Serious Problems with DNA Fingerprinting
Is there any piece of physical evidence so foolproof it could be used to prove or disprove anyone's case in a trial? Many people believe the answer to this question is DNA. In theory, this argument is true, but many believe certain factors can lead to inconsistent data gathered from DNA. There are many differing opinions on how DNA should be used, or if it should be used at all.
Many people are uninformed about what DNA actually is or how it is used in criminal trials. DNA is the generic term for deoxyribonucleic acid. It is a molecule found throughout the entire body that determines all inherited characteristics (Forensic Testing Division, 1998). Someone receives half of his or her genetic makeup from each biological parent, making each person's genetic makeup unique, except for identical twins.
Since the genetic makeup of each individual is entirely different from another, it is believed that DNA can be used to prove exactly who was at a crime scene and who was not. The process to determine whose DNA has been gathered at a crime scene is known as DNA fingerprinting. In actuality, only 2% of DNA are genes; the rest is called "junk DNA" which biological purpose is unknown (Verrengia, 1997). Junk DNA is what is mainly used in DNA fingerprinting.
DNA can be found in many different substances including hair, saliva, blood, and other fluids or tissues. That junk DNA found in these substances are tested in different ways including Restriction Fragment Length Polymorphism and Polymerase Chain Reaction. These tests are usually referred as the RFLP and PCR tests, respectively.
In these tests, DNA is exposed to enzymes which cause the strands to divide at different points. "Variable number tandem repeats" is the name given to this phenomena, and it enables technicians to test DNA in an interesting way. The fragments are subjected to electrophoresis-a process in which an electric charge propels the fragments through a gel (Williams, 1989). Logically, the shorter strands will move at a faster rate than longer ones, thus leaving different patterns for different people. The process is not finished, though. The sample is given radioactive probes which bonds to the DNA. Lastly, the sample is blotted against film which shows a unique pattern for every individual, similar to a bar code. This bar code is then compared to a sample from the suspect in question. It should be known that the theoretical chances of someone having the some DNA fingerprint of someone else is said by some to be as little as one in one quadrillion. This is why many scientists and prosecutors believe DNA is a great way to create an open-and-shut case.
Although the process used in DNA fingerprinting is very complicated, it is a little easier to understand the arguments posed for or against this process. In many cases ranging from the famed O.J. Simpson murder trial to the JonBenet...