Which gene variant has been linked to aggression in some studies, with around one-third of men carrying it?

Which gene variant has been linked to aggression in some studies, with around one-third of men carrying it?

• A. MAOA Warrior gene
• B. SERT gene
• C. DRD4
• D. COMT

Answer: (A)

This item hinges on the idea that a specific gene variant has been linked to aggression in some studies and is carried by a substantial portion of men. The gene is MAOA, which codes for the enzyme monoamine oxidase A that helps break down neurotransmitters such as serotonin, norepinephrine, and dopamine. A low-activity version of this gene (often called MAOA-L) means these chemicals can linger longer in brain circuits involved in impulse control and aggression, potentially contributing to aggressive behavior under certain conditions. Importantly, the effect isn’t automatic—research shows a gene–environment interaction, where MAOA-L carriers who experience adverse early-life environments are at higher risk for aggressive or antisocial outcomes. That’s why it’s often discussed as the so-called “warrior gene,” though the link is probabilistic and context-dependent. The other options aren’t as directly tied to aggression in the same way. The serotonin transporter gene is more commonly linked to mood and anxiety traits, not aggression per se. DRD4 is associated with novelty seeking and some risk-taking or attention-related traits, while COMT influences prefrontal dopamine and executive function with varied behavioral links. So the best-supported link to aggression, including the statistic about about a third of men carrying it, points to the MAOA variant.

This item hinges on the idea that a specific gene variant has been linked to aggression in some studies and is carried by a substantial portion of men. The gene is MAOA, which codes for the enzyme monoamine oxidase A that helps break down neurotransmitters such as serotonin, norepinephrine, and dopamine. A low-activity version of this gene (often called MAOA-L) means these chemicals can linger longer in brain circuits involved in impulse control and aggression, potentially contributing to aggressive behavior under certain conditions. Importantly, the effect isn’t automatic—research shows a gene–environment interaction, where MAOA-L carriers who experience adverse early-life environments are at higher risk for aggressive or antisocial outcomes. That’s why it’s often discussed as the so-called “warrior gene,” though the link is probabilistic and context-dependent.

The other options aren’t as directly tied to aggression in the same way. The serotonin transporter gene is more commonly linked to mood and anxiety traits, not aggression per se. DRD4 is associated with novelty seeking and some risk-taking or attention-related traits, while COMT influences prefrontal dopamine and executive function with varied behavioral links. So the best-supported link to aggression, including the statistic about about a third of men carrying it, points to the MAOA variant.