been such a right-wing push-back against genetic science in recent years, perhaps?

[ That said, James is narrativising genetic science in a very similar way, albeit on behalf of the other side of the debating chamber. The political polarisation of science worries me regardless of who’s doing it, because it puts the primacy onto agenda-driven interpretation rather than evidence; nowhere is this more clear than in climate science, where progressive/left-wing attempts to counter the right’s conspiracy theories with their own rhetoric have obscured the facts of the matter even further. ]