ForensicBiologyIILab_protocolanddatasheet_Sp20 (1).docx -...

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Forensic Biology II Lab Objectives 1. Explain the principles of DNA electrophoresis in STR analysis. 2. Compare DNA profiles from potential suspects. Safety 1. Closed-toe shoes must be worn 2. Long hair tied back 3. Goggles must be worn at all times while experiments are being conducted in the classroom. Even if you’re done. 4. Gloves should be worn while performing the experiments. 5. All pipet tips should be ejected into the tip waste bin on your bench. 6. All microcentrifuge tubes should be disposed of in the tip waste bin. 7. Place your used gel in the biohazardous waste container. 8. Have your TA double check your gel box set up before turning on the power . 9. When all experiments and clean-up is complete, wash your hands with soap and water. Gel Electrophoresis 1. You will run the gel as a table (two groups of 4). Make sure that your table has a gel tray, electrophoresis chamber (gel box), and well comb. 2. Raise the end gates on the gel tray and finger tighten the set screws to hold it in place. 3. Take the gel tray to the sink and fill the gel tray with water and observe for any leaks. If there are no leaks, proceed below. If your tray leaks, check that all of the set screws are tightened and try again. 4. Use a “hot hands” hand protector to retrieve a flask of molten 2.0% agarose from the incubator. BE CAREFUL, MOLTEN AGAROSE IS HOT!!! (above 60°C). 5. Carefully, pour agarose into the gel tray and fill it to just below the center notch. 6. Insert the 12-well comb in one set of notches near an end gate. Allow the gel to solidify. 7. While the gel sets, practice loading sample wells using the agar plates, and set up your DNA sample for the gel run. Gel Loading Practice 1. Obtain a punched agar plate and fill it with enough water to cover the well holes. This will simulation the conditions you will encounter when loading your sample onto the agarose gel. 2. Using your P20 micropipettor, adjust the pipettor to 10.0 µl, and using the appropriate tip, pipet 10.0 µl of practice loading dye into the tip. 1
3. Bracing your wrist to hold the pipettor steady, place the pipet tip just barely into the well in your practice gel. This will be below the surface of the water. Slowly and carefully depress the plunger to express the sample from the tip into the well. The density of the loading dye is greater than that of the surrounding liquid, so the dye should “fall” into the well. When you reach the second stop on

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