Extraction of DNA from Beef Liver
1. Obtain a 10-g to 15-g sample of beef liver and place it in the mortar.
2. Using scissors, cut the liver into small pieces.
3. Add 10 mL of 0.9% NaCl solution to the diced liver. Use a 10-mL graduated cylinder to
measure out the NaCl. Add a pinch of sand into the mixture to act as an abrasive, and grind
the tissue thoroughly for approximately 5 min.
4. Strain the liver cell suspension through several layers of cheesecloth to eliminate any
unpulverized liver. Collect the filtrate into a 50-mL beaker.
5. Add 3 mL of 10% SDS solution. If a centrifuge is available, spin the suspension, and remove
and save the supernatant. If a centrifuge is not available, mix the suspension thoroughly for 30
s and proceed to step 6.
6. Gently layer twice the volume of cold 95% ethanol on the supernatant as the total volume of
the cell suspension–SDS mixture. Use a 50-mL graduated cylinder to measure out the
ethanol.
7. Using the glass rod, stir gently and slowly. A white, mucuslike substance will appear at the
interface between the solutions. This substance is the DNA–nucleoprotein complex. After the
complex has formed, twirl the stirring rod slowly and collect it onto the rod. Record your
observations.