Is criminality genetic? MAOA-3R


Yeah, whatever
PREMO Member
Some studies argue that certain genes are a good predictor of future criminality.

The MAOA warrior gene was the first candidate gene to be linked to antisocial behavior, identified in 1993 in a large Dutch family that was notorious for violence. A geneticist called Rod Lea reported that the MAOA-3R mutation was more common in the violent indigenous Maori population of New Zealand than in caucasian males (56% vs 34%). Lea went on to link this gene to a whole host of undesirable traits, such as violence, aggression, risk-taking and gambling/addiction.
Beaver (2013) conducted research into MAOA-3R in America and found that it increased the likelihood of an individual joining a violent gang.

Studies have found differences in the frequency distribution of variants of the MAOA gene between ethnic groups: of the participants, 59% of Black men, 54% of Chinese men, 56% of Maori men, and 34% of Caucasian men carried the 3R allele

According to a large meta-analysis in 2014, the 3R allele had a small main effect on aggression and antisocial behavior, even in the absence of other interaction factors

if there was a mutation to the gene that is involved in the process of promoting or inhibiting MAO enzymes, it could affect a person's personality or behaviour and could therefore make them more prone to aggression.

Scientists say it's the "warrior gene," a controversial name for a genetic variation that research has shown to have an ugly side tied to violence, risk taking and aggression.Found in one-in-three western men, it is literally a shorter, less active version of a gene allele on the X chromosome known as Monoaminine oxidrase A gene.
"In many, many studies it appears implicated in behaviors that look like they're related to physical aggression or some kind of conduct disorder,"

The genetic variant is located on the X chromosome of DNA and because men only have one X chromosome the connections to violence are seen more readily in men. Studies have also linked the variant to gambling, gang membership and weapon use.


Up. Identified. Lase. Fire. On the way.
PREMO Member
This stuff is pretty cool (and in the wheelhouse of my current pursuit; though at a very simple level).

We have to be careful not to oversimplify. No single gene is responsible for anything. Instead, it is almost always a complex interaction of genes and environment. Ref #1 gets it quite correct, I think: "It is important to note, however, that current research indicates that social environment, specifically abuse during childhood, appears to be a necessary requirement for the faulty version of this gene to trigger violent tendencies." I would add, "probably not the only one, either."

As such, I tend to favor the "Swiss cheese" model used in addictions counseling. This model essentially says there are multiple "requirements" for something to happen (the various slices) and that the holes in each slice must line up at least partially for an addiction to switch on. Same sort of thing is research-supported in auto-immune diseases, for example. That's, for instance, one reason with things like addictions or autoimmune you often also hear "co-morbid": complicated to treat. So if it's complicated to treat it's probably complicated in origin.

The whole MAOA "thing" is fascinating. Along with TCAs, MOA-x inhibitors were the first generation antidepressants (and meds for other neurological conditions, such as biploar or Parkinson's). So clearly the various types of MOA-x function at a very important level in the brain chemistry. So important that their activities were probably fairly easy to "find" and a natural focus for researchers to try to assign correlation. Anyway, my point is that it's more complicated than that so that not everyone with MOA-x issues will suffer from depression or violent tendencies. As someone once said, this sort of thing is descriptive not prescriptive.

There are, of course, very important socio-political-legal implications when we talk "genes," but that's a discussion for another time.

Thanks for the post; gave me an opportunity to muse aloud.

--- End of line (MCP)


Yeah, whatever
PREMO Member
The current show we are binge watching, The Blacklist, has an episode about the warrior gene. Some psycho doctor is tapping into this gene to cause people to break the law. This might be an eye opening episode.

Paul Rubens is in this show. He looks like a young Ringo Starr with his Beatles haircut.


Yeah, whatever
PREMO Member
A possible therapy (CRISPR) to overcome violent antisocial behavior. This might work for the young, criminally inclined youths.

The reading is way above my level of intellect on the subject. But it is fascinating that some are doing research into what is basically how to remove the criminality out of some people.

MAOA inhibitor can reverse antisocial behavior to normal behavior in animal models. However, this disorder cannot be treated permanently; to treat it permanently in the future, technologies such as CRISPR/Cas9, iPSCs and ssODN are required. These technologies have succeeded to correct erroneous segments in the F8 gene and F9 gene. Both genes occupy the X chromosome. The MAOA gene also occupies the X chromosome. It is reasonable to state that CRISPR/Cas9 and iPSCs technique for instance can be beneficial tools to edit the MAOA gene to treat antisocial behavior. CRISPR/Cas9 can be used in combination with iPSCs or ssODN for instance. This combination can greatly help the permanent healing of antisocial behavioral disorders.
(PDF) Moderate the MAOA-L Allele Expression with CRISPR/Cas9 System Nelwan Institution for Human Resource Development (