Acts
of violence and extreme violence are often attributed to mental
instability. In addition, violent
behaviour can also lead one to commit an act of violence. While the general
conception is often rooted within how criminals think, a significant molecular
component takes into account for violent behaviour. Dr. James Fallon, in his
book The Psychopath Inside, discusses
how genes affect certain kinds of behaviour. He introduces this concept by
discussing genetics, the effects of different neurotransmitters, and SNPs. All
three of these factors have influenced the transmissions and regulation of
certain genes that contribute to violent behaviour. He takes a while to discuss
the MAO-A enzyme and the warrior gene and how that affects brain behaviour,
most notably in accordance to violence. An article by Melissa Hogenboon, a
correspondent for BBC science, compiled an article in which she found two genes
that contribute to violent behaviour: MAOA gene (same as Fallon) and another
called the CDH13 gene.
Hogenboom’s article explained that
900 offenders underwent a genetic analysis. A profile was given to each
offender and his or her offenses had to be categorized into violent and non-violent.
Those who were categorized in “violent” were shown to have a low activity
version of the MAOA enzyme. A deficiency of this causes dopamine levels to
rise. Fallon discusses the effect of MAO-A in his book and explains that the enzyme
often leads to an aggressive behaviour. The MAO-A enzyme is in accordance to
the warrior gene. The warrior gene creates MAO-A. MAO-A gene codes for
monoamine oxidase A. Monoamine oxidase A controls the levels of dopamine within
the body. In addition to MAO-A, a variation of a cadherin (CDH13) is linked
with ADHD and substance abuse. MAO-A and CDH13 were not found in non-violent
offenders. According to Fallon, the warrior gene causes MAO-A to be
under-produced. When MAO-A is under-produced, monoamine is unable to be broken
down. Thus, a surplus of monoamines arises and that includes serotonin. This
causes the brain to create fewer receptors for serotonin and ends up changing
the connection, structure, and size of cells. Therefore, this whole brain area
is changed. Fallon introduced a study that was done by a Dutch researcher in
which men with a low production of MAO-A were shown to have inappropriate
behaviour and committed crimes. This correlates with the study done that was
stated in the article by Hogenboom, that those with a deficiency of MAO-A showed
aggressive behaviour. Fallon also states that the warrior gene is linked to
show changes in brain structure, primarily in males. The areas that were
changed were linked to show antisocial behaviour and psychopathy. Since the
warrior gene is located on the X chromosome, the gene tends to affect males
more.
Genetics and biology are crucial
factors in determining our behaviour. Our violence and aggression can be
attributed to our biology, our brain, and our genes. When we think of crime, we
think of the person. However, we do not have a tendency to delve deeper and
find reasons why such behaviour and aggression exist. Now, as Fallon stated, we
are finding ways to determine what particular genes are associated with certain
symptoms. Through that, we are able to diagnose and determine certain
behaviours. While Hogenboom’s article also agrees that we should consider
biology, the article clearly takes the position that environmental factors
should be taken into account, a contrasting view of Fallon’s. Therefore,
alleles and genes can be further studied in order to determine certain
behaviours and how it affects the brain.
Two genes linked with violent crime. (2014,
October 1). Retrieved February 27, 2015, from http://www.bbc.com/news/science-environment-29760212
Fallon, J. (2013). The psychopath
inside: A neuroscientist's personal journey into the dark side of the brain.
New York: Current.
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