Which one of the following is caused due to point mutation?

The correct answer is Option (1) → Sickle cell anaemia

Option (1) Sickle cell anaemia — Correct. In sickle-cell anaemia a single base of the β-globin gene is changed: GAG becomes GUG at the sixth codon. A change in a single base pair is a point mutation, and here it puts valine in place of glutamic acid.

Note: A similar question was also asked in CUET (UG) 2026 on 25-05-2026 (Slot 1).

NCERT Extract:
Mutation – “Mutation is a phenomenon which results in alteration of DNA sequences and consequently results in changes in the genotype and the phenotype of an organism. In addition to recombination, mutation is another phenomenon that leads to variation in DNA. As you will learn in Chapter 5, one DNA helix runs continuously from one end to the other in each chromatid, in a highly supercoiled form. Therefore loss (deletions) or gain (insertion/duplication) of a segment of DNA, result in alteration in chromosomes. Since genes are known to be located on chromosomes, alteration in chromosomes results in abnormalities or aberrations. Chromosomal aberrations are commonly observed in cancer cells. In addition to the above, mutation also arise due to change in a single base pair of DNA. This is known as point mutation. A classical example of such a mutation is sickle cell anemia.”