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The MAOA gene for aggression or happiness?

Author: Аldanova Aziza

Editor: Аibulova Diana






       Aggressive behavior, negative attitudes, hostile stance is like an inability to control one's anti-social impulses. Forensic scientists have been actively engaged in the study of this issue, since such behavior is typical for people who commit crimes and atrocities. For a long time specialists blindly believed that weak control over emotions lies in a full-fledged upbringing or in its absence. However, since the 2000s, with advances in the study of DNA, scientists have come to the conclusion that genes also play an important role in the formation of personality.


        While studying the genetic traits of aggressive people, scientists found that several variants of the monoamine oxidase A (MAOA) gene are found in them. So where did this MAOA gene come from? We have the MAOA gene in our body and it is located in the X chromosome and encodes the activities of the monoamine oxidase A and B enzymes. The enzyme encoded by the MAOA gene breaks down the neurotransmitters of the monoamine class such as serotonin, epinephrine, dopamine and norepinephrine that transmit signals between nerve cells in the brain. Under normal conditions, the gene is active, utilizing residual neurotransmitters. But with an MAOA mutation, it causes a deficiency in the monoamine oxidase A enzyme, which has no time to dispose of neurotransmitters in time, and almost contributes to overstimulation, significantly reducing the activity of MAOA. This pathology mostly affects men, since they have only one X chromosome, and the X-linked mutation is characterized by mental retardation (IQ below 85), problematic impulsive behavior (aggression, violence), sleep disorders and mood swings. In the mid-90s, 14 men with the MAOA mutation were found, of whom 5 were arsonists and the rest were prone to sexual abuse and attempted murder.


        However, we should not put all people who have MAOA mutations under the same dome. There are a number of reasons why people with MAOA mutations may not always be "dangerous to society. First of all, an MAOA mutation implies an absence of the monoamine oxidase A enzyme or a decrease in its activity. If in the first case the behavior is uncontrollable, in the second picture, the enzyme is only unable to do its job due to low activity. The person is impulsive, gets excited and gives in to aggression only under certain circumstances. Secondly, the social aspect plays an important role. Morals and responsibilities, upbringing, environment - these are factors that act on the personality. In 2002, an article with a 26-year study was published in Science magazine. Researchers followed children adopted by families, and 12% of the children among all had low MAOA and were from a dysfunctional family. Subsequently, these 12% committed 44% of all violent crimes reported in the 26-year study. Of course, there is the fact that the children may have had a post-traumatic condition prior to the experiment and this may have been a trigger. Nevertheless, there are a number of studies where social affluence does not contribute to the activation of highly active MAOA precisely from an early age.


        There is also the other side of the coin: women with low-active MAOA are not prone to aggression, alcoholism, and hostility. On the contrary, they feel a sense of happiness. The study, conducted at the University of South Florida, included 193 women and 152 men. Age, well-being, income, social importance of the subjects and various all sorts of factors were taken into account. In conclusion, the women felt happier than the men. The researchers attributed this to the fact that women have less testosterone, which cannot affect the positive functionality of MAOA.


       There are a number of studies on the harms of inactive MAOA and a rebuttal to it. However, do not assume that people with low expression of the MAOA gene are potential criminals, according to some scientists, there is no exact correlation line between the gene and the nature of crime. One thing that is certain is the mechanism at work in low MAOA activity in men and women. If it is a trigger of aggression for one, it acts in a positive way for the other.