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PCR methods
"Polymerase chain reaction" is a technology to copy a piece of DNA.
Especially, the process is said "PCR methods".
The process was invented by Kary Mullis in 1983, he was awarded the Nobel Prize in Chemistry.
Since it influensed researching DNA.
・We can chose the piece of DNA to increase.
・We can do it in short time, about 2 hours.
・We can do easialy without special machine.
・We need a little DNA.
PCR methods is marvellous for this reason.
Let's see the procedure.
Procedure
PCR methods use the feature of DNA.
The structure of DNA change the appearance in accordance with the situation.
DNA separates into two independent lines in high temperature.
①Heat up DNA to 94 degrees Celsius and wait to separate
The separated DNA recombine by complementarity. It is said "Annealing".
Then, it takes time to combine cooled quickly, because DNA is big substance.
If there are the materials of DNA, it combines with them before does with original.
The materials are said "Praimers".
Praimers are short with a length of about twenty bases.
They are drift around there beforehand.
②Cool to 55 degrees Celsius and Annealing single DNA with praimers
The praimers are unstable, therefore it will come off soon.
"DNA polymerase" works not to be so.
DNA polymerase can conbine them fast.
You may think it is better heating up and using it soon, however DNA polymerase needs the base of the praimer.
So, it is necessary to cool once, and make the bese.
③Heat up to 72 degrees Celcius and make active DNA polomerase to conbine praimers
Thus, just one DNA chain becomes two DNA chains as the original.
There are the sequels of the reaction.
①Heat up DNA to 94 degrees Celsius and wait to separate
②Cool to 55 degrees Celsius and Annealing single DNA with praimers
③Heat up to 72 degrees Celcius and make active DNA polomerase to conbine praimers
As you look, the DNA chains increase exponentially.
It will be over one million in 20 times.
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