VI.) Touching DNA: Strawberry
DNA Isolation using
(wear eye protection, or be
Working in groups, but each
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)
shampoo without conditioner or dishwashing liquid
Frozen Strawberries: allow to come to room
temperature, or at
bags (good ones with good zip-locks)
cloth or coffee filter
aluminum foil (to make a funnel)
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!
To disrupt cell membranes to liberate
To shield the negative charges
on DNA to allow precipitation
To cause DNA to precipitate