iLabs – Sounds of Science – Gel Electrophoresis: Part I
One of our most popular classes is the Gel Electrophoresis class. Students learn how to use micropipettes, work with agarose gels and gel chambers, and microcentrifuge DNA samples to actually set up, run, stain, and read a DNA electrophoresis.
First, students practice loading “fake” gels with a blue-dyed sugar solution. The micropipettes are inserted into the tiny wells (slots) in the Jello-like material. Blue-dyed sugar solution, substituting for DNA material, is deposited in the wells.
Once they master this, the students go on to load actual agarose gels with “fake DNA crime samples” – i.e., samples from a victim, the crime scene evidence, and two suspect DNA samples. These gels are then placed in a chamber and an electrical current is run through the chamber so that the various-sized DNA fragments are carried across the gel. Different-sized fragments travel different distances through the gel material. At the end of the process, the gels are stained and then bar patterns emerge. These represent the various DNA fragments from each of the 4 samples that stopped at different distances from the well. Students look to see if one of the suspects’ DNA samples matches the “evidence” one.
In the process of doing these activities they learn not only the procedures to do this test but why the process works the way it does. They also perform a DNA extraction from wheat germ.
Here are some shots from the class. In part II of this topic, videos of the class in action will be posted.