1. What is DNA Copy Number?

DNA copy number represents the number of copies of a specific DNA molecule present in a given volume. It's crucial for molecular biology applications like PCR, sequencing, and cloning.

2. How Does the Calculator Work?

The calculator uses the DNA copy number formula:

Where:

• \( CN \) — Copy number (copies/μL)
• \( C \) — DNA concentration (ng/μL)
• \( L \) — DNA length (base pairs)
• \( 6.022 \times 10^{23} \) — Avogadro's number (molecules/mol)
• \( 660 \) — Average molecular weight of a DNA base pair (g/mol)

Explanation: The equation converts mass concentration to molar concentration, then calculates the number of molecules using Avogadro's number.

3. Importance of Copy Number Calculation

Details: Accurate copy number calculation is essential for quantitative PCR (qPCR), next-generation sequencing library preparation, and ensuring proper template amounts in molecular biology experiments.

4. Using the Calculator

Tips: Enter DNA concentration in ng/μL and length in base pairs. Both values must be positive numbers. The calculator will compute the number of DNA copies per microliter.

5. Frequently Asked Questions (FAQ)

Q1: Why is 660 g/mol used for DNA base pairs?
A: This is the average molecular weight of a DNA base pair, accounting for different nucleotide compositions.

Q2: How accurate is this calculation?
A: It provides a good estimate but assumes average base pair weight. Accuracy depends on precise concentration measurement.

Q3: Can I use this for RNA?
A: No, RNA calculations require different molecular weights. Use 340 g/mol for single-stranded RNA.

Q4: What's a typical copy number range for PCR?
A: Most qPCR reactions use 1,000-100,000 copies per reaction, depending on application.

Q5: How do I convert from ng/μL to nM?
A: Use the formula: nM = (ng/μL × 10^6) / (660 × length)