Question

A gene has 3 exons and 2 introns. While analyzing a mutant, you discover that 9 basepairs are inserted in the middle of intron 1 of this gene. What is the effect of this insertion on the protein?

Select one:

a. this insertion will have no effect on the protein

b. The protein is likely non-functional because the insertion caused a frameshift

c. The protein has 3 extra amino acids

d. the transcription will be terminated

e. the type of amino acid replacement will determine the effect of this insertion

Answer 1

Answer: The effect of insertion of 9 base pairs in the middle of intron 1 of this gene on protein:

The correct answer is option A. (this insertion will have no effect on the protein)

This is because intron is the non-coding region of a gene. Any insertion in an intron will have no effect on protein function/sequence.

Option b is incorrect because the insertion of 9 base pairs will not cause a frame shift mutation. Frame shift mutation occurs when there is insertions which are not in multiples of 3. (3 base pairs or 3 nucleotides or codon triplets code for different amino acids)

Option c and e is incorrect because the insertion is in intron region, so it does not code for any amino acid.

Option d is incorrect because the transcription will not be terminated in this case. For transcription to be terminated, we need to have specific codon sequences which stop the transcription process.