LiveScience reports that a 'violent gene' has been discovered . . . but there's a twist to the tale.
The mutation, which is found only in Finnish populations, shows up three times more often in violent criminal offenders than in psychologically healthy Finns, the study found. However, the researchers caution that the mutation itself does not cause impulsivity, but may play a role along with factors like gender, alcohol consumption and stress.
"We've known that impulsivity is strongly influenced genetically, but here's a severe genetic variant that does contribute to it," study author David Goldman, a geneticist at the National Institute on Alcohol Abuse and Alcoholism (NIAAA), told LiveScience.
. . .
In the current study, researchers recruited 96 Finnish men who were in jail for violent offenses and 96 psychologically healthy Finnish men who were not incarcerated. Finns were chosen for the study, because the Finnish population is more isolated than other populations and therefore hosts a less-diverse array of genetic mutations.
Goldman and his colleagues analyzed each man's genome, focusing on 14 genes known to be related to the function of the neurotransmitters dopamine and serotonin. They found a mutation on a gene called HTR2B was associated with impulsive, violent behavior.
. . .
Seventeen of the 96 inmates had the gene mutation, a rate three times that of the non-incarcerated participants. On average, the prisoners had committed five violent crimes apiece, 94 percent of which occurred under the influence of alcohol. The crimes were not premeditated and were usually an overreaction to a minor incident, the researchers report. The study also revealed that 70 percent of participants with the mutation had displayed suicidal behavior.
There's more at the link.
I find it particularly interesting and intriguing that this genetic mutation has been found only in Finnish men. It may shed new light on a phenomenon from Viking times. The Vikings were Northmen, from what is today Scandinavia, comprising (from west to east) Norway, Sweden and Finland. Some Vikings were known as 'berserkers', men who "are reported in the Old Norse literature to have fought in a nearly uncontrollable, trance-like fury, a characteristic which later gave rise to the English word berserk."
Could it be that the 'berserkers' of old included men who carried this genetic mutation? If we could find the graves of such men, and conduct DNA analysis of their remains, it might explain much about what made them fight like that. Certainly, the geographic restriction of the genetic mutation to an area from which many Vikings came is highly suggestive of a link.