I recently delivered a presentation/workshop at the Beauty of Play (BoP) conference in Stone, Staffordshire. As I said at the time, in my pre-session taster, Perry* had asked me a couple of months ago to present something at BoP, and I had chosen the most challenging of the two suggestions! My subject matter for research, presentation and discussion was how the field of epigenetics can be seen in terms of children’s play. I’ve been thinking all week on how to write this presentation up in an easier to manage fashion. Here is that thinking.
What we are, in essence
Most of us have heard about ‘our genes’ and how we inherit these from our parents. We’ve heard about DNA and maybe even chromosomes. However, do we know what they actually are? When we have this understanding, we can start to look at what epigenetics is all about.
Our DNA is our basic ‘building blocks’ of life. That phrase has been around for a while. DNA is a collection of acids. We are, as I said in my presentation, essentially just a swill of chemicals floating around in sacks of skin! (The theme of BoP was ‘the essence of play’, and this phrase seemed to work quite well).
Our genes are sequences of DNA. Genes are instruction manuals for cell development and are contained in our chromosomes (which we have in every cell in our bodies). We have 23 pairs of chromosomes (46 in total, which is – by the way – two fewer than the average potato!) Each chromosome has several hundred, sometimes several thousand, genes in them. All our genes are collectively called the genome, and we have around 25,000 genes in our genome.
So, our genes are instruction manuals that provide us with brown or blue eyes, height, weight, etc. What we inherit from both our parents combines to make us, us. What we also have, it’s been discovered, is the epigenome. This is additional cellular material that ‘sits above’ (‘epi’) the genome. I gather, once referred to as ‘junk DNA’ because it wasn’t clear what its function was, it’s now known that the epigenetic material acts as a switch, turning certain genes on or off. That is, the genes themselves don’t change, they’re just switched – or expressed – and that expression of on/off has huge implications.
What does all of this have to do with children’s play? Well, for the moment, I shall just say that children are at a perfect point in life for the epigenetic on/off switch process to start taking place. I shall come back to this.
When chemical changes take place in the body, ‘epigenetic marks’ are left on the genes. These marks are then inherited. So, in a nutshell, the child – in formation – then passes on those epigenetic marks, as well as their genes, to their own children. It doesn’t stop there: those epigenetic marks are then passed on to their children’s children. The epigenetic marks are caused by what’s known as ‘environmental stressors’ (e.g. stress, starvation). So, in effect, what’s happening in the environment around the child will affect that child’s own grandchildren, even though those grandchildren aren’t subjected to the original environmental stressor themselves.
This is pretty profound to me. It makes me think of the huge responsibility we adults carry in affecting the children around us.
Research (Swedish harvests study)
The thinking on this environmental affect is bound up in plenty of research: in retrospective studies on human genetics (because artificial laboratory experiments on humans is unethical) and on laboratory animal studies (which others would say are just as unethical, but have been undertaken nonetheless).
A main study was one carried out by Swedish researcher, Lars Olov Bygren, and later added to by Marcus Pembrey, Professor of Clinical Genetics at the Institute of Child Health in London. The Swedish study of Överkalix parish’s records showed that the grandchildren of 19th century children – who were subjected to periods of famine and over-eating – were epigenetically affected: genes for life expectancy were affected so that, by and large, the grandchildren died some thirty years earlier than they would have done otherwise. In other words, their grandparents’ diets (as a result of their environment) affected the grandchildren, even though those grandchildren weren’t directly affected themselves.
Professor Pembrey’s 2006 study added to this thinking. He highlighted fathers who said they’d started smoking before the age of 11. This is a critical time for boys because, just before puberty, the boys’ sperm is in formation. This is an ideal time for epigenetic marks to be imprinted on the genes. Professor Pembrey’s study leads to the understanding that the sons of fathers who smoked in prepuberty are at higher risk of obesity and shorter life spans. It is the genetic switching process in action here.
Keep in mind how the adult environment affects children’s play. I will come back to this, but before I do . . .
Research (stress and pregnant women)
Pregnant women have long been advised about the dangers of smoking, drugs and alcohol on unborn children, and how stress can also affect the baby. However, when we think about epigenetic marks on the genes, we can start to realise that not only the baby, but that child’s own children can be affected. Take the Twin Towers attack in 2001 as an example of how pregnant women’s stress levels can dramatically alter. Studies by Rachel Yehuda, psychologist at the Mount Sinai School of Medicine in New York, suggest that children of women caught up in the Twin Towers attacks are more prone to stress. Their cortisol hormone levels are lower, making them more susceptible to post traumatic stress disorder. This gene switch may well pass down a further generation, even though the children of the children of the women at the Twin Towers weren’t there themselves.
Research (brain plasticity, mother-infant interactions)
It’s been known for a while in neuroscience how the environment affects what’s called the ‘plasticity of the brain’. Simply put, studies on rats in ‘rich environments’ shows that these environments are far better for the rats’ brains than ‘impoverished’ or boring environments. The brain grows by making use of itself. Play makes this happen. Adding an epigenetic twist to this thinking, studies in different mother-infant care quality in rats has shown an affect in the off-spring, and the off-spring’s offspring could be seen to be epigenetically affected too (here, in the case of poorer relationships).
Research (environmental toxins)
Now we get to an even more disturbing experiment on rats. Gestating rats were systematically exposed to various toxins (fungicide, pesticide, a plastic mixture, dioxin, and a hydrocarbon mixture). It was found, by a process of epigenetic marking or switching on/off of genes, that at least four generations of off-spring developed ovarian disease because of the toxins, even though those later generations weren’t directly exposed to the toxins themselves.
Research (affect on many generations)
Fruitfly and roundworm experiments showed that some 13 and 40 generations, respectively, were epigenetically affected by exposure to drugs in the original generation. Just to reiterate here, the DNA and genes weren’t changed; it was the genes that were switched on/off.
Does that mean that the environmental stressors are permanent on all future generations? Well, no. When the stressors (like starvation, diet, stress) aren’t there any more, the affect fades. Fading is a process though, and we can conclude from this that – even though there’s a fade out – the affects are still there to some degree.
Research (rich environments)
It’s not all doom and gloom. Experiments with some mice have shown that those mice exposed to rich environments showed better memory potential and this trait was epigenetically passed on to future generations, even though they themselves weren’t exposed to that rich (i.e. highly playable in) environment.
What this all means
So, we come back to children and their play and the environments around them. The huge responsibility we carry around with us, when we affect children, because we do do this, can be seen in physiological, psychological and sociological contexts:
Toxicants (outdoors and indoors) can affect the susceptibility to disease;
Children’s diets affect future generations’ life expectancies;
‘Modest stressors’, e.g. variations of natural light, extremes of temperature, etc, are beginning to be conditioned out in modern lifestyles. This results in an increased inability to cope with acute stress (there is an underactivation of the prefrontal cortex);
The adult care/interaction environment with children has the potential to affect children and their children:
Hugely stressful environments for children can, potentially, alter their ability to regulate stress; excessively imposed restrictions/psychological restraint could result in biochemical changes, e.g. stress hormone, or reduction in brain plasticity;
A decreased neuronal plasticity (brain growth) due to impoverished mother-infant interactions and play environments;
‘Prolonged emotional stress in infancy may deactivate areas of the brain responsible for processing social information, impacting on emotion regulation’;
‘Attachment pathologies (breakdown or absence of secure attachments), leading to empathy disorders and a limited ability to read the emotions of others.’
‘Where [environmental] stress is prolonged . . . behaviours are likely to become more stereotypical, limited and limiting.’
Drugs use (e.g. Ritalin) causes dopamine changes in the brain (causing the more rational prefrontal cortex to over-ride the emotional limbic system – the emotional aspect being, as some might see it, the more natural state of the child); the effect being that doped-up children are easier to manage and to fit in with the ‘social construct’ of adults, making them more easily ‘educateable’, mouldable. When we think what the epigenetic affect could be, it’s scary. One research source claims that, in 2003, some 13 million US children were prescribed Ritalin! You should draw your own conclusions on the potential epigenetic affect here . . .
The environments we create, epigenetics, and the affect on generations
For the most part, this list above suggests a direct affect on the child. However, if we think of the epigenetic marking, the switching on/off of genes as a result of chemical changes, of how the children of the children exposed to the environments listed above are also affected – even though they weren’t directly exposed to those environments themselves – we can start to see the magnitude of all of this:
The environment we create, in which our children play and manoeuvre, will not only affect those children, but their children and their children’s children.
That, I think, is a huge responsibility for us to bear in mind.**
*For those readers not familiar with playwork circles, Perry Else is – according to his recent book (The Value of Play, 2009) – the course leader for BA Hons Children and Playwork at Sheffield Hallam University, and co-author of the Colorado Paper (1998) on psycholudics.
**As this is not an academic paper in itself, research material references have been left out. However, if any readers are interested, all references can be provided on request.