Question

Mutations and its effect on the genes.
What will happen to each of the below mutations:
- No protein at all
- Normal protein
- Functional protein with one amino acid different from normal
- Probable non-functional with one amino acid different from normal
- Probable non-functional with many amino acids different from normal

a) two base pair deletion in an intron - results in premature end, no protein.
b) one base pair insertion right before the part that specifies the active site of the enzyme
c) three base pair deletion in a part of the gene that specifies a non-essential loop of the enzyme
d) silent in the middle of the gene

Answer 1

a. Change in intron could hinder the initiation process and either there would be no protein or truncated protein due to shift in the frame of the protein which would entirely change the sequence of the protein which can insert termination codons at in-between sites which could truncate the peptide.

b. Since the mutation is in the active site of the enzyme, it would result in a probable non-functional protein with one amino acid difference in the active site. The second probablity is also there if the base changed is wobble base, the protein produced would be normal protein.

c. It would produce a normal protein but due to a deletion of three inframe nucleotides, an amino acid would be deleted but protein would be functional as the deletion is in the non-essential loop part of the enzyme.

d. Silent mutation have no effect on the protein sequence hence the protein would be normal and functional.