Strawberry DNA Extraction
DNA Isolation using Strawberries (wear eye protection, or be careful).
Working in groups (for supervision), but each individual will do their own.
- Place 1 strawberry in the plastic bag. Remove air and seal.
- Mash strawberry for 2 minutes.
- Add ~10 ml DNA Extraction buffer (Pre-measured). Remove air and seal.
- Mash for 1 minute.
- Pour solution through coffee filter into paper cup
- Pour ~2 ml of this solution back into the 15 ml tube. It will be very red.
- Pour ~ 4 ml (2X the volume of strawberry solution) of cold ethanol (found on freeze door in 50 ml tubes) so that it lays on top of the strawberry solution. (NOTE: can use 1X volume of room temperature isopropanol, rubbing alcohol, as a substitute)
- If the tube just sits, there will be DNA at the interface with bubbles in it. If you gently rock the tube, more will come out of solution and eventually float to the top. (NOTE: if the DNA doesn’t come out of solution at home, add a little more salt)
100 ml shampoo without conditioner or dishwashing liquid
900 ml distilled water
15 grams NaCl
Frozen Strawberries: allow to come to room temperature, or at least un-freeze.
Sandwich bags (good ones with good zip-locks)
Cheese cloth or coffee filter
Funnel or aluminum foil (to make a funnel)
Cups, or flask, 15ml centrifuge tubes
Strawberries? 8 times the amount of DNA of normal cells
Why frozen? Ice disrupts cells. Can use fresh strawberries, too. Cheap!
Detergent? To disrupt cell membranes to liberate the DNA
Salt? To shield the negative charges on DNA to allow precipitation
Alcohol? To cause DNA to precipitate