1. Intro to PCR
PCR (polymerase chain reaction) was invented by Kary Mullis in Mullis as a chemist working on small nucleotide strands for a biotech company envisioned a faster way of doing things. His discovery has impacted nearly every aspect of biotechnology. For this he won the Nobel peace prize in 1993.

2. PCR is simply a way to rapidly and accurately make copies of DNA.
Accuracy is accomplished through use of primers
Complimentary strands of DNA to target (template) DNA
Forward primers attach to the 3’ side of the sense strand at the beginning of the targeted region
Reverse primers attach to the 3’ side of the antisense strand at the end of the targeted region
PCR products are called amplicons
What is PCR

3. Stages of PCR There are 3 stages to PCR reactions
Denaturation – separation of strands
Annealing – applying the primers
Extension – making copies

4. Denaturation Target DNA is heated to 94C
Double stranded DNA must be separated before it can be copied.
The heat causes the H-bonds that hold the double helix to release
Results in ssDNA (single stranded DNA)

5. Annealing
Primers are added to the ssDNA and are cooled to between C
Optimum temp for annealing but too hot for the double helix to reform
Produces a template-primer hybrid

6. Extension
DNA polymerase is added to replicated the ssDNA at the primers
Taq Polymerase is commonly used as it optimally replicates at 72C
Was discovered in thermophilic bacteria
Extension is 5’-3’ (read 3’-5’ and replicated 5’-3’)

7. Produces amplicons from the 5’ end of one primer to the 5’ end of the other
After 5 PCR cycles 25 copies of the original sequence or 32 copies
After 15 PCR cycles 212 copies of the original sequence or 8,192 copies
After 25 PCR cycles 222 copies of the original sequence or 4,194,304 copies
After 25 PCR cycles 232 copies of the original sequence or 4,294,967,296,copies
PCR Products