http://www.mun.ca/biology/scarr/Drift_among_populations.gif
Genetic Drift over Time in smaller versus larger populations

From an initial q = 0.50 in each of 20 populations with either 2N = 18 or 100 starting individuals, q = f(A) diverges at random over time from the starting value, and the divergence in more rapid among smaller populations than larger. Where 2N = 18, several populations reached either loss (q = 0.0) (n = 5) or fixation (q = 1.0) (n = 7) of the allele in less than 20 generations, whereas in the right-hand graph, all populations maintain both alleles after the same time.


Text material © 2018 by Steven M. Carr