What is genetic drift?

Genetic drift refers specifically to the random fluctuations in allele frequencies within a population from one generation to the next. This phenomenon occurs due to chance events rather than as a result of natural selection, which is a systematic process favoring certain traits. Genetic drift can have significant effects, especially in small populations, where random events can lead to large changes in allele frequencies.

For instance, if a random event reduces the population size—such as a natural disaster—the alleles of the surviving individuals may not be representative of the original population. This can lead to a loss of genetic variation or even the fixation of certain alleles purely by chance, regardless of whether they confer any advantage for survival. This is why understanding genetic drift is crucial when studying population genetics and evolution, as it highlights the role of random processes in shaping genetic diversity.