The 2-repeat allele of the MAOA gene confers an increased risk for shooting and stabbing behaviors Kevin M Beaver 1 , J C Barnes, Brian B Boutwell PMID: 24326626 DOI: 10.1007/s11126-013-9287-x Abstract There has been a great deal of research examining the link between a polymorphism in the promoter region of the MAOA gene and antisocial phenotypes. The results of these studies have consistently revealed that low activity MAOA alleles are related to antisocial behaviors for males who were maltreated as children. Recently, though, some evidence has emerged indicating that a rare allele of the MAOA gene-that is, the 2-repeat...