Question

Sol.(b) [Key Concept: Harmful Mutations — Persistence in Gene Pool] Harmful mutations do not get eliminated from the gene pool because they are recessive and carried by heterozygous individuals (carriers). In heterozygotes, the harmful recessive allele is masked by the dominant normal allele, so carriers show no ill effects but carry the mutation. The recessive mutation is only expressed when two carriers mate and produce homozygous recessive offspring. This sheltering of recessive alleles in carriers prevents their elimination.