There’s evidence that environmental stressors and trauma can be passed down from one generation to the next(1), but now new research is showing that lifestyle factors play a role in the DNA of future generations as well.
The idea that our genetic slate is wiped clean for our offspring is an appealing one, but it’s not entirely accurate. Our environment is constantly changing our DNA via our epigenomes – switching genes in our DNA off and on as we age.
A recent study in the journal Cell(2) now claims to prove that a handful of these changes are actually passed on from parents to children. Until now, conventional wisdom was that all these epigenetic changes were essentially erased between one generation and the next.
“The information needs to be reset in every generation before further information is added to regulate development of a newly fertilized egg,” said Azim Surani, a researcher for the Wellcome Trust and the University of Cambridge(3). Surani compared this process to the erasing of data on a computer disk in order to add new data.
Indeed, Surani’s research clearly shows that a significant amount of epigenetic DNA changes are essentially “wiped clean” with each new generation – but what came as a surprise to researchers was that some regions of our DNA are able to resist this reprogramming.
This results in a small amount of these changes being passed on to our offspring – specifically changes associated with health conditions such as obesity and schizophrenia.
The change-resistant segments of our DNA are small – they make up about 5% of our total DNA – but they contain genes that are especially active in neuronal cells, which can be crucial in our development.
Good Genes Aren’t Enough
This new research indicates that in order to keep from passing on traits that might be harmful to our kids, it’s important to keep our DNA healthy.
While there’s much more to learn about this process and how these changes can affect our future children, epigenetic reprogramming has many potential ramifications.
“Our study has given us a good resource of potential candidates of regions of the genome where epigenetic information is passed down not just to the next generation but to future generations, too,” said Walfred Tang, a PhD student who worked on the study.
“We know that some of these regions are the same in mice, too, which may provide us with the opportunity to study their function in greater detail.”
While some DNA changes can be beneficial for us and even drive evolution, others can be detrimental, especially if they interfere with our genes. To control this process, our bodies use a process known as methylation in order to suppress the retroelements’ activities(4).
“Methylation is effective at controlling potentially harmful retroelements that might harm us, but if, as we’ve seen, methylation patterns are erased in our germ cells, we could potentially lose the first line of our defense,” Surani says.
Researchers are particularly curious about “escapee” retroelements in our genome that humans have acquired during our most recent evolutionary history, believing it’s possible that the reason our body keeps some of our epigenetic information intact is to protect us from potentially detrimental effects.
Whatever the reason, this new evidence shows that it’s not only in our own best interest to take steps to avoid diseases like obesity – it’s in the best interest of our offspring, as well.