One of the more profound questions we ask as we learn more about the effects genetics can have on behaviour, is can we actually control our actions? Did I have a choice in writing this blog post, or did the genes I possess lead me to getting on this train, getting bored easily, and starting to write? Was I always going to end up here? And when I do something lazy, or unkind, did I truly choose to do that, or was it always going to happen?
While our genetics (combined with our environmental influences) offer explanations for a large amount of variation in humans, the increasing use of our genetic make-up as a way of passing the blame for our behaviour is actually quite worrying. On a small scale, it’s quite nice to say “well, nature made me this way”. I like to use my biologically programmed body clock as an excuse for sleeping in late, and trying to claim that I’m snappy and impatient because “it’s in my genes” would be tempting (who knows if that would even be possible). Criminal behaviour, however, is a whole other story. We can’t really use our genetics as an excuse for murder… can we?
On the X chromosome lies a gene we call “MAOA”, which codes for an enzyme which is involved in regulating the metabolism of neurotransmitters, including dopamine and serotonin. The MAOA gene contains a repeat sequence, which in most people repeats four times. However, men (note: these results were only found in men, not women) who possess three repeats of this sequence, in addition to certain psychosocial factors, are more likely to exhibit criminal behaviour than those with four repeats. What this means is that men who possess the MAOA gene with three copies of the repeats of the sequence, rather than four are more likely to display violent behaviour, but only when coupled with a violent upbringing. Regardless of whether their upbringing is violent or not, men with four repeats show no change in the number of instances of violent behaviour. 5% of the population have three repeats of the sequence instead of four, yet not all of those possessing this “violent” variation of the gene are violent. As per usual however, upon finding out, the headline in The Daily Mail read “Are criminals born with a MURDER GENE?” (Yes, they capitalised the words “murder gene” just like that.) The link between this gene and violent behaviour is strong, but only when accompanied by environmental factors; a study found that of those with the combination of a violent upbringing, and the shorter MAOA sequence, 85% developed antisocial behaviour.
The existence of this genetic variant has actually been used in court cases. In an Italian case, Abdelmalek Bayout stabbed a man to death, and his sentence was cut by one year after evidence of his possession of the shorter MAOA gene was given. In the minds of some people, possessing a gene which causes them to have a predisposition to violent behaviour makes them less accountable for their actions, as if they had no choice; their genes had forced them to hurt someone. Perhaps possessing this gene in combination with the environmental factor of maltreatment in childhood makes it harder for some men to refrain from violence, but it is still difficult to see how this prevents them from being held responsible when they act on these impulses. The information on this gene could be useful, if not to weasel out of longer sentences, to provide some form of help to men who possess the gene and have had a violent upbringing – maybe there are ways of countering the effects of these, and stopping them from acting on violent impulses, preventing the court cases from occurring in the first place.
But this whole discussion raises a more interesting question (which in itself doesn’t quite make sense): where do our genes stop and we begin? If we look introspectively at what makes us ourselves, we are a combination of our genetics and our environment. Both of these influences combine together in all sorts of ways, each one even being able to influence the other: our environment can alter the way our genes are expressed and our genes can alter the environments we place ourselves in. If this is so, are our genes not “us”? Is saying “my genes did it” really any different from saying “I did it”? Of course, there is sense in the fact that we can’t control our genes: they can make us ill, and make us different from each other, and a lot of that, we don’t have control over, though I believe we can control our actions, and some aspects of our environment. We don’t have a choice in our genetics, so there’s no need to blame ourselves for all those nigggly little things about our looks or personality that we don’t like. But can we really say that because we were influenced by our genes, it’s not our fault?