How the Environment Interacts with our Genes

I talk a lot about the role of genes in everything from child behavior to addiction and mental health – mostly because that’s the part that’s often overlooked, that people aren’t talking about – but that doesn’t mean that the environment doesn’t play a critical role as well.  It absolutely does.

About half of all the differences between people – whether we’re talking about how risk-taking or impulsive or anxious or conscientious people are – are due to differences in the DNA sequences we were born with, and about half is due to differences in our environments.

But here’s the piece I think is really interesting. You can’t understand the way your environment impacts your life without taking into account your genetic make-up.

In other words, genes and environments can’t exist on their own.

DNA sequences in a petri dish don’t spontaneously generate human beings, that DNA sequence needs an environment (a mother’s womb) to grow. Conversely, the environment is different for each of us depending on our DNA. That’s why my husband and I can walk outside, at the same time to the same temperature, and I think it’s freezing, and he thinks it feels great. Same environment, but we’re different people, with different wiring, so it affects us differently.

This means it doesn’t actually make sense to think of the environment and our genes as separate things that impact us. They are intertwined and inseparable. Nature VERSUS nurture was a silly debate. You can’t understand one without the other. Which is why when we talk about wanting to make a change, it’s unfortunate that we often only focus on the environment; we’re ignoring the other critical half of the puzzle. 

So let’s unpack the environment a bit more with that in mind.

Some environments are random – for example, whether we experience a natural disaster like a hurricane or a tornado, or maybe even if we get hit by a car. But most environments don’t just happen to us. You don’t just wake up and discover you’re in a library, or a bar.

We play a role in choosing our environments, and our genes are involved in those choices. 

So, people who have a love of reading, or who enjoy quiet spaces, are more likely to spend time at the library. And people who are more predisposed to be extraverted, are more likely to enjoy being at parties or bars. Maybe that car accident wasn’t just because someone randomly hit you; maybe you’re a risk-taker and you were speeding. Our genetic predispositions influence the environments we find ourselves in, and then those environments further shape us. So it creates a feedback loop between our genes and our environments.

Not only that, the way we respond to certain environments – including other people in our lives – is shaped by our genes. 

This why something your child does that drives you crazy, may not be a big deal to your spouse. Or, you may have a co-worker that you can’t stand, but your friend thinks they are great. Same person, difference experiences due to our own unique wiring and how it interacts with that person’s wiring. And on an even larger scale, these differences in how we respond to the environment is part of the reason why some people can just bounce back from stress or adversity, and others may experience depression. Or why some people can drink socially, but for others, it leads to addiction.

So, our genes influence the environments we seek out, and the way we respond to different environments. So yes, the environment is a critical part of our lives, but you actually can’t disentangle the environment from your own genetic wiring. And that’s why it’s so important to understand our dispositions. 

Because by understanding our dispositions we can start to break cycles that aren’t working for us.

I have spent more than 20 years studying the ways that our genes influence our lives. I’ve written hundreds of scientific papers and run dozens of projects funded by the National Institutes of Health, the National Science Foundation, and lots of private foundations.  

And now I want to help you harness the power of your genes to live your best life.