Separation of DNA Fragments by Agarose Gel Electrophoresis.
The aim of this experiment is to separate DNA fragments with the use of agarose gels, and analysing the results using DNA fingerprinting in order to compare suspect samples A, B, and C to sample X recovered from the crime scene. This separation was done using gel tank apparatus which with the supply of a voltage produces a current which allows the dye to migrate slowly towards the positive end of the gel tank. I obtained estimated values for the band sizes for each sample from a calibration graph plotted using the marker values, which showed the similarities between suspect sample A and the crime scene sample X. After analysing both the values obtained from the graph and the photographic documentation of my gel, I interpret and conclude that the DNA found at the crime scene matches the DNA from suspect A, and therefore, it is likely that suspect A committed the crime.
Materials and Methods:
In order to cut up the DNA a restriction enzyme was added to all the samples, which were left to incubate at 37°C from 10:39AM to 11:10AM, for a total of 31 minutes. The apparatus used for the DNA fragment analysis is a gel tank, and after preparing the agarose gel solution the inside joints of the gel tank were sealed using a small amount of the gel solution in order to prevent leaks which can be caused when pouring the gel solution into the gel former. Air bubbles formed in the gel solution were burst using a pipette tip. The samples were prepared and then loaded into the wells of the gel in the following loading order: (A, B, C, X, Control, M (marker)). The empty slots on each side of the apparatus were filled in with the filler mix, which results in a more constant current flow through the gel. With the help of a demonstrator, the gel tank was connected to a power supply with a set voltage of 90V. This run was started at 12:00PM and stopped at 1:20PM. The gel was then examined using a UV...