Scientist Profile:
Kary B. Mullis
One
cycle of the PCR process, which consists of three main
steps, takes under two minutes. In the first step, called
denaturation, the DNA, stored in a vial, is
heated for thirty seconds at a temperature of about 90
degrees Celsius. This heating breaks apart the two
strands of the DNA molecule. The temperature is
lowered to 55 degrees Celsius for the next twenty
seconds. During this period, called annealing, oligonucleotide primers bond to
the individual strands of DNA. The oligonucleotide
primers serve to initiate DNA replication. The
temperature of the solution is raised to 75 degrees
Celsius during the polymerization period, in which an enzyme called polymerase replicates the strands of DNA.
Thirty iterations of this process will create over one
billion copies of an original DNA segment.
PCR is valuable to scientists by assisting gene mapping, the study of gene functions, cell identification, and to forensic scientists in criminal identification. Cetus Corporation, Mullis' employer at the time of his discovery, was the first to commercialize the PCR process. In 1991, Cetus sold the PCR patent to Hoffman-La Roche for a price of $300 million. It is currently an indispensable tool for molecular biologists and the development genetic engineering.
Technique: Polymerase
Chain Reaction
Animation: Polymerase
Chain Reaction
Technique: Recombinant
DNA
Timeline 1967: DNA Ligase
Isolated
Timeline 1970: First
Restriction Enzyme Isolated
Web Link:
PCR:
Xeroxing DNA
Biography:
Kary B. Mullis
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