What is genetic drift?

Genetic drift refers to random fluctuations in allele frequencies within a population, particularly noticeable in small populations. This randomness can significantly affect the genetic makeup over time. When a population is small, chance events can lead to alleles being lost or becoming fixed, which means that they reach a frequency of 100% in that population. As a result, certain traits can rapidly become more or less common regardless of their advantage or disadvantage in terms of survival or reproduction.

This concept is crucial in understanding evolutionary processes because it highlights how random events, rather than selective pressures, can lead to changes in population genetics. For instance, if a few individuals with a certain allele happen to reproduce more than others just by chance, that allele can increase in frequency and alter the population’s genetic landscape over generations. In larger populations, the effects of genetic drift are often minimized because the larger number of individuals tends to buffer against random changes.