A couple of years ago, a group of researchers injected rats with a bunch of nicotine. But they weren't looking to see how the nicotine would affect those same rats. Instead, the scientists were investigating inherited changes--in other words, how nicotine experienced by one rat might affect the rat's children, and the rat's grandchildren.
When those same researchers discovered that the grandchildren of the nicotine-injected rats had, like their parents, developed asthma, it wasn’t the first finding to be tied to the exciting, emerging field of epigenetics, nor would it be the last. The idea that a person’s experiences and life decisions can influence the layer of proteins that encase DNA, and therefore switch on or switch off gene expression down the hereditary line, has captivated a new era of genetic research. Epigenetic research is now altering our understanding of everything from obesity to diabetes.
But the new story being told about the nuanced interaction between nature and nurture has struck a strange, mom-blaming tone, some researchers contend. Take, for instance, the asthmatic rats: When Discover Magazine covered the study, it framed the findings in terms of original female sin. The headline read “Grandma’s curse,” underneath which ran a photo of a teenage girl smoking a cigarette. The caption: “Think of your grandchildren!”
Last week, seven researchers, led by Harvard University history of science professor Sarah Richardson, highlighted an ongoing pattern of mom-blaming coverage of epigenetics in Nature. After all, they argue, epigenetics looks at changes passed down from fathers, too. But more importantly, the researchers say, science coverage often attempts to blame an individual Mom Zero, when epigenetics often highlights causal forces far beyond a mother’s choices instead.
Researchers have found, for example, that a pregnant mouse mom’s poor diet can create metabolic disorders, like obesity, in male offspring. A growing body of research also suggests that chronic stress or trauma can trigger epigenetic changes, too. But before making moms even more paranoid about eating or meditating properly during a pregnancy, the Nature co-authors argue that these findings should force us to look at bigger societal patterns, not individual blame.
“We’re not looking at the larger consequences,” says report co-author Janet Golden, a professor of history at Rutgers University and author of a book tracking popular misconceptions about fetal alcohol syndrome. “Are people underemployed and therefore unable to afford a healthy diet? Have food stamp cutbacks mean that women are cutting back on their own food to make sure that their children are adequately fed?”
She applies similar questions to stress. “Are your shifts changing every week so you’re sleep-deprived? Are you being abused by your partner?” Golden asks.
It’s also a big leap to conclude that effects seen in mice will be replicated exactly in humans. Chris Kuzowa, an epigenetics researcher and Nature co-author, points out that human babies are bigger investments than mouse offspring, biologically speaking. They take longer to incubate, they don’t come in litters, and they’re insulated from environmental forces in the womb in a different manner than mice or rats. The most robust research, he adds, suggests that epigenetic changes can come from factors a mother might not be able to change at all.
“I think the big message that comes out of this research is the finding that things that beyond the mother’s control [can be] harmful. Stressors, pollutants, toxins, discrimination, extreme stress--these are the kinds of things that seem to be having long-term effects on health,” Kuzowa says. “That’s a story about how society treats people, and how society treats different aspects of a population. These aren’t things that mothers choose; they’re things that mothers have to deal with.”
A day after the researchers’ piece published in Nature, Science provided yet another interpretation of epigenetic research that sought to blame a mother--and her choices--for genetic dysfunction. After a mouse study found that mothers’ malnourishment negatively affected the sperm of male offspring, the editor’s summary, headlined as “The nutritional sins of the mother” reported that offspring “feel the effects of maternal assault.”
[Top Photo: Flickr user Jerry Lai]