Case File: DNA Fingerprinting

     Dna Profiling involves the identification of a person's DNA. How do we do this, if 97 percent of our DNA is all the same? DNA Fingerprinting, or profiling, is the process by which we use to differ one person's identification from another. It involves small segments of DNA called microsatelites, which repeat throughout the DNA numerous times. They are ideal for forensics because they tend to be highly variable. Restriction enzymes, which come from bacteria, cut DNA into multiple fragments if they recognize sites that are repeated in the DNA, and thus creating a unique banding pattern in every peice of DNA. The location of restriction sites decide the length of each fragment. Agarose gel Electrophoresis is how we can measure the length of the bands. The pores in the agarose gel act as small passageways that the smaller segments of DNA pass through more easily than larger ones. The reason the DNA segments travel, that were cut by restriction enzymes, is because they are attracted to the positive pole of the gel. DNA is obviously negative, and opposites attract. The DNA is then stained and can be seen in the gel.

     More specific to the overview of this lab, Restriction enzymes are used to cut the DNA into palindrome sequences. These cuts will produce RFLP's, or restriction fragment length polymorphisms, which are specific patterns that the enzymes cut in someones DNA. The following step involves "running a gel", which involves cutting the gel into a square peice with little divets. The DNA, by pipet, is injected into the divets of the agarose gel and will travel to the opposite end (positive pole). The DNA will be stained and recorded as different patterns in the gel.
     The Crime Scene case file will be solved by running 6 segments of DNA through the agarose gel. One of them is the DNA found at the scene (the victim). The banding patterns of the 6 DNA fragments will be compared. Two of them will match up and we can finally punish the accused suspect that committed the crime! Some sources of error involve getting DNA mixed with other columns before the overnight banding patterns begin to develop. Another might be putting the DNA into the wrong columns.
     My hypothesis on this lab is practically useless, but I will take a wild stab. Number 4 will be the culprit. However, the results will show the real criminal and the reason we will know, if our work was not incorrect in the making, is because the banding patterns in the gel will match up.
     The results have been recorded. Katie Records, a known local person convicted of several felonies, was the criminal. The banding patterns of the original given DNA matches up almost identical to the number 3, Katie Records.This lab has not only increased my knowledge of how modern DNA forensics are practiced, but has led me to conclude that society can have an efficient system of DNA records to help in crimes today.