Why are two primers used in PCR while only one primer is used during Sanger Sequencing?

Question

Why are two primers used in PCR while only one primer is used during Sanger Sequencing?

In: Biology

Answer 1

Should post this in AskScience. It would take an essay to ELY5 for this kind of question. In general though, for PCR you’re trying to amplify one gene or any specific length amplicon, you want exponential amplification for efficient detection, so you go from both sides of the gene, so you get doubling each cycle. For Sanger, you want to know the actual sequence, you’re not trying to amplify, you’re trying to synthesize and stop at random places then as you know the exact length of each fragment and on what nucleotide it stopped, you can know the sequence. So in a way Sanger is one directional because knowing the sequence of one strand is all it takes. For PCR goal is amplification, so you need doubling.