Empirical evidence of resource dependent evolution of payoff matrices in Saccharomyces cerevisiae populations.

Abstract

In evolutionary game theory, a relative comparison of the cost and benefit associated with obtaining a resource, called payoff, is used as an indicator of fitness of an organism. Such payoff matrices are used to understand complex inter-species and intra-species interactions like cooperation, mutualism, and altruism. In the absence of any empirical data, the evolution of these payoff matrices has been investigated theoretically by tweaking well-established game theory models. In this paper, we present empirical evidence of three types of resource-dependent changes in the payoff matrices of evolving Saccharomyces cerevisiae populations. We show that depending on the carbon source and participating genotypes, the payoff matrix could either (a) evolve quantitatively yet maintain a cheater-cooperator game, (b) change qualitatively such that the cheater-cooperator game collapses, or (c) change qualitatively to result in the birth of a cheater-cooperator game. Our results highlight the need to consider the dynamic nature of payoff matrices while making even short-term predictions about population interactions and dynamics.