Chapter 1
Get Started
About Relative Standard Curve and Comparative C
T
Experiments
11
Applied Biosystems 7500/7500 Fast Real-Time PCR System Getting Started Guide for Relative Standard Curve
and Comparative C
T
Experiments
Notes
Supported
Reagents
TaqMan
®
and SYBR
®
Green Reagents
Applied Biosystems offers TaqMan
®
and SYBR
®
Green reagents for use on the
7500/7500 Fast system. Both reagent types are briefly described in the table below.
Note:
If you use TaqMan
®
or SYBR
®
Green reagents, the 7500 software automatically
calculates reaction volumes in the Reaction Setup screen.
Reagent Type
Process
TaqMan
®
reagents or kits
Description
TaqMan reagents use a fluorogenic probe to enable
detection of a specific PCR product as it accumulates
during PCR cycles.
Advantages
• Increased specificity with the addition of a
fluorogenic probe.
• Provides multiplex capability.
• Preformulated assays, optimized to run under
universal thermal cycling conditions, are available.
• Can be used for either 1- or 2-step RT-PCR.
Limitations
Requires synthesis of a unique fluorogenic probe.
SYBR
®
Green reagents
Description
SYBR Green reagents use SYBR
®
Green I dye, a
double-stranded DNA binding dye, to detect PCR
products as they accumulate during PCR cycles.
Advantages
• Economical (no probe needed).
• Allows for melt curve analysis to measure the Tm
of all PCR products.
• Can be used for either 1- or 2-step RT-PCR.
Limitations
Binds nonspecifically to all double-stranded DNA
sequences. To avoid false-positive signals, check for
nonspecific product formation using melt curve or gel
analysis.
b. Denatured Template and Annealing of A
ss
ay Component
s
Forward primer
Rever
s
e primer
Q
M
G
B
F
LE
G
END
FAM™ dye
Probe
5
'
3
'
a. A
ss
ay Component
s
cDNA Template
Forward primer
Rever
s
e primer
Probe
Q
M
G
B
F
Probe
Q
M
G
B
F
5
'
3
'
PCR and Detection of cDNA
cDNA
5
'
3
'
5
'
3
'
c.
S
ignal
G
eneration
Rever
s
e primer
F
Forward primer
5
'
3
'
3
'
5
'
5
'
3
'
M
G
B
Q
Minor
G
roove
Binder
Template
AmpliTa
q
G
old
®
DNA Polymera
s
e
Q
uencher
Primer
Extended Primer
FORWARD
PRIMER
REVER
S
E
PRIMER
S
tep 1: Reaction
s
etup
The
S
YBR®
G
reen I dye
fluore
s
ce
s
when bound to
double-
s
tranded DNA.
S
tep 2: Denaturation
When the DNA i
s
denatured into
s
ingle-
s
tranded DNA, the
®
S
YBR
G
reen I dye i
s
relea
s
ed and
the fluore
s
cence i
s
dra
s
tically reduced.
S
tep 3: Polymerization
During exten
s
ion, primer
s
anneal and PCR product
i
s
generated.
S
tep 4: Polymerization completed
S
YBR®
G
reen I dye bind
s
to the
double-
s
tranded product,
re
s
ulting in a net increa
s
e in
fluore
s
cence detected by the
in
s
trument.