The PNAS paper is the first experimental test of whether MAOA-L individuals display higher levels of actual behavioral aggression in response to provocation. A total of 78 subjects took part in the experiment over networked computers (all were male students from the University of California–Santa Barbara).

The results support previous research suggesting that MAOA influences aggressive behavior, with potentially important implications for interpersonal aggression, violence, political decision-making, and crime. The finding of genetic influences on aggression and punishment behavior also questions the recently proposed idea that humans are “altruistic” punishers, who willingly punish free-riders for the good of the group.

Another name for the result of having warrior genes comes to mind and that would be bully.