Question

Genetic drift operates in
(a) Non-reproduction population
(b) Slow reproduction population
(c) Small isolated population
(d) Large isolated population

Answer 1

Hint: Genetic drift is also termed as the Sewall Wright effect or allelic drift, which is the change within the frequency of an existing gene allele during a population because of a random sampling of organisms.

Complete answer: The production of random evolutionary changes in small breeding populations is understood as Genetic drift. When there are fewer or few copies of an allele, the effect of genetic drift is larger, and when there are many copies the effect is smaller. Genetic drift occurs mainly in a small isolated population. The reason is the irregular phenomenon of alleles getting lost with higher probability. When this loss of alleles starts then the genetic drift continues until that specific allele is completely lost within the entire population.

Addition information:
1. The alleles within the offspring are a sample of these within the parents, and chance features a role in determining whether a given individual survives and reproduces.
2. It is also possible that just one allele remains present at a gene locus within that population.
3. Genetic drift, although it tends to extend the genetic differences among different populations, it also can decrease genetic variation within a population.
4. In natural populations, the genetic drift and natural selection do not take action in isolation; both phenomena are always at rest, together with mutation and migration.
5. Neutral evolution is the result of both mutation and drift, not of drift alone.

So, Genetic drift operates in a ‘Small isolated population’.
Note: The Hardy–Weinberg principle states that within sufficiently large populations, the allele frequencies remain constant from one generation to subsequent unless the equilibrium is disturbed by migration, genetic mutations, or selection.