The binomial sampling equation with equal fitnesses produces a normal, bell-shaped distribution of next-generation frequencies whose mean equals the initial frequency

The dynamics of the warm/cold system cannot be inferred from a type recursion in which fitness coefficients are set equal and next-generation frequencies are determined entirely by the “drift” term, effective population size in the binomial sampling equation. When fitnesses are equal, the frequency of each type is determined solely by the binomial sampling equation above (since post-selection frequency, the input to the sampling equation, is just pre-selection frequency). Such a determination ma