Question

Why are primers required in Sanger’s method of DNA sequencing?

Hint:

Primers provide the starting 3-OH end for DNA polymerase to initiate synthesis in Sanger sequencing.

Answer 1

In Sanger’s DNA sequencing method, primers are short single-stranded DNA sequences that provide a starting point for DNA polymerase to begin synthesis of the new DNA strand.

• Primers anneal to the single-stranded DNA template at a specific site, ensuring that DNA synthesis starts at a known location.
• DNA polymerase can only add nucleotides to an existing 3-OH group; primers provide this 3-OH group.
• Without primers, DNA polymerase cannot initiate DNA strand synthesis, so sequencing would not proceed.

Thus, primers are essential for initiating the DNA replication process during sequencing.