PCRing

The trip to the Life Lab at the Centre for Life in Newcastle went ahead today. Here is what happened…

First we were asked to chew the inside of our cheeks to dislodge some cells. I think I may have taken this instruction too literally as my cheeks are still a bit sore! We rinsed with Lucozade and spat this back into the cup.

We then separated the cheek cells from the liquid by using a centrifuge which caused the cells to form a pellet. We then added detergent to the cells to break down the cell membranes and heated the liquid.

Then we used our newly acquired micropipetting skills to make up our PCR solution. Nucleotides, primers, polymerases, buffers, some dye, and, of course, our DNA were mixed together and put into the PCR machine.

We went on to make our agar plates, by which point it was time to have lunch. A spontaneous (!) debate erupted after lunch concerning the moral side of genetic testing and the impact of advances in genetic technologies on everyday life.

Enough of the talking, it was time to get back to the lab. We carefully transferred the gel into the electrophoresis box and filled the box with buffer solution.

Next, we transferred our DNA samples, which had completed their time in the PCR machine, into the slots in the gel. We connected the electrodes on the box to the power supply and then sat back and relaxed.

After an origami interlude (some people were disturbingly good at origami), we checked our gels to see that the electrophoresis has done its job and dragged the samples through the gel, hopefully separating the different length strands of DNA.

But, of course, DNA is colourless, so we had to stain the gel to make the individual lines show up. A few swishes and then washes later and we had our dyed gel with DNA samples exposed on it.

A trip to the light box revealed lines showing where some of the DNA had been separated. Unfortunately, not all of the samples showed the telltale lines, and the lightbox made the photos come out all funny. But the end results showed the principles of gel electrophoresis on DNA samples, even if it was difficult to discern some of the lines.

So all in all a good day in the lab. Hopefully the students found the day useful and helpful. Remember, there are useful animations explaining PCR and electrophoresis on this post.