"New Zealand's indigenous Maori population reacted angrily on Wednesday to a researcher's findings that Maori have a high representation of a gene linked to aggression, as the nation faces a domestic violence crisis."
According to a Yahoo news story, genetic epidemiologist Rod Lea recently presented research in Australia that Maori men were twice as likely to carry monoamine oxidase than European men, describing it as "the warrior gene." This gene has apparently been tied to aggression and risk-taking behaviors such as smoking and gambling.
"I believe this gene has an influence on behavior of humans in general, but I also believe that the influence is rather small," Lea told New Zealand's National Radio on Wednesday."We have to be clear that behavioral traits such as susceptibility to addiction, aggressive behavior, risk taking, all those sort of things, are extremely complex and they are due to numerous factors including non-genetic environmental factors like upbringing and other lifestyle factors," he said.
The Maori people are concerned that this will only serve to confirm stereotypes regarding their tribe: that they are violent, aggressive, with high crime and domestic violence rates. However, there is a persistent problem with domestic violence; the New Zealand government found that Maori children under 5 years old are twice as likely to be admitted to the hospital for an "intentional injury" than other groups.
Now this news piece did a not-so-great reporting job on the science. I think what they meant to say was that Maori men were more likely to carry the gene that encodes monoamine oxidase (MAOs; although there are two types MAO-A and MAO-B), which are both located on the X chromosome. MAO-A and MAO-B are attached to the outer membrane of the mitochondria and function to oxidize amine neurotransmitters such as dopamine and serotonin.
MAOs are extremely important for proper brain function as they inactivate neurotransmitters. When MAOs are in over abundance, there is too much inactivation of neurotransmitters. Neurological disorders like depression, criminal behavior, phobias, ADD, and addiction can arise. In fact, a major treatment for depression is MAO inhibitors, and these drugs are also given to Parkinson's patients to enhance the effectiveness of dopamine replacement through L-Dopa. MAOs also increase with age, and apoptotic cells (dying cells) often have increased MAOs as well.
But back to the Maori, what seems to be suggested is that they have an increased incidence of MAO genes resulting in more MAO produced as compared to other populations. As the researcher himself notes, the gene may exert some influence but behavior is complex---it results from environment as well. Perhaps the Maori are overlooking a really useful bit of information here: MAOs can be inhibited. If it is shown to be true that MAOs can increase aggressiveness, depression, etc, high-risk individuals could be treated with MAO blockers.
Comments
You missed the funny part:
Posted by: somnilista, FCD | August 10, 2006 10:01 AM
In point of fact, one of the biggest risk factors for domestic violence is unemployment specifically, and lack of economic opportunity in general. People who feel trapped are more likely to lash out.
I would not dismiss the possibility of genetic influences. But as the author implied, any single gene probably does not have a big impact.
As you point out, there are theoretical reasons to think that MAOI inhibitors could be useful. I would think, though, that improving economic opportunity would have a greater impact.
Posted by: Joseph j7uy5 | August 10, 2006 10:20 AM
Ha, very funny somnilista! Maybe they shouldn't have reacted so predictably! :)
Yes, very true Joeseph, but a much bigger fish to fry. Improving socioecomic situations should always be ther goal, perhaps MAOIs could assist?
Posted by: Shelley Batts | August 10, 2006 11:40 AM
I have a bit of an anecdote that might be salient to this discussion. Several years ago I was performing a study as part of a lab component for a class I was taking that compared the performance of mice with MAO-A and MAO-B knockouts in a intracranial self-stimulation task to wildtype mice.
During that study I discovered that the mice with the MAO knockouts were far more aggressive, in that they were far more likely to bite me, than the wildtype mice. Moreover, when I had mentioned this to the professor that was supervising my study he mentioned that he had much the same experience.
This (while only anecdotal and limited to the experience of two people) seems to run contrary to the suggestion made in the article.
Posted by: CK Loo | August 10, 2006 11:57 AM
CK- From my very brief survey of the literature last night, I got the impression that too much or too little MAOs can cause problems. An overabundance of certain neurotransmitters may be as problematic as a detriment of them. Especially a knockout which would mean nearly no neurotransmitter inactivation? (Just guessing here)
Posted by: Shelley Batts | August 10, 2006 12:14 PM
I haven't read the study, but I'm very weary of studies of this type.
The simple fact is that Māori unemployment is about 5% higher than the national average and they have fewer educational opportunities. This places them right at the bottom of the socio-economic pile. Combine this with cultural pressures that value macho behaviour (true for all New Zealanders, but especially for Māori) and you have have a potent combination of socio-cultural factors that result in a higher incidence of violence.
Treatment with MAOIs is a ridiculous idea! Fix the problems plaguing Māori and there will be a reduction in the violence associated with Māori.
And what difference in the levels of MAO are we talking about here? Smoking causes a decrease in the levels of MAO. Should we all we wearing of smokers lest they beat us up?
Posted by: Lincoln | August 13, 2006 6:52 PM