Gene amplification : PCR and its applications

Content
Genetic Engineering and Biotechnology 1.  Recombinant DNA and PCR (Cloning and Amplification of DNA)
Restriction enzymes in cloning
Techniques used in recombinant DNA 
Cloning vectors for recombinant DNA
Plasmids as vectors
Bacteriophages as vectors
Plant and animal viruses as vectors
Transposons as vectors
Artificial chromosome vectors for cloning large DNA segments
Construction of chimeric DNA
Palindromes and staggered cleavage
Adding poly dA at the 3' ends of the vector and poly dT at the 3' ends of DNA clone
Blunt end ligation by T4 DNA ligase
Cloning in bacteria and eukaryotes
Cloning in bacteria
Cloning in eukaryotes
Molecular probes 
Labelling of probes
Applications of molecular probes
Construction and screening of genomic and cDNA libraries
Gene amplification : PCR and its applications
cDNA library from mRNA
Colony (or plaque) hybridization for screening of libraries
Gene Amplification : PCR and Its Applications
The basic polymerase chain reaction (PCR)
Different schemes of PCR
Gene Amplification : PCR and Its Applications
Earlier in this section, we discussed the techniques of recombinant DNA and gene cloning, which permits us to obtain an unlimited supply of identical copies of a gene sequence or DNA segment, which is cloned in a prokaryotic or a eukaryotic cell with the help of a vector. This technique discovered around 1975, proved extremely useful in all experiments of molecular biology and genetic engineering and thus became an essential tool in all molecular biology laboratories.

In 1985, yet another remarkable tool in molecular biology was discovered (by Kary Mullis), which is known as 'polymerase chain reaction', nick named now as 'peoples choice reaction'. The methodology is so important that the prestigious journal Science, published from USA, considered PCR as the major scientific development of the year 1989, and had chosen Taq DNA polymerase, the enzyme used in PCR, as the molecule of the year 1989. In view of the significance of this methodology (PCR), and its varied applications, the 1993 Nobel Prize in Chemistry was shared by Kary Mullis for the discovery of PCR (with Michael Smith for site directed mutagenesis).