Discover Science Home Lab Series: Learn About DNA Extraction

During this discover science home lab we’re going to learn about DNA extraction. DNA (Deoxyribonucleic Acid) is found in every living thing. It is a molecule that contains the genetic code of all organisms and is, in effect, a blueprint that acts as an on-going set of plans for all of the substances produced during their lifetime.

We hear about DNA all the time. DNA is in the news virtually on a daily basis, it provides plenty of plot devices for TV and movies, and it is all around us…in every living thing! But how many of us have actually seen DNA? An actual DNA molecule is too small to see but there is an easy home experiment you can do with your child (of any grade level!) as a home school lab that will allow you to use some common household materials to extract a relatively large quantity of DNA from split peas and learn about DNA extraction in the process!

Here’s what you will need:

Meat tenderizer (any brand)
Isopropyl (rubbing) alcohol
Liquid dish washing detergent
Split Peas
Blender
A clear glass container (to act as a “beaker”)
Stirring rod or spoon

Learn About DNA Extraction Step 1: Blend about ½ cup split peas in about a cup of water. This should make a soupy mixture. What we are going to want to use is the homogeneous solution in the middle. You probably won’t need all of this but it’s good to have extra just in case.

Learn About DNA Extraction Step 2: Pour enough of the solution into your container to a level of two inches or so. Pour slowly out of the blender so you get the middle layer of solution.

Learn About DNA Extraction Step 3: Add one tablespoonful of dish washing detergent to the above solution. SLOWLY stir this for five minutes.

Learn About DNA Extraction Step 4: Add a pinch of meat tenderizer to the above solution. Again, stir for five minutes.

Learn About DNA Extraction Step 5: Drizzle (Tilt the container and pour SLOWLY down the inside of the glass) alcohol into the above container. If you do this correctly, a clear layer of alcohol will be floating on top of the denser split pea solution. Add enough alcohol so there is a three inch layer above the split pea solution.

Now, let the container sit and observe the alcohol layer. While you are doing this, here are a few things you can ask your child:

Q: Why did we use split peas?
A: They are cheap! They are also a great source of DNA!

Q: What does the detergent do?
A: Breaks down the cell membrane to release the contents of the cell.

Q: What is the meat tenderizer for?
A: Dissolves the nuclear membrane releasing the DNA inside the nucleus.

And finally, why did we drizzle the alcohol layer? To answer that question, let’s take a look at our container. We should be seeing bubbles forming in the alcohol. These bubbles are attached to strands of DNA! Wait about 15 minutes and all of the DNA should have floated to the top and can be scooped out.

This is a great at-home experiment that enables your children to learn about DNA extraction and shows that DNA is something more than a news story or a lesson in a biology book…Have fun!

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