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Genetic drift: this simulation tracks allele frequencies in a population of diploid, asexual individuals characterized by two alleles (red and green) at one genetic locus.
In every generation, indivduals migrate and mate at random. Matings result in zero to three new individuals, but no genotype has any selective advantage. If the total population size exceeds the population size set on the popsize control, individuals are removed at random. Homozygotes are indicated by red or green dots. Heterozygotes are indicated by brown dots. The frequency of the red allele is indicated in a small window and is also plotted.
Set popsize and then set up. Click GO and watch how long it takes for the population to fix. That is, watch how long it takes for one or the other allele to completely disappear from the population. Do this several times for the same popsize.
Now try it with populations that are much smaller or larger. Reset popsize, set up, and GO. Do this several times, and note what kinds of times-to-fixation you see.
What are typical times-to-fixation for small populations? For large ones?
This simulation was created by Ted Wong in December 2003.