We’ve heard before that babies feel the effects of a mom’s high anxiety or depression. But so far, no one has been able to explain how an expecting mom’s emotional state could carry forward to her baby.
But this month in the journal Cell, researchers report a piece of the puzzle — not only that, they suggests the effects of stress are not just passed down from mom to child, but could actually carry forward through another generation as well.
Here’s how the scientists say that stress may reach down through the generations:
In the study, the researchers used the drosophila fly — of course an infinitely less complex creature than humans but one that proves useful for looking a basic genetic mechanisms.
They found that when the fly’s eggs were subjected to environmental stress, it caused a particular protein (ATF-2) to detach from the flies DNA. The ATF-2 protein acts as a “zipper” to keep densely packed DNA together. Environmental stress led the DNA to unzip, causing genes to be turned on that otherwise would not be.
The surprise was that the tweaks to the fly’s DNA could be passed down not just to their offspring, but even one generation beyond. The researchers say that mammals have a counterpart to ATF-2, called ATF-7, and it’s already been shown that mice exposed to psychological stress do experience the kind of unzipping seen in the flies.
We know that babies get DNA from their grandparents, but the suggestion here is that it’s not just genes that are passed down, the environment of grandparents could go on to affect subsequent generations too.
We’re talking about flies and mice — of course we can’t transfer the data directly to humans. We also don’t know the end result here — whether stress makes changes to offspring that are good and adaptive or not (stress is a normal and unavoidable part of life). But we have seen lately how environment and lifestyle affect babies in ways we never expected. For example, a dad’s health habits (not his genes) may be passed down to his offspring. Clearly the effects of our environment (and apparently, our grandparents) are more complex than we imagined.