Chinese morra helps us understand biodiversity

If the engine of evolution is competition between species, why do we have an extraordinary biodiversity on the planet?

Since we were children we ask ourselves questions that are not always easily answered.

Why is the sky blue? Why does the horizon always move, where does it end? And so on. An article in "Science" begins one of those questions, but perhaps more an adult questoin: "If the engine of evolution were a simple competition between species, in the end only a handful of" supercompetitive "species would survive. So how do you explain the extraordinary biodiversity of the planet?"

Perhaps with a mechanism that regulates coexistence between species in a similar way to the game of Chinese morra: the more players we have, the more stable and rich the system.

Jeff Hasty, a researcher at the University of California in San Diego, has spent his twenty-year career designing strategies to make the genetic circuits of engineered bacteria work together. These are bacteria that are studied and used mainly in immunotherapy. They are bacteria that do not make you sick, because they are rendered harmless, but at the same time they help the immune response. So they are very useful for us.

For Hasty the results have not always been encouraging, especially with a specific bacterium Escherichia coli, apparently very humble among the various bacteria. While managing to make it useful, engineered, the new features soon faded. This until the new collaboration with his PhD student Michael Liao and the work with other researchers. Together they developed a different approach. They have concluded that it is not always necessary to change the characteristics of the bacterium directly, but instead to use a sort of "social pressure" by comparing different strains.

... "The team used three engineered E. colic strains working in tandem. Each of the strains produces a toxin, the corresponding antitoxin to protect against and another antitoxin with which it defends itself from one of the other strains. The first strain is able to kill the second but not the third; the second can kill the third but not the first; and the third can kill the first but not the second "...

And when they learned that other researchers in the field of ecology had addressed the same issue, the team recognized the rules of the Chinese morra game in the new and more effective method. The stone beats the scissors, the scissors beat the paper and the paper beats the stone. None of the players take the lead and the odds of winning are always the same, whatever the choice. When playing with two, it is always clear who the winner is.

If you add other players, however, the game becomes more complex, and the success of the various strategies often rises and falls cyclically.

... "The biologists who studied this game have built models of its performance when many tens or even hundreds of species participate in it. They also studied how things change when the landscapes in which the species interact are different, and when the species they differ in mobility and competitiveness. "...

An ancient children's game helps us to understand the dynamics of evolution, and why we have such biodiversity. And maybe who knows, the idea of ​​this game was born from our innate connection with the cycles of nature. Sometimes the answers are already with us.

Articolo completo di Carrie Arnold su "Le Scienze" aprile 2020

We wonder if there are other social dynamics in which we recognize the rules of the Chinese morra game. Some idea?

Jeff Hasty Molecular Biology - University of California- San Diego. His research focuses on the construction and utilization of synthetic gene circuits for dissecting, analyzing, and controlling the dynamical interactions involved in gene regulation.

#science #biology #Research #jeffhasty