Group selection models in prebiotic evolution - art. no. 011911

The evolution of enzyme production is studied analytically using ideas of t he group selection theory for the evolution of altruistic behavior. In part icular, we argue that the mathematical formulation of Wilson's structured d eme model [The Evolution of Populations and Communities (Benjamin-Cumings, Menlo Park, 1980)] is a mean-held approach in which the actual environment that a particular individual experiences is replaced by an average environm ent. That formalism is further developed so as to avoid the mean-field appr oximation and then applied to the problem of enzyme production in the prebi otic context, where the enzyme producer molecules play the altruists role w hile the molecules that benefit from the catalyst without paying its produc tion cost play the nonaltruists role. The effects of synergism (i.e., divis ion of labor) as well as of mutations are also considered and the results o f the equilibrium analysis are summarized in phase diagrams showing the reg ions of the space of parameters where the altruistic, nonaltruistic, and th e coexistence regimes are stable. In general, those regions are delimitated by discontinuous transition lines which end at critical points.