A specific mutation in the monoamine oxidase A (MAOA) gene has been linked to violent behavior. All men belonging to a family in the Netherlands harboring this mutation were arsonists and rapists. And, mice without an MAOA gene have been found to be excessively aggressive. Low-expression of the MAOA gene is linked to violent tendencies.
Using magnetic resonance imaging (MRI) and DNA analysis, 142 healthy men and women, who had no history of violence, were shown pictures of angry and fearful faces. Researchers found:

Those with the low-expressing version of MAOA were more impulsive.
People with low-expressing MAOA had …read more