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Home School Life Journal ................................................................................................................painting by Katie Bergenholtz

Strawberry DNA Extraction

Put strawberries and a plastic bag. We used about three good-sized ones.
Add a teaspoon or so of water and mushed up the strawberries.

Carefully pour only the liquid of the strawberries into a test tube. Try to avoid clumps of strawberries. I have my test tubes packed, so I used a clean spice jar.
Add 1/4 teaspoon of dish washing soap. Stir it up with a wooden skewer or just shake the tube around a little to mix together.
Very carefully add ice cold rubbing alcohol (from the refrigerator) to the test tube. You want the alcohol to remain on top of the strawberry juice.

Now just watch and see something amazing happen in just minutes.
We have DNA! The little white strands are what you are looking for.


The Science Behind It
In higher organisms like plants and animals, DNA is stored in a compartment called a nucleus where the long, string-like DNA is tightly coiled. To separate DNA from the organism that contains it, you have to break the cells apart (lysis), filter out the big pieces of cell parts and collect the remaining liquid, or supernatent, and add chemicals like salt and alcohol to separate (precipitate) the DNA from the rest of the supernatent.

9 comments:

  1. Thank you for posting this. I was JUST telling Keilee about doing this. Love it!

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  2. That's amazing! Does the process work with anything else?

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    1. You can get DNA from anything that is living, but some things take a more complicated process...check out this site...http://learn.genetics.utah.edu/content/labs/extraction/howto/

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  3. That is crazy cool!

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  4. Fun!!! As always. ;)

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  5. We did this in a CSI class I did for my Homeschool Co-Op, but your way is a lot less complicated than our way! :0)

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    1. A lot of them call for using meat tenderizer and salt. According to this web site,
      http://learn.genetics.utah.edu/content/labs/extraction/howto/faq.html
      "Salty water helps the DNA precipitate (solidify and appear) when alcohol is added...We have found no difference in the "product" (nucleic acids) that is observable, whether using meat tenderizer or not...Even though it's not necessary, it may be doing something we can't see. For example, perhaps by using the meat tenderizer you get a purer sample of DNA, with less protein contaminating the sample."

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  6. But then you can't eat the strawberries!

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    1. You only use about three and actually, you just need some of the juice. Katie ate the mush that was leftover after we got some of the juice out of them!

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