February 25, 2011

DNA Fingerprinting:

This lab was meant to help us identify a few samples of DNA retrieved from a crime

scene. We had 5 samples from suspects and one from the crime scene. The first part

consists of cutting the DNA at specific sites using a certain restriction enzyme that

specifically binds to the desired segment to cut. The second part consists of the actual

electrophoresis of the samples. Here the DNA will displace itself according to the size of

the molecules in each well. Since the restriction enzyme cuts at certain segments, then

it should cut the criminals DNA in the same place it would on any other molecule. The

difference is that when the DNA is cut, the variation among humans will create different

lengths of DNA meaning that, if the criminal’s DNA is cut by the same enzyme 20 times,

then you will get the same results all 20 times. After electrophoresis, the DNA that

moved to the exact same spot that the crime scene sample moved to was suspect 3.

This means that this suspect’s DNA is the same to the DNA sample found in the crime

scene.