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Wishing for a genetic zodiac sign: How much can genes really tell us about personality?

Brain MRIGiven all the recent news on how gene expression influences our brain, from Alzheimer's to addiction and even our personalities, readers might come away thinking that we’re close to breaking the code and using genetics to understand why we behave the way we do. But, things aren’t that simple.

In a post on the science blog Last Word on Nothing, Eric Vance explores what getting your personal genetic sequence means for your personality - something he calls, tongue-in-cheek, “a genetic tarot card.”

Vance delves into an explanation of one specific mutation in the COMT gene. The gene creates an enzyme that neutralizes dopamine, a neurotransmitter. The gene comes in two forms, and the difference in these two forms is just one base-pair, the individual links in our DNA code. One version of the resulting enzyme is efficient at clearing away extra dopamine. But if the gene codes for the other version, “then the enzyme becomes a wastrel... Work piles up and the brain accumulates a bunch of extra dopamine.”

Because dopamine is such a powerful regulator of mood, and by extension personality, Vance then describes, in surprising detail, personality types he expects people with either version of the gene to have. But genetic information like this is meant to be used at the population, not personal, level. In fact, none of the people in his circle of friends who have had their genome sequenced turns out to be who he expects them to be (which begs the question, how many people does he know who’ve had their DNA sequenced?). Disappointed, he laments:

But that’s not how I want it work. While I don’t like the idea of boiling human emotions down to a couple squishy turning gears, I do like how tidy it is. I want to be able to look up my genome and make broad generalizations about myself. I want to have a genetic tarot card that I can inspect and say “ohhh, that’s why I always forget people’s names” or “that’s why I got in that fight in the third grade.”

Vance concludes, “But that’s not what nature gave us. Nature has given us messy, confusing and vastly complicated brains.” We are more, it turns out, than the sum of our base pairs.

Previously: New research sheds light on connection between dopamine and depression symptoms

Photo by deradrian

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