Extract DNA from fruit

DNA is the blueprint for life. This simple experiment will show you how to extract DNA from fruit like a banana or strawberry. All you need are some fruit and some things you probably have around the house right now.

What you need:

  • Half of a banana, kiwi, or strawberry
  • Coffee filter
  • 4 tsp. 91% isopropyl alcohol – chilled
  • 2-3 pinches of salt
  • 2 tsp. clear shampoo

  • Eye dropper
  • teaspoon
  • 3 plastic cups
  • Small test tube or glass
  • Water

 

Before you start:
A blue print is a detailed drawing or map that directs the construction of a building. DNA (deoxyribonucleic acid) is the hereditary material that directs the construction of living things. Nearly every cell in a person’s body has the same DNA.

What to do:

  1. Mix shampoo, salt and 4 tsp of tap water. Try not to create bubbles.
  2. In a separate cup, mash the fruit and a little water into a pulp.
  3. Add 4 tsp. of fruit mush to shampoo/salt mixture. Gently mix until it is a uniform consistency. Try not to make too many bubbles.
  4. Place the coffee filter in a cup then carefully pour the shampoo/fruit mixture into filter. Filter until there is about 2 tsp of fluid in the cup.
  5. Pour alcohol into small glass or test tube. Using the eye dropper, pick up filtered fruit fluid and slowly drop it into the container of alcohol. Don’t shake it! Observe the DNA that appears.

CONGRATULATIONS! You have isolated DNA, the blueprint for all things living.

How it works:
The shampoo breaks up the membranes of the cell, allowing the DNA to come out of the cell. Filtering the fruit “goo” gets rid of the debris you don’t need. The salt can dissolve in water, but not in alcohol. In the fruit “goo”, the salt binds to the DNA and when put into the alcohol the salt solidifies and can be seen with the DNA. The salt falls to the bottom of the test tube, leaving only the DNA. The alcohol is kept cold because it helps protect the DNA.

20 replies
  1. Jayden
    Jayden says:

    I got an A on my science fair project and won first place with this and I’m only in the 6th grade. Thank you who ever did this. Thank you!

  2. Shizuko Ziglar
    Shizuko Ziglar says:

    Wow that was unusual. I just wrote an very long comment but after I clicked submit my comment didn’t show up. Grrrr… well I’m not writing all that over again. Anyway, just wanted to say excellent blog!

  3. Connie
    Connie says:

    this is really nice and i am using this for my sscience fair project on wednesday is when the actual science fair is going to happen. i really hope that this will get me first place. ill tell you how it goes. 🙂 thanks for all the help.

  4. Carl
    Carl says:

    Yes, you can use the same procedure for other fruits. Some work better than others. I’ve had a lot of success with strawberries and bananas. Try some others and let us know how it works out!

  5. Carl
    Carl says:

    Hi Demi,

    I have never used pears, but there is no reason it should not work. Pears contain DNA, so give a try and let me know how it works for you!

    Carl

  6. kathleen
    kathleen says:

    Hi – I was reading an activity that did this by swishing salt water in your mouth, so I did try it. It did not produce as impressive results as the fruit does. I am doing this with my 8th grade class

  7. M
    M says:

    Hi, Can you tell me if you are able to quantify the amount of DNA generated? As part of the class project we would like to quantify for each fruit and would like to know how to do that in order to compare. Can you post any of your pictures on how it looks. We tried with black berries and noticed white slimy stuff surface up.

  8. Carl
    Carl says:

    Hi Mandy, I would start by using the same amount of water, soap, alcohol and fruit for each trial. These would be your controls.

    If you have access to a digital scale you could measure the amount of DNA extracted at the end of the procedure by weight.

    Carl

  9. Jordan
    Jordan says:

    I tried six different fruits and only the kiwi, mango, and banana showed the DNA strands better. Grapes, pomegranate, plums did not show anything. Not sure why, do you know?

  10. T
    T says:

    I have done this lab multiple times as well however now i am doing this lab with as extension to quantify the amount of DNA that I get in my test tubes, is their any way to figure that out?

  11. Carl
    Carl says:

    Hi Timo,
    There certainty are ways to quantify the amount of DNA you’ve extracted, however, I don’t know of any simple “at home” way to do so. Most laboratory methods involve equipment and chemicals that are typically not available to the “at home” scientist. You might try contacting your local university biology department to see if they could lend a hand.
    Carl

  12. noriae
    noriae says:

    Wow I really hope this work for the science fair soon good luck for me…………..,……………

  13. Student
    Student says:

    Yeah, I’ve got a question and I’m in need of an answer, quick!
    “The alcohol is kept cold because it helps protect the DNA.”
    what does it protect it from?
    REPLY ASAP!

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