A new study suggests people share more than just common interests with their friends -- they may also share genes.
Researchers at the University of California, San Diego surveyed nearly 2,000 people in a study and found best friends have the most genetic similarities.
"There's a lot of explanations on why we would tend to associate with other people who are similar," said Matthew Jackson, a professor of economics at Stanford University. "This sort of adds a whole other layer to it. A deeper layer than one we had anticipated."
Jackson also said one of the most interesting parts of the study is the claim friends have a similar sense of smell, which is something that can bring them together.
"So somehow evolutionary pressures must push us to sense these things and to be able to recognize them even though we don't necessarily consciously see that," Jackson said.