The Influence Of Rs6323Polymorphism In The MAOA Gene And Parenting Behavior On Children’s Proactive And Reactive Aggression

The influencing factors and the mechanism of the individual’s aggression havebeen the important basic issues of psychological research. How gene and environmentaffect the individuals’ development is one of the core theories and scientific issues ofdevelopmental psychology. Although most psychologists hold out the interaction ofgene and environment on individual s’ psychological and behavioral development, butthe current researches have been mostly limited to exam either the genetic or theenvironmental effects, and the systematically researches about the underlyingmechanism of how gene and family environment influence children’s aggressivebehavior is very scare. What’s more, there are no researches exploring the correlatecandidate gene and the gene-environment interaction of the proactive and reactiveaggression, which are the two subtypes of aggressive behavior. With the advancementof molecular genetics, the identification of the specific candidate genes andinvestigations into the gene-environment interactions related to aggression have beenamong the most active and important research topics of research on humanaggression(Moffitt,2005; Reiss&Leve,2007; Taylor&Kim-Cohen,2007; Rutter,2007).So this study attempts to be based on the international frontier of the aggressivebehavior research, and to explore the influences of gene and family environment onchildren’s proactive and reactive aggression and the underlying mechanism.Scientificexplorations in the realm can be expected to deepen the scientific understanding of theorigin and development of aggression, and at the same time provide importantimplications for intervention with children and adolescent aggression.Based on the differential susceptibility model, this study adopted thegene-environment interaction design to exam the effect of the MAOA gene and parenting on proactive and reactive aggression, and to explore whether thegene-environment interaction can be moderated by gender among1449children insixth grade. Children’s aggressive behavior was measured by the teacher assessment,and the parenting was measured by the mother report. DNA samples were collected inorder to assess the rs6323functional polymorphism in the MAOA gene. The mainconclusions were as follows:(1) There was significant gender difference in parenting, especially girls receivedmore positive parenting such as parental warmth and encouragement, but boysreceived more negative parenting such as parental rejection, punishment andindulgence. Significant gender differences also exited in children’s proactive andreactive aggression, and both the proactive and reactive aggression levels among boyswere higher than those among girls.(2) The two types of aggression were significant associated with parenting, suchthat the negative parenting was positively correlated with children’s aggressivebehavior, but the positive parenting was negatively correlated with children’saggressive behavior.(3) MAOA gene had no significant main effect on the children’s proactive andreactive aggression.(4) MAOA gene significantly interacted with parenting in predicting children’sproactive aggression, but not the reactive aggression. What’s more, this observedinteraction pattern on children’s proactive was in accordance with the perspective ofthe differential susceptibility model.(5) The effects of MAOA gene and parenting on children proactive aggressioncould be moderated by gender. Furthermore, the moderation effects were mainlyreflected in the environment variables(namely parenting in this study), such that boyscarrying the T allele were more sensitive to the positive parenting, but girls carryingthe same allele were more sensitive to the negative parenting.