Simulation of Genetic Drift in
finite populations
(N = 100 & N = 1,000)
Beginning at t = 0 with f(A1)
= p = 0.5, five replicate simulations with starting
size N = 100
or N =
1,000 are allowed to
drift randomly until loss or fixation of A1
[f(A1) = 0.0 or 1.0,
respectively]. In these simulations, note that A1
goes to fixation in all five N = 100 replicates, the
first before t < 100 and the last before t
< 350. [Ignore uniform fixation: 2 or 3
populations would be expected to go one way or the other].
In the N = 1,000 simulations, four of five
simulations remains in the range 0.0 < p < 1.0,
with the fifth population having gone to loss > t =
800. Note that one sample has drifted as high as
p = 0.90, and as low as p = 0.25., and at t
= 1000 remains near p = 0.50.