Your genes help you pick your friends

Researchers examined data from the National Longitudinal Study of Adolescent Health. They found that people who have the genetic marker DRD2, associated with alcoholism, tend to befriend each other, and those who do not have this marker tend to associate with others who lack it. On other other hand, they found a different relationship with a gene involved in the system that metabolizes foreign substances, such as nicotine. It seems that people with this particular marker befriend people who don't have it.