This is absolutely fascinating.
The val/met polymorphism on the COMT gene, which has been known about for quite some time. If you have the val allele, you have a lot less dopamine in your prefrontal cortex, which means that your memory, IQ, and executive cognition is impaired. So the val allele makes you sort of dumb, so why doesn’t it go away?
The val allele is actually more common than mets.
Having the met allele, although it brings higher intelligence, IQ, memory, and executive function, makes you a little neurotic. It is associated with higher risk for depression, anxiety, schizophrenia – the met is the more emotional, deep thinker. The val allele is the more “guns and muscles” brain, with poorer executive function like memory, but he is emotionally a lot more stable.
The COOL thing is that this is a prime example of a gene environment interaction, or balanced selection. The one polymorphism leads to two different types of people, both of which we need. We might need the mets for laying down the law and solving problems, and the vals for keeping the walls of the fort up.
Haha, so how introspective are you? Are you possibly a val, or a met?
Sochat, Vanessa. "Thinkers and Muscles - Why We Have Both." @vsoch (blog), 09 Jun 2009, https://vsoch.github.io/2009/thinkers-and-muscles-why-we-have-both/ (accessed 20 Mar 23).