1. What is the Copy Number Calculator?

The Thermofisher Copy Number Calculator estimates the number of copies of a DNA or RNA molecule per nanogram based on its molecular weight. This is essential for quantitative PCR, sequencing, and other molecular biology applications.

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• Mass — Amount of nucleic acid in nanograms (ng)
• MW — Molecular weight of the nucleic acid in grams per mole (g/mol)
• 6.022 × 10²³ — Avogadro's number (molecules per mole)
• 10⁹ — Conversion factor between grams and nanograms

Explanation: The equation converts mass to molar quantity, then to molecular count using Avogadro's number.

3. Importance of Copy Number Calculation

Details: Accurate copy number determination is crucial for:

• Standard curve preparation in qPCR
• Determining input amounts for NGS libraries
• Normalizing samples in molecular biology experiments
• Ensuring reproducibility in quantitative assays

4. Using the Calculator

Tips:

• Enter mass in nanograms (ng)
• Enter molecular weight in g/mol (for dsDNA: ~660 g/mol per base pair)
• Both values must be positive numbers

5. Frequently Asked Questions (FAQ)

Q1: How do I calculate molecular weight for DNA?
A: For double-stranded DNA: MW ≈ (number of base pairs) × 660 g/mol. For single-stranded DNA or RNA: MW ≈ (number of bases) × 330 g/mol.

Q2: Why is Avogadro's number used?
A: Avogadro's number converts between molar quantity (moles) and molecular count (molecules).

Q3: What's a typical copy number range?
A: For qPCR standards, common ranges are 10⁶-10¹⁰ copies/µL. For NGS libraries, 1-10 nM is typical.

Q4: How accurate is this calculation?
A: The calculation is mathematically precise, but actual experimental results depend on accurate mass and MW measurements.

Q5: Can this be used for proteins?
A: Yes, the same principle applies to any molecule when you know its molecular weight.