What is genetic drift?

Genetic drift refers specifically to the random changes in allele frequencies within a population that occur due to chance events. This phenomenon is particularly significant in small populations, where random events can lead to large fluctuations in genetic makeup from one generation to the next. As certain alleles may be passed on by chance, others might be lost, leading to a shift in the genetic composition of the population over time.

Understanding genetic drift is essential for explaining how evolutionary changes can occur independently of natural selection. Unlike the process of intentional selection seen in breeding programs or adaptive evolution driven by environmental pressures, genetic drift operates purely by random chance. It can result in the fixation or loss of alleles, which may not necessarily confer any advantage or disadvantage regarding survival or reproduction. This random process highlights the role of chance in evolution and how it can shape the genetic diversity of a population over generations, sometimes leading to reduced genetic variation.