Guns, Gangs, and Genes: Evidence of an Underlying Genetic Influence on Gang Involvement and Carrying a Handgun

Gangs and guns represent two key sources of violence in America and around the world. While a considerable amount of research has been devoted to studying each outcome, neither has been extensively studied from a biosocial perspective. The current study addressed this gap in the literature by estimating the genetic and environmental underpinnings to gang membership, carrying a handgun, and the covariance between the two. Analyses of kinship pairs from the NLSY97 data revealed significant genetic influences on all of them. Specifically, genetic factors explained 77% of the variance in gang membership, 27% of the variance in carrying a handgun, and 66% of the covariance between gang membership and carrying a handgun. Just as important, however, is that the shared environment explained none of the variance/covariance across models, with all of the remaining variance being accounted for by nonshared environmental effects (plus error).

These findings have at least two main implications for criminological research. First, research that is interested in understanding the factors that might influence youth to join gangs need to begin to focus on genetic influences. Of course, environmental factors matter too, but the important environmental factors that matter appear to be nonshared environmental influences, not shared environmental influences. As a result, etiological research on gang membership should begin to search for specific nonshared environments that might be at play and abandon any concerted efforts that focus solely on shared criminogenic risk factors, such as neighborhood-wide subcultures and family-wide socialization practices. Indeed, recent research has revealed that neighborhood-level effects on delinquent behavior are conditioned by individual characteristics, which are under genetic influence, and unique environmental experiences (Barnes & Jacobs, 2013). Focusing on these key individual-level influences should provide a much more complete and accurate picture of the factors that may promote gang membership among youth. As a result, this newer information regarding the etiology of gang membership can be used to create more targeted intervention/prevention programs designed to thwart gang membership. Precisely what this type of gang prevention program would look like obviously depends on the findings that will emerge from this line of future research. However, biosocial findings are beginning to show significant promise in the prevention and treatment of other types of antisocial behaviors (Casey, Day, Vess, & Ward, 2013; Cujpers, Van Straten, & Smit, 2005; Farrington & Welsh, 2007) and thus the benefits could easily extend into gang membership.

Second, research that is interested in determining the mechanisms that are involved in the nexus between gang membership and handgun carrying need to place a great deal of emphasis on genetic influences and, to a lesser extent, nonshared environmental influences. Based on the results of this study, the overlap between gang membership and carrying a handgun is due largely to a shared genetic etiology. What this means is that the same genetic influences that contribute to gang membership also contribute to carrying a handgun. The precise genetic polymorphisms that are able to explain this covariance could not be studied with the NLSY97 because they do not include genotypic data. Future research, however, could add greatly to the existing knowledge base by examining specific genetic markers that might influence gang membership and gun-carrying behaviors. While speculative, it is likely that these genes would be related to a general antisocial and violent predisposition which, in turn, would ultimately be responsible for youth being predisposed to select to join a gang (i.e., active gene–environment correlation). With respect to gun carrying, it is possible that the same genes that influence antisocial behavioral traits and wanting to join a gang also function to increase the likelihood of carrying a handgun especially around fellow gang members. Specifically, 10 Youth Violence and Juvenile Justice Downloaded from at FLORIDA STATE UNIV LIBRARY on January 1, 2015 this process could be explained by either an active gene–environment correlation or an evocative gene–environment correlation.

To illustrate, individuals with a genetic predisposition for joining a gang may also demonstrate high levels of aggression and combativeness which functions to increase the likelihood that they will select to associate with peers who share similar antisocial traits and approve of carrying a handgun (active gene–environment correlation). Additionally, findings from this study may also reflect an evocative gene–environment correlation, wherein individuals may evoke certain behavioral responses from other gang members based on their genetically influenced personality. For example, fellow gang members may observe that an individual’s violent behavioral tendencies are similar to their own violent behavioral tendencies. After observing that they share common personality traits, gang members may respond to an individual’s proclivity for violence by offering them a handgun so that they can participate in a similar gun-related violent activity that other gang members are involved in.

Even though the current study is the first to explore the genetic and environmental underpinnings to gang membership and carrying a handgun, the results need to be subjected to replication because of a number of limitations. First, and perhaps most importantly, the findings were generated on a sample of kinship pairs. Consequently, the extent to which the findings generalize to respondents not from a kinship pair remains to be determined. It is important to note, however, that previous research has examined potential differences in antisocial behavior between twin pairs and non twin pairs and has shown that there are few significant differences, meaning that the findings are likely generalizable to a sample of non-twin/kinship pairs (Barnes & Boutwell, 2013). Second, the measure of gang membership was based on self-reports and thus it was not possible to determine what type of gang the youth had joined and whether it was a violent gang or a more social gang. Third, based on the measures of gang involvement and handgun carrying used in this study, we were unable to establish causal order between both outcomes. Because comprehensive measures were used, which spanned across nine survey waves, there may be concern over whether heritability estimates would fluctuate as a result of individual differences in the amount of time involved in gang-related activity. Although this question falls outside the scope of this study, we cautiously speculate that there would be slight differences in genetic and environmental influences on variation in gang involvement across the life course. However, we expect that these estimates would not deviate too much from the estimates reported in this study since antisocial behavioral traits—which correlate with gang involvement—tend to demonstrate stability over long periods of time (Loeber & Hay, 1997; Olweus, 1979). Fourth, the measure of gun-carrying behaviors simply asked the respondent whether they had ever carried a firearm other than a shotgun or a rifle. There was no information as to whether the gun-carrying behavior was legal or illegal or whether the gun-carrying behavior was for a specific purpose (e.g., for a job, for a competition, or for hunting). Whether the findings would diverge from those reported here with other measures of gun-carrying behavior remains to be determined. With that said, the models focusing on the covariance between gang membership and gun-carrying behaviors likely capture those youth who are carrying guns illegally.

Gang violence and gun violence pose significant threats to public safety, including the safety of youth and law-abiding citizens. Concerted attempts to reduce these types of violence have not been nearly as successful as initially hoped (Greene & Pranis, 2007). Perhaps one way to increase the effectiveness of gang and gun violence reduction among youth is to focus on a broader spectrum of factors, including genetic and nonshared environmental influences. Doing so might be rather unique, but as other fields of study have revealed, a multidisciplinary approach to understanding the causes of deleterious outcomes frequently leads to programs that are quite effective at preventing and treating even the most difficult to change outcomes (Farrington & Welsh, 2007). Gang and gun violence would thus seem to be a natural fit for creating programs based on a multidisciplinary approach, such as the biosocial perspective.

Guns, Gangs, and Genes: Evidence of an Underlying Genetic Influence on Gang Involvement and Carrying a Handgun
Eric J. Connolly1 and Kevin M. Beaver2,3
Youth Violence and Juvenile Justice 1-15 ª The Author(s) 2014 Reprints and permission: DOI: 10.1177/1541204014539522


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