How has our knowledge of DNA improved the study of criminal forensics?
Through genetics, the study of DNA, we are able to figure out what and how genes are responsible for many things like our hair color or why do some people look a lot like their parents and others don’t. It also allows us to understand better how species evolve and how are they related to each other. It is important to understand how DNA mutates, changes and replicates in order to get information about what mechanisms cause DNA to change.
In the 1970s scientists developed a DNA sequencing technique and other methods to manipulate and analyze DNA. This gave them the basic tools to start exploring the ...view middle of the document...
Each human being contains a copy of DNA that allows analysis to be performed on samples of hair, skin, blood, sweat, saliva and semen. Forensics scientists used the DNA in those samples found in a crime scene in order to identify a matching DNA of an individual. This process is called “DNA profiling” but it may also be called “genetic fingerprinting”. We can use DNA analysis to identify an individual because about 0.1% of human genomes differ from others (Lyle 2005).
DNA Profiling and the Polymerase Chain Reaction
In 1984 an English geneticist, Alex Jeffreys of the University of Leicester developed DNA profiling, which was later used in 1986 to exonerate an innocent man and then led to the arrest of a rapist and murderer in the Enderby murders cases in England (Lyle 2005). Another important event that helped the advancement of DNA use in forensic sciences was the Polymerase Chain Reaction. In 1983, Kary B. Mulis developed the Polymerase Chain Reaction which is sometimes called “Molecular photocopying”. This technique helped the progress of DNA technology because before its development, the available methods used to amplify or generate copies of recombinant DNA fragments were time-consuming and labor-intensive (Encyclopedia Britannica). In contrast, PCR is a fast and inexpensive technique used to amplify small segments of DNA so that it can be analyzed by scientists. The process requires the DNA specimen, free DNA nucleotides, synthetic “primer” DNA, DNA polymerase, and simple lab equipment such as a test tube and a source of heat. To amplify a segment of DNA using PCR, the sample is heated so the DNA separates into two pieces of single-stranded DNA. Then an enzyme builds two new strands of DNA using the original strands as templates. Then each of these strands can be used to create new two new copies and so and so on (Genome Project).
DNA in the Criminal Justice System
In 1994, in the United States the DNA Identification Act gave the FBI the authority to start a national DNA index to assist with solving crimes and the National DNA Index System (NDIS) began operating in 1998. Nowadays, the NDIS is the highest level of the three-tiered Combined DNA Index System known as CODIS. All 50 states have passed legislation mandating that DNA profiles of particular convicted offenders be sent to CODIS. Currently the database has more than a million entries in its Convicted Offender Index and 50,000 profiles collected form crimes scenes that have not been matched to any specific criminal (Lyle 2005).
The new development of DNA technology and the ability of getting genetic matching on small samples of blood, skin, saliva or hair have led to many cases being re-opened. The Innocence Project is a nonprofit group dedicated to post-conviction DNA testing and they keep the number of exonerated people constantly updated in their homepage: www.innocentproject.org. As of February 2014, their website stated that DNA testing had absolved 312 people from wrongful...