Step 1: Start with a biological specimen. A banana, a mushroom, a tablespoon of green peas... whatever.
Step 2: Add a buffer
- something to keep the proteins from attacking the DNA once it is separated from its protective protein neighbors.
A simple buffer*:
4 ounces water
1/4 teaspoon table salt
one teaspoon baking soda
one teaspoon shampoo or liquid laundry detergent
[*source: S Carlson, Spooling the Stuff of Life, Scientific American
, September 1998]
Step 3: Grind up your sample to break open the cell walls. A blender will work well. Or a mortar and pestle (ceramic or plastic), or even a garlic press.
Step 4: Separate out the cell parts from the liquid containing the DNA.
... to be continued ...
DNA is a sugar, and dissolves well in water. It will clump up - precipitate - in a salt solution, or in alcohol.
Cells are bound by cell membranes - sort of oil/water mixes. In organisms other than animals there is also a cell wall on the outside of the cell membrane. To get at the DNA, the cell membrane needs to be broken open.
DNA is wrapped up with a bunch of proteins, these and other proteins can interfere with extracting the DNA and even cut the DNA up given a chance.
- will keep proteins from attacking DNA once it is separated from its protective protein neighbors.
Next: Visualize the DNA with Gel Electrophoresis
Gel Electrophoresis rig & Power Supply
better cheaper electrophoresis buffer: SB (Sodium Borate) at Faster Better Media