Question

One of the following is also the Sewall Wright effect
(A) Isolation
(B) Gene pool
(C) Genetic drift
(D) Gene flow

Answer 1

Hint: One of the above which is also the Sewall Wright effect is defined as the change in the frequency of an existing gene variant (allele) in a population due to some random sampling of organisms.

Complete answer:
Genetic drift is also known as the Sewall Wright effect. It has been observed that genetic drift sometimes may lead to gene variants to disappear completely and thus results in the reduction of genetic variation. It may even lead to an increase in the frequency of the initially rare alleles and to become far more fixed.

Additional Information: 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. In the middle of the ${ 20 }^{ th }$ century, including genetic drift vigorous debates occurred over the relative importance of survival versus neutral processes.

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 is the one who explained survival using Mendelian genetics, also held the view on the genetic drift that genetic drift plays at the foremost a bit part in evolution, and this remained the dominant view for several decades. In the year 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.
So, the correct answer is ‘Genetic drift’.

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.