The Social Life of Genes by David Dobbs at Pacific Standard
The recent explosion of interest in “epigenetics” — a term literally meaning “around the gene,” and referring to anything that changes a gene’s effect without changing the actual DNA sequence — has tended to focus on the long game of gene-environment interactions: how famine among expectant mothers in the Netherlands during World War II, for instance, affected gene expression and behavior in their children; or how mother rats, by licking and grooming their pups more or less assiduously, can alter the wrappings around their offspring’s DNA in ways that influence how anxious the pups will be for the rest of their lives. The idea that experience can echo in our genes across generations is certainly a powerful one. But to focus only on these narrow, long-reaching effects is to miss much of the action where epigenetic influence and gene activity is concerned. This fresh work by Robinson, Fernald, Clayton, and others — encompassing studies of multiple organisms, from bees and birds to monkeys and humans — suggests something more exciting: that our social lives can change our gene expression with a rapidity, breadth, and depth previously overlooked.
Why would we have evolved this way? The most probable answer is that an organism that responds quickly to fast-changing social environments will more likely survive them. That organism won’t have to wait around, as it were, for better genes to evolve on the species level. Immunologists discovered something similar 25 years ago: Adapting to new pathogens the old-fashioned way — waiting for natural selection to favor genes that create resistance to specific pathogens — would happen too slowly to counter the rapidly changing pathogen environment. Instead, the immune system uses networks of genes that can respond quickly and flexibly to new threats.
We appear to respond in the same way to our social environment. Faced with an unpredictable, complex, ever-changing population to whom we must respond successfully, our genes behave accordingly — as if a fast, fluid response is a matter of life or death.