How culture can invert genetic risk

Neuron Culture has a fantastic piece on how a long touted ‘depression gene’ turned out to reduce the risk of mood problems in people in East Asians and why we can’t always understand genetic effects on behaviour without understanding culture.

The piece riffs on the long-established finding that the short variant of the serotonin transporter or 5-HTTLPR gene is more common in people with depression, until psychologist Joan Chiao found that East Asians are more than twice as likely to have the gene but only have half the rate of mood problems.

Why is this the case? Probably because 5-HTTLPR isn’t so much a gene for depression, but more likely for social sensitivity, and East Asian culture is more likely to be collectivist, where social connections matter more in your psychological make-up:

So how does individualism-v-collectivism relate to depression and depression genes? Here Chiao and Blizinsky, as well as Way and Lieberman (these connections were apparently ripe) turned to another emerging idea: That the short SERT gene seems to sensitize people not just to bad experience, but to all experience, good or bad…

This starts to explain the purported interplay of the S/S allele and a collectivist culture: If short-SERT people get more out of social support, a more supportive culture could buffer them against depression, easing any selective pressure against the gene. Meanwhile the gene’s growing prevalence would make the culture increasingly supportive, since those who carry it might be more empathetic. Studies have shown, for instance, that short-SERT people more readily recognize and react to others’ emotional states.

For those who keep an eye on such things, Neuron Culture has just become part of the newly launched Wired Science blog network which is already full of great stuff.