DNA Spooling Lab

Materials Needed:

• 20 ml chilled buffer solution.
• approximately 10 ml chilled ethanol.
• coffee stirrer.
• 25 ml graduated cylinder.
• (1) small plastic container.
• (1) beaker (100 or 150 ml).
• methylene blue stain.

Procedure:

1. Place pieces of the onion in a blender with a little distilled water and pulse in short bursts.
2. Place 10 ml of the onion mash into the beaker.
3. Add 20 ml of chilled buffer.
4. Stir vigorously for at least 2 minutes.
5. Pour the mixture through filter paper and collect the liquid in the plastic container.
6. Add an equal volume of chilled alcohol to the DNA / buffer solution. Tilt the container and allow the alcohol to dribble down the side. The alcohol is less dense and will float on top of the DNA / buffer.
7. To spool the DNA, insert a wooden coffee stirrer through the alcohol in the DNA / buffer solution. Gently twirl the stick just below the boundary of the two layers. After a minute of twirling, slowly pull the stick up through the alcohol. The DNA (white precipitate) will adhere to the stick.
8. You may add a small amount of blue food coloring to the plastic container to see any uncollected DNA.

Buffer Procedure:

In a clean glass, mix together the following:

1. 4 ounces (120 ml) of water
2. 1/4 teaspoon (1.5 gm) salt
3. 1 teaspoon (5 gm) baking soda
4. 1 teaspoon (5ml) of shampoo

For best results, chill this buffer.