DNA: Are our friends actually family?

Many of us are lucky to have close friends, who feel like family, in our lives. In recent years, genetic research has supported the theory that friends are more likely to share certain similarities in their genetic makeup.

When I was growing up, Uncle Max was always hanging around our house, chatting with my parents. He helped steer my father right with his do-it-yourself home projects, he told jokes at the dinner table, and he always came bearing little treats for my siblings and me. He visited so often that he was considered a member of the family.

I had always assumed that he was a second cousin or somehow distantly related to us. It was only when I was a teenager that I discovered that “Uncle” Max was not my uncle, but a very close friend of my parents. He had shared several stages of life with them and had essentially become family. Growing up, we were closer with Max than we were to many of our other aunts and uncles.

Even today, Max’s family and ours share a strong connection. We continue to have holiday meals together, and my children play with Max’s grandchildren. It is a friendship full of shared experiences and happy memories that will endure for generations to come.

When the bond of friendship is so strong, it’s easy to wonder if there is more than just common interests and “chemistry” that draws close friends together.

According to a study published a few years ago in PNAS, the Journal of the U.S. National Academy of Sciences, good friends – who are particularly close and feel like family – often share genes. According to James Fowler, professor of medical genetics and political science at UC San Diego, we may have more genetically in common with our good friends than with others:

Looking across the whole genome, we find that, on average, we are genetically similar to our friends. We have more DNA in common with the people we pick as friends than we do with strangers in the same population

Yale and University of California researchers examined 1.5 million genetic markers of 1,932 people, using data from earlier studies that had collected both genetic information and data on friendships. Investigators compared the genetic codes of friends with those of strangers. Results revealed that individuals who carry a particular genetic marker for a gene called DRD2, a dopamine receptor associated with alcoholism (among other traits), tend to make friends with other DRD2-positive people. Conversely, those who lacked the gene tended to form friendships with people who were also DRD2-negative.

We have long known that our genes determine much of our physical makeup and many other characteristics. Ever since DNA was first identified in the late 1860s, the conclusion has been that traits are inherited from generation to generation. It is now a popular belief that more than 50% of our traits are inherited, including obedience to authority, vulnerability to stress and risk-seeking.

Researchers suggest that many of our choices about life issues, such as politics and religion, are more determined by our genes than we would think. The idea that the people we spend time with – and the choice of our social environment – can actually be linked to specific genes is revolutionary. It helps explain why we enjoy spending time in the company of specific people whom we choose as friends.

So, the next time a dear friend comes to visit, remember  that you may be more than just good friends who share interests — you may actually share common genes!

Does your family have close friends who have become like members of the family? Let us know below!