Answer: Single base mutation in haemoglobin gene (point mutation).
- A Large-scale deletion spanning the entire beta-globin gene cluster
- B Single base mutation in haemoglobin gene (point mutation)
- C Retroviral insertion disrupting globin gene expression
- D Complete loss of chromosome 11 in red cell precursors
Correct answer: B. Single base mutation in haemoglobin gene (point mutation)
Explanation: Sickle cell anaemia: single point mutation (GAG→GTG in DNA; glutamic acid→valine in protein) causes abnormal haemoglobin.
Punnett square for a monohybrid cross between two heterozygous (Tt) parents, showing the 3:1 phenotypic ratio predicted by Mendel's Law of Segregation.
Concept context
Mendel's laws, inheritance patterns, DNA structure, and molecular biology. Core of NEET biology.
Read the full Principles of Inheritance and Variation notes →