Check out Top 10 Theories About How Biology Creates A Criminal

7 The Warrior Gene

Researchers suggest that some people are hardwired to commit violent crime. After taking blood samples from violent prisoners in Finland, the researchers found that repeat offenders had the genetic variants CDH13 and MAOA. They nicknamed it the “warrior gene.”MAOA metabolizes dopamine. If MAOA activity is decreased, the use of alcohol or drugs might induce a larger dopamine burst and spark aggressive behavior. CDH13 helps the development of neuronal connections in the brain and is an important factor in ADHD. Having both variations supposedly makes someone 13 times more likely to commit a violent crime. MAOA is located on the X chromosome, which could explain why most mass murderers are men. Women have two copies of the gene, so if one carries the variant, another normal gene could offset the effect. However, men have only one copy of the X chromosome, so they suffer the full effects of the variant if they have it.That is not to say that having either variant definitely makes someone a violent criminal. Researcher Jim Fallon found that he had the gene but did not have a history of violence. Environmental factors are also important, and MAOA is associated with higher rates of crime when the individual experienced childhood adversity.