Institute for Behavioral Genetics Institute of Behavioral Science

The National Youth Survey Family Study is providing valuable information about the relationship between genes, environment, and behavior. Through DNA and data collection, researchers are able to look at how certain behaviors (measured by the answers on interviews and questionnaires) are related to certain environments (from questionnaires and interviews) and genes (measured by the results of DNA analysis). Researchers are beginning to look at specific genes and test whether or not they are related to specific behaviors. In the following study, researchers looked at the relationship between the MAOA gene, victimization in childhood, and violent behavior in adulthood.

Researchers chose to look at the MAOA gene because it is a gene responsible for regulating different chemicals in the human body. These chemicals (such as dopamine and serotonin) have been shown to increase aggressive behavior in mice and in humans. Prior research1 has also reported a connection between one form of the MAOA gene and violent or antisocial behavior when combined with a severely adverse environment in childhood.

Using data from the NYSFS, researchers found that individuals with a history of violent behavior showed no difference in the MAOA gene than individuals without a history of violence. In this study, the MAOA gene was not found to have an influence on violent behavior. However, researchers did find that the environment in childhood had a strong influence on violent behavior in adulthood.

Individuals who were victims of violence in childhood were more than 3 times as likely to participate in violent behavior as adults than individuals who were not victims of childhood violence. Events such as being robbed, assaulted, or beaten by a family member in childhood greatly increased the probability of violent behavior in adulthood, including arrest for a violent offense. In this study, an adverse environment in childhood had a profound impact on violent behavior in adulthood.

Next, researchers will locate and test more candidate genes (genes that they suspect may be involved) to see if they are related to violent behavior. They have found one environmental influence on violent behavior, and are looking for possible genetic influences. Because of the wealth of data collected on the NYSFS, researchers are continuing to discover new relationships between genes, environment and behaviors.

1. Caspi, A. McClay, J., Moffitt, T., Mill, J., Martin, J., Craig, I., Taylor, A., Poulton, R. Role of Genotype in the Cycle of Violence in Maltreated Children Science. 2002 Aug 2;297(5582):851-4.

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