In both scenarios, at each time step, the dominant (most frequent) genotype is determined and its entropy calculated from equation S4.The value of this entropy is recorded for the duration of the simulation. It should be noted that these simulations are not based on an elaboration of S-I-R models of the usual type where susceptibles and infectives interact via conventional mass-action terms. Here, the population of infectives is directly manipulated to reflect the kind of epidemiological dynamics that are typically seen in the emergent and equilibrium phases [42] .