Lets make many copies of DNA!

Ever wondered how we can make millions of copies of a DNA sample in a short amount of time? We owe acknowledgement to Kary Mullis that invented the polymerase chain reaction (PCR) in 1985. This technique and programmable machine below have made a difference in our world for multiple fields to make jobs easier and testing in the medical field revolutionary.

Polymerase chain reaction (PCR) technique is used to amplify DNA and RNA from a sample. A machine called the thermal cycler is used to create large amounts for research and experiments.

Requirements:

• Sample of DNA or RNA is needed

• Short single-stranded DNA, DNA primers

• An enzyme to aid synthesis for the strand, DNA polymerase

• Build duplicate DNA strands by nucleotide mix with adenine, thymidine, cytosine and guanine

PCR machine (thermal cycler) steps:

1. Denaturation: double-stranded DNA is heated and separated into two strands; for 1 to 5 minutes at 94-98 Celsius

2. Annealing: Temperature is lowered so DNA sequences bind to complementary sequences on single-stranded DNA; 50-60 Celsius

3. Extension: DNA polymerase (Taq polymerase) extends to primers by adding nucleotides to synthesize new DNA strand. Temperature cycles from 95 Celsius to 60 Celsius is repeated 35-40 times which provides amplified copies of DNA.

   
   

   

   
   

After we have used the thermal cycler it is important to analyze the product with electrophoresis. The PCR generated nucleotide are loaded into a separating gel where an electrical current runs through the gel to form bands. The bands we see confirm the success of the PCR reaction and determine the size and characterization of the amplified DNA. We need PCR to medically diagnosis disease, genetic disorders, research and identify individuals. Without PCR we wouldn't be able to create medicine or get the forensic analysis needed in the timeframe needed. We'd be slow and nearly impossible to get research and results when required, we'd definitely be back in the stone age!

A fun little video to watch on the technique: