How does a mother’s weight-loss surgery affect her child’s risk of obesity? It’s a question scientists have been struggling with since a Laval University study published in April, which looked at children born to mothers who’d undergone gastric bypass surgery prior to their pregnancy. Researchers knew the children were less prone to obesity, but as they tried to figure out why, they found something unexpected. The children’s genes were different — not their genetic code itself, but the markers in between that code. It was a small study, but the results were striking: more than 5,000 genes were expressed differently when parents had undergone the surgery. The surgery had changed something in the mother’s DNA, and when the children were born just a few years later, it appeared to have changed in them too.
Passed from parent to child without ever touching the genetic code
The finding is part of a raft of studies looking at the phenomenon of epigenetic inheritance — how characteristics can be passed down from parent to child without ever touching the genetic code. Together, these studies are having a profound impact on how scientists look at biological inheritance and pointing the way towards new ways of thinking about our bodies, particularly for inherited factors like obesity or cancer risk. Instead of DNA’s coded string of nucleotides (all those Gs, Ts, As and Cs you learned in school), this new kind of inheritance deals with methyl markers found between the nucleotides. Those markers change the way your body’s RNA reads the code, altering the proteins that come out of it. More importantly, the markers can be added and removed in response to external stimuli, making them a kind of running commentary in the margins of your DNA.
Well, this ought to rattle a few wigs. Apparently nature and nurture can merge under certain circumstances.