Drunk Rats Point to Alcoholism's Roots

On a genetic level, booze-loving rodents are quite different from their sober counterparts.

Is alcoholism written in our genes? It hasn’t been easy for scientists to figure out whether some humans are born boozers because so much of our drinking behavior is shaped by our environment, confounding any habits that might actually be due to our genes.

But hard-drinking rats may have just revealed the answer: In a study published Thursday in the journal PLOS Genetics, hundreds of genes associated with alcoholism in rats have just been identified.

To carry out their study, the Indiana University and Purdue University researchers created a population of hard-drinking rats by coaxing booze-preferring individuals to mate. After several generations, the initial population had split into two groups — alcoholic rats and their normal counterparts. Comparing the sequenced genomes of these rats, the scientists were able to pinpoint 930 genetic differences associated with alcoholism.

Some of the genes found only in the alcoholic rats were related to crucial brain functions, including the formation of memories and the activity of the reward system.

“This research highlights that alcoholism (alcohol use disorder, or AUD) in rats has a strong genetic component and is influenced by many hundreds of genes, each with small effects,” said study co-author William Muir, Ph.D., in a release. It’s important to note, he pointed out, “that there is no single gene responsible for AUD.”

It’s too early to say whether the genes they found in alcoholic rats have human counterparts. Still, the research is an important first step in developing treatments for alcohol use disorder, which affects some 16.3 million American adults each year and killed nearly 88,000 people in 2014.

If future research does succeed in tracing human alcohol abuse down to a handful of genes, it could drastically change the way we deal with alcoholism: With a checklist of genes to look out for, it’ll be possible to identify people who are genetically at risk for the disorder. Furthermore, figuring out what those genes actually do will make it a lot easier for drug researchers to develop medications to thwart their activity.