This is rather like a dart game where the target for each throw is not the bull's-eye but the site of the previous dart. This process repeats at each generation, with a small, random change in gene frequency each time. The behavior of random walks can also appear paradoxical. There is no expectation for movement in one particular direction to be preferred over another. This applies not only at the beginning but indefinitely, so that from any point away from the starting position, there is no preference for moving back toward the start nor further away from the start.
Genetic drift is a random walk.
The most likely expectation, or the expected average over many trials, is given accurately by the Hardy-Weinberg theorem. However, in any particular case, the more generations that pass, the farther are gene frequencies likely to be from the initial expectation. In finite populations, one allele will be lost when its frequency drifts too close to zero. 510 index page Overview. Context for this chapter.