1. Polymerase Chain Reaction (PCR)
NUBIO: WhY are We Different?
By: Kabi Neupane, Ph.D.
Edited by: Leah Spee

2. Polymerase Chain Reaction
Polymerase: DNA polymerase
DNA polymerase is an enzyme that duplicates DNA during interphase of the cell cycle.
Chain Reaction: The product of a reaction is used to amplify the same reaction
Results in rapid increase in the product

3. Discovery PCR was discovered by Kary Mullis Nobel Prize in Chemistry
On a long motorcycle drive
Mentally visualized the process
Nobel Prize in Chemistry
1993

4. Properties of DNA polymearse
DNA polymerase works best under optimal temperature, pH and salt concentration (as do all enzymes)
PCR buffer provides optimal pH and salt condition
The thermal cycler provides the proper temperatures.

5. Taq DNA polymerase Derived from the bacteriaThermus aquaticus
Heat stable DNA polymerase
Ideal temperature 72°C

6. Thermal Cycling
A PCR machine controls the temperatures needed to amplify DNA
Typical PCR go through three steps
Denaturation
Annealing (also called hybridization)
Extension

7. Step 1: Denaturation Heating DNA to 94-96 °C separates the double
stranded DNA
Heat
Cool

8. Step 2: Annealing Two primers are supplied.
They bind to the complementary region.
Typical temperature from °C

9. What is a PRIMER?
Short chains of bases that hybridize to a target piece of DNA.
Primers determine the DNA fragment to be amplified in the PCR process.

10. Step 3: Extension Taq polymerase duplicates DNA
Optimal temperature 72°C

11. A few PCR Applications:
Genetic testing in potential parents for presence of genetic mutations that could be passed down to offspring.
PCR can be used to test for HIV through detection of the actual viral genome within cells.
Minute samples of DNA can be isolated from a crime scene and compared to suspects.

12. PCR Animation