Game Theory and Population Dynamics in Complex Genetical Systems: The Role of Sex in Short Term and in Long Term Evolution

The article maintains three major points: (1) In sexual populations with recombination, there is a qualitative difference between one process of natural selection which manifests itself in terms of changes of frequencies of genotypes already present in the population (say, short term selection) and another process which manifests itself in terms of selective gene substitutions (say, long term selection). (2) It is only the process of long term selection (due to gene substitutions) and not the process of short term selection (due to changes in genotype frequencies) that, quite generally, leads to the individual optimization of certain evolutionarily relevant payment functions and thus guarantees the stabilization of ESS population strategies. (3) These findings, based on theoretical analysis of the well studied genetic structure of sexual reproduction, fit into the main bulk of current theories about the evolution of the sexual system of reproduction in a changing environment. They can, in turn, throw some new light on the role of sex in preventing fast adaptation to short—term, notersisting environmental changes and, at the same time, allow (and, as I claim, even facilitate)) slow adaptation to long—term, persisting environmental changes.