The Wright-Fisher model is one of the simplest models of genetic drift in a population. It assumes that:

- the generations of a population do not overlap, so that we can view generation change as discrete time steps (e.g., annual plants);
- the population is diploid and has a finite constant size N that does not change between generations;
- if
$m$ alleles are present with proportion$p = \frac{m}{2N}$ in one generation, then each of the$2N$ chromosomes in the next generation selects the allele with probability$p$ .