The Nuance

The Explosive Science of Epigenetics

The health choices you make today could affect the expression of your kids’ (and grandkids’) DNA — and maybe their risk for disease

Markham Heid
Elemental
Published in
5 min readSep 26, 2019

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Illustration: Kieran Blakey

TThe “nature versus nurture” debate has been raging for thousands of years. Are people the products of their DNA, or of their upbringing and environment? The writings of both Plato and Shakespeare discuss this question. As recently as the past century, some big thinkers still subscribed to the philosopher John Locke’s “blank slate” theory, which held that each individual is born “formless” and is shaped by their environment and upbringing. Even more recently, some genetic scientists argued in favor of biological determinism, or the view that everything about a person is predetermined by their DNA.

Today, experts recognize that nature and nurture — far from being independent or at odds — engage in a complex dance. While DNA has a lot to say, a person’s genes and environment interact throughout their life to produce any number of outcomes. And the science of epigenetics lies at the heart of this interaction.

“Epigenetics describes how the human genome can adapt to cope with environmental factors,” says Jian Feng, an assistant professor in the Department of Biological Sciences at Florida State University. Specifically, epigenetics is the study of things that change the way genes are expressed — that is, whether they’re turned on or off. Changing gene expression can fundamentally alter the activity of that gene without giving it a mutation.

For example, a 2018 study from the Icahn School of Medicine at Mount Sinai found that giving cocaine to mice changed the activity of genes in the reward centers of the rodents’ brains, and these gene modifications led to addiction-like behaviors. “Substance use changes gene expression in ways that promote abuse,” Feng says, summarizing the study’s conclusions. Research has also found evidence that abused children undergo epigenetic changes that may increase their risk for obesity, heart disease, depression, and other medical conditions later in life.

“W“We know that there are all these molecular marks and processes around the DNA that regulate how the DNA functions,” says…

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Markham Heid
Elemental

I’m a long-time contributor at TIME and other media orgs. I write mostly about health. I grew up in Michigan, but these days I live in southwest Germany.