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‘Six Degrees of Kevin Bacon’ was a popular game in the eighties and nineties, requiring players to link celebrities to the actor in as few steps as possible via the movies they have in common.

The theory was that nobody is more than six relationships away from any other person in the world, and the game became a viral phenomenon.

But now, scientists believe there is evidence of this concept, which they call “high betweenness centrality”, and they have now named the identified gene responsible for this the ‘Degrees of Kevin Bacon Gene’, or dokb.

Senior author Joel Levine, a professor of biology at the University of Toronto who went to high school with Bacon in Philadelphia, said the actor was a good human example of “high betweenness centrality.”

Aware of Levine’s link with Bacon, study lead author Rebecca Rooke, a biology postdoctoral fellow at the University of Toronto Mississauga, suggested the gene’s name.

“The degrees of separation is a real-world thing.”

Many species of animals form social groups and behave collectively: An elephant herd follows its matriarch, flocking birds fly in unison, and humans gather at concert events. Researchers have found that even humble fruit flies organise themselves into regularly spaced clusters.

Within those social networks, certain individuals will often stand out as “gatekeepers,” playing an important role in cohesion and communication within that group.

Having high measures of centrality in a group network can be positive or negative, Levine explained.

“Patterns of sharing and communication can be absolutely wonderful,” he said. “You also have patterns that contribute to the spread of lethal diseases and infectious diseases, but the structure of the group is the same structure. It’s not a good or a bad or a positive or a negative.”

Fruit flies, or Drosophila melanogaster, are best known for hovering around fruit bowls and have been a model organism to explore genetics for more than 100 years. The insects breed quickly and are easy to keep.

While flies are very different from humans, the creatures have long been central to biological and genetic discovery.

“Fruit flies are useful because of the power of manipulation. We can investigate things experimentally in Drosophila that we can only examine indirectly in most organisms,” Moore said.

The tiny creatures share nearly 60% of our genes, including those responsible for Alzheimer’s, Parkinson’s, cancer and heart disease. Research involving fruit flies has previously shed light on the mechanisms of inheritance, circadian rhythms and mutation-causing X-rays.

Levine said that the “degrees of Kevin Bacon” gene was specific to fruit flies’ central nervous systems, but he thought similar genetic pathways would exist in other animals, including humans. The study opened up new opportunities for exploring the molecular evolution of social networks and collective behaviour in other animals.

The researchers investigated a number of gene candidates in fruit flies, a common lab organism used in the study of genetics. “We found two versions of the dokb gene and one version produces networks with high betweenness centrality and the other version produces networks with low betweenness centrality,” Levine said.

“A network with a high average betweenness centrality indicates there are individuals in the network important for the flow of information from one part of the network to other parts.”

Allen J. Moore, a distinguished research professor at the University of Georgia’s Department of Entomology, said in an email that the research was “careful work” and he agreed with the findings.

“Although a first step — and we (and they) don’t know exactly how it works — it is fascinating to find a single gene that influences social cohesion.”

From Footloose to fruit flies, Kevin Bacon is the gift that keeps on giving.

[source:cnn]