But notice what we do with the DNA primer. We modify the sequence of the DNA primer. Now, if we look at this codon here, CTT, this codon would have a complementary sequence, a correct complementary sequence of GAA. And GAA would code for the glutamate amino acid in that protein. But instead of creating a DNA primer with the correct GAA sequence, we can create a DNA primer that contains a mismatched base. Instead of having an a here, we can place a c. And so instead of having GAA that codes for glutamate.