Think of how many supposed "psychos" go off in assorted incidents, especially those of violent shootings, knifings etc. where no clear mental health issues had been visible. What might have provoked these outbursts? Beyond that, why is it that some personalities evolve to be so paranoid, given to negativity or lashing out at others in sociopathic ways? According to the budding science of Epigenetics these behaviors may have origins in methyl groups attaching to our DNA – especially following traumatic events, incidents in one’s past- or one’s ancestors’ past.
According to this Epigenetic theory (see, e.g. DISCOVER, May, pp. 50-55)any traumatic experience – even in the genetic past- is capable of leaving molecular “scars” adhering to our DNA. The form and kind of trauma can run the gamut: Jews with great grandparents confined to Auschwitz – who survived, Chinese Gen X’s whose grandparents lived through Mao’s horrific cultural revolution, immigrants from the Congo or Rwanda whose grandparents survived massacres- genocide, or adults of every ethnicity who grew up with alcoholic or emotionally-physically abusive parents. In each case, more than just toxic memories are in play which hamper future psycho-social development.
Like muck that gums up the cogs of a finely tuned machine, these past nasty events accumulate via chemical additions – methyl groups- as a molecular residue clinging to our DNA. While the DNA itself is unchanged, behavioral alterations are imposed by the addition of the chemical interloper. More to the point, these alterations can be genetically passed on. Hence, you might have not only inherited your grandpa’s knobby knees but also his predisposition to depression or negative outlook, or even paranoia. Maybe this was caused by the neglect he suffered as a newborn, but the addition of methyl groups resulting leaves its mark – to be passed on.
However, this is not a foregone conclusion. Maybe at some subsequent stage your grandpa was adopted by nurturing parents, in which case the adverse effects of the methyl groups from the original trauma were neutralized. In this case, grandpa grew up to be epigenetically sound - no methyl contamination- with a healthy and outgoing personality, positive social tendencies. You are then the beneficiary of this, and thereby capable of passing the benefits on to your own offspring. The point is, the mechanisms of behavioral epigenetics underlie not only deficits, weaknesses but also strengths, resiliencies.
What model do we come away with here? Basically that there exists not only a genome but also epigenome. The first embodies the basic blueprint for life, but the matter is more akin to life’s ‘etch-a-sketch’ – altering in response to any external influences be they positive or negative. Ideally, mitigating methyl groups results in more positive, healthy personalities – but how can it be assured?
First, what is a methyl group? It’s basically an organic compound consisting of one carbon atom bonded to three hydrogen atoms, i.e. CH3. When such a methyl group becomes attached to the nucleotide base cytosine, then the DNA is said to be methylated. These methyl groups can then attach to DNA for life, effectively changing the activity of any gene involved. The behavioral traits then associated with those genes are changed and transmitted across generations.
Experiments done using mice, pups raised by bad mothers and good ones, disclose the rank effects of methylation. In the case of the bad mouse mothers, that is inattentive or detached ones, one finds the pups affected by methylation. In particular, the genes regulating the production of glucocorticoid receptors – which regulate sensitivity to stress hormones – are highly methylated resulting in pups that are highly agitated, skittish and asocial or anti-social. In the opposite case, the pups disclosed high levels of glucocorticoid receptors which enabled the pups to display calmness, outgoing and brave behavior. Most fascinating, in tweaks of these experiments - methylated mouse pups put in the care of good mouse mothers saw their deficient glucocorticoid receptors improve, methyl attachments diminish and negative behaviors abate, while the opposite was observed in the case of the non-methylated mouse pups put in the care of inattentive mouse mothers.
Application to humans? Yes, we have the documentation too from the human experiments cited by Harvey A. Hornstein in his terrific book Cruelty and Kindness: A New Look at Aggression and Altruism, Prentice-Hall, 1976, 'We and They', p.13. He recounts and describes assorted mother-child alienation episodes-experiments, such as performed by John Bowlby with detached human mothers. These expose how chronic indifference by such mothers, say in caring for their newborns, can generate socially alienated, skittish, easily suspicious and emotionally aroused people. Undoubtedly, if the mouse experiments are a reasonable guide, alienated humans are also saddled with methyl groups that deform behavior toward negative, anti-social ends.
In the case of the mice, the injection of trichostatin A into the brain removed the methyl groups and the behavioral deficits. It was almost like rebooting a computer that had seized up. While a pharmaceutical solution sounds ideal, it isn’t clear that injections of trichostatin A into the brain can be as efficacious as for mice, or as harmless. No wonder then that many pharmaceutical firms are diligently searching for compounds to remove methylation and deliver more integrated, healthy personalities. If they succeed, and that’s still a big if, one could theoretically be liberated from all the negativity of one’s past or one’s ancestors’ pasts. Instead of being an asocial, schizoid personality untrusting of nearly everyone, one might then have a much richer life with broader social connections and satisfaction.