DNA Extraction

Experiment to purify DNA from fruit

Step 1: Mash up the fruit of your choice in a bowl. Bananas, kiwis and strawberries all work well. (Remove the skin of the bananas and kiwi, we just want the insides!)

Step 2: In a separate bowl, mix the washing up liquid, salt and tap water. Stir gently trying to avoid making too many bubbles in the mixture. This is your extraction buffer.

Step 3: Add the fruit to the extraction buffer and mix again. Mash your fruit sample as much as you can, but again, try to avoid making too many bubbles.

Step 4: Make a water bath with a temperature of about 60 °C. (A large washing up bowl works well for this.) Leave the fruit extraction mixture to incubate for 15 minutes.

Step 5: After 15 minutes, filter your fruit mixture through a fine sieve or coffee filter. This will remove all the solid material that you don’t want. You should be left with a clear(ish) liquid.

Step 6: Take the ice cold alcohol and very slowly, drop by drop, pour it down the inside of the container with your fruit mixture. What you want to do is produce a layer of the alcohol floating on top of the fruit mixture.

Step 7: At the interface between the alcohol and the fruit mixture, you should see a white cloud-like substance forming. Use a hook (a bent paperclip would work) to slowly draw the DNA up and out of the solution.