Question

Why is the elimination of a recessive deleterious allele by natural selection difficult? Relate your answer to the appropriate formula.

Answer 1

Recessive allele cannot be eliminated from the population completely because heterozygous offspring contain both dominant and recessive allele.

AA( beneficial allele)

aa( deleterious allele)

Aa ( heterozygous genotype with A as dominant allele and a as recessive allele).

Even if the aa genotype get eliminated but the allele remain in the heterozygous condition.

Natural selection favour beneficial allele over deleterious allele. Natural selection cannot completely remove the deleterious allele.But in case of genetic drift some allele get lost and some allele get fixed . Genetic Drift is more prominent in small population than in large population.

No allele can be completely eliminated from the population by natural selection.