A genetic mutation that makes men impulsive and aggressive, especially when drunk, has been isolated in Finnish men.
Research on violent criminals in Finland has uncovered a genetic variant of a brain receptor molecule that contributes that makes people more likely to be aggressive when they have been drinking.
The findings could lead to a better understanding into why some people are more prone to sudden bouts of violence and to the treatment of violent offenders.
Finnish men watch an ice hockey match while having a sauna in Helsinki. A genetic mutation in some Finnish men makes them more pre-disposed towards violence
Incredibly, the gene is only found in men from Finland and so cannot explain similar behaviour in other countries such as the UK.
A report of the findings appears in the December 23rd issue of Nature.
“Impulsivity, or action without foresight, is a factor in many pathological behaviours including suicide, aggression, and addiction,” says David Goldman chief of the Laboratory of Neurogenetics at the NIH”s National Institute on Alcohol Abuse and Alcoholism (NIAAA).
“But it is also a trait that can be of value if a quick decision must be made or in situations where risk-taking is favoured.”
In collaboration with researchers in Finland and France, Dr. Goldman and colleagues studied a sample of violent criminal offenders in Finland.
The hallmark of the violent crimes committed by individuals in the study sample was that they were spontaneous and purposeless.
“We conducted this study in Finland because of its unique population history and medical genetics,” says Dr. Goldman.
“Modern Finns are descended from a relatively small number of original settlers, which has reduced the genetic complexity of diseases in that country.
‘Studying the genetics of violent criminal offenders within Finland increased our chances of finding genes that influence impulsive behaviour.”
The researchers sequenced DNA of the impulsive subjects and compared those sequences with DNA from an equal number of non-impulsive Finnish control subjects.
They found that a single DNA change that blocks a gene known as HTR2B predicted highly impulsive behaviour. HTR2B encodes one type of serotonin receptor in the brain.
They discovered that carries of the gene who had acted violently were all male and had all been drinking alcohol before the incident.
The researchers then conducted studies in mice and found that when the equivalent HTR2B gene is knocked out or turned off, mice also become more impulsive.
Scientists say that the gene itself is not the only reason for the violent behaviour as there are many different environmental and social issues which can also lead to violence.