If you consider your friends to be like family, you may be onto something. Researchers at the University of California, San Diego, and Yale University have found that friends have more DNA in common with one another than they do with strangers. In fact, the similarities in gene signatures equate to 1 percent of a person’s total genetic makeup, which means friends are roughly as “related” as fourth cousins, relatives who share great-great-great grandparents. “The striking thing here is that friends are actually significantly more similar to one another than we were expecting,” UC San Diego geneticist James Fowler tells NPR.org. The study drew on data from more than 1,900 people and found that friends were most genetically similar in areas affecting the sense of smell, which researchers say may serve to draw people with similar tastes to congregate in the same place. Friends do, however, tend to have different kinds of immune systems. But such divergences may have evolutionary advantages, since a person who is susceptible to a certain type of disease would lower his or her risk of catching it by associating with others who are fortified against it. “The biggest implication is that evolution can’t be studied as a Robinson Crusoe phenomenon,” Fowler says. “We didn’t evolve isolated. We evolved with our friends.”
I honestly don't know what to make of it.
I do know that one of the things I have been interested in as I do my family tree is who is it that I am friends with who is also my cousin, no matter how distant. I was talking with the wife of my mother's second cousin and she was telling me tales of a great grandparent of hers - who, after she left, I learned was also a great grandparent of mine. I think she and her husband are sixth cousins or something, so that may make she and I 6th cousins once removed....
In any event, that has nothing to do with the article above, just interesting to know that the people I love are actually genetically similar to me. How cool