"There's a lot of focus these days on tailoring treatments for diseases to individuals based on their genes, but friends' genes might be just as relevant, scientists argue. It turns out that there are genetic correlations among people in the same social group. “It’s possible that part of the story is that our fitness as individuals depends not just on our own genes, but on the genes of other people," Fowler said. It's true that people who drink a lot might naturally gravitate toward each other anyway at a bar, for example. But the result that opposites attract for the other marker may reveal a deeper connection: You also choose friends who would not necessarily find themselves in the same venues that you would, indicating that there could be something going on at the genetic level, too, Fowler said. (What Friends' Genes Say About You)"
If this article would not have talked about exact genes, I would not have believed that we are attracted to our friends on a genetic level. I would have thought it to be something dealing more with something psychological such as we pick friends who like things that we like because they are like ourselves or we like friends who are opposite us because from an evolutionary stand-point we want to cover our "weaknesses" by finding friends who have our "weaknesses" as "strengths" so we can fill what we don't have. But I guess our genes decide our "weaknesses and strengths" so they would have a part in that aspect of friend choosing. However, even though this article is listing specific genes I still am not sure if I believe this or not, maybe if I had a better understanding of the topic I could better put together in my mind what they are trying to say. But with my understanding of the topic, I still think this is more of a psychological matter than genetic.