Health Science Reviews

By Zarah Palha

I began watching Riverdale, along with the rest of the world, in 2017. Now, this is a judgment-free zone, so I can admit that while others may have stopped watching due to the show’s inconsistent themes and plots, I stayed loyal. In season 3, the Serial Killer genes were introduced, which Betty Cooper, one of the main characters, possessed. According to the show, the presence of these abnormal genes caused the bearer to enter a trance-like state in which they exhibited massive amounts of aggression and were “predisposed” to murder. Interesting, scary and highly unlikely. But is this based on science, or is it the work of a very active imagination? The answer is both!

The most mentioned gene in the show is the MAOA gene, which is a genetic marker related to aggression. It has also been termed the “Warrior gene” by scientists. But is there a real connection between MAOA and criminal behaviour?

What is the MAOA gene?

The MAOA gene, situated on the X chromosome, encodes an enzyme which is responsible for the regulation of mood-related neurotransmitters such as serotonin and dopamine. The activity level of the MAOA gene is what determines an individual’s predisposition to violence. This is determined by the number of tandem repeats of the gene’s nucleotide sequence. Individuals with fewer repeats (1 or 2) have low activity (MAOA-L) and therefore are more likely to exhibit aggression and anti-social behaviour. This is due to the decreased ability of the brain to regulate mood, which affects the central nervous system significantly. MAOA-L has been found to be linked to increased reactive aggression, increased angry hostility, increased impulsive behaviour, reward dependence and increased tendency to inflict pain on others.  As previously mentioned, the gene is located on the X chromosome, meaning abnormalities of the gene affect males more due to the lack of a second chromosome that could counteract low activity levels.

Nature vs Nurture

In the past, researchers hoped to find a specific gene linking all criminals. This “criminal gene” does not exist. It is important to note the wording used when discussing genes and behaviour. Genetics can predispose someone to a certain behaviour, but it is not a causal effect. Genes determine genotype, whereas one’s environment determines their phenotype. This is due to psychosocial influences causing changes in gene functioning. Genetics have been found to only contribute to 50% of the variance in anti-social behaviour. This introduces the gene x environment interaction; both of these factors can be used to predict more accurate outcomes in terms of individual behaviour.

The majority of the literature confirms that the link between MAOA-L and anti-social behaviour is due to both gene and environmental factors. Childhood maltreatment consistently appeared as the most significant environmental factor, leading to structural changes in the brain, which were an attribute of later antisocial and violent impulsive behaviour exhibited. Such brain changes affected areas of the amygdala, prefrontal cortex and hippocampus, all of which are involved in emotion regulation.

Staggering statistics

In a study done in 2005, researchers found that 85% of people who experienced severe childhood maltreatment and had the MAOA-L gene committed serious crimes before the age of 26. People with this specific gene-environment interaction (MAOA-L and childhood maltreatment) make up 12% of the population; however, they account for 44% of violent crime convictions. Males are three times more likely than females to carry the MAOA-L variant. In men, this is associated with violent criminal behaviour, whereas in women, the same gene has been linked to anxiety and depression.

How accurate was Riverdale?

Does a gene make a killer? No, a person with the MAOA gene with low activity and a history of childhood abuse may be more prone to impulsive and highly reactive acts of violence, but that doesn’t make a serial killer.

Some of Betty’s acts of violence could be explained by her MAOA gene and childhood trauma, but any premeditated acts of violence or aggression cannot be attributed to the MAOA gene. The “trance-like” state those with the gene experience in the show is 100% a work of fiction. One would be more likely to experience an angry outburst than a hypnotic state of murder.

Essentially, genes cannot predict the future; they shape how we may respond to the world but do not dictate who we become. While MAOA may increase the risk of impulsive aggression in certain situations, it doesn’t determine a person’s fate. Understanding this can help us put prevention and early interventions into place.

So, Riverdale didn’t get the science completely right, but at least we now know that a gene doesn’t make a killer.

References:

González-Tapia, M.I. & Obsuth, I. 2015. “Bad genes” & criminal responsibility. International Journal of Law and Psychiatry. 39:60-71. DOI:https://doi.org/10.1016/j.ijlp.2015.01.022.