Some cocaine-addicted rats and their offspring have blown science’s view of how genes are inherited wide open.
Some sons of cocaine-addicted rats who dislike the drug could change the way we understand genetic inheritance. “Epigenetics” was a buzzword at the Society for Neuroscience meeting in DC last week; it’s a new avenue of study, examining environmental influences that can turn genes on or off in an immediately heritable way. A paper on the epigenetics of cocaine addiction in rats seized the attention of the world’s top brain scientists. The study found that “cocaine-induced changes in the brain can be inherited by sons from their fathers,” says co-author Chris Pierce, of the University of Pennsylvania Medical School. Let’s think about that: in biology class, we were taught to scoff at Lysenkoism—a discredited Soviet approach to genetics that insisted on the heritability of acquired characteristics. But neuroscientists are now saying, Not so fast. Not only were certain changes in gene expression in the brain heritable in the cocaine-addicted rats, but the results of those changes were utterly unexpected. The sons of the addicted male rats didn’t like coke much at all. They were more resistant to the reward effects of the drug, and so less likely to become addicted. The implications are complex and mind-boggling. Researchers must now confront the notion that lasting brain changes caused by drug or alcohol addiction might represent heritable risks—or epigenetic benefits—to their kids. Says Nora Volkov, director of the National Institute on Drug Abuse: “Maybe we can learn to silence certain genes during pregnancy that would help protect against addiction.”