Sokolowski – gene by environment interaction

So gene-by environment interaction is, because of those differences in the alleles, you have different sensitivity to the same environment. So you have one environment, that let’s say is an adverse early environment, and one individual that has a certain form of that gene is really not affected by that adverse environment, and the other is highly affected. So for the individual that isn’t affected this is like the child who can move from place to place, family moves, different situations, lots of stress, and they seem to do okay. Whereas the other child that has early adversity, is highly sensitive, the gene expression, the amount of protein that gene makes with that particular DNA polymorphism, the gene expression is altered in that case and the child is highly vulnerable, But if you water that child carefully and you nurture it, the child will do exceptionally well, but if that child experiences a very bad adversity early in life it’s very hard on them.  

So genes contribute to sensitivity or susceptibility to environmental adversity, also to environmental enrichment. We’re not just talking about adversity here, and so it’s useful to think about enrichment because we don’t want to focus on problems or diseases, we want to also focus on promotion and prevention, so promotion of good health.  

So gene-by environment interaction is when you have different alleles or forms of a gene and they respond differently to the same environment. Now you could also build it in and say well, we have different environments, and poorer and a better environment and you could ask how do those individuals perform. Now of course it’s more complicated than one gene. There are many, many genes in the genome, over 20,000 in humans, and some genes have larger effects than others. And that’s where we can pull out the effects of certain genes and say, for instance, the serotonin transporter gene is important for sensitivity to the environment in certain situations of early experience, but it is also the case that other genes are also important.