1. What is DNA Copy Number Calculation?

The DNA copy number calculation converts DNA concentration (in ng/μL) to the number of DNA molecules per microliter. This is essential for applications requiring precise molecule counts like qPCR, digital PCR, and NGS library preparation.

2. How Does the Calculator Work?

The calculator uses the following formula:

Where:

• \( C \) — DNA concentration (ng/μL)
• \( MW \) — Molecular weight (g/mol)
• \( 6.022 \times 10^{23} \) — Avogadro's number (molecules/mol)
• \( 10^9 \) — Conversion factor (ng to g)

Explanation: The formula calculates how many molecules are present in a given concentration by accounting for the molecular weight of the DNA and Avogadro's number.

3. Importance of Copy Number Calculation

Details: Accurate copy number determination is crucial for quantitative molecular biology techniques where the exact number of starting molecules affects the interpretation of results.

4. Using the Calculator

Tips: Enter DNA concentration in ng/μL and molecular weight in g/mol. For double-stranded DNA, molecular weight can be calculated as (length in bp × 650 g/mol/bp).

5. Frequently Asked Questions (FAQ)

Q1: How do I determine molecular weight?
A: For DNA, MW ≈ 650 g/mol per base pair. For a 500bp fragment: 500 × 650 = 325,000 g/mol.

Q2: Does this work for single-stranded DNA?
A: Yes, but use the appropriate molecular weight (≈330 g/mol per nucleotide for ssDNA).

Q3: What's a typical copy number range?
A: For qPCR, ideal working range is 10^3-10^6 copies/μL for template DNA.

Q4: Can I use this for RNA?
A: Yes, but use RNA molecular weight (≈340 g/mol per nucleotide).

Q5: Why is my copy number so large?
A: DNA molecules are extremely small, so even tiny concentrations contain vast numbers of molecules.