What does genetic drift refer to?

Genetic drift refers to a random change in the genetic composition of a population, particularly in small populations. This phenomenon occurs due to chance events that can lead to changes in allele frequencies from one generation to the next, independent of any selective pressures.

For example, if a few individuals carry a certain allele and they happen to reproduce more successfully simply by chance, the allele frequency may increase in subsequent generations. Conversely, if a random event leads to the death of individuals with certain alleles, those alleles might diminish or disappear altogether. Over time, genetic drift can result in significant changes to a population’s genetic makeup, contributing to the divergence between populations and potentially leading to speciation.

This concept is distinct from the effects of natural selection, which involves non-random processes where certain traits confer advantages that enhance survival and reproduction. While both genetic drift and natural selection play roles in evolution, genetic drift does so through random events, making it particularly influential in smaller populations where the effects of chance can be magnified.