There’s something encouraging about the fact that we are not simply our genes. We’ve moved on -evolved, I guess. They are still the recipes, the instructions, but as every chef knows, you don’t always have to include all of the ingredients to get a good result. Genes are perhaps more akin to a first draft for a project. Suggestions. Options. They are, in effect, travel guides -road maps- that tell you what you could do and how you might go about doing it, but although the tickets are bought, you don’t have to get on the bus. Who we are –what we are- is not as pre-ordained as we previously thought. Just because there is a light switch on the wall, doesn’t mean it has to be turned on unless it’s needed. There is a mechanism, as Wikipedia puts it, for ‘cellular and physiological phenotypic trait variations that are caused by external or environmental factors that switch genes on and off and affect how cells read genes instead of being caused by changes in the DNA sequence.’ It is called epigenetics.
Genetic evolution usually takes a long time –often a very long time- and circumstances can arise that were not originally anticipated. But there are several mechanisms to silence or inhibit those genes from carrying out their initial instructions and these allow extra opportunities for an organism to survive and adapt to circumstances perhaps not present during its initial evolution. Unfortunately, it can be a two-way street…
Food, food, glorious food -well that’s how I remember the words anyway (apologies to Flanders and Swann). It’s something that is often as pleasant in retrospect as it’s anticipation is in prospect. Something that transcends the here and now. Like culture, it involves feelings and judgments. It is a part of the fabric of our realities, part of the habits that are difficult to change without conscious effort and strong motivation. We wear our preferences as uniforms -identities. Food is not simply what we consume -it reflects a train of thought. There are allegiances, unspoken loyalties that pass from generation to generation. And it is often how others see us -evaluate us. To change or vary, risks awkward questions at the very least. So it’s fascinating to reflect on the importance of food in defining not only who and what we are, but also on it’s influence on what we might become. And what our children might become as a result…
It is not a trifling matter. Food has always had a central role in culture and what a mother eats in her pregnancy has long inspired myths about the child she will deliver. Famines have been instructive: in more recent times, the Dutch Famine of 1944 during World War ll led to intrauterine growth restriction and subsequent chronic diseases such as coronary heart disease later in the offspring’s life.
A similar twist on the importance of prenatal nutrition was highlighted in an article in BBC News: http://www.bbc.co.uk/news/magazine-34222452 ‘.A team from Britain’s Medical Research Council, which has been collecting data on births, marriages and deaths in Keneba since the 1940s, discovered some years ago that in this part of The Gambia when you are conceived makes a huge difference to your chances of dying prematurely.’
This seemingly bizarre finding is corroborated in animal experiments in which, ‘it is possible to make the genes in an embryo more active, or turn them off entirely, simply by varying their mother’s diet.’ And indeed, as the author explains, ‘the studies done in The Gambia certainly provide compelling evidence that these so-called “epigenetic changes” may also happen in humans in response to a change in diet. That if, during very early development, a mother eats a diet rich in leafy green vegetables, then this will change forever just how active some of her child’s genes are.’
There are other epigenetic ramifications that are also important: this ‘happens through a process called methylation and researchers in The Gambia have recently shown that babies conceived in the wet season have very different levels of activity of a particular gene that’s important for regulating the immune system. As Matt Silver, part of the MRC team, says: “Variation in methylation state in this gene could affect your ability to fight viral infections and it may also affect your chances of survival from cancers such as leukaemia and lung cancer.”
Prenatal influences are far greater than we had ever suspected; we were naïve indeed to feel that the importance of diet was primarily to provide nutrients for the developing fetus -ingredients for the recipe. We were too narrow in our conceptions. Too dull, maybe. There is so much about the world –about ourselves- that we are only beginning to understand. We truly live in exciting times… and yet it has always been exciting times for those interested enough to open their eyes hasn’t it? We’ve always lived at the edge of some river or other. It merely takes someone curious enough to travel down it. As Shakespeare said: We know what we are, but know not what we may be.