Does This Gene Determine How You Handle Your Booze?

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SSome people can really hold their alcohol. Even after a night of heavy drinking, they don’t get upset or lose control. Others are more immediately sensitive to the intoxicating effects of alcohol, having difficulty expressing themselves or losing their balance after just a few drinks. How a person responds to pints and spirits can shape their vulnerability to alcohol addiction.

Many factors play a role in alcohol sensitivity, including a person’s body composition, variation in alcohol metabolism enzymes, and whether tolerance has been developed. Now, researchers have discovered new evidence that a gene known as CHRNA3a nervous system regulator found in a wide range of animals, from roundworms to humans, can also help determine how an organism responds to alcohol.

The researchers examined juvenile zebrafish in the laboratory, giving them the opportunity to self-administer alcohol. For some zebrafish, at low concentrations, alcohol had a sedative effect, reducing anxiety-like behavior. But at higher doses, these fish began swimming uncoordinated. Within minutes, their initial attraction to alcohol gave way to aversion.

Things were different for fish with a mutation in their CHRNA3 gene: the sedative effects were attenuated even at higher doses. Instead, these fish seemed to behave in an increasingly gregarious manner and they continued to drink, seeking out alcohol at every opportunity.

The team of researchers published their results in the Journal of Neuroscienceand claim that their study provides experimental evidence of a link that had previously been reported in human genetic studies between the CHRNA3 genetic and alcoholic susceptibility. (CHRNA3 has also been associated with nicotine addiction in humans.)

“What we have learned over the past decade is that the heritability of addiction…has both general and substance-specific factors,” wrote study author Ajay Mathuru, a professor of physiology at the National University of Singapore, in an email to Nautilus. “This study provides direct functional evidence that CHRNA3 modulates alcohol sensitivity (here in zebrafish), thereby isolating the contribution of a gene to a defined phenotype. Humans suffering from alcohol addiction may each have a different set of genes that play a role in this behavior, he says, which will determine the type of intervention best suited.

Next, the team aims to analyze different variants of CHRNA3 in humans and see how they correlate with differences in sensitivity to alcohol. What they learn could help identify people with specific vulnerabilities when it comes to substance abuse and dependence, and head off problems before they walk through the door.

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Main image: N Universe / Shutterstock

• Kristen French

  Published on October 29, 2025

  Kristen French is an associate editor at Nautilus. She has worked in science journalism since 2013, reporting and writing articles and news for publications such as Wired, Backchannel, The Verge, And New York Review. She holds a master’s degree in science journalism from Columbia University.