The change in frequency of alleles at a locus that occurs by chance is known as:

Explanation

Genetic drift is a mechanism of evolution that refers to random changes in allele frequencies within a population, especially in small populations. Unlike natural selection, which involves traits being favored due to survival or reproductive advantages, genetic drift occurs by chance. Over time, it can lead to the loss of genetic variation, fixation of certain alleles, or even the divergence of populations. Events like the bottleneck effect (drastic population size reduction) or the founder effect (a new population started by a small group) are examples where genetic drift can have a strong impact.