It's delusional to believe that everything can be explained by geneticsby Philip Ball / November 13, 2014 / Leave a comment
You might think it’s sheer bad luck to be struck by lightning. But some of us are cursed with a struck-by-lightning (SBL) gene. Sure, as with many genetic conditions, if you have the SBL gene it doesn’t mean you will be struck by lightning, just that your chances are higher (by a factor of about three or four) than those without it. But that seems a fairly big risk factor to me—and I should know, because I’ve got the gene.
Yet no one is working on a genetic remedy. Scandalous? Not really, because SBL can be identified as the gene better known as SRY, the sex-determining gene on the Y chromosome, which makes an embryo develop into a male. Yes, men get hit by lightning more often, because their behaviour—rushing about on golf courses and football pitches in the rain, that sort of thing—makes it more likely. Call it stereotyping, but the statistics don’t lie.
The geneticist Steve Jones has used this example to point to the absurdity of the concept of a “gene for.” If we knew nothing else about what SRY does, and it fell out of a statistical search for genetic associations with being hit by lightning, we might indeed conclude that it warranted the label SBL. But the association with lightning strikes is merely a side-product of the way the gene’s effects play out in a particular environment. SRY could equally be misattributed as a gene for criminality, murder, baldness, watching Top Gear.
“The most dangerous word in genetics is ‘for’,” Jones has said. “Only 15 years ago people expected that they would find genes for cancer, heart disease or diabetes. But medicine’s big secret is that we haven’t found them. And we haven’t found them because they are not there.” Compare that with Bill Clinton promising, while standing next to a group of smiling scientists in 2000, that the decoding of the human genome means “doctors increasingly will be able to cure diseases like Alzheimer’s, Parkinson’s, diabetes and cancer by attacking their genetic roots.”