New research has shown for the first time that traces of our poor lifestyles, environmental stressors and trauma can be passed down to future generations through our DNA, potentially making our children more prone to conditions such as mental illness and obesity.
Scientists already knew that significant traumatic events such as famine could leave their mark on future generations, but this is the first time they've been able to observe the mechanism by which this happens. And they've found that, contrary to previously assumed, our genetic slate doesn't get completely wiped clean for our offspring.
Our DNA is constantly being altered by our environment through what are known as our epigenomes. Basically, epigenetic changes are changes that affect which genes in our DNA are switched on and off throughout our lives, which means they have a pretty profound effect on our health. But before this, scientists thought that all of these epigenetic changes - which are influenced by things such as our diets and stress levels - couldn't be passed down through our sperm and egg cells, and each generation started with a 'clean slate'.
"The information needs to be reset in every generation before further information is added to regulate development of a newly fertilised egg. It's like erasing a computer disk before you add new data," Azim Surani from the Wellcome Trust and the University of Cambridge in the UK, who led the research, said in a press release.
The team have now been able to describe this epigenetic erasing process in humans - which occurs between weeks two and nine of an embryo's development - for the first time, and have shown that not all of these environmental changes get wiped clean. In fact, around 5 percent of our DNA is resistant to reprogramming, and can carry our mistakes onto the next generation, their research revealed.
These erase-resistant genes are particularly active in brain cells, and are associated with conditions such as schizophrenia, obesity and metabolic disorders, according to the researchers.
"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 potentially to future generations, too," said Walfred Tang, the lead author of 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."
The research has been published in the journal Cell, and suggests that having 'good genes' may not be enough to ensure healthy children – we might need to keep our DNA healthy, too.
There's clearly still a lot more to learn about exactly what we can and can't pass on, and the team are now trying to work out whether these environmental DNA changes can be inherited by more than one generation.
Is it just us, or is anyone else suddenly feeling really guilty about all those all-nighters/cocktails/cheeseburgers? Sorry, kids.