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Abstract
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Dopaminergic genes have been frequently found to be associated with aggressive behavior, but the results are inconsistent. One reason for the inconsistencies is there might be the U-shaped relationship between dopaminergic genetic variants and aggressive behavior. More specifically, evidence has suggested an inverted U-shaped relationship between dopamine activity and prefrontal cortex (PFC) function (a critical region related to aggression), with both dopaminergic hypofunction and hyperfunction, were related to poor PFC function. It is possible that the relationship between dopaminergic genes and aggression approximates a U-shaped function. However, such U-shaped relationship is rarely investigated in previous studies. Moreover, several concerns have been raised about the ignoring the polygenic traits of aggressive behavior when conducting gene by environment interaction (G×E) research using single loci. Therefore, the present study aimed to examine the interaction between dopaminergic genetic variants and maternal negative parenting on adolescent aggressive behavior by adopting the approach of multilocus genetic profile score (MGPS).
Participants were 1044 adolescents (mean age 13.32 ± 0.49 years old at Time 1, 50.2% females) recruited from the community. The adolescents completed two assessments with an interval of one year. Saliva samples, mother-reported parenting data and data on peer-nominated aggressive behavior were collected. All measures showed good reliability. The MGPS was created by COMT rs4680 polymorphisms, DRD2 rs1799978 polymorphisms and DAT1 rs27072 polymorphisms. Genotyping in three dopaminergic genes were performed for each participant in real time with MassARRAY RT software version 3.0.0.4 and analyzed using the MassARRAY Typer software version 3.4 (Sequenom). To examine whether negative parenting moderates the effects of MGPS on adolescent aggressive behavior, hierarchical regression analyses were conducted.
The results found that after controlling for gender, maternal negative parenting was a significant risk factor for adolescent aggressive behavior, with higher negative parenting related to more aggressive behavior. The main effect of the quadratic term of MGPS on adolescents' aggressive behavior was significant at Time 2, indicating a U-shaped relationship between MGPS and adolescent aggressive behavior. Moreover, the quadratic term of MGPS significantly interacted with maternal negative parenting in predicting aggressive behavior at Time 1 and Time 2, respectively. Specifically, there was a U-shaped relationship between MGPS and adolescent aggressive behavior, indicating that adolescents with higher and lower MGPS exhibited higher levels of aggressive behavior when experiencing higher levels of maternal negative parenting. No significant effect of MGPS on adolescent aggressive behavior when experiencing lower levels of maternal negative parenting existed.
This study provides evidence for the molecular mechanisms of multilocus genetic profile scores and gene-environment interactions in adolescent aggressive behavior.
Language: en |