Investigating CSI – Background material Table of Contents I ...
Investigating CSI – Background material Table of Contents I ...
Investigating CSI – Background material Table of Contents I ...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Real-Time Polymerase Chain Reaction (PCR)<br />
Polymerase chain reaction (PCR) allows the logarithmic copying <strong>of</strong> part <strong>of</strong><br />
a DNA molecule using a DNA polymerase enzyme that is tolerant to<br />
elevated temperatures. RT PCR uses mRNA as a template to make<br />
DNA. The steps involved are discussed below:<br />
1. mRNA is copied to cDNA (chromosomal DNA) by reverse transcriptase<br />
using an oligo dT primer (random oligomers may also be used). In realtime<br />
PCR, we usually use a reverse transcriptase that has an endo H<br />
activity. This removes the mRNA allowing the second strand <strong>of</strong> DNA to be<br />
formed. A PCR mix is then set up which includes a heat-stable<br />
polymerase (such as Taq polymerase), specific primers for the gene <strong>of</strong><br />
interest, deoxynucleotides and a suitable buffer.<br />
40