|1.) Pick out your veggie
You will want to pick out softer vegetables with a lot of pulp because they are easier to grind and break open the cells. We prefer tomatoes, bananas, kiwis, or mangos.
2.) Cut up the tomato
Cut the tomato into pieces small enough to fit in the bowl.
3.) Add extraction buffer and soap
Add about 2 tablespoons of extraction buffer and a couple of drops of liquid soap. The extraction buffer contains salts that mimic the environment inside the cell, allowing the cell's contents to spill out. The liquid soap breaks open the membranes surrounding the cell and the nucleus, where the DNA is. These membranes are made of greasy fats and, just like liquid soap cuts through grease on your dishes, it breaks open the fats that surround the cell and the nucleus and the DNA spills out. But first we must break open the cell wall that holds the cell in place.
4.) Grind the tomato
Grinding for a minute breaks open the cell wall so the liquid soap can break open the cell membranes and the nuclear membrane.
5.) Strain the slurry
This removes all the cells you have not opened yet.
6.) Add water and ethanol
Pour half a tablespoon of the slurry into a clear glass or tube and add an equal amount of water. Carefully add 4 tablespoons of cold ethanol.
The ethanol precipitates the DNA from solution.
7.) Swirl the two solutions to see DNA.
DNA is the snotty looking substance. A lot of this is water, but it also contains a good deal of DNA.
8.) Congratulations, You are a genetic engineer!