Who Do You Think You Are?: Epigenetics – How Your Brain Works #3

Our genes are inherited. They are a part of our nature. They determine who we are. They’re our blueprint. But are we limited by them?

Well, the dispiriting idea that our genes are unalterable has received significant re-evaluation over the last few decades. New research into epigenetics reinforces the growing belief that genes can be turned on and off. But, what does this mean? And, how can we affect this process?

Epigenetics is defined by Merriam-Webster’s medical dictionary as “the modification in gene expression that is independent of the DNA sequence of a gene”.[1] Now, this might sound scary, but let’s decode it. An epigenome doesn’t change your DNA but it decides how much, or whether, particular genes are expressed – made more or less prominent – in different cells in your body. It is like reading two sentences, each with the same letters and words, but with slightly different punctuation. Just as the sentence’s meaning changes with different emphasis, different genetic punctuation changes how we are expressed in the world.

The hardware of your DNA will be the same throughout your life, but epigenetic tags that tell the genome what to do can change throughout your life. They decide what genes get expressed or not. Epigenomes are the software that tells the hardware, the genes, what to do. Methyl groups act like switches, turning genes on and off, and histones act like dimmer switches, compacting and de-compacting chromatin depending on epigenetic marks that determine whether and how much a gene is expressed.

The epigenome can change depending on the intensity and duration of particular environmental factors. Epigenetic tags can be incurred by a variety of experiences, like smoking and bad eating habits. A bad diet can actually lead to methyl groups binding to the wrong place and making mistakes, leading to cellular abnormality and an increased likelihood of disease. Because of mood congruent cognition – a process by which a negative/positive moodstate leads us to think more negatively/positively, negative patterns of behaviour and thinking can have a powerful epigenetic effect, leading to psychological and physical problems. But positive patterns can help us flourish.

So, experience and environment actually modify genes. What this means is that nurture is as, if not more, important than nature. For instance, research demonstrates that negative or positive levels of sleep, social support, and stress have epigenetic effects on the body. The repercussions of bad sleep, bad social support,[2] and high levels of stress[3] can have a significant and lasting impact on your cognitive style, leading to further rumination and worry that fuels this negative epigenetic cycle. In some cases, they can even lead to the development of a disorder.[4] Our behaviour and cognition are subject to epigenetic variation.

What it boils down to is an ultimatum. We have a choice about how we use our minds and our bodies: if we care for them we will develop healthier traits that encourage wellbeing, if we don’t we will suffer adverse effects. And it is not only a current concern; these changes can be hereditary. The more scientists study epigenetics, the realisation that some epigenetic information is passed from parent to child is gaining momentum. It is important that we make good, healthy choices because later generations will feel the positive, or negative, effects. By picking up good habits, we can create lasting change in the expression of our genes and, by consequence, our daily lives.

Moving from the individual to the wider group, in ‘Social Physics’, as popularised by Alex Pentland, we see that our decisions are heavily influenced by the social networks and groups we surround ourselves with.[5] If our behaviour and cognition are epigenetic and social learning is the most powerful influence on behaviour, it follows that our culture, social network, and work environment are influencing the expression of our genes. Now, this is only a hypothesis and is as yet unproven. But let’s say norms and commonly held beliefs within groups might have an epigenetic effect, strengthening and weakening over time depending on habit and external contingencies. In order to change negative expressions, we can diversify and widen our social networks to encourage fresh exchange of ideas. This can bring about positive epigenetic change on a larger scale. By changing how we interact with our environment, we change ourselves.

We can change who we are – to a degree. And this is a liberating prospect. Intelligence, for example, may be influenced by the genes we inherit but it is not defined and restricted. By manipulating numerous social factors and experiential opportunities to our advantage, we can make lasting improvements, learning new skills or even increasing your IQ.

On a psychological level, epigenetic changes in brain cells impact on memory and cognitive function. These are key indicators of performance that can be influenced. What’s more, studies have shown that if we are treated (by ourselves and others) with care and compassion, the epigenetic effects can reduce our levels of fear and stress over time.[6] Epigenetic mechanisms have a considerable effect on our psychology and physiology, meaning that to maintain wellbeing and optimum performance, it is key to understand their significance and nurture ourselves and others wisely.

We are in a constant process of development, moulded by our choices and the environments we inhabit. But the mind, as Milton proclaimed, can make a heaven out of hell and a hell out of heaven. Importantly, we can take control of our future selves and shape them for the better if we so choose. Remember that next time you make a decision.

[1] http://www.merriam-webster.com/medical/epigenetic

[2] L. Goossens et al. ‘The genetics of loneliness: linking evolutionary theory to genome-wide genetics, epigenetics, and social science’

[3] Adrian M. Stankiewicz, ‘Epigenetics of stress adaptations in the brain’

[4] I. A. Qureshi, M. F. Mehler, ‘Epigenetics of sleep and chronobiology’

[5] Alex Pentland, Social Physics

[6] Richard G. Hunter, ‘Epigenetic effects of stress and corticosteroids in the brain’

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