By Ida Hammerich Nielson
ihn@adm.au.dk
One in every three men has got it: the warrior gene. But before you start worrying or wondering about your male colleagues or yourself, you need to hear the full story. Because the warrior gene only causes problems in men who have also had a difficult childhood.
This warrior gene, or the MAOA gene to give it the proper scientific name, is a variation of a specific gene whose function involves breaking down neurotransmitters in the brain. The variation means that the gene cannot break down these neurotransmitters very effectively, and this has consequences for human behaviour. Professor Anders Børglum from the Department of Human Genetics at the Faculty of Health Sciences explains that a number of studies now indicate that when coupled with a bad childhood, the warrior gene tends to lead to violent and anti-social behaviour.
“Several studies show with a good degree of certainty that you run a greater risk of developing anti-social behaviour if you have this gene variation as well as having had a difficult childhood. But the MAOA gene seems to have no effect if you have had a normal childhood. A few studies have revealed a small effect in such cases, but this has been impossible to confirm subsequently,” he says.
Gene reduces sentence
The warrior gene attracted media attention recently when an Italian judge reduced the sentence passed on a murderer by one year – based partly on scientific documentation of the killer’s genetic makeup, including the warrior gene. This was the first time in Europe that a judge had taken account of genetic analysis in passing sentence. In the USA in the past five years there have been about 200 cases in which the defence has tried to persuade the judge to consider the genetic makeup of people in the dock. However, this plea has only been successful in a few cases. Anders Børglum issues a powerful warning against using the warrior gene indiscriminately as an argument in court cases.
“The so-called warrior gene is only a tiny part of the whole genetic picture. People often have other genetic variations as well that reduce the importance of the warrior gene. The significance of the MAOA gene is far too small to say anything reliable about the risk of people developing anti-social behaviour. We need to do a lot more work before we can be certain about all this,” he concludes.
