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