BCH4024 Sp25 OC E4 Q42: Peptide sequencing analysis of the g…

BCH4024 Sp25 OC E4 Q42: Peptide sequencing analysis of the gene products of a wild-type and a mutant bacteria strain reveals that these strains express different versions of a particular protein, protein P. Portions of the wild-type and mutant sequences for protein P are shown below. The part of the RNA sequence corresponding to this part of the peptide sequence of protein P in the wild-type strain is also shown. Which of the following is the most likely molecular explanation for how the mutant peptide sequence could have arisen based on a change to the wild-type DNA sequence that encoded the protein?