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Why People Vote: Is it in the Genes?

Candidates trying to drive up their poll numbers this election year might want to target more than voters' politics. They may also want to consider their genes.

That's what a pair of studies suggest by claiming the first-ever link between voting behavior and genetic factors.

The studies -- based in part on the voting records of identical twins -- suggest that DNA may explain half or more of differences in peoples' participation in politics. Researchers even singled out a pair of genes that could play an especially large roll in voting.

The genes have nothing to do with voters' choices at the polling place, says James Fowler, a professor of political science at the University of California at San Diego, who led the studies. Instead, they may play a role on people's desire to participate in social behavior like collective decision-making and distribution of resources.

"We did not want people to come away from this thinking that we had found a voter gene. There's no such thing," Fowler tells WebMD. "There are going to be hundreds of genes and hundreds of environmental factors that are all going to be interacting in very complicated ways in order to produce this behavior."

In one study, Fowler and his team checked the voting records of 168 identical twin pairs and 102 fraternal twin pairs in Southern California. Using twins is a common approach in genetic studies since identical twins share the exact same DNA, while fraternal twins do not. At the same time, both kinds of twins are usually raised in similar family and social circumstances, giving researchers a way to tease out how much of a particular behavior might be genetically driven.

The researchers found that genetic factors explained 53% of the variation in whether subjects voted or not. When they applied their model to a national database, the link jumped to 72%.

In a second study, researchers singled out a pair of genes known as MAOA and 5HTT. Both genes help control how the brain processes the neurotransmitter serotonin. Again, they found a solid link between activity of the two genes and people's decision to vote or stay home.

The genes probably don't explain voting directly. Instead, they likely play a role in emotions, intelligence, and even personality that in turn influence political participation, says Nancy Segal, PhD, a psychologist who studies twins and their behavior at California State University in Fullerton.

"The fact we find a genetic influence on voting behavior doesn't surprise me in the slightest. Now the question becomes, what are the mechanisms?" Segal tells WebMD.

Fowler says his team's next step is to match voter records with clinical trials of depression drugs. Many of those drugs act directly on the brain's serotonin pathways, and the researchers want to see if people are more likely to vote after those pathways have been "switched on" by medications.

By Todd Zwillich
Reviewed by Louise Chang
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