1. What is DNA Molar Ratio?

The DNA molar ratio compares the number of moles of one DNA fragment to another. It's essential for molecular biology applications like ligations, PCR, and cloning to ensure proper stoichiometry.

2. How Does the Calculator Work?

The calculator uses the DNA molar ratio equation:

Where moles are calculated as:

• \( moles = \frac{concentration\ (ng/μL)}{(length\ (bp) \times 617.96 + 36.04)} \)
• 617.96 — Average molecular weight of a DNA base pair (g/mol)
• 36.04 — Molecular weight correction for terminal phosphates

Explanation: The equation accounts for both concentration and length of DNA fragments to determine their molar ratio.

3. Importance of Molar Ratio

Details: Proper molar ratios are crucial for efficient ligation reactions, accurate PCR amplification, and successful cloning experiments.

4. Using the Calculator

Tips: Enter DNA concentrations in ng/μL and lengths in base pairs. Typical ratios for ligations range from 1:1 to 3:1 (insert:vector).

5. Frequently Asked Questions (FAQ)

Q1: Why is molar ratio more important than mass ratio?
A: Molar ratio ensures equal numbers of molecules are present, which is critical for reaction efficiency.

Q2: What's a typical ratio for cloning?
A: For standard cloning, 3:1 insert:vector ratio is common, but optimization may be needed.

Q3: How does DNA length affect the ratio?
A: Longer DNA fragments have more mass per mole, so concentration alone doesn't reflect molecule count.

Q4: Should I use this for PCR primer ratios?
A: Yes, but primers are typically used in large molar excess (10-50:1) relative to template.

Q5: What if my DNA is single-stranded?
A: Use 330 g/mol as the molecular weight per base instead of 617.96.