Real-Time PCR Quantification
Definition
A method that measures the concentration of human-specific amplifiable DNA in a forensic extract by monitoring fluorescent signal accumulation during PCR in real time. Modern kits simultaneously report total human DNA, male DNA from the Y chromosome, and a degradation index from the ratio of short-to-long target amplification.
- Method
- Fluorescent signal monitoring during PCR
- Measures
- Total human DNA, male-specific DNA
- Also reports
- Degradation index
- Stage
- Before STR amplification setup
Common questions
Why quantify DNA before running STR typing rather than just amplifying whatever was extracted?+
STR kits need input DNA within a defined concentration range to produce balanced, interpretable profiles, so quantification tells the analyst how much extract to add and whether the sample has enough usable DNA to proceed at all.
What does the degradation index reveal that a total-DNA quantity figure does not?+
It compares amplification of a short target against a longer target on the same locus; a low ratio signals that the DNA is fragmented, which predicts allele dropout at larger STR loci and helps the analyst choose a degradation-tolerant typing strategy.
Related terms
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