DNA Copy Number and Concentration Calculator

This tool helps you accurately dilute a DNA stock solution to achieve a specified DNA copy number per microliter (µL).

Calculator start by with standard molar mass per base pair (bp) of your DNA (650 g/mol per base pair). If your DNA has a known molar mass different from the default, adjust this value accordingly.

Next, select the source of your DNA. You can choose from various organisms or opt for a “Custom DNA fragment.” If you select a custom fragment, be sure to input the length of the DNA fragment.

Enter the measured concentration of your DNA stock solution.

Specify the desired concentration in copies per microliter (copies/µL) and the total volume of the solution you need.

The calculator will then determine the exact volumes of the stock solution and diluent required to achieve your target concentration.

DNA Copy Number and Concentration Calculator

DNA Copy Number and Concentration Calculator

Custom DNA Fragment
Stock Solution
Dilution

The DNA Copy Number and Concentration Calculator is a powerful tool designed for molecular biologists, geneticists, and bioinformaticians. It facilitates the calculation of DNA copy number, stock solution concentration, and the preparation of dilutions. This tool is particularly useful for experiments requiring precise DNA quantification, such as qPCR, cloning, and sequencing.

Basic Concepts

Understanding the basic concepts of DNA copy number and concentration calculations is essential for using this tool effectively.

  1. DNA Copy Number:
    • DNA copy number refers to the number of copies of a specific DNA fragment in a given sample. It is crucial for quantifying the amount of DNA in applications like quantitative PCR (qPCR) and other molecular biology techniques.
    • The calculation of DNA copy number involves determining the number of molecules in a specific mass of DNA. This is typically expressed as copies per nanogram (copies/ng).
  2. Molar Mass:
    • The molar mass of a DNA fragment is the mass of one mole of that fragment. For double-stranded DNA (dsDNA), the average molar mass per base pair (bp) is approximately 650 g/mol. This value can be adjusted for different DNA types or organisms.
    • The molar mass of a DNA fragment can be calculated by multiplying the fragment length (in base pairs) by the average molar mass per base pair.
  3. Stock Solution Concentration:
    • Stock solution concentration refers to the concentration of DNA in a stock solution, typically expressed in nanograms per microliter (ng/µL).
    • Knowing the concentration of the stock solution is essential for preparing dilutions and ensuring accurate measurements in experiments.
  4. Dilution:
    • Dilution involves reducing the concentration of a DNA solution to a desired level. This is achieved by adding a diluent (e.g., water or TE buffer) to the stock solution.
    • The tool calculates the volume of stock solution and diluent needed to achieve the desired concentration and total volume.

Formulas and Calculations

The DNA Copy Number and Concentration Calculator uses several key formulas to perform its calculations. Below is an explanation of these formulas and how they are applied.

  1. Molar Mass Calculation:
    • Molar Mass (g/mol) = Fragment Length (bp) × Average Molar Mass per Base Pair (650 g/mol/bp)
    • This formula calculates the molar mass of the DNA fragment based on its length and the average molar mass per base pair.
  2. DNA Copy Number Calculation:
    • Copies per ng (copies/ng) = (6.022 × 10^23) / Molar Mass (g/mol) × 10^-9
    • Avogadro’s number (6.022 × 10^23) is used to convert moles to molecules. This formula calculates the number of copies of the DNA fragment in one nanogram of DNA.
  3. Stock Solution Copies Calculation:
    • Copies per µL in stock = Copies per ng × Stock Concentration (ng/µL)
    • This formula calculates the number of DNA copies per microliter in the stock solution based on its concentration.
  4. Molarity Calculation:
    • Molarity (M) = Copies per µL / 6.022 × 10^17
    • This formula converts the number of copies per microliter to molarity (moles per liter) using Avogadro’s number.
  5. Dilution Calculation:
    • Volume of Stock (µL) = (Desired Concentration (copies/µL) × Total Volume (µL)) / Copies per µL in stock
    • Dilution Volume (µL) = Total Volume (µL) – Volume of Stock (µL)
    • These formulas calculate the volume of the stock solution and diluent needed to achieve the desired DNA concentration and total volume.

Example Usage

Example 1: Calculating DNA Copy Number

  1. Enter the fragment length: 1,000,000 bp
  2. The tool calculates the molar mass: 650,000,000 g/mol
  3. The tool calculates the copies per ng: 926,462 copies/ng

Example 2: Preparing a Stock Solution

  1. Enter the stock concentration: 100 ng/µL
  2. The tool calculates the copies per µL in stock: 92,646,200 copies/µL
  3. The tool calculates the molarity of stock: 0.15 nM

Example 3: Preparing a Dilution

  1. Enter the desired concentration: 10,000 copies/µL
  2. Enter the total volume: 500 µL
  3. The tool calculates the volume of stock: 0.05 µL
  4. The tool calculates the dilution volume: 499.95 µL

The DNA Copy Number and Concentration Calculator is an invaluable tool for researchers and professionals working with DNA. It streamlines the process of calculating DNA copy number, preparing stock solutions, and making precise dilutions. By understanding the underlying concepts and formulas, users can effectively utilize this tool to enhance their molecular biology experiments and research.