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DNA Fingerprinting


What is DNA?
What is DNA Fingerprinting?
Types of DNA Fingerprinting
How does one create a DNA fingerprint?
The Uses of DNA Fingerprinting
Problems with DNA Fingerprinting
Gel Electrophoresis


PCR is the short form of Polymerase Chain Reaction. PCR takes analysis of small amounts of genetic material that may even be damaged to a new level of precision and reliability.  PCR is a cheap and practical use for copying DNA.  With the technique of PCR one can accomplish what used to take a year in a single week.  All the equipment needed to perform the process of PCR is a reaction tube, reagents, and a source of heat.  The source that can change the heat to different amounts of degrees is a key piece in PCR.  The DNA can be copied in a matter of minutes.  The more copies of the specific DNA that you want means you have to execute the cycle more times.   For every cycle that is preformed the number of specific DNA copies is doubled.

PCR Steps

      The process of PCR starts at 35 degrees Celsius

      The DNA is then melted at a temperature of 95 degrees Celsius

      That causes the target molecules to separate

      The temperature is then lowered to 60 degrees Celsius so that the oglionucleotide primers can bind to the target DNA  

      Each primer binds specifically to the 3’ end of the sequence on the appropriate strands of DNA

      Taq polymerase are then sent in and under the direction of the primers

      Only the DNA that has the target sequence is copied because the taq can only copy the molecules with a primer attached to it

      At the end of cycle one both strands are copied from two partially stranded DNA molecules

      The temperature can be raised from 60 to 75 degrees Celsius to speed up when the polymerase are added

      At the end of cycle two four partially strands are made

      The same steps are repeated from cycle one to produce all the other cycles

      At the end of cycle 30 there are 60 longer strands of target DNA and 1,073,766 target pieces




PCR In The Future
PCR right now is done in a machine roughly the size of a microwave and cost thousands of dollars but an improvement is in sight.  Researches are now able to copy larger and larger pieces of DNA.  The equipment needed is currently undergoing change.  Experimenters are presently trying to fit the pieces needed to perform PCR into a piece of equipment the size of a potato chip.  This little piece of equipment would be heated electrically and would be able to heat up and cool down faster, thus speeding up the over time needed to copy small or large numbers of DNA copies.  If or when they come put with this technology patients would be able to get on the spot readouts of their DNA.  This advance in technology would allow for doctors to diagnose infections or genetic disorders right from their office.  Thanks to PCR we can now look back at the genetic past and look into the genetic future.

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