People who have a shortened MAOA gene do not produce a protein needed to break down old serotonin in their brains. These people are more likely to be agitated, aggressive, and impulsive.
The gene can come in the form of 2, 3, 3.5, 4, or 5 allele. A 3-repeat allele is considered dysfunctional and is what is referred to as the “warrior gene” in the video below. A 2-repeat allele is considered very dysfunctional. People with a 2-repeat allele MAOA gene have a permanent chemical imbalance in their brain making the person more likely to be agitated, aggressive, and impulsive.
According to the study published in Comprehensive Psychiatry, 34.6% of whites and 53.4% of blacks have 2-repeat allele or less. However, only .5% of whites have the 2-repeat allele version compared to 4.7% of blacks.
That means blacks are 9.4 times more likely to have the extremely dysfunctional version of the gene than whites. Considering that black Americans are 9 times more likely to commit murder, this is very significant.
Other studies have shown even higher rates of occurrence of the 2-repeat allele version of the gene in blacks. Other studies show that the 2-repeat allele version is almost completely non-existent in Asians.
Notes: There are other genes associated with violent and/or impulsive behavior. The MAOA gene is only one of them. However, the effects of a shortened MAOA gene are well documented. The chemical imbalance its creates can be observed in a laboratory.
The term “warrior gene” could be considered a propaganda term to put a positive spin on those who possess the dysfunctional versions of MAOA.