Menus Subscribe Search

Follow us


Genes Are Us

dna-wooden-blocks

DNA sequence as represented by wooden blocks. (Photo: dullhunk/Flickr)

Do Your Grandmother’s Experiences Really Make It Into Your Genes?

• March 07, 2014 • 6:00 AM

DNA sequence as represented by wooden blocks. (Photo: dullhunk/Flickr)

Epigenetics is a hot field right now, and while many recent findings aren’t nearly as revolutionary as its practitioners believe, we have seen some provocative study results that are hard to dismiss.

You inherit some of your grandmother’s genes, but do you also inherit her experiences? Last month, a group of Swedish researchers at the Karolinska Institute and the University of Umeå released their latest in a series of reports on a long-term health study of people born between 1890 and 1920 in Överkalix, a small town in northern Sweden. These scientists have been making waves for more than a decade with claims that our health is influenced by the experiences of our grandparents. Using statistics of 19th-century harvests in Northern Sweden to determine how much food was available to the ancestors of the residents of Överkalix, the researchers concluded that the risk for cardiovascular disease among their study participants was influenced by the dramatic swings from feast to famine experienced by the participants’ grandparents during childhood.

Studies like this one are part of the hodgepodge of research that gets lumped together in the growing and increasingly ill-defined field of epigenetics. Scientific interest in this field has boomed over the past decade, thanks in part to technological advances that make new types of experiments possible. Epigenetics is hot in the popular press as well. It made the cover of Time in 2010. In Germany, Der Spiegel declared that epigenetics is a “victory over the gene,” illustrating both the victory itself and the sexiness of the science with an image of naked woman emerging from the confines of her gene pool. And of course, epigenetics is touted as the new secret to curing cancer. But the popularity of epigenetics is misplaced: It’s a badly over-hyped field whose recent findings aren’t nearly as revolutionary as many of its practitioners believe.

The epigenetic states of the DNA in your ancestors’ liver, muscle, and neurons are irrelevant. The real mystery is how the epigenetic effects of some environments and life experiences manage to get transmitted to our reproductive systems.

What is epigenetics? The term was coined in 1942 by British biologist Conrad Waddington, as a name for the study of how genes produce a fully developed organism from a single fertilized egg. More recently, epigenetics is commonly defined as the study of processes that transcend our genes—processes that produce different outcomes from a single, fixed set of genes by controlling how those genes get used. A classic example is a strain of laboratory mice that carry a particular version of a gene that can cause two different coat colors. Two mice may carry identical versions of this gene but nevertheless appear very different, with either light or dark fur, depending on its epigenetic state—whether the gene is in an on or off state.

What is surprising about this gene is that its epigenetic state can be passed from parents to offspring. This is not supposed to happen. Biological development depends on a complex process of switching the epigenetic states of tens of thousands of genes, as a newly fertilized egg gradually transforms itself into an adult organism made up of trillions of cells that come in hundreds of different types. In order for all of this epigenetic switching to happen correctly, genes must reset to a default state at conception. But researchers are finding evidence of exceptions, genes that somehow escape the reset. If states of genes can be inherited, and not just the genes themselves, then life experiences that happen to alter the epigenetic state of your grandparents’ genes can be passed on to you.

Recently developed technologies make it possible for scientists to measure the epigenetic states of genes more comprehensively than ever before. The result is a wave of studies showing how our life experiences impact the state of our genes. These studies are fascinating, but the results shouldn’t be particularly surprising to anyone familiar with the last 60 years of molecular biology. DNA is not a static biological blueprint. Much as your body adapts to a high-altitude environment by ramping up the production of red blood cells, our genomes respond to environmental signals by changing which genes get expressed. This is not news. A trio of French scientists won a Nobel Prize in 1965 for showing how this process works in bacteria, and there have been decades of studies of this phenomenon in humans.

So we shouldn’t be surprised that our physical and even our mental environment can influence the behavior of our genes in many different cells in our body. Epigenetic states of genes are manifestations of DNA doing its job, and many scientists are currently focused on trying to understand what those different epigenetic states mean. This research is important and interesting, but not paradigm-breaking.

The question of inherited epigenetic states is another matter. When it comes to inheriting your grandmother’s experiences, only a few epigenetic states count: the states of the genes in reproductive cells. DNA get passed on only through sperm and egg cells, and so the epigenetic states of the DNA in your ancestors’ liver, muscle, and neurons are irrelevant. The real mystery is how the epigenetic effects of some environments and life experiences manage to get transmitted to our reproductive systems.

Only a minority of epigenetic research is focused on this specific issue, and it’s unclear how widespread the phenomenon actually is. In the case of most human studies, as one review noted, “cultural confounders are almost impossible to rule out.” The University of Bristol’s George Davey Smith, after reviewing the evidence, wrote that “The conclusion from over 100 years of research must be that epigenetic inheritance is not a major contributor to phenotypic resemblance across generations.”

Despite such justified skepticism, the epigenetics field on occasion produces a provocative result that is hard to dismiss. In January, Brian Dias and Kerry Ressler of Emory University reported that male mice conditioned to be startled by a particular odor passed on that startle response to their offspring. This effect persisted for two generations, despite the fact that the offspring were conceived by in vitro fertilization and never had any physical or social contact with the original, odor-conditioned mice. As far as I can tell, this study was properly done, and includes all of the right controls to rule out confounding effects. Nobody has any idea how a specific, learned behavior gets epigenetically transmitted to sperm, preserved through embryonic development, and embedded in an adult offspring. Epigenetics, like many developing scientific fields when they enter the limelight, is rife with overblown claims and weak studies. But it’s a field to watch—despite the hype, there are genuine mysteries to solve.

Michael White
Michael White is a systems biologist at the Department of Genetics and the Center for Genome Sciences and Systems Biology at the Washington University School of Medicine in St. Louis, where he studies how DNA encodes information for gene regulation. He co-founded the online science pub The Finch and Pea. Follow him on Twitter @genologos.

More From Michael White

A weekly roundup of the best of Pacific Standard and PSmag.com, delivered straight to your inbox.

Recent Posts

October 31 • 4:00 PM

Should the Victims of the War on Drugs Receive Reparations?

A drug war Truth and Reconciliation Commission along the lines of post-apartheid South Africa is a radical idea proposed by the Green Party. Substance.com asks their candidates for New York State’s gubernatorial election to tell us more.


October 31 • 2:00 PM

India’s Struggle to Get Reliable Power to Hundreds of Millions of People

India’s new Prime Minister Narendra Modi is known as a “big thinker” when it comes to energy. But in his country’s case, could thinking big be a huge mistake?


October 31 • 12:00 PM

In the Picture: SNAP Food Benefits, Birthday Cake, and Walmart

In every issue, we fix our gaze on an everyday photograph and chase down facts about details in the frame.


October 31 • 10:15 AM

Levels of Depression Could Be Evaluated Through Measurements of Acoustic Speech

Engineers find tell-tale signs in speech patterns of the depressed.


October 31 • 8:00 AM

Who Wants a Cute Congressman?

You probably do—even if you won’t admit it. In politics, looks aren’t everything, but they’re definitely something.


October 31 • 7:00 AM

Why Scientists Make Promises They Can’t Keep

A research proposal that is totally upfront about the uncertainty of the scientific process and its potential benefits might never pass governmental muster.


October 31 • 6:12 AM

The Psychology of a Horror Movie Fan

Scientists have tried to figure out the appeal of axe murderers and creepy dolls, but it mostly remains a spooky mystery.


October 31 • 4:00 AM

The Power of Third Person Plural on Support for Public Policies

Researchers find citizens react differently to policy proposals when they’re framed as impacting “people,” as opposed to “you.”


October 30 • 4:00 PM

I Should Have Told My High School Students About My Struggle With Drinking

As a teacher, my students confided in me about many harrowing aspects of their lives. I never crossed the line and shared my biggest problem with them—but now I wish I had.


October 30 • 2:00 PM

How Dark Money Got a Mining Company Everything It Wanted

An accidentally released court filing reveals how one company secretly gave money to a non-profit that helped get favorable mining legislation passed.


October 30 • 12:00 PM

The Halloween Industrial Complex

The scariest thing about Halloween might be just how seriously we take it. For this week’s holiday, Americans of all ages will spend more than $5 billion on disposable costumes and bite-size candy.


October 30 • 10:00 AM

Sky’s the Limit: The Case for Selling Air Rights

Lower taxes and debt, increased revenue for the city, and a much better use of space in already dense environments: Selling air rights and encouraging upward growth seem like no-brainers, but NIMBY resistance and philosophical barriers remain.


October 30 • 9:00 AM

Cycles of Fear and Bias in the Criminal Justice System

Exploring the psychological roots of racial disparity in U.S. prisons.


October 30 • 8:00 AM

How Do You Make a Living, Email Newsletter Writer?

Noah Davis talks to Wait But Why writer Tim Urban about the newsletter concept, the research process, and escaping “money-flushing toilet” status.



October 30 • 6:00 AM

Dreamers of the Carbon-Free Dream

Can California go full-renewable?


October 30 • 5:08 AM

We’re Not So Great at Rejecting Each Other

And it’s probably something we should work on.


October 30 • 4:00 AM

He’s Definitely a Liberal—Just Check Out His Brain Scan

New research finds political ideology can be easily determined by examining how one’s brain reacts to disgusting images.


October 29 • 4:00 PM

Should We Prosecute Climate Change Protesters Who Break the Law?

A conversation with Bristol County, Massachusetts, District Attorney Sam Sutter, who dropped steep charges against two climate change protesters.


October 29 • 2:23 PM

Innovation Geography: The Beginning of the End for Silicon Valley

Will a lack of affordable housing hinder the growth of creative start-ups?


October 29 • 2:00 PM

Trapped in the Tobacco Debt Trap

A refinance of Niagara County, New York’s tobacco bonds was good news—but for investors, not taxpayers.


October 29 • 12:00 PM

Purity and Self-Mutilation in Thailand

During the nine-day Phuket Vegetarian Festival, a group of chosen ones known as the mah song torture themselves in order to redirect bad luck and misfortune away from their communities and ensure a year of prosperity.


October 29 • 10:00 AM

Can Proposition 47 Solve California’s Problem With Mass Incarceration?

Reducing penalties for low-level felonies could be the next step in rolling back draconian sentencing laws and addressing the criminal justice system’s long legacy of racism.


October 29 • 9:00 AM

Chronic Fatigue Syndrome and the Brain

Neuroscientists find less—but potentially stronger—white matter in the brains of patients with CFS.


October 29 • 8:00 AM

America’s Bathrooms Are a Total Failure

No matter which American bathroom is crowned in this year’s America’s Best Restroom contest, it will still have a host of terrible flaws.


Follow us


Levels of Depression Could Be Evaluated Through Measurements of Acoustic Speech

Engineers find tell-tale signs in speech patterns of the depressed.

We’re Not So Great at Rejecting Each Other

And it's probably something we should work on.

Chronic Fatigue Syndrome and the Brain

Neuroscientists find less—but potentially stronger—white matter in the brains of patients with CFS.

Incumbents, Pray for Rain

Come next Tuesday, rain could push voters toward safer, more predictable candidates.

Could Economics Benefit From Computer Science Thinking?

Computational complexity could offer new insight into old ideas in biology and, yes, even the dismal science.

The Big One

One town, Champlain, New York, was the source of nearly half the scams targeting small businesses in the United States last year. November/December 2014

Copyright © 2014 by Pacific Standard and The Miller-McCune Center for Research, Media, and Public Policy. All Rights Reserved.