Crime genes

  • “In developed countries, the majority of all violent crime is committed by a small group of antisocial recidivistic offenders, but no genes have been shown to contribute to recidivistic violent offending or severe violent behavior, such as homicide. Our results, from two independent cohorts of Finnish prisoners, revealed that a monoamine oxidase A (MAOA) low-activity genotype (contributing to low dopamine turnover rate) as well as the CDH13 gene (coding for neuronal membrane adhesion protein) are associated with extremely violent behavior (at least 10 committed homicides, attempted homicides or batteries). No substantial signal was observed for either MAOA or CDH13 among non-violent offenders, indicating that findings were specific for violent offending, and not largely attributable to substance abuse or antisocial personality disorder. These results indicate both low monoamine metabolism and neuronal membrane dysfunction as plausible factors in the etiology of extreme criminal violent behavior, and imply that at least about 5–10% of all severe violent crime in Finland is attributable to the aforementioned MAOA and CDH13 genotypes. “(Tiihonen, et al., 2015)

There are more research works in recent years like above trying to associate human behaviors, personalities and even careers with genes. Till now, science communities don’t reach an agreement on how much genes affect our daily life. We already have too many tags attached to us,  normal ones like education, profession, personality, eating habits, also private ones like medical history, bank account records, and now genes.

The reveal of crime genes would arouse several problems. The first problem is, if these two genes are really related to violent behaviors, would you like to know whether you match the same genotypes? If someone knows he has the potential to behave violence, will he remind himself to control emotions, or feel inferior to others because he has ‘defects’ in genes, or attribute his violent behaviors to instinct reactions ? Second, does family members or partners have the right to know crime genes of each other ? In this case, could they treat the ‘violent genes’ same as lactose intolerance, Low immunity or poor eyesight ? Similarly, if it is known by friends, classmates or colleagues, would he be discriminated or alienated ? The third trouble is, offenders with mental diseases can be reduced time of sentence or even exempt from penalty because criminal behaviors cannot be controlled by themselves. So how about these people with ‘criminal genes’ ? Could they be treated same with mental patients ? These questions all should be considered cautiously.

Meanwhile, I think we also need to ask why researchers want to investigate relations between crimes and genes. If from the perspective of ‘before birth’ , should this kind of ‘violent genes’ be regarded equally with Down’s syndrome ? How to protect the rights of embryos from being seen as commodities that parents can choose one they are most satisfied ? If from the perspective of ‘after birth’, why do we create a new tag that just indicates a potential to implement violent behaviors ?



Tiihonen, J., Rautiainen, M. R., Ollila, H. M., Repo-Tiihonen, E., Virkkunen, M., Palotie, A., … & Saarela, J. (2015). Genetic background of extreme violent behavior. Molecular psychiatry20(6), 786.

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