1. What is the DNA Copy Number Formula?

The Thermo Fisher DNA copy number formula calculates the number of DNA molecules in a given volume of solution based on concentration, volume, and molecular weight. This is essential for molecular biology applications like qPCR, sequencing, and cloning.

2. How Does the Calculator Work?

The calculator uses the DNA copy number formula:

Where:

• \( CN \) — Copy number (dimensionless)
• \( C \) — DNA concentration (g/mL)
• \( V \) — Volume of solution (mL)
• \( MW \) — Molecular weight of DNA (g/mol)
• \( 6.022 \times 10^{23} \) — Avogadro's number (molecules/mol)

Explanation: The formula converts mass of DNA to number of molecules using Avogadro's number and the molecular weight of the DNA.

3. Importance of Copy Number Calculation

Details: Accurate copy number determination is crucial for quantitative PCR, next-generation sequencing library preparation, and ensuring consistent results in molecular biology experiments.

4. Using the Calculator

Tips: Enter concentration in g/mL, volume in mL, and molecular weight in g/mol. All values must be positive numbers. For dsDNA, molecular weight can be calculated as (length in bp) × 650 g/mol/bp.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine DNA concentration?
A: Measure absorbance at 260 nm using a spectrophotometer. 1 A260 unit ≈ 50 μg/mL for dsDNA.

Q2: What if I have concentration in ng/μL?
A: Convert to g/mL by multiplying by 10^-6 (1 ng/μL = 10^-6 g/mL).

Q3: How to calculate molecular weight?
A: For dsDNA, MW ≈ (length in bp) × 650 g/mol. For ssDNA, MW ≈ (length in nt) × 330 g/mol.

Q4: Why is Avogadro's number used?
A: It converts between molar quantity (moles) and molecular quantity (molecules).

Q5: What's a typical copy number range?
A: For qPCR standards, common ranges are 10²-10¹⁰ copies/μL. Library prep often uses 1-10 ng/μL.