Genetic Drift among Populations over Time
The Wright-Fisher model
for 10 populations, each with N = 100 and
initial q = f(a) = 0.5, over
150 generations. In any single population in any single
generation, f(a) is equally likely to fluctuate "up"
or "down." By generation 150, two populations have
"lost" allele a (q = 0),
four have "fixed" it (q = 1), and of the
remaining polymorphic populations, two have q
> 0.5 and two have q < 0.5. The global mean
f(a) over all populations remains
constant at ~0.5, while variance increases over time.
Figure & Text material © 2021 by Steven M. Carr