DNA Fingerprinting (activity)
- The origin of the DNA samples for this exercise will be explained by the Instructor as numerous scenarios may be used (Edvotek Cat. #109)
- Prepare a 1% agarose gel by adding 60ml Tris-Borate-EDTA buffer (TBE) to 0.6g agarose in an erlenmeyer flask
- Place flask in microwave or on heat until agarose is melted
- stop periodically and swirl solution and do not permit to boil over
- Assemble the casting tray by blocking the ends with tape or plastic gaskets
- Place the comb into the casting tray at the NEGATIVE end
- The instructor will add 6μl Sybr Safe to his/her own gel solution at this time
- You may place the casting trays inside a refrigerator and pour the solution into the tray
- Wait until the gel is solidified
- Carefully separate the gaskets from the tray ensuring not to tear apart the wells made by the comb
- Remove the comb and place the casting tray into an electrophoresis chamber
- Cover the gel with TBE buffer
- Using a micropipettor, load 40-50μl dye samples sequentially into the wells
- Cover the electrophoresis chamber with the lid and ensure good contact between electrodes
- It is conventional that the POSITIVE side of the tank is nearest to you
- With the POSITIVE side nearest to you, load the samples from left to right
- Set the power supply to 100-120V and press the Run button (you should see bubbles at each electrode) and allow to run for at least 40 minutes
- After 40 minutes, stop the current and remove the gel in casting tray
- Slide the gels into the staining solution if they do not include Sybr Safe for visualization the subsequent meeting time
- The instructor will slide the gel onto a UV transilluminator behind a shield and show the results to the class
- Document the findings of the gel by photographing with your phone
- The instructor will discuss the results and ask for you to interpret the findings
- Why are the samples loaded at the negative side of the gel?
- What is the role of the dye in these samples? Should we be alarmed that the samples are all the same color?
- What does it mean that there are multiple bands in a lane? What does it mean that there is only one band in a lane?
- What can we conclude from the banding patterns in this forensics or paternity case? Is this sufficient data for these conclusions?
Tags: visual communication, integration of knowledge