Home
Back
dsDNA Copy Number Equation:
| From: | To: |
The dsDNA copy number calculation estimates the relative quantity of double-stranded DNA by comparing cycle threshold (Ct) values from quantitative PCR (qPCR) experiments. It provides a measure of how many more copies of a target sequence are present in one sample compared to another.
The calculator uses the equation:
Where:
Explanation: The equation assumes 100% PCR efficiency (doubling of product each cycle), which is why the base is 2. Each difference of 1 in Ct values represents a 2-fold difference in starting quantity.
Details: Calculating relative copy numbers is essential for gene expression studies, viral load quantification, genetic variation analysis, and many other molecular biology applications.
Tips: Enter Ct values from your qPCR experiment. Ct1 should be the reference sample (e.g., control or calibrator), and Ct2 should be your test sample. The calculator will determine how many more (or fewer) copies are in your test sample compared to the reference.
Q1: What if my PCR efficiency isn't 100%?
A: For non-ideal efficiency, use the equation: CN = (1 + E)^(Ct1 - Ct2), where E is efficiency (0 to 1). 100% efficiency = 1.0.
Q2: How precise are Ct values?
A: Typically ±0.5 cycles for technical replicates. Biological variation is usually greater than technical variation.
Q3: What does a CN of 1 mean?
A: CN=1 means equal quantities in both samples. CN=2 means twice as many copies in test sample, CN=0.5 means half as many.
Q4: Should I use average Ct values?
A: Yes, use the mean of technical replicates for each sample to improve accuracy.
Q5: Can I compare across different runs?
A: Only if you include the same reference sample in each run for normalization between runs.