Найдено генетическое объяснение импульсивности
Вот уж не ожидал, что его поисками занимались горячие финские парни. Исследования проводились на группе заключенных, отбывавших наказания за насилие и поджоги. Видно, финны полагают, что подпустить петуха удел импульсивных людей. Дальше все просто - мутация в гене HTR2B приводит к проблемам с серотонином, что сказывается на работе участков мозга, отвечающих за анализ последствий от предпринятых действий. Рекомендую всем биологизаторам этноса внимательнее следить за подобными исследованиями. Генетические особенности (биология) может задавать предрасположенность к тем или иным поведенческим проявлениям, но не детерминировать поведенческий выбор. Поведенческий выбор во многом обусловлен культурой - ценностями и нормами. Импульсивными могут быть и финны, и итальянцы, но проявляться импульсивность может по-разному, в зависимости от регуляторов общественной среды. Более того, определенные генетические мутации могут быть присущи в большей степени одной группе, в данном случае финнам, хотя другие на предмет именно этой мутации на сегодня мало изучены. Реальная ситуация такова, что биология первична, а этнос вторичен, то есть представители различных антропологических типов могут быть в составе одной и той же этнической группы. Так среди русских, особенно на северо-западе может быть значительное число представителей некогда ассимилированных финно-угорских групп, на юге, среди казаков, смешения происходили с представителями тюркских и северокавказских народов. Или, возьмем, турок. Современные турки - это горючая смесь гаплогрупп. Кого только нет - и сами тюрки, некогда с Алтая, и армяне, и курды, и черкесы, и албанцы, и картвелы, и сербы, и болгары, и греки... Поэтому если и есть поведенческая узнаваемость, то не биологической заданностью, а нормами и ценностями, ранней социализацией. Почему ничего не написал об армянах? Сами домысливайте. .
'Impulsivity gene' found in violent offenders
23 December 2010 by Andy Coghlan
A gene mutation linked with impulsivity and possible violent outbursts has been discovered in Finnish men convicted of violence and arson.
The mutation, in a gene called HTR2B, prevents production of the serotonin 2B receptor, a key docking point in brain cells for the neurotransmitter serotonin. One consequence could be depletion of serotonin in the nucleus accumbens, a part of the brain involved in providing restraint and foresight into the consequences of actions.
The mutation was three times as common in violent criminals as in the general population. Of 228 Finnish inmates serving sentences for violent crimes who were screened, 17 carried the mutation, compared with only 7 of 295 healthy controls.
Although the mutation appears confined to Finnish people, it could have counterparts in populations elsewhere, with similar negative consequences, say the researchers.
"We would anticipate that over time, a large number of functional variants [of HTR2B] will be identified, with a range of behavioural effects," says David Goldman at the US National Institute on Alcohol Abuse and Alcoholism in Bethesda, Maryland, and head of the team that carried out the work.
Impulsivity played a pivotal role in the criminal behaviour of all 17 prisoners carrying the mutation, who were convicted of crimes ranging from murder and attempted murder to arson, battery and assault. "The crimes occurred as disproportionate reactions to minor irritations and were unpremeditated, without potential for financial gain and recurrent," say the researchers in Nature.
Alcohol trigger
In almost all cases, the men had been drinking heavily, suggesting that the mutation is only a problem in combination with alcohol. "[People with the gene] behave as if they have a very short fuse, and it becomes even shorter when they're disinhibited by alcohol," says Goldman.
Goldman and his colleagues supported their findings by demonstrating that the mutation causes impulsive behaviour in animals. In five standard tests of impulsivity, such as showing boldness in exploring unfamiliar environments, mice engineered to lack a functional HTR2B gene were more impulsive than healthy mice.
But the team cautions against screening for the gene and others like it to identify potentially violent and impulsive individuals, because only a fraction of carriers turn to violence. "The vast majority of carriers are normal behaviourally and cognitively, so population screening would not be justified," Goldman says.
Other researchers echo his warnings against exaggerating the effects of the mutation in human carriers, pointing out that there are probably around 100,000 carriers in Finland, but only a fraction of these have turned or will ever turn to violence.
"Even though this genetic predisposition is a strong risk factor for violence, it still needs other factors to bring it out, in this case alcohol," says Han Brunner at Radboud University in Nijmegen, the Netherlands.
Other genetic factors
In 1993, Brunner discovered a predisposition to violence in a single Dutch family carrying a mutation in the gene which makes monoamine oxidase A (MAOA), another enzyme vital for regulating neurotransmitter levels in the brain.
A more common variant of MAOA linked with antisocial behaviour was discovered in 2002 by a team led by Avshalom Caspi at Duke University in Durham, North Carolina. Its negative effects only kicked in if children were poorly cared for in infanthood.
For perspective, Brunner points out that a well-known genetic trait affects half the world's population and makes its carriers nine times more likely to commit violent crime than those who don't carry it. "That's the Y chromosome, which makes people male," he says.
Journal reference:
Nature, DOI: 10.1038/nature09629
'Impulsivity gene' found in violent offenders
23 December 2010 by Andy Coghlan
A gene mutation linked with impulsivity and possible violent outbursts has been discovered in Finnish men convicted of violence and arson.
The mutation, in a gene called HTR2B, prevents production of the serotonin 2B receptor, a key docking point in brain cells for the neurotransmitter serotonin. One consequence could be depletion of serotonin in the nucleus accumbens, a part of the brain involved in providing restraint and foresight into the consequences of actions.
The mutation was three times as common in violent criminals as in the general population. Of 228 Finnish inmates serving sentences for violent crimes who were screened, 17 carried the mutation, compared with only 7 of 295 healthy controls.
Although the mutation appears confined to Finnish people, it could have counterparts in populations elsewhere, with similar negative consequences, say the researchers.
"We would anticipate that over time, a large number of functional variants [of HTR2B] will be identified, with a range of behavioural effects," says David Goldman at the US National Institute on Alcohol Abuse and Alcoholism in Bethesda, Maryland, and head of the team that carried out the work.
Impulsivity played a pivotal role in the criminal behaviour of all 17 prisoners carrying the mutation, who were convicted of crimes ranging from murder and attempted murder to arson, battery and assault. "The crimes occurred as disproportionate reactions to minor irritations and were unpremeditated, without potential for financial gain and recurrent," say the researchers in Nature.
Alcohol trigger
In almost all cases, the men had been drinking heavily, suggesting that the mutation is only a problem in combination with alcohol. "[People with the gene] behave as if they have a very short fuse, and it becomes even shorter when they're disinhibited by alcohol," says Goldman.
Goldman and his colleagues supported their findings by demonstrating that the mutation causes impulsive behaviour in animals. In five standard tests of impulsivity, such as showing boldness in exploring unfamiliar environments, mice engineered to lack a functional HTR2B gene were more impulsive than healthy mice.
But the team cautions against screening for the gene and others like it to identify potentially violent and impulsive individuals, because only a fraction of carriers turn to violence. "The vast majority of carriers are normal behaviourally and cognitively, so population screening would not be justified," Goldman says.
Other researchers echo his warnings against exaggerating the effects of the mutation in human carriers, pointing out that there are probably around 100,000 carriers in Finland, but only a fraction of these have turned or will ever turn to violence.
"Even though this genetic predisposition is a strong risk factor for violence, it still needs other factors to bring it out, in this case alcohol," says Han Brunner at Radboud University in Nijmegen, the Netherlands.
Other genetic factors
In 1993, Brunner discovered a predisposition to violence in a single Dutch family carrying a mutation in the gene which makes monoamine oxidase A (MAOA), another enzyme vital for regulating neurotransmitter levels in the brain.
A more common variant of MAOA linked with antisocial behaviour was discovered in 2002 by a team led by Avshalom Caspi at Duke University in Durham, North Carolina. Its negative effects only kicked in if children were poorly cared for in infanthood.
For perspective, Brunner points out that a well-known genetic trait affects half the world's population and makes its carriers nine times more likely to commit violent crime than those who don't carry it. "That's the Y chromosome, which makes people male," he says.
Journal reference:
Nature, DOI: 10.1038/nature09629