1. What is DNA Copy Number?

DNA copy number represents the number of DNA molecules present in a given volume. It's essential for quantitative PCR, sequencing library preparation, and other molecular biology applications where knowing the exact number of DNA molecules is crucial.

2. How Does the Calculator Work?

The calculator uses the DNA copy number equation:

Where:

• \( CN \) — DNA copy number (dimensionless)
• \( C \) — DNA concentration (g/μL)
• \( MW \) — Molecular weight (g/mol)
• \( 6.022 \times 10^{23} \) — Avogadro's number (molecules/mol)

Explanation: The equation converts mass concentration to molecular count using Avogadro's number and the molecular weight of the DNA.

3. Importance of Copy Number Calculation

Details: Accurate copy number calculation is critical for qPCR standard curves, NGS library quantification, single-cell genomics, and other applications requiring precise molecule counts.

4. Using the Calculator

Tips: Enter DNA concentration in g/μL and molecular weight in g/mol. For dsDNA, MW can be calculated as (length in bp × 607.4) + 157.9.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine molecular weight?
A: For dsDNA: MW = (length in bp × 607.4) + 157.9. For ssDNA: MW = (length in nt × 303.7) + 79.0.

Q2: What are typical copy number ranges?
A: qPCR standards often range from 10^1 to 10^9 copies/μL. Library concentrations for NGS are typically 1-20 nM (6e11-1.2e13 copies/mL).

Q3: Does this work for RNA?
A: Yes, but use RNA-specific molecular weight: MW = (length in nt × 320.5) + 159.0.

Q4: What about plasmid DNA?
A: Calculate MW based on plasmid size, remembering to include any insert DNA.

Q5: How accurate is this calculation?
A: It's mathematically precise, but actual counts depend on accurate concentration measurements (preferably by fluorometry).