1. What is DNA Copy Number?

DNA copy number refers to the number of copies of a particular DNA molecule in a given sample. It's essential for quantitative PCR, molecular biology experiments, and determining DNA concentration in molar terms.

2. How Does the Calculator Work?

The calculator uses the DNA copy number formula:

Where:

• \( C \) — DNA concentration (g/L)
• \( N_A \) — Avogadro's number (6.022 × 10²³ molecules/mol)
• \( V \) — Volume of solution (L)
• \( MW \) — Molecular weight of DNA (g/mol)

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

3. Importance of DNA Copy Number

Details: Knowing the exact copy number is crucial for qPCR standard curves, determining template amounts for PCR, and ensuring consistent results in molecular biology experiments.

4. Using the Calculator

Tips: Enter DNA concentration in g/L, volume in liters, and molecular weight in g/mol. For double-stranded DNA, use the molecular weight of the entire molecule.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine molecular weight of my DNA?
A: For synthetic oligonucleotides, use the formula: MW = (A × 313.2) + (T × 304.2) + (C × 289.2) + (G × 329.2) + 79.0 (for 5' phosphate).

Q2: Can I use ng/μL instead of g/L?
A: Yes, but convert ng/μL to g/L first (1 ng/μL = 1 g/L). The calculator expects g/L as input.

Q3: What's a typical copy number range for qPCR?
A: Standard curves often range from 10¹ to 10⁹ copies per reaction, depending on application.

Q4: Does this work for plasmid DNA?
A: Yes, use the plasmid's molecular weight (base pairs × 650 g/mol/bp for dsDNA).

Q5: How accurate is this calculation?
A: It's mathematically precise, but accuracy depends on your input measurements (concentration, volume, and MW).