Washington, Oct 2 : Adolescent males who possess a certain type of variation in a specific gene are more likely to develop affinity with delinquent peers, says a new study.
In a landmark study, a research team led by Florida State University criminologist Kevin M. Beaver has established a link between affinity for antisocial peer groups and a particular variation (called the 10-repeat allele) of the dopamine transporter gene (DAT1).
"This research is groundbreaking because it shows that the propensity in some adolescents to affiliate with delinquent peers is tied up in the genome," said Beaver, an assistant professor in the FSU College of Criminology and Criminal Justice.
However, the study also suggests that family environment plays a crucial role in this association.
The analysis of family, peer and DNA data from 1,816 boys in middle and high school found that the association between DAT1 and delinquent peer affiliation applied primarily for those who had both the 10-repeat allele and a high-risk family environment, the environment marked by a disengaged mother and an absence of maternal affection.
On the other hand, adolescent males with the very same gene variation who lived in low-risk families, one with high levels of maternal engagement and warmth showed no statistically relevant affinity for antisocial friends.
"Our research has confirmed the importance of not only the genome but also the environment," Beaver said.
"We can only hypothesize why we saw the effect of DAT1 only in male adolescents from high-risk families," said Beaver, who will continue his research into the close relationship between genotype and environmental factors -- a phenomenon known in the field of behavioural genetics as the "gene X environment correlation."
"Perhaps the 10-repeat allele is triggered by constant stress or the general lack of support, whereas in low-risk households, the variation might remain inactive," he said.
"Or it's possible that the 10-repeat allele increases an adolescent boy's attraction to delinquent peers regardless of family type, but parents from low-risk families are simply better able to monitor and control such genetic tendencies," he added.
The study appears in the Journal of Genetic Psychology.