The MAOA-L allele has been shown to produce violence:

Question

Quizplus · Accepted Answer

MAOA-L has been shown to produce violence mostly in males who have experienced childhood physical abuse. Research suggests that MAOA-L interacts with environmental factors such as childhood maltreatment to increase the risk for violence and aggression. There is no evidence to suggest that MAOA-L produces violence in females or under all environmental conditions that have been studied. Defensive aggression is not the only type of aggression associated with MAOA-L.

The MAOA-L Allele Has Been Shown to Produce Violence