Final answer:
The scientist is performing PCR-based site-directed mutagenesis by amplifying a region of DNA using a primer in which one of the bases has been changed. The primer is complementary to the template DNA sequence and guides the DNA polymerase to start copying the template.
Step-by-step explanation:
The scientist is performing PCR-based site-directed mutagenesis by amplifying a region of DNA using a primer in which one of the bases has been changed. PCR, or polymerase chain reaction, is a technique used to amplify a specific DNA sequence. In this case, the primer is designed to introduce a specific mutation into the DNA sequence, allowing for the study of the effects of that mutation on the protein or nucleic acid.
In PCR, a short DNA or RNA sequence called a primer is used to initiate DNA synthesis. The primer is complementary to the template DNA sequence and guides the DNA polymerase to start copying the template. By changing one of the bases in the primer, the scientist can introduce a mutation in the amplified DNA.