DNA Fingerprinting is also referred to as DNA profiling and DNA typing. It was first developed as an identification technique in England in 1985. The original use was to expose the presence of any genetic diseases. About three years later it became used to identify criminals through the analysis of genetic material and to settle paternity disputes. It is still used for those reasons today.
The DNA fingerprinting process is called gel electrophoresis. It is a process that can sort pieces of DNA according to its size. The process is done by taking samples of DNA from the crime scene and comparing it with samples from the accused. Samples are taken from biological materials like blood, semen, hair, and saliva. In the testing process the DNA samples are first entered into the wells in a gel like substance called Agarose. The gel is placed between two electrodes, one negatively charged and the other positively charged. The wells in the Agarose are inserted on the negative side because DNA has a negative charge. Molecules of DNA then travel in lanes toward the positive side. Small molecules will travel farther than the bigger ones, because they have an easier time moving through the gel. So the molecules will then be assorted according to their size. Next, the gel is X-rayed to see the parallel bands (showed by black bars on the film) in each lane. The separated molecules of DNA form a pattern of parallel bands that show the structure of the DNA. The pattern should never change for one person. In a court of law, the results of a DNA fingerprinting examination can be used to convict or acquit an accused person. If the accused’s DNA matches the one at the crime scene then that person could be convicted.
Critics believe that a DNA fingerprint may not yet be reliable enough to use in the court system. They question how accurate a DNA fingerprint is and the cost of it. They believe that it is not very accurate because only a segment of DNA is used and not the complete strand. A DNA fingerprint may not be unique. The confirmation of the uniqueness has not been confirmed yet. Also the process is done in private laboratories so the exact testing standards may not be followed and standardized quality controls may not be used. Human error can have false results if they do not use the exact testing standards with quality controls. The testing is very expensive and if the accused can’t pay for the testing then they will not be able to defend themselves using the results of the test. Also a question is, will people misuse the process? A misuse that scares them is the unauthorized use of the database that will be created with the increasing use of the DNA fingerprint. An example of an unauthorized use is identifying individuals with a genetic disease by looking up their personal profile without their permission.
Katie Hoskins at the age of 15 found the body of her murdered mother, Glenda Hoskins, inside a rolled up carpet in their loft. She was attacked by her former lover, Victor Farrant, while taking a bath. She was planning to end their three-year relationship. Before her attack she received a letter from Victor stating, “take these instructions to be very serious. F*** me about or refuse to do anything I ask and you will be tied up and gagged. I will not repeat myself. You will not get a second chance. If I have to use any violence to get what I want, I will. It will make no difference to me, I’m going to get what I want either way. The choice is yours. Be good and willing to me and you will come to no harm. I will be gentle, but remember you must show willing and be responsive.” In the investigation of her body they found that she was pulled by her ankles while in the tub so he could suffocate her under the water. It also turns out that he attempted to kill a prostitute, Ann Fidler, two weeks before the death of Mrs. Hoskins. Mrs. Fidler was a prostitute who worked out of her home. Mr. Fidler found his barely alive wife after a visit by Mr. Farrant. He used an iron to beat her head so hard that it fell off the handle and he also used the necks of three bottles. She had such severe head injures that part of her brain had to be removed. Through DNA fingerprinting the blood samples at the crime scene matched Mr. Farrant that resulted in his arrest in July, 1996.
In Narborough, England two high school girls at the age of fifteen were raped and killed. A seventeen-year-old boy, Rodney Buckland turned himself in for one of the murders, in 1986. His DNA sample didn’t match the semen found in the girls bodies. So he was the first person in history to be cleared of a crime by DNA fingerprinting. After Rodney was cleared, they started a DNA based manhunt. Every man in that area between the ages of 18 and 35 was asked to turn in their blood samples voluntarily. A conversation discussing this matter between Colin Pitchfork and his friends was over heard by someone in a local pub. They were discussing how a friend was going to turn in a blood sample for him so he would not get caught. The police were called and Colin was arrested. His blood sample matched the one from the crime scenes. He was sentenced to two life sentences, in 1987. He was the first murderer to be convicted by a DNA fingerprint.
Belair, Robert DNA Fingerprinting Microsoft Encarta 98 Encyclopedia, 1993-1997
Lampton, Christopher DNA Fingerprinting, book, 1991