Lab step 2: DNA collection

Today we collected the DNA from the murder suspect's, and used soap to break the cell wall of the cheek cells with liquid detergent instead of enzymes.

Process

1. Murder suspect will complete this procedure.  Swish 2 teaspoons (10 ml) 0.9 percent salt water in your mouth for 30 seconds. This amount of swishing will actually become quite laborious -- hang in there!
2. Spit the water into the cup.
3. Make your soap and water solution (enough for all your DNA samples) Using a large test tube containing 12.25 ml of liquid detergent to 50 ml of water (25% mild detergent)
4. Using a pipette take 5 ml of each sample of DNA that you plan on collecting and place them in their own test tube. Be sure to label each test tube carefully.
5. Add 5 ml of your mild detergent to each test tube using a dropper.
6. Cap tube and gently rock it on its side for 2-3 minutes.
7. Transfer samples to labeled 15 ml test tubes.