December 17

Did Epigenetics Save Luke Skywalker from the Dark Side? A Neurobiological Perspective on Darth Vader

Good versus Evil

It’s less than a week before Christmas, and just a few short days away from opening night of The Force Awakens (Episode VII of the THIRD and final Star Wars trilogy). The Christmas season (coincidentally also the season of blockbuster releases) is ripe with distinctions between “naughty” and “nice”, from children who are incentivized to be on their best behavior with the threat of coal in their stockings, to romantic pop songs based on this premise, to constant talk of the “Christmas spirit” (i.e. that which makes you want to give to others and be jolly).

Implicit in these distinctions is the idea that, for most of us, it is easier to be “good” than “bad”, whether it’s “misbehaving” as a child, succumbing to the temptation to have a second piece of pie, or twisting the truth to loved ones because it has fewer consequences than telling the whole story. There’s also the sentiment that being “good” comes naturally to some, and is harder for others. What is it that makes this true? Is “goodness” genetic and innate? Or something learned and practiced?

The myths and stories that we learn from a small age, which distinguish good and evil as a binary choice for each individual to make, shape our perspective in ways we may not even realize. The stories and movies and legends that capture our imaginations and rile us up are, more often than not, tales of good versus evil (The Hunger Games, Marvel Comic movies, Harry Potter all make the list of biggest box office winners).

Star Wars is no different. In A New Hope (EPISODE IV from the middle and original trilogy), we are introduced to a young hero, who battles evil (SPOILER ALERT) in the form of his father, reinforcing the cultural adage that “good” and “evil” are not engraved in our genetics, but are rather choices. Using Darth Vader and Luke as an example, let’s explore how we “choose” which side of the Force with which to identify, from a biological perspective.


You’re a sky full of stars

Star Wars’ Luke Skywalker fits the hero archetype precisely, and A New Hope reportedly alludes to many predecessor cinematic and literary epics, the most obvious of which is to King Arthur (another archetypal hero): Luke, like Arthur, is of royal birth but is raised by adopted parents; he has an older mentor who trains him to use the powers he never knew he had; he uses this new-found power on his journey to overcome his father and defeat evil. Ultimately, by the “goodness” of his heart, Luke saves his father’s spirit eternally. If not genetics, what is it that is it that makes Luke adhere to the Jedi principles (“good”) when faced with the very same temptations that caused his father to abandon them and join the Sith (“bad”)?

If we remember what Yoda taught us maybe find an answer we will:
“Fear is the path to the dark side. Fear leads to anger. Anger leads to hate. Hate leads to suffering.”

Luke grew up modestly, raised by his Aunt Beru and Uncle Owen (the step-brother of his father), and was watched over by Obi-Wan Kenobi, who lived nearby. Until the tragic death of the people who raised him, his existence had been free of trauma. His only real hardships were monetary; he complained of wanting to go away to school but was asked to stay another year to help his aunt and uncle with the “dew harvest”.

In contrast, Darth Vader (or Anakin Skywalker) spent his early childhood in an apprenticeship/slavery to the mean-spirited owner of a junk shop. He left home at the age of 9 to be trained as a Jedi, but was refused entry to the group for fear there was too much of “the Dark Force” in him. He lost his first mentor to death, engaged in multiple conflicts on the side of the Jedi but was ultimately denied the rank of Jedi Master. Following all this, he became afraid* (noted this fear is, hmmm?)  of losing his wife in childbirth, and pledged himself to Senator Palpatine who promised to help him “cheat death”. Sadly, his wife passed away in spite of his “deal with the devil”. In short, his life was a series of hardships and disappointments, which we are made to presume led him to turn to “the Dark Side”.


Nature versus Nurture: An Epigenetic Battle

If we deconstruct our cultural obsession with good and evil, apparent in the timeless popularity of A New Hope,  from a biological perspective, what can we learn about the mechanism by which one becomes “good” or “bad”?  To start, the circumstances of one’s upbringing have an impact on one’s life, fortunately, or unfortunately, as the case may be. This is not to say that our lives are constrained or predetermined (that’s a conversation for another time), but simply that we are affected by the events of our lives, even if we can choose, to a large extent, our reactions to them. This is especially true during childhood and development. If we accept this, it has certain policy implications , which though they hold true across time and space, are also best left for another time.

Research has shown that a person’s genetic composition is important in determining physical attributes, disease risk and some aspects of personality and mental processing, but, increasingly, the expression pattern of one’s genes, is deemed equally important. Gene expression refers to the process of translating the genetic code into proteins that carry out various functions in the brain or body. The amount of protein expressed at any one time depends on many factors. Stable and heritable changes in the expression of genes are collectively called epigenetics.

Epigenetics has been implicated in everything from cancer to behavior, and can be caused by everything from changing one’s diet to learning something new. Altered epigenetic states have even been suggested to play a role in addiction and mental health. The epigenetic landscape remains poorly understood, but its involvement in many aspects of neuronal processing and other cellular functions make it a growing field of interestWhile epigenetics can refer to any changes in gene expression that are stable over a period of time, histone modifications and methylation changes are two of the best studied processes to date.


Histone modifications refer to chemical changes to the proteins around which DNA wraps in its compacted form. Modifications that change the conformation of the wrapped DNA to a more open state can make a gene accessible to its transcription factor (a key player in the process of making a protein from DNA), thereby increasing its protein expression. Conversely, conformational changes leading to more compacted DNA may limit a protein’s expression by limited access by transcription factors. Methylation is a chemical process that involves adding a methyl group to specific base pairs in the DNA. Methylation can occur with specificity at promoter regions (regions where the transcription factor binds), but also occurs extensively in other parts of the genome, where its function is less understood. Like histone modifications, methylation is believed to affect gene expression by increasing or decreasing access of transcription factors to genes of interest.


Nurture FTW (for the win)

Ten years ago, researchers at McGill University in the lab of Dr. Michael Meaney demonstrated molecular changes to the genome that were correlated with the quality of maternal care received by rat pups. The observed changes were associated with histone modifications, and altered methylation at a receptor gene known to be involved in the stress reactivity system, or the HPA axis. Changes at this receptor have also been observed in human studies.

Meaney and colleagues discovered that pups of “high-licking and grooming” rats (i.e. doting mothers) had different expression levels for genes involved in the HPA axis, as well as differences in expression of histone-modifying proteins, as compared to pups raised by “low-licking and grooming” rats. Interestingly, the pups grew up to mimic the maternal behavior they had received, even when pups were switched at birth from the nest of a “high-licking” to “low-licking” mother (or vice versa). The researches suggest this phenomenon is mediated by the observed changes in gene expression patterns. In other words, “nurture” or experience, is more important than “nature” in determining the grown pup’s parenting behavior.

Michael Meaney and Francis Champagne’s work (check out the Radiolab story here) has continued to address the epigenetic marks and behavioral outcomes of early life adversity and has championed the idea that social behaviors transmitted across generations might be mediated by epigenetic pathways.


The Apple Doesn’t Fall Far From the Death Star?


Okay, back to the Skywalker family. For our purposes, Darth Vader’s upbringing amounts to the equivalent of a rat pup raised by a “low-licking and grooming” mother. As such, we have to imagine that, had Darth Vader raised Luke and Leia himself after his wife’s untimely demise, his children would also have been exposed to all the epigenetic marks of Vader’s traumatic life, and perhaps been more tempted to the “easy” ways of “the Dark Side”. Luke and Leia were, for our purposes, raised by “high-licking and grooming” mothers. Thus, in a single generation, the negative effects of Darth Vader’s upbringing were reversed in his offspring, who worked to destroy the Galactic Empire and “restore balance to the force”.


Is There a Happy Ending Somewhere? 

While opinions about what constitutes moral behavior may be fluid across cultures, generations, circumstances and galaxies, the concept of “good” versus “evil” is universally appealing. If we look to the where biology and Star Wars intersect for answers about what it means to be “good”, we see that Darth Vader, a “bad” character, equates most to rats exposed to an aversive early environment, who pass on the effects of their upbring to their own offspring through learned negligence. Perhaps the take-away is that kindness, especially in the form of caring for others, is archetypally accepted as “good”, while allowing our actions to be controlled by the fear of losing those we love, or our own bad experiences (ultimately forms of selfishness) is seen as weak, greedy and verging on “evil”. As human beings on the planet Earth so far, far away from the Skywalkers, even if we accept this definition of “good”, we are left to wrestle with what this means functionally, and with how to balance the diverse needs of those we love, without giving too much of ourselves. A challenging task indeed this is.


But, my young padawan, rest assured, that epigenetically speaking, while we are to some degree a product of the environment in which we were reared, the choices we make for ourselves about lifestyle, social environment, etc. in adulthood can affect our epigenome, and make it similar to, or different from our parents’.  Darth Vader could have chosen to renounce his grief and alliance to Palpatine and the Empire, and poured himself into caring for his children. Though he might have had to settle for a making his livelihood as a “dew farmer” like his step-brother, and risked reprisal from the Emperor, he had choices, just as each of us has, to change his epigenetic marks. It is never too late to choose a new epigenetic path, for yourself, and maybe even your offspring (or future offspring) by changing something as simple as your thought patterns.

As you go forth, and behold The Force Awakens, remember that what makes Star Wars so captivating is not just its special effects, but the simplicity with which it portrays good and evil, and the hope it offers each of us to forge our own moral path, no matter what patterns we’ve learned or hardships we’ve suffered. And, remember, now and always,


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