Social butterfly: Behind the “Kevin Bacon” gene that could determines how popular a bug is

Science has a term for how popular you are among your network of friends and family. That is, how much you set the tone for their behavior and communication, how important you are to your group's cohesion, and how close you are to the center of your social network. It's called "betweeness centrality."

Animals have this in their networks too. As it turns out, being the trendsetting popular kid could actually be genetic. And, according to a recent study of fruit flies in Nature Communications, it could be controlled by gene number CG14109 — a.k.a. the "degrees of Kevin Bacon" gene (DOKB). It is, of course, in reference to the parlor game "six degrees of Kevin Bacon," in which the goal is to connect a random actor with the Mr. Bacon, the prolific actor who starred in "Tremors" and "Footloose," among other films.

So what does any of that have to do with genetics? It's simply a metaphor that helps us understand the role genes play in building social networks (the literal kind, not to be confused with websites like Instagram.)

"Social networks are a mathematical representation of interactions among individuals which are prevalent across various animal species. Studies of human populations have shown the breadth of what can spread throughout a social network: obesity, smoking cessation, happiness, drug use and divorce," researchers from the University of Toronto wrote in their paper. 

While past results have been unable to pinpoint the likely source of the influential "it" factor, researchers said prior studies across several species suggested it could be inherited. Taking to the lab, the research team dug down into the DOKB gene to identify strain-specific alleles within the gene which had distinct amino acid patterns. Then they took the strain-specific DOKB allele and plugged into other strains in a fruit fly. And just like that — the fruit fly who got the Kevin Bacon gene-implant was suddenly six degrees more popular among all its fly friends. 

"These findings define a novel genetic entry point to study social network structure and thereby establish gene-to-social structure relationships," the team said. "While DOKB sequence homology is exclusive to (fruit flies), we anticipate that DOKB-associated molecular pathways could unveil convergent neural mechanisms of social behavior that apply in diverse animal species."