5.2 The Wright-Fisher model
The Wright-Fisher model is one of the most commonly used models of genetic drift.
In this model, we assume that a population:
- Mates randomly
- Number of individuals remains constant between generations
- Today, we’ll also assume that the population is haploid
Populations in the real world don’t behave like an ideal Wright-Fisher population, so their effective population size Ne is usually much smaller than their actual population size. The effective population size of the human population is only 12,800–14,400 individuals, even though its actual size is around 8 billion.