Introduction:
The
molecular technique called PCR is in
vitro amplification of a specific segment of DNA using a thermostable
enzyme. Although it is a fairly new
technique, invented in 1985 by Cary Mullis, it is widely used in hundreds of
labs all over the world. The PCR process
makes millions of copies of DNA in just a few hours. It is a replication reaction, which uses
reagents very similar to what is needed for DNA replication inside a cell. Each strand serves as a template for synthesis
of its complementary strand.
PCR
has many applications. 1) It is a form of direct cloning of DNA (without the
need for bacteria). This is convenient
when there is little DNA to work with.
2) PCR can produce a DNA fingerprinting pattern for forensics purposes,
such as identifying blood at a crime scene.
3) PCR can be used in prenatal diagnosis of genetic diseases. 4) It can
be used for evolutionary analyses, to look at genetic relationships among or
within taxa (genera, species, populations).
5) PCR can detect allelic sequence variation and chromosomal
rearrangements. 6) It is involved in the
DNA sequencing process. 7) It is the
newest technique in detecting viral or bacterial infection within a host.