Question

An exon within a coding region of a gene contains the following sequence: 5';-ATTGCACCTG-3'. Exposure of cells to a mutagen results in this sequence changing to 5'-ATTCGCACCTG-3'. Which of the following is true?

This gene has experienced a deletion.
This gene has experienced a double mutation.
This gene has experienced a frameshift.
This gene is now considered wild-type.

Answer 1

A gene has experienced a frameshift mutation.

Step-by-step explanation:

An exon within a coding region of a gene contains the following sequence: 5';-ATTGCACCTG-3'. Exposure of cells to a mutagen results in this sequence changing to 5'-ATTCGCACCTG-3'. This gene has experienced a frameshift mutation.

A frameshift mutation occurs when there is an insertion or deletion of nucleotides that is not evenly divisible by three, disrupting the reading frame of the codons. In this case, the mutation resulted in the insertion of an extra C, which shifted all of the codons that follow it.

As a result, the codons that follow the mutation will code for different amino acids, leading to a change in the protein product. In this case, the change in the codons resulted in the production of a premature stop codon, truncating the protein.