CSI: Acalanes

Restriction Fragment Length Polymorphism (RFLP) is the method forensic labs use for DNA profiling.  It gives a unique banding pattern based on the restriction sites that are represented in a person's DNA sequence.  In this lab we will compare band patterns produced by restriction enzyme cleavage of DNA samples when separated on an agarose gel.  We will be trying to find the culprit of a "crime" based on DNA taken from a crime scene in the case.  Restriction enzymes are key in this lab, they are naturally found in bacterium to protect itself from viruses or bacteriophages.  What they do is they find specific sequences of DNA base pairs that it recognizes from the phage and they cut it at that point.  The effect is that the DNA from the invading cell is never sequenced therefore the phage does not succeed in creating a replication plant from the bacteria cell.  If a restriction enzyme notices multiple codes of the DNA it is looking for it will make cuts at both sites, which will then result in differing lengths of DNA fragments.  This is what is key in our lab and in the fingerprinting process.  Then we will use the process known as agarose gel electrophoresis to create a plasmid map of the DNA.  We will place the DNA fragments in a conductive solution.  Then we will shoot a current through the gel and because the DNA is negatively charged it will move towards the positive end of the gel.  But the smaller fragments will be able to travel farther than the large ones, and the large ones will congregate together.  Then we will compare the plasmid map with that of the DNA of the suspect, and the ones that match will be the criminal.

I was not there for the first day of the lab, but we successfully put the DNA fragments into the gel using the pipets.  Then when we charged the solution we saw the fragments moving through the gel.  After the gel was finished moving we were able to analyze the results.  We saw that the gel most closely resembled that of Chloe's, so we believed that she was the culprit in the crime.  It was cool to actually use the process that real crime scenes use and to be able to analyze the results and come up with our own conclusion on who did it.  Unfortunately I was not there on the day when the lab was set up, but I wish I was because I thought it was a really cool lab.