The Polymerase Chain Reaction is a technique used very extensively in molecular genetics, forensics and other fields to greatly amplify a specific DNA sequence. Kary Mullis who received the 1993 Nobel Prize in Physiology and Medicine for the discovery invented it in 1983.

A PCR amplification reaction includes: the source DNA containing the sequence of interest (as few as 1 copy), two unique single-stranded DNA primers that bracket the desired sequence, deoxyribonucleotides (the building blocks of DNA), and Taq DNA polymerase (from the thermophilic organism Thermus aquaticus). The reaction is cycled between three temperatures that facilitate the construction of new copies of the desired DNA sequence. At 95°C, the double stranded source (or template) DNA is denatured into single strands. Then, at 55°C, the primers bind (anneal) to complimentary sequences on the template DNA that bracket the sequence to be amplified. Last, at 72°C, the Taq DNA polymerase adds deoxyribonucleotides in sequence to the primer as it builds a complementary strand to the template DNA. This cycle is repeated until a very large number of copies are obtained. The reaction is usually carried out in a machine called a thermal cycler that quickly changes the temperature of the reaction mixture between the three necessary temperatures. A good graphic illustration of the process can be found at http://www.accessexcellence.org/AB/GG/polymerase.html.

The PCR Dash is a game that will help illustrate the PCR process for students. The game is best played by several teams in a fun competition. Each team should have 4 people.

Due to the nature of the exercises, the file should be downloaded and opened with Microsoft Word.

– The PCR Dash (Microsoft Word)

– The PCR Dash (Web Format)

Microsoft Word Viewer (size: 3952016 bytes) is a free utility available for download from the Microsoft WWW site.