1. 1/03VisTE Project - Copyright 2002 Biotechnology The Polymerase Chain Reaction (PCR)

2. 1/03VisTE Project - Copyright 2002 So, What is PCR? A technique that works like a molecular copy machine It allows scientists to isolate one single gene in a DNA sample and copy it over and over again It provides scientists with large quantities of a specific DNA region they want to analyze It allows scientists to extract DNA from minute samples, like a drop of blood, or a single strand of hair

3. 1/03VisTE Project - Copyright 2002 So, What is PCR? It is used for many purposes in medicine, forensic science, agriculture, and research It manipulates a naturally occurring system-- DNA replication It has revolutionized DNA science

4. 1/03VisTE Project - Copyright 2002 Facts About the PCR Discovery The PCR was discovered in 1985 by Kary Mullis, a native North Carolinian. He was awarded the Nobel Prize in 1989. Prior to the PCR, scientists had to insert pieces of DNA into a bacterial or yeast cell--a process that copied entire DNA fragments. Was made possible by the scientific understanding of how DNA works

5. 1/03VisTE Project - Copyright 2002 DNA’s Structural Units DNA’s spiraling strands have a sugar phosphate backbone and are connected to each other by base pairs The bases: Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

6. 1/03VisTE Project - Copyright 2002 How Does the PCR Work? PCR brackets an area of interest, a “target region” in a DNA sample, by using: Primers--small synthetic segments of DNA that attach only to specific areas on the DNA DNA polymerase--a naturally occurring enzyme that builds DNA

7. 1/03VisTE Project - Copyright 2002 How Does PCR Work? Cycles through three steps at specific temperatures DNA must be extracted from cells DNA along with other components is put into a small test tube--a bullet tube The tube is placed in a PCR machine

8. 1/03VisTE Project - Copyright 2002 What’s in the Test Tube? Sample DNA Polymerase Primers Nucleotides Buffer Mineral oil

9. 1/03VisTE Project - Copyright 2002 The PCR Process Step 1 Step 1: Denaturation--The sample is heated (90ºC- 96ºC) in order to denature, or separate the DNA strands Step 2: Step 2: Annealing--The sample is cooled (50ºC -68ºC) in order for the primers to anneal or attach Step 3: Step 3: Extension--The sample is heated again (72ºC) in order for the polymerase to replicate or extend the DNA from the primer locations The process is repeated until a usable amount of DNA is created.

10. 1/03VisTE Project - Copyright 2002 The PCR Process View PCR Simulation

11. 1/03VisTE Project - Copyright 2002 Current PCR Machines

12. 1/03VisTE Project - Copyright 2002 Genetically Modified Organisms Are used in agriculture to: – Improve shelf life – Enhance nutrition – Eliminate pests – Increase production – Manufacture drugs & other products

13. 1/03VisTE Project - Copyright 2002 Genetic Modification Lab No More Modifications Please!