How does pcr differ from dna replication?
1 Answer
Both PCR and in-vivo DNA replication are polymerase chain reactions. Key differences are:
-
Machinery involved : DNA replication is carried out at body temperature (37C in humans) with the help of a complex machinery. for example, helicase unwinds dsDNA, single-strand-binding-proteins stabilize these unwound strands, etc. The PCR reaction utilizes temperature cycles (with extremes of 70-90C) to cause denaturation and annealing of DNA strands.
-
Type of polymerase : There are many DNA polymerases in eukaryotes. In PCR, thermostable DNA polymerases derived from bacteria or archaea are used (eg. Taq polymerase)
-
Length of DNA : Whole genomic DNA is routinely replicated in the body. in the PCR reaction, the polymerase used has a much shorter half-life, and is only efficient for much smaller fragments of DNA
-
Features of polymerase used : High fidelity, speed, proofreading and repair are desirable features required of DNA replication. PCR reactions use simpler polymerases that are not as "feature-rich". For example, the commonly used Taq polymerase has no proofreading ability. However, more accurate options are commercially available (ampliTaqGold, PlatinumTaqPolymerase, Pfu DNA polymerase, etc)
