The Genetic Self: Epigenetics

How your past is written on your DNA

Summary

• Nucleic DNA is not our destiny. Experiences turn gene expression on/off through epigenetic adaptations that mask or unmask our DNA.

• Nonetheless, we inherit epigenetic adaptations from our ancestors — meaning that we can be neurobiologically predisposed to disordered thought and behavior patterns resulting from either our trauma or our parents trauma.

• Redesigning our epigenome requires understanding our traumatic and overwriting old experiences by reliving that trauma from a position of control.

• Imaginative play may be a more effective way to do that than enlisting romantic partners, family members, or children in your own unconscious drama.

Introduction

In Debunking DNA, I described how the fallacy of genetic determinism prepares people for work in the hierarchical, industrialized organizational structures that dominated the 1960’s. The popular understanding of DNA as the central controller of human chemical synthesis unconsciously primed people to be subsumed into the machinery of the factories that were made society rich.

For example, in his scathing critique of modern education, the late Sir Ken Robinson says:

I believe we have a system of education that is modeled on the interests of industrialization and in the image of it.

I'll give you a couple of examples schools are still pretty much organized on factory lines ringing bells separate facilities specialized into separate subjects.

We still educate children by batches We put them through the system by age group.

Why do we do that?

It's like the most important thing about them is their date of manufacture.

That is, telling schoolchildren that they are machines risks condemning them to adulthoods of resigned helplessness.

One way to recapture your agency is to better understand the mechanisms of your genetic expression, and how they pre-dispose you to certain patterns of thought and behavior, so that you can consciously redesign them.

To do that, we must understand how our biology keeps a chemical record of our traumatic experiences that controls expression of our DNA, and how that historical record can be changed.

If if we can’t change the past, we can rewrite our chemical record of it.

Epigenetics

Since completion of the Human Genome Project twenty years ago, scientists have discovered that there is more to the function of our DNA than the sequence of nucliec acids from which it is made. The expression of of our DNA can be turned on and off by experiences and exposures. In particular, experiences with trauma and deprivation can result in chemical masking of genes that create neurobiological and metabolic changes that may adapt our bodies to be better suited to handle threats.

The study of gene expression is called epigenetics, and so far it seems to be a much more significant scientific breakthrough than deciphering the human genome — partly because epigenetic adaptations can be passed down through several generations.

In this way, our epigenome serves as a chemical “memory” of our past, and our ancestors’ past.

Early experiences impact children’s future outcomes through biological embedding: the process whereby experiences produce lasting changes in the function of a biological system with consequences for development, behavior, and health. Early life social experiences (e.g., early caregiving, trauma, maternal mental health) are known to contribute to individual differences in susceptibility and resilience for a range of physical and mental health outcomes.

— Aristizabal et al. 2020.

The breakthrough discovery here is that experience (Nurture) causes modifications to the expression of DNA (Nature), altering chemical functions within the body. That is, epigenomic adaptations represent a biochemical history of organism experiences. For example, children conceived during the Dutch Hunger Winter (1944-1945) bear epigenetic markers in their DNA that modify their metabolism (Vaserman & Luschak. 2021). These metabolic modifications were the result of their experience of famine, and may have better prepared them to survive on low calorie, malnourished diets by causing them to partition more of their available food into body fat instead of growth. However, these metabolic adaptations that helped them survive malnutrition as infants became problematic as adults, when food was more plentiful.

You might be curious to know, “Why don’t the epigenetic adaptations go away when the environment that provoked them changes?”

It turns out that, as a biochemical record of history, epigenetic adaptations can be persistent.

So persistent that they can be passed down to offspring for several generations. That means a child conceived during the Dutch famine could have several grandchildren that carry epigenetic modifications putting them at greater risk of obesity. And your own DNA expression may be controlled by some trauma experienced by your great grandparents, or even earlier.

From an evolutionary biology perspective, heritable adaptability may confer a tremendous advantage to offspring when they can be expected to encounter consistent environmental conditions. For example, when scientists conditioned adult male rats to fear a certain odor, the baby rats (pups) sired by those males exhibited the same fear despite never having been previously exposed to the odor (Dias & Ressler 2013). In this case, the rat pups inherited the fear from their fathers epigenome. In an environment in which the odor indicates the same threat their father was conditioned to fear, those epigeneticly programed rat pups would gain an evolutionary survival advantage.

In a sense, the pups were born with a biochemical memory of the experience of their fathers. However, should the environmental circumstances change such that the odor now indicates a rich food source (rather than the poison or predator their fathers experienced), then the epigenetic inheritance of fear would put the poor rat pups at a serious evolutionary disadvantage.

Inherited, non-genetic modifications and their consequences on behaviour can be beneficial if the offspring encounters similar (matching) environments in which the modifications can make them better adapted, and improve well-being or survival. However, they can be maladaptive if the environment has changed, and the acquired adaptations are no longer advantageous.

- Bohasak & Mansu 2015.

Human circumstances now change faster than our epigenome can adapt. Thus, the epigenomic adaptations that helped keep our parents or grandparents alive as children may be hurting us now, as discordance between the experience of our ancestors and the demands of our current circumstances grows.

Nonetheless, recent research has begun to explore the possibility that new experiences can erase prior epigenetic records and enable new adaptations.

Positive aspects of the environment such as cognitive stimulation, healthy diet, and exercise may also promote resilience through epigenetic mechanisms… . Although challenging to translate into humans, healthy lifestyle factors such as moderate physical activity, dietary quality and cognitive stimulation are associated with resilience-building. Little work has been conducted to investigate the impact of these factors upon the epigenome, but minimal alcohol intake, fruit and vegetable consumption, and moderate exercise have been associated with a lower epigenetic age, a resilience-associated epigenetic factor.

Psychotherapeutic interventions may also impact the epigenome alongside their therapeutic effect. For example, changes in DNA methylation of candidate stress-related genes (FKBP5, SLC6A4) have been observed in patients undergoing psychological treatments for PTSD, phobia, or anxiety symptoms.

— Smeeth et al. 2021.

In other words, although epigenetics are persistent, they are not immutable. Making improvement in metabolism and mental health may cause epigentic adaptations that both benefit you and your unborn grandchildren, should you have any.

And that means your DNA is not your destiny. Although you cannot change your DNA without gene therapy, you can change its expression.

The biochemical record of your experience & adaptation

The range of epigenetically heritable characteristics demonstrated in laboratory experiments is extraordinary, including: sociability, anxiety, response to stress (i.e., resilience), addiction, intelligence, and metabolic health.

Traumatic stress is a type of life experience that has transgenerational effects in mammals. Traumatic experiences, both in early and adult life, are major risk factors for behavioral dysfunctions and mental disorders. Importantly, there is increasing evidence for inter- and transgenerational cycles of behavioral adaptation in response to traumatic stress, which are largely mediated by epigenetic mechanisms. In most scenarios, stressful experiences negatively affect behaviors across generations and constitute heritable risk factors for neuropsychiatric disorders. For example, early life traumatic stress leads to a multitude of behavioral abnormalities including depressive-like behaviors across successive offspring in mice.

- Jawaid et al. 2018.

Because our experiences are written not only into the memories encoded in our brains, but into a biochemical record encoded into our epigenetic genome, we carry trauma in our bodies.

One of the first to recognize this was Alice Miller, who wrote The Body Never Lies (2006) and The Drama of the Gifted Child (2008). She pointed out that experiences we had when we were very young can leave a lasting imprint, even when we don’t remember them.

Consider the origins of anorexia in a woman named Beatrice,

Beatrice learned as a breastfeeding infant that her Mother’s approval depended on postponing her hunger. Is it any wonder that she should grow up anorexic, as if she was programmed with an instinct to seek her Mother’s approval long after she was weaned?

As an infant, denying herself food ensured that she remained in good standing with her Mother. Not every infant will respond to a distracted, irritated, or angry Mother in this way, but Beatrice did. And once she discovered that denial of her own hunger worked, she perfected it.

Given the rapid state of brain development in infancy, it is likely that Beatrice’s young brain was organized around this survival principal of appetite suppression in a way that most of us cannot imagine. By adolescence, Beatrice’s preternatural ability to disconnect from her own hunger must have been honed by thousands of hours of unconscious practice.

This is what author Miller means by “gifted.” Beatrice as an infant found a creative, resourceful solution to the problem of her Mother’s withdrawal by denying expression of her own feelings.

But what if Beatrice’s “gift” was not some exceptional infant intelligence, but instead an epiegentic priming inherited by her own Mother’s experiences with food or famine, passed down to Beatrice in her Mother’s epigenome?

While we could attribute Beatrice’s adult anorexia to her classic conditioning as an infant, twin studies demonstrate that anorexia has a strong heritable component (Gorwood et al. 2003, Yao et al. 2021). Beatrice’s formative early experiences might have done little more than amplify an epigentic pre-disposition for self-denial of food that resulted from adaptations her ancestors were forced to make. To make matters worse, Beatrice might have received encouragement, attention, or rewards for her anorexia from other cultural cues that valued or approved of her lean body, such that her epigeneitc predisposition was reinforced by classic conditioning.

Now 58 years later, Beatrice has finally discovered that the denial of the feelings she learned would please her Mother is the cause of her depression. According to Miller, Beatrice must learn to experience her feelings — not just hunger, but anger for the baby who was denied.

Compulsion to repeat

To Beatrice, the whole exercise of emotional self expression might seem pointless. Some of the people I’ve spoken with who suffer from analogous disorders have told me, “It all happened so long ago. What’s the point?”

But Beatrice’s anorexic compulsion is not a weakness in her character. It is a biologically hard-wired response to her trauma. For example, in The Body Keeps The Score (van der Kolk 2014) describes the way that traumatic experience manifests in our physiology by altering our biology. Moreover, every time we recall the traumatic experience in our imagination, we strengthen the neural pathways that govern our response. We might even be altering the expression of our genes to code for behavioral responses that are suited to the threat environment that traumatized us.

In this way, repetition of the experience in our imagination might provide two adaptive advantages:

1. Allow the imagination to experiment with new resolutions that result from “What if… ?” creative problem-solving, or

2. Reinforce adaptations that strengthen automatic threat-avoidance reactions.

The first case, imaginative re-experiencing as a way of exploring alternate outcomes, sometimes takes place in therapeutic relationships. However, the risk in attempting the first is that imaginative re-experiencing in talk therapy may also re-traumatize and consequently re-enforce maladaptive patterns.

Nonetheless, because epigenetic adaptations are the result of experience, it makes sense that rewriting the epigenome requires to overriding prior experiences with new.

As it turns out, the mammalian brain will seek to do exactly this. After we experience trauma, our brains will strive to resolve it by reliving the trauma from a position of control. Peter Levine describes this phenomena in his book Trauma, Memory (2015), in which he includes this description of three cheetah cubs who survived a lion attack:

In his example, the cheetah cubs replay the traumatic event, exploring different options and resolutions in an effort to resolve the life-threatening trauma of the attack in imaginative, problem-solving play — until the cubs are satisfied that they have gained control of the experience.

Empowered by their new attack-avoidance experiences, they no longer need fear a repetition of the traumatic event. Although they will retain the memory of the attack, they will have released the negative emotions associated with that memory, because in the successful reliving of the trauma they will have gained confidence that they can handle the threat.

Humans work in the same way that cheetah cubs do.

For example, in Lawrence Cohen’s Playful Parenting (2002) he describes how a toddler might respond to the trauma of a visit to the doctor’s office for shots.

A three-year-old gets a shot at the doctor’s office. She comes home, and what game does she want to play?

Doctor, of course.

And who does she want to be?

The doctor or nurse—definitely not the patient.

And who does she want to to give (the shot) to?

Well, her first choice is a parent or another adult. If no one is available, she might use a stuffed animal or doll.

And how does she want the game to go?

She wants you to pretend to howl and say, “No, no, no please don’t give me a shot. I hate shots! No, no, no,” and act as if you are in agony of pain and terror.

This response lets the child be in the more powerful position. It is a simple game of role reversal, but it is very satisfactory… .

The play shot might be pretend, but the need for emotional recovery is real. The child chooses this fantasy game because she wants a hand with her genuine feelings about the actual shot. This isn’t just play for fun… .

The purpose is to go through the incident again, but this time letting the scary feelings out. That’s why a child likes to play this kind of game over and over and over.

Reliving the experience in play rearranges the meaning of the story and those rearrangements have profound consequences. They change our emotions, our identities, our capabilities, and our prospects. They change our perceptions, our beliefs, and consequently they change the biochemistry of our bodies.

Beliefs drive chemical changes in our bodies

In The Biology of Belief (Lipton 2005) Bruce Lipton explains that the most important driver of our biochemistry is our thoughts, not our genome. That is, our cells have no choice but to respond to the signals they receive from the environment. Those signals might be electrical (from the nervous system) or hormonal (from the endocrine system), but either way the molecules of our body must respond according to the laws of physics.

Thus, when we have negative thoughts, we prepare the cells of our body to respond and adapt to threats. And when we have positive thoughts, the our biochemistry adapts to prepare for an abundant environment.

Most of us lack the discipline to interrupt the negative thoughts that automatically pop into our minds. I have acquaintances who have spent years studying meditation, and even they struggle to manage their own thoughts.

However, van der Kolk describes an unusual therapeutic technique for resolving trauma that reminds me of the child-like play in Cohen’s description. For van der Kolk, recreating a traumatic experience in an improvisational theater setting that positions the traumatized subject to achive a more satisfactory outcome has the power to resolve the compulsion to repeat and rewrite the biochemistry of a traumatic experience.

Of course we can never undo what happened, but we can create the emotional scenarios intense and real enough to defuse and counter some of those old (traumas).

- van der Kolk 2014.

Recoding our epigenome

Each of us carries trauma from our childhoods.

Rarely do we understand that our response to that trauma was a resourceful and self-response that served us well in that moment.

It was Jason Silva’s YouTube series Shots of Awe that first brought the possibility of rewriting our biochemical record to my attention. Silva’s thesis is that our memories of our pasts are nothing but a complex network of neural and biochemical connections and that because these connections are malleable, they are also changeable.

At first this sounds like a contradiction a total paradoxical idea. I mean how could you change something that already happened?

But think about it why does the past matter at all? What do we get to keep from something that already happened? Well we get to keep the memory right?

Supposedly, either the bliss or the trauma. It’s really the memory that we’re talking about here — the story that runs on a loop in the back of our minds of what has happened and somehow the fact that what has happened has shaped us and will shape our future.

We feel in a way haunted or condemned to be a certain way because of what has happened to us.

Epigenetics tells us that we are the sum of our experiences — that we that our cells are a technology that turn experience into biology — that everything that happens to us lays itself like tire tracks tattooing itself across our body.

— Jason Silva, “Can We Change the Past?”

What I’ve discovered is that going back to the traumatic memories of my childhood and re-enacting them in my imagination allows me to change the meaning I make of those experiences.

It’s as if I had a time machine that allowed me to visit the past and change it in a way that alters my present.

Since this discovery, I’ve relived several moments that were terrible for me. However, in this reliving I am no longer alone. The child in my memory now has a grown-up mentor or companion because in the relived scene, my adult self is with my child self the entire time, supporting, interpreting, explaining the story that my child self needs to hear.

One example involved an experience from when I was 7 years old, riding bikes around with my older sister, who was almost 9 at the time. We were riding over the dirt roads by ourselves (it was the early 1970’s) in the area around our new summer home.

We got lost.

But we came out from the dirt onto a paved road by a famous landmark in the little New England town where our parents had decided we would spend our summers.

We were right across from the Old Mill, a site my Mother had taken us to for a picnic the summer before. I remembered it so well despite my young age, because I was fascinated by the Mill and the picnic remained a salient, pleasant memory.

I knew the way home was north, and I told my older sister so.

She insisted it was south, and I knew she was wrong. Towards the south I could see the roof of the massive hospital building, which would only take us further from home.

My older sister didn’t care. She was ready to ride her bike the wrong way, without consideration for my superior memory and sense of direction. Because it wasn’t in her nature to admit that her little brother might be right and she might be wrong, she insisted.

I was faced with a moral quandary that I have carried with me for four decades since.

Do I proceed north, go closer to home and abandon my sister (who is so obviously lost) to save myself? Or do I follow my sister south in the hope that I might keep her safe by finding our way back when she finally realizes her mistake?

In my mind, she’s riding her bike away from me… and I’m forced to decide before she disappears around the bend in the road.

Which is exactly when my Mother’s massive blue Dodge van crested the hill… from the north.

Mom had been driving around looking for her two oldest children, and she’d found us.

We packed our bikes into the back of the van and Mom drove us home.

I don’t remember what happened afterwards. I know we weren’t punished. I know that my sense of direction was correct. I know my older sister never admitted her mistake.

But I didn’t get the answer to my moral quandary and I couldn’t shake the feeling that I had failed.

This became my first re-parenting experience.

In my re-living of this scene, my child self approaches my grown-up, adult self and asks, “Dr. Seager, what should I have done?”

And Dr. Seager, as if I were my own Father, says (with kindness) to young Tommy:

“Little Tommy, when you are with your older sister and she refuses your advice, you ride your bike home to me as fast as you can. You tell me where you last saw her and what direction she was going. We will leave together and we will find her and we will bring her home.

“Should you be with your younger sister, then do not ever leave her. Stay with her, so that she is never alone, even if she insists on going the wrong way.

“I will always find you.”

The re-experiencing of the trauma releases the biochemical programming that generates the compulsion to repeat. Because now, Little Tommy knows what to do if he were ever faced with a similar conundrum again, my child brain need not obsess over the quandary.

The challenge of epigenetic recoding

Talk therapy is rarely successful at resolving trauma.

Part of the reason is that resolution requires reliving the traumatic experience.

Most talk therapy is about feeling better, which would naturally avoid the challenge of revisting traumatic experiences. Moreover, without some skill and guidance towards resolution, revisiting the traumatic experience will reinforce it, rather than resolve it.

The problem is that, until we resolving our trauma, we are doomed to hand it down to our children.

I’ve met many people who blame themselves for the compulsions they experience as a result of their trauma. They fear that they are somehow fundamentally broken inside, as if they were genetically defective.

They sometimes buy into the popular trope that they “self-sabotage” instead of recognizing that their bodies are operating in exact accordance with their epigenetic programming.

The myth of genetic fatalism reinforces this view that there is little they can do to fix their own trauma wounds. Sometimes, in parents, this shame is compounded by guilt for having children — as if their fundamental broken-ness was inevitably passed down to their offspring.

When these feelings of being broken become overwhelming, the shame of their experience can cause them to remove themselves from the gene pool by suicide. In those moments, they convince themselves that their kids would somehow be better off without any further contact with them.

I know, because I’ve been there.

What’s different for me now is that I understand that genetic fatalism is a self-limiting mythology. I have the power to control my compulsions, my thoughts, and my epigenetic encoding.

Exercising that power requires me to rebuild the stories I tell myself in ways that construct new meanings. For example, by re-parenting myself in my imagination, I can resolve traumatic experiences from my youth in ways that give me the confidence to be a better parent to my own kids.

The experiences that will rewrite my epigenetic code need not exist anywhere but my imagination. Because my biochemistry has no choice but to respond to my thoughts, reliving my experiences in my imagination may erase both the neural pathways and the epigenetic encoding that previously made me a prisoner to my past.

The same is true for you.

Selected References

• Aristizabal et al. 2020. Biological embedding of experience: A primer
  on epigenetics. PNAS. 117(38):23261–23269

• Bohacek & Mansuy. 2015. Molecular insights into transgenerational non-genetic inheritance of acquired behaviours. Nat Rev Genet 16:641–652

• Jawaid et al. 2018. Chapter twelve - Transgenerational epigenetics of traumatic stress. Progress in Molecular Biology and Translational Science. 158:273-298

• Rahn et al. 2013. Cellular, molecular, and epigenetic mechanisms in non-associative conditioning: Implications for pain and memory,

  Neurobiology of Learning and Memory. 105:133-150

• Smeeth et al. 2021. The role of epigenetics in psychological resilience. The Lancet Psychiatry, 8(7):620–29

• Vaserman & Luschak. 2021. Prenatal famine exposure and adult health outcomes: an epigenetic link. Environmental Epigenetics. 7(1):1–5