1. What is Molar Ratio?

The molar ratio is the ratio of moles of insert DNA to moles of vector DNA in a ligation reaction. It's crucial for efficient cloning, with typical ratios ranging from 2:1 to 10:1 (insert:vector).

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• Insert moles — Amount of insert DNA in moles
• Vector moles — Amount of vector DNA in moles

Explanation: The ratio determines how many insert molecules are available for each vector molecule during ligation.

3. Importance of Molar Ratio in Cloning

Details: Proper molar ratios help prevent:

• Vector self-ligation (too little insert)
• Multiple inserts (too much insert)
• Inefficient cloning (incorrect ratios)

4. Using the Calculator

Tips:

• Calculate moles from concentration (ng/μL) and molecular weight
• Typical ratios are 3:1 to 5:1 for standard cloning
• For blunt-end ligations, higher ratios (10:1) may be needed

5. Frequently Asked Questions (FAQ)

Q1: What's the ideal molar ratio for cloning?
A: For sticky-end ligations, 3:1 insert:vector is often optimal. For blunt ends, try 5:1 to 10:1.

Q2: How do I convert ng to moles?
A: Use the formula: moles = (mass in g) / (molecular weight in g/mol). For DNA: MW = (length in bp) × 650 g/mol/bp.

Q3: What if my ratio is too high?
A: Excessive insert can lead to multiple inserts in one vector. Reduce insert amount or increase vector amount.

Q4: Does ratio affect transformation efficiency?
A: Yes, incorrect ratios can significantly reduce the number of correct clones obtained.

Q5: Should I use total DNA amount or molar ratio?
A: Molar ratio is more important than total DNA amount for efficient ligation.