The Wright-Fisher model for 10 simulated
population, each with **2N = 100** and initial f(**A**)
= f(**a**) = 0.5, over 100 generations. In any single
population in any single generation, **f(A)** is
equally likely to fluctuate "*up*" or "*down*."
Note that one population has become "*fixe**d*"
for allele **A** in Generation 83 [top line], and one
is fixed for the alternative allele** a** (it has "*lost*"
allele **A**) in Generation 100 [bottom line]. After
100 generations, four of the populations have f(**A**)
> 0.5, and six have f(**A**) < 0.5: the mean f(**A**)
remains constant at 0.5.

Figure ©2013 by Sinauer; Text material © 2018 by Steven M. Carr