Define genetic drift.

Hint: Genetic drift is defined as the change in the frequency of an existing gene variant (allele) in a population due to some random sampling of organisms. It is also known as allelic drift or the Sewall Wright effect.

Complete answer:
It is seen that genetic drift sometimes can cause gene variants to disappear completely and thereby reduce genetic variation. It can also cause initially rare alleles to become far more frequent and even fixed. It is seen that when there are only a few copies of an allele, the effect of genetic drift has a larger impact in nature, and when there are many copies the effect is smaller. Within the middle of the ${ 20 }^{ th }$ century, vigorous debates occurred over the relative importance of survival versus neutral processes, including genetic drift. A random statistical effect, genetic drift can occur only in small, isolated populations during which the gene pool is little enough that chance events can change its makeup substantially. Ronald Fisher, who explained survival using Mendelian genetics, held the view that genetic drift plays at the foremost a bit part in evolution, and this remained the dominant view for several decades. In 1968, population geneticist Motoo Kimura rekindled the talk together with his neutral theory of molecular evolution, which claims that the majority of instances where a genetic change spreads across a population) are caused by genetic drift working on neutral mutations.

Note: Like the process, natural selection depends on the allele's beneficial or harmful effects, the genetic drift is not depending on an allele’s beneficial or harmful effects. In Fact, in genetic drift, the allele frequencies occur purely by chance randomly with the subsets of individuals. These individuals will provide the next generation.