NEET 2026 (cancelled) · Question 159 · Class 12

Principles of Inheritance and Variation

The sixth mutant codon of beta globin gene causing polymerization of Haemoglobin and change in RBC shape is _______.

  1. (A)CAG
  2. (B)AUG
  3. (C)GUG
  4. (D)GAG

The NCERT line that answers it

Verbatim line

The substitution of amino acid in the globin protein results due to the single base substitution at the sixth codon of the beta globin gene from GAG to GUG.

Chapter
Principles of Inheritance and Variation
Section
4.8.2 Mendelian Disorders
Page
24
Words matched
29 of 29

The answer appears as a continuous sentence in NCERT. This is that sentence.

How this line gives the answer

0, emb=1.0, combined=1.0). Verified: high — The span explicitly states the substitution at the sixth codon from GAG to GUG, which directly identifies GUG as the mutant codon causing sickle-cell anaemia.

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Question text is reproduced from the published NEET 2026 (cancelled) paper for study and commentary. NCERT text is quoted, not redistributed; textbooks remain at ncert.nic.in. Our mapping method, including its measured error rates, is published at /methodology.