Genetic Drift Simulator

Run

Seed

The same seed gives the same paths every time.

Replicate paths

More paths show how much drift varies between identical starts.

Max generations

Playback stops earlier once all paths are fixed or lost.

Speed

Generations per second during playback.

Population

Population size N

Diploid individuals; each generation samples 2N allele copies.

Initial frequency

Rounded to the nearest whole allele copy at reset.

Selection

Add selection pressure

Selection coefficient s

Fitness effect of allele A in AA homozygotes.

Dominance h

Share of s that Aa heterozygotes receive.

Selection model: genotype fitness is AA = 1 + s, Aa = 1 + hs, and aa = 1.

Positive s favors allele A; negative s selects against it. h = 0 makes the A effect recessive, h = 0.5 makes it additive, and h = 1 makes it dominant.

Allele frequency through time

first path replicates fixed A lost A

Generation 0

Mean frequency 0.500

Fixed A 0 / 10

Lost A 0 / 10

Mean stop time -

Model: neutral Wright-Fisher drift, starting at p = 0.500 in N = 100 diploid individuals.