Genes Can Determine How You Choose Your Friends

Jasmin Wu/UCSD Guardian

According to new research, your genes may play a determining factor in what clique you belong to. A recent study conducted by School of Medicine professor James Fowler, Ph.D. student Jaime Settle and Harvard University professor Nicholas Christakis considered which variations of genes are exhibited in groups of friends.

“The purpose [of this study] is to answer the fundamental question of whether or not people who are not related to one another, but were friends share the same genes,” Fowler said.

The scientists studied six genes, two of which — the DRD2 and the CYP2A6 — turned out to be correlated with friendship. The study showed that friends usually shared the same version of the DRD2 gene. But they also exhibited a negative correlation with the CYP2A6 gene, with friends having opposing versions of the gene.

“Part of this investigation is trying to figure out if there’s evolutionary basis for social networks,” Fowler said.

Fowler’s team found evidence that genes influence how central we are to a social network and how many people name us as friends. Transitivity, a property influenced by the genes, is the probability that two of your friends are friends with each other. According to Fowler, this means that our genes influence whether two other people are friends.

“We got into this because we wanted to explain this ‘birds of a feather flock together’ phenomenon,” Fowler said.

Genes are already known to influence certain behavior, the choices we make and our susceptibility to peer pressure. These behaviors spread easily through our networks, because the people within them are also susceptible and connected to one another.

He also said that the principle underlying the property being studied questioned the metagenomic status of humans — whether we’re only influenced by our genes or by the genes of the people who surround us.

“The fundamental question that comes out of that bigger question is well, if that’s true, then what we would expect is that people who we choose to associate with — our friends — ought to have similar genes to us,” Fowler said. “We already know they have similar traits; we tend to hang out with people the same level of education, we tend to hang out with people who have the same political ideals.”

The study suggests that the social environment, which is a product formed by an individiual’s genes and the genes of those surrounding them yourselves with, affect people’s outlines.

There are about 25,000 genes with which Fowler and his team want to do a full genome study to understand the consequences of shared genes. The future studies will test to see if there is evidence that human beings as a species have co-evolved with their social networks.

“Social networks are in our nature, they’re part of what makes us unique as human species,” Fowler said.