Study finds genetic link to violence, delinquency

BEIJING, July 15 (Xinhuanet) -- Genes may play an important role in determining why some young men raised in rough neighborhoods or deprived families become violent criminals while others do not, accordidng to the August issue of the American Sociological Review as quoted by media Tuesday.

One gene called MAOA that plays an especially strong role has been shown in other studies to affect antisocial behavior -- and it is disturbingly common, according to the team at the University of North Carolina.

People with a particular variation of the MAOA gene called 2R were very prone to criminal and delinquent behavior, said sociology professor Guang Guo, who led the study.

"I don't want to say it is a crime gene, but 1 percent of people have it and scored very high in violence and delinquency," Guo said in a telephone interview with media.

Guo's team found specific variations in three genes -- the monoamine oxidase A (MAOA) gene, the dopamine transporter 1(DAT1) gene and the dopamine D2 receptor (DRD2) gene -- were associated with bad behavior.

Guo's team, which studied only boys, used data from the National Longitudinal Study of Adolescent Health, a nationally representative sample of about 20,000 adolescents in grades 7 to 12. The young men in the study were interviewed in person regularly, and some gave blood samples.

His team constructed a "serious delinquency scale" based on some of the questions the youngsters answered.

"Nonviolent delinquency includes stealing amounts larger or smaller than 50 U.S. dollars, breaking and entering, and selling drugs," it wrote in the Review.

"Violent delinquency includes serious physical fighting that resulted in injuries needing medical treatment, use of weapons to get something from someone, involvement in physical fighting between groups, shooting or stabbing someone,deliberately damaging property, and pulling a knife or gun on someone."

(Agencies)