Genetic Drift among Populations over Time
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 "fixed"
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