Polymerase Chain Reaction

It is possible to replicate substrings of a DNA sequence starting at almost any point as long as we know a small number of the nucleotides, appearing just before that point. This replication is done using a technology called polymerase chain reaction, which has had a tremendous impact on experimental molecular biology.

Reaction of replication in a cell starts as a consequence of initiation a replication and then by an enzyme which continues that replication (according to the reading direction of the DNA). When considering polymerase chain reaction we perform the initiation and let the enzyme do the rest.

Knowing few nucleotides allows one to synthesize a string that is complementary to those few nucleotides. This complementary string can be used to create a 'primer', which finds its way to the point in the long DNA sequence containing the complement of the primer. It then hybridizes (bonds) with the longer string at that point. This creates the conditions that allow the replication of part of the original string: the replication is done by exposing the DNA to an enzyme which has the ability to duplicate strings called DNA polymerase. After a while we get two substrings. Now we can warm what we got for a short time and the bonds will separate - and again we can apply the enzyme and do the same to the separated substrings and get more and more copies.