Question
What is mutation? Explain with the help of an example, how a point mutation does affect the genetic code. Name another type of mutation.
✓
Answer
- Mutation refers to the phenomenon of alternation in DNA sequences and consequently changes in the genotype and phenotype of an organism.
- Point mutation refers to a change in a single base pair of DNA.
- Sickle-cell anaemia is due to a change in the sixth codon of the beta globin gene from GAG to GUG.
- Consequently, the sixth amino acid, glutamic acid in the beta globin chain is substituted by valine.
- The defective haemoglobin undergoes polymerisation at low oxygen tension causing a change in the shape of RBC from biconcave cell to sickle-shaped structure.
- Frameshift mutation is another type of mutation.
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