How to Extract DNA From Human Cheek Cells

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Animated DNA Molecule (brian0918)
Animated DNA Molecule (brian0918)

It’s easy to extract DNA from human cheek cells. You don’t even need a lab. Here’s how to do this experiment in your kitchen.

What Is DNA?

DNA is deoxyribonucleic acid. It’s the genetic material in every cell in your body, except mature red blood cells, which have lost their cellular nuclei. DNA codes for proteins, which are used to build structural material, such as teeth and bones, and also cells, which combine to form tissues and organs. Your DNA is unique to you!

Materials for DNA Extraction

  • sodium chloride (table salt)
  • liquid soap or detergent
  • distilled water
  • rubbing alcohol
  • yourself or a volunteer
  • a scale and a measuring cup or beaker for small volumes

How to Extract DNA

  1. First, you want to make an 8% salt solution. This means you dissolve 8 grams of salt in 92 milliliters of distilled water. If the salt won’t dissolve, you can microwave it for a few seconds to warm the water.
  2. In another container, mix together 25 milliliters liquid soap with 75 milliliters distilled water.
  3. Pour 10 milliliters of water into a cup. Swirl this water around in your mouth for 30 seconds to a minute.
  4. Spit the water into a small cup.
  5. Pour 1 milliliter of your salt solution into the cup.
  6. Add 1 milliliter of the liquid soap solution.
  7. Gently swirl the contents of the cup to mix them together.
  8. Pour 5 milliliters of rubbing alcohol down the side of the cup so that it slowly flows into the liquid.
  9. Within a few minutes, the DNA will rise to the surface of the cup as a cloudy, slimy-looking substance.
  10. Pour 1 milliliter of alcohol into a small, clear container (a test tube is great, if you have one handy).
  11. Use a glass rod or plastic toothpick to remove the DNA from its container. Do this by twirling the rod into the DNA, like twirling spaghetti onto a fork.
  12. Dip the rod into the container of alcohol. You may need to swish it around gently to dislodge the DNA you just extracted. That’s it!
  13. If you want more DNA, you can repeat the earlier steps and add the new DNA to the same final container. You’ll need to swish the water around in your mouth longer to get a good sample. Or, if you don’t really care about having the same DNA, add a sample from someone else’s mouth.

You can examine the DNA more closely using a magnifying glass or a microscope. The same process works with other types of cells. Try extracting DNA from a banana.