Chapter 1 Introduction
About the 7300/7500/7500 Fast System
2 Applied Biosystems 7300/7500/7500 Fast Real-Time PCR System Relative Quantification Getting Started Guide
Notes
About the 7300/7500/7500 Fast System
Description The Applied Biosystems 7300/7500/7500 Fast Real-Time PCR System uses fluorescent-
based PCR chemistries to provide quantitative detection of nucleic acid sequences using
real-time analysis and qualitative detection of nucleic acid sequences using end-point
and dissociation-curve analysis. The Applied Biosystems 7500 Fast Real-Time PCR
System allows the user to perform high speed thermal cycling giving run times for
quantitative real-time PCR applications (such as relative quantification) in fewer than 40
minutes.
Relative
Quantification
Assay
The 7300/7500/7500 Fast system allows the user to perform several assay types using
plates or tubes in the 96-well format. This guide describes the relative quantification
(RQ) assay type.
For information about the other assay types, refer to the Real-Time PCR Systems
Chemistry Guide (PN 4378658) and the Online Help for the 7300/7500/7500 Fast
system (Online Help).
About Relative Quantification
Real-time PCR
Assays
RQ is performed using real-time PCR. In real-time PCR assays, you monitor the
progress of the PCR as it occurs. Data are collected throughout the PCR process rather
than at the end of the PCR process (end-point PCR).
In real-time PCR, reactions are characterized by the point in time during cycling when
amplification of a target is first detected rather than by the amount of target accumulated
at the end of PCR.
There are two types of quantitative real-time PCR: absolute and relative.
Definition Relative quantification determines the change in expression of a nucleic acid sequence
(target) in a test sample relative to the same sequence in a calibrator sample. The
calibrator sample can be an untreated control or a sample at time zero in a time-course
study (Livak and Schmittgen, 2001). For example, relative quantification is commonly
used to compare expression levels of wild-type with mutated alleles or the expression
levels of a gene in different tissues.
RQ provides accurate comparison between the initial level of template in each sample,
without requiring the exact copy number of the template. Further, the relative levels of
templates in samples can be determined without the use of standard curves.