Genetic Drift of neutral alleles
(f(B)(0) = 0.5, N = 50, W0 = W1 = W2)
In the absence of natural
selection, the frequency f(B) of an allele is subject only
to random genetic drift. Replicate populations with N
= 50 drift from an identical initial f(B) = 0.5
to fixation and loss, respectively, in 100 ~ 200
generations. Note that in one population f(B) drifts
to q < 0.1 before drifting to fixation, while the
other drifts twice to q > 0.5 prior to loss. The
trajectories are random: careful inspection would show that
the count of positive and negative changes of f(B)
over time are about equal, whereas the magnitude of
dq in either is normally distributed.
Text material © 2021 by Steven M. Carr