A study from the University of California, San Diego (United States) suggests thatwe tend to forge friendships with people with whom we share certain genetic traits. To reach this conclusion, James Fowler and his colleagues analyzed genetic markers in six genes and compared their similarity in people who were friends and those who were not related, using information from two independent American health studies.
Analyzing specific genetic markers within the social network of each individual, they discovered that the individuals who carried themarker DRD2, which encodes a receptor for the neurotransmitter dopamine and is associated with habits such as smoking or consuming alcohol, tended to be friends with others with the same genetic trait, while those who lacked the gene were associated with other individuals negative for this marker. On the other hand, the people who carrieda certain gene that has been associated with an overt personality (CYP2A6)they tended to choose their friends from those who lacked him.
As the authors conclude in the journalProceedings of the National Academy of Sciences, the results would explain why some people instinctively feel mutual attraction or rejection as soon as they meet. Nicholas Christakis, a researcher at Harvard University and co-author of the work, also assures thatin evolutionary terms it may be beneficial to have friends with a similar genetic pattern. For example, if several friends are less susceptible to bacterial infections, the group’s health will increase. Genetic clustering on social media could play an important role in human history, they suggest.
