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How to Extract DNA from Anything Living

Do Try This at Home Home DO Try This at Home! How to Extract DNA From Anything Living

How to Extract DNA from Anything Living

DNA! You mean I can see it? How?

Just follow these 3 easy steps:

eNzymes (meat tenderizer)

It's that simple? Tell me more!

First, you need to find something that contains DNA. Since DNA is the blueprint for life, everything living contains DNA.

green split peas

For this experiment, we like to use green split peas.

But there are lots of other DNA sources too, such as:

  • Spinach
  • Chicken liver
  • Onions
  • Broccoli

Here's the fun part. Put in a blender:
  • Your DNA source (about 100ml or 1/2 cup of split peas)
  • A large pinch of table salt (less than 1ml or 1/8 teaspoon)
  • Twice as much cold water as the DNA source (about 200ml or 1 cup)
blending DNA

Blend on high for 15 seconds.

The blender separates the pea cells from each other, so you now have a really thin pea-cell soup. Because this step is pretty messy, certain sources of DNA should not be used, such as:

  • Your family pet, Fido the dog
  • Your little sister's big toe
  • Bugs you caught in the yard
And now, those 3 easy steps:

1. Pour your thin pea-cell soup through a strainer into another container (like a measuring cup).

How much pea soup do you have? Add about 1/6 of that amount of liquid Detergent (about 30ml or 2 tablespoons) and swirl to mix. Let the mixture sit for 5-10 minutes.


liquid detergents

Try one of these detergents or whatever you have on hand.

Why am I adding detergent?

meat tenderizer

2. Add a pinch of enzymes to each test tube and stir gently. Be careful! If you stir too hard, you'll break up the DNA, making it harder to see.

Use meat tenderizer for enzymes. If you can't find tenderizer, try using pineapple juice or contact lens cleaning solution.

What is an enzyme?

pouring alcohol


extracting DNA

DNA will rise into the alcohol layer from the pea layer. You can use a wooden stick or other hook to draw the DNA into the alcohol.

What is that stringy stuff?

Alcohol is less dense than water, so it floats on top. Since two separate layers are formed, all of the grease and the protein that we broke up in the first two steps and the DNA have to decide:
"Hmmm...which layer should I go to?"

This is sort of like looking around the room for the most comfortable seat. Some will choose the couch, others might choose the rocking chair.

In this case, the protein and grease parts find the bottom, watery layer the most comfortable place, while the DNA prefers the top, alcohol layer.

DNA is a long, stringy molecule that likes to clump together.

Congratulations! You have just completed a DNA extraction!

Now that you've successfully extracted DNA from one source, you're ready to experiment further. Try these ideas or some of your own:

  • Experiment with other DNA sources. Which source gives you the most DNA? How can you compare them?
  • Experiment with different soaps and detergents. Do powdered soaps work as well as liquid detergents? How about shampoo or body scrub?
  • Experiment with leaving out or changing steps. We've told you that you need each step, but is this true? Find out for yourself. Try leaving out a step or changing how much of each ingredient you use.
  • Do only living organisms contain DNA? Try extracting DNA from things that you think might not have DNA.
Frequently Asked Questions
1. I'm pretty sure I'm not seeing DNA. What did I do wrong?


If you are sure you don't see DNA, then the next step is to make sure that you started with enough DNA in the first place. Many food sources of DNA, such as grapes, also contain a lot of water. If the blended cell soup is too watery, there won't be enough DNA to see. To fix this, go back to the first step and add less water. The cell soup should be opaque, meaning that you can't see through it.


2. Why does the DNA clump together?


Imagine this: the human body contains about 100 trillion cells, each of which contains six feet of DNA. If you do the math, you'll find that our bodies contain more than a billion miles of DNA!



4. Isn't the white, stringy stuff actually a mix of DNA and RNA?


Want to learn more?

Here are some books to try:

  • DNA Is Here to Stay, by Dr. Fran Balkwill. 1992. ISBN # 0-00-191165-1 (Ages 9-15)
  • Amazing Schemes within Your Genes, by Dr. Fran Balkwill. 1993. ISBN # 0-00-196465-1 (Ages 9-15)
  • Double Talking Helix Blues, by Joel Herskowitz. 1993. Book and cassette tape. ISBN # 0-87969-431-9 (Ages 8 and up)
  • Ingenious Genes, by Patrick A. Baeuerle and Norbert Landa. Barron's Educational Series, Inc., Hauppauge, NY. 1997. ISBN # 0-7641-5063-4 (Ages 8-12).
  • How the Y Makes the Guy, by Norbert Landa and Patrick A. Baeuerle. Barron's Educational Series, Inc., Hauppauge, NY. 1997. ISBN # 0-7641-5064-2 (Ages 8-12).

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