Question

Which of the following is called Sewall Wright effect?
A. Gene pool
B. Gene flow
C. Genetic drift
D. Isolation

Answer 1

Hint: Sewall Wright was the initiator of the branch of biology now known as ‘population genetics’. He put forward a concept which states that allele frequency of a small population can change all of a sudden by some sampling error.

Complete answer:
The genetic drift concept was given by well-known science person Sewall Wright who is also a founder of the subject ‘population genetics’. Genetic drift refers to the change in the frequency of an existing allele (gene variant) in a population. It occurs due to random sampling of organisms. Genetic drift is also called the allelic drift. The impact of genetic drift on a small population is greater if compared to that of a larger population. Large population accurately reflects the allelic frequency of a parental population due to its large size and the large number of gametes produced. An example of the genetic drift; A population of rabbits can have brown fur and white fur with brown fur being the dominant allele. By random chance, the offspring may all be brown and this could reduce or eliminate the allele for white fur. Genetic drift can lead to an evolution in a population.

So, the correct answer is option C.

Note: The set of different forms of genes within an interbreeding population is called a gene pool. According to the genetic drift concept, change in a small population's gene pool occurs strictly by chance. The bottleneck effect is really an extreme instance of genetic drift which arises when the population size is severely decreased.