What is the function of a forward primer in PCR?

The function of a forward primer in PCR (Polymerase Chain Reaction) is to initiate the synthesis of a new DNA strand by binding to a specific sequence on the template DNA. This binding occurs at the region of interest, specifically at the start site of the target sequence that is being amplified.

When the forward primer attaches to the template strand, it provides a free 3' hydroxyl group, which is essential for DNA polymerase to begin adding complementary nucleotides to synthesize the new strand. This process is crucial for the amplification of the desired DNA segment because it defines the starting point for replication.

In addition, it's important to note the roles of the stop codon, DNA polymerase enhancement, and reverse strand amplification. The forward primer does not bind to stop codons or directly enhance DNA polymerase; instead, it serves primarily to replicate the DNA starting from the specific sequence it binds to. As such, understanding the role of the forward primer lays the foundation for grasping how PCR selectively amplifies the target DNA sequence.