Genetic Similarity between Adolescent Best Friends

Guang Guo, University of North Carolina at Chapel Hill
Yilan Fu, University of North Carolina at Chapel Hill

Two sets of well-established findings suggest the hypothesis of a genetic similarity among close friends: (1) friends share certain attitudes, traits and behaviors; (2) many of these attitudes, traits, and behaviors have been shown to be partially genetic. These findings point to the possibility of a genetic similarity among best friends because they are similar in certain characteristics and because the source of the similarity is partially genetic. Evidence for our hypothesis will have implications for the debate of friends versus selection effects. If best friends are, to some extent, genetically similar, it would suggest a genetic role in friendship selection and formation. Our preliminary analysis based about 1,000 genetic variables (SNPs) in Add Health Wave III samples, best friends among adolescents do appear to share some genes although this sharing seems to be limited only to certain locations and the sharing also appears to be moderate in strength.