Thermodynamical Interpretation of Evolutionary Dynamics on a Fitness Landscape in an Evolution Reactor, I

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A theory for describing evolution as adaptive walks by a finite population with M walkers (M greater than or equal to 1) on an anisotropic Mt. Fuji-type fitness landscape is presented, from a thermodynamical point of view. Introducing the 'free fitness' as the sum of a fitness term and an entropy term and 'evolutionary force' as the gradient of free fitness on a fitness coordinate, we demonstrate that the behavior of these theoretical walkers is almost consistent with the thermodynamical schemes. The major conclusions are as follows: (1) an adaptive walk (=evolution) is driven by an evolutionary force in the direction in which free fitness increases; (2) the expectation of the climbing, rate obeys an equation analogous to the Einstein relation in Brownian motion; (3) the standard deviation of the climbing rate is a quantity analogous to the mean thermal energy of a particle, kT (x constant). In addition, on the interpretation that the walkers climb the landscape by absorbing 'fitness information' from the surroundings, we succeeded in quantifying the fitness information and formulating a macroscopic scheme from an informational point of view. (C) 2003 Society for Mathematical Biology Published by Elsevier Ltd. All rights reserved.


  • Bulletin of mathematical biology

    Bulletin of mathematical biology 66(5), 1371-1403, 2004

    Springer New York


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