Demonstration of PCR and Gel Electrophoresis



In this demo, we take a specific segment of Zebrafish DNA and multiply it by a billion. We then look at it under UV light

PCR (Polymerase Chain Reaction)

This tube contains

  • Zebrafish DNA
  • Primers (Primers attach themselves to beginning of the DNA segment we want to copy. The primers you choose determines what segment of DNA gets copied)
  • Nucleotides (These get assembled to create the copies)
  • Taq polymerase (Assembles the copy of the selected DNA segment )
  • Magnesium Chloride
  • Blue and yellow dyes (we’ll see these as separate color spots when we’re finished. The DNA that gets copied will be found between them)



To double the amount of the selected DNA segment, the temperature of the sample is changed to 94C, 55C then 72C. After doing this 30 times, we end up with about a billion times as much. The thermocycler handles the temperature changes.






The program


Gel Electrophoresis

Takes the DNA segments that were just created, separates them from the rest of the tube contents, then binds it with a florescent dye so we can see it under UV light.


Casting tray

Gel Electrophoresis apparatus, buffer

Power supply set to 122 volts


Examining the results

Lane 1: A “ladder”.

Lane 2: Sample with DNA

Lane 3: Sample without DNA


The DNA that was just created isn’t visible under normal light. What you see on the left is green dye that has separated into its blue and yellow components

Under UV light the DNA can be seen as a black rectangle in the 2nd lane

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