Two genes linked with violent crime

Those with the genes were 13 times more likely to have a history of repeated violent behaviour. The authors of the study, published in the journal Molecular Psychiatry, said at least 4-10% of all violent crime in Finland could be attributed to individuals with these genotypes, BBC News reports. But they stressed the genes could not be used to screen criminals. Many more genes may be involved in violent behaviour and environmental factors are also known to have a fundamental role. Even if an individual has a "high-risk combination" of these genes the majority will never commit a crime, the lead author of the work Jari Tiihonen of the Karolinska Institutet in Sweden said. "Committing a severe, violent crime is extremely rare in the general population. So even though the relative risk would be increased, the absolute risk is very low," he told the BBC. The study, which involved analysis of almost 900 criminals, is the first to have looked at the genetic make-up of so many violent criminals in this way. Warrior gene Each criminal was given a profile based on their offences, categorising them into violent or non-violent. The association between genes and previous behaviour was strongest for the 78 who fitted the "extremely violent offender" profile. This group had committed a total of 1,154 murders, manslaughters, attempted homicides or batteries. A replication group of 114 criminals had all committed at least one murder. These all carried a low-activity version of the MAOA gene, which previous research has dubbed the "warrior gene" because of its link to aggressive behaviour. Read more