Friends have more DNA in common than strangers

By Casey Frye, CCNN Writer

friends and genes
Our friends really are like family!

Your friends are basically like an extension of your family. You like to do the same things together, laugh at the same jokes, listen to the same music, and engage in the same hobbies. Anyone who knows you and your BFF would swear you’re like siblings! Unlike family, though, friends don’t share the same genes – the body’s blueprints that tell it how to grow. Or do they? According to new evidence, we have more genes in common with friends than random strangers!

Researchers analyzed data from about 1,932 subjects, who were divided into two groups. The first group of participants was made up of pairs of best friends who were not related, and the second group consisted of strangers who also had no family connections. After comparing everyone’s genes, the researchers found an interesting trend: friends share about 1% of the same genetic material, which is the same as fourth cousins – people who share a common great-great-great grandparent! What possible reasoning could there be to explain this?

Well, for one, friends tend to share the same genes related to our sense of smell. This may not mean much for today’s modern world, but back when humans lived in prehistoric societies and needed to hunt for food, researchers predict that people who liked the smell of blood would hunt together while those who liked flowers would gather herbs together.

On the other hand, researchers found that friends’ immune systems (the body’s defenses against disease) tend to balance each other, meaning that if one friend is better at fighting certain diseases, their friends will be better off at fighting different diseases. The idea is that together, they can resist more illnesses overall, and reduce the risk of passing on viruses to one another.

“Human beings are one of the few species who form long-term [friendships] with other members of our species,” said James Fowler, one of the experimenters who worked on the study. “This role… is important. It ties into the success of our species.”

Image of three girls courtesy of Ahsan Saeed on Flickr.