Primer

[aftabac]

Hi
what is actaully ment by forward and reverse primer, or more easily which primer we call that it is forward primer and which is call as reverse primer???


regards
aftab

[kmunson779]

Since I don't feel like typing it all out, check out this thread on a different forum.

[moleculardude]

Yeah I agree with the one poster, kind of...

there is really no "forward" and "reverse" although I would argue that the DNA polymerase does have a processivity for 5' to 3' nucleotide addition.

Proof-reading PCR DNA polymerase do have 3' to 5' exonuclease activity but it is not nearly as processive as 5' to 3' processivity which can add up to 1000 nucleotides at a time or even more.

Therefore yes, the direction of PCR synthesis is indeed in the same direction however, starting at different ends.

So yes, the terms forward and reverse are used in PCR to visually demonstrate the need to synthesize BOTH strands of the DNA duplex during PCR amplification.

It is important to know that DNA polymerases synthesize in the 5' to 3' direction, adding nucleotides to free 3' hydroxyl (OH) groups. DNA polymerase cannot start without the free OH, thus the need for a primer which provides one.

Thus, you can amplify any region by selecting flanking primers which will allow the DNA polymerase to efficiently synthesize both strands of the DNA duplex. Multiple rounds of PCR cylce, including denaturation and elongation will amplify your area of interest.