This limits the accurate detection of the target sequence
and necessitates methodologies that assess the specificity of the
amplification products. To this end the use of SYBR Green enable
us to perform a Melting point analysis, also referred to as dissociation
curve analysis, is frequently used to monitor the homogeneity
of the qPCR products. During this procedure, the fluorescence
intensity emitted by SYBR Green intercalated into PCR products
is recorded at temperatures rising in small increments from 65 C
to 95 C. This increasing temperature gradually denatures dsDNA,
which induces a consequent reduction of the fluorescent signal,
which appears as a sharp drop in signal intensity when both
strands separate completely. As the Tm of a DNA duplex is dependent
upon length and base composition, the number of points of
inflection in the melting curve indicates the number of PCR products
(including the primer-dimers) generated. An acceptable dissociation
curve has a single peak (i.e. one PCR product), while the
occurrence of multiple peaks indicates the presence of non-specific
amplification products.