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          Game theory is a concept that applies to not only humans but also to any biological population in the world. It has been used since the beginning of time, starting with the first species to inhabit the earth: viruses. In this article, two scientists undergo experiments to test their predictions that viruses have a dominant strategy of “cheating” or taking advantage of other species to undergo selfish profits. This claim is very similar to the prisoner’s dilemma game, in which the equilibrium strategy for both players is to confess, or cheat the other person so as to gain freedom or the highest payoff.

         Their experiments involved a population of RNA viruses called phi-6, and a bacterial colony called P. Phaseolicola. They created six separate samples; three of them contain both the RNA viruses and the bacteria colonies which are allowed to co-infect each other, while the other three consist of both the virus and the bacteria such that a virus can only infect a single bacteria cell. After, 50 days, or 250 generations of bacterial growth, the six samples were taken for observation. The scientists found that the viruses that were allowed to co-infect had greater viral fitness than the ones that were only allowed to infect a single cell. Furthermore, the viruses that were able to co-infect evolved their genotypes so that they could efficiently use the resources of other viruses while keeping its original key genes. These were called the “cheaters.” It was also found that there were viruses in the co-infecting environment that did not evolve, which were named the “cooperators.”

           To further test their claim, they performed tests that consist of varying amounts of evolved viruses and ancestral, or unchanged, viruses. Eventually, they found that as the population of evolved viruses decreased in size, they tend to take advantage of the cooperators and infect them. On the other hand, if the population of “cheaters” increases, they had to infect each other. This shows that the fitness of the evolved viruses depends on the frequency, or the amount of competition that occurs within a community. It also shows that through time, the evolved viruses will emerge dominant over the ancestral viruses. In conclusion, the equilibrium strategy for viruses is to cheat.

This matrix sums up the kind of game that viruses play with each other and with othe species. What is interesting to see is how the behavior of viruses can be related to the behavior of other organisms, or even people. In the end, will the defying dictators of the world succeed, while the cooperators weaken? Will the selfish people be destined to become better off than the caring, cooperative people? Also, how can this game be changed so that the social welfare of both players increases?