Below is the protocol for extracting DNA from strawberries. Feel free to try the extraction on any other fruits or vegetables or even liver (keep in mind strawberries are the easiest to mach up!). If you try the experiment at home, remember to take pictures, write down any observations you make, and record any changes you make to the steps. Homework extra credit will be offered for this experiment.
Materials:
- Zip lock bag
- 1 strawberry
- 2 teaspoons soap/salt water
- Gauze, cut into squares
- Ice-cold rubbing alcohol
- Test tube
- Small cup
- Wooden swab
Extraction Buffer Recipe:
2 tsp dish detergent + 1 cup of water + ¼ tsp salt
Strawberry Extraction Procedure:
- Place a strawberry in a zip lock bag and crush it until no chunks remain – don’t break bag!
- Add 2 teaspoons of the extraction buffer to the bag, zip it up and squeeze for 1 min to thoroughly mix the contents.
- Hold a square of gauze, paper towel, or coffee filter on top of the cup and slowly strain the strawberry mash into the cup.
- Next, carefully pour the strawberry juice from the cup into a test tube or small glass (medicine cup, etc).
- Slightly tilt the test tube and and pour alcohol slowly so that it runs down the side and stays on top. (Equal volume of alcohol to strawberry juice). Draw a picture in the box on the right.
- DO NOT MIX!
- Record your observations after 1-2 minutes. How many layers do you see? Does anything new appear?
- Stick the wooden end of the swab or toothpick into the top layer of liquid and slowly swirl.
- The precipitate (stuff that comes out of solution) should look like mucous and should be the DNA!
If you take pictures, we can add them to this post! Enjoy,
Mr. H
