Dna Testing

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  • Topic: DNA, Restriction fragment length polymorphism, Polymerase chain reaction
  • Pages : 6 (2323 words )
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  • Published : December 12, 2012
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Running Head: DNA Testing

DNA Testing

CRJ 311 Forensics
Timothy Knox
November 4, 2012

Thesis
DNA testing has become a major part of forensic science. It helps in so many areas of life. Catching criminals, freeing the innocent, determining paternity of children, amongst other things, are just a few ways DNA testing helps. It has a few cons like the financial burden of it. But in the end it is worth it. Without DNA there would be many offenders roaming the streets, while hundreds of innocents are prosecuted and imprisoned wrongly. Definition of DNA

DNA is an abbreviation for deoxyribonucleic acid. It is an important substance of the human body. DNA is a nucleic acid which contains genetic information about human bodies. It has the function to store information about your body. However DNA is not only found in humans. It can be found in animal as well. (dnadefinition.net, 2012). DNA is genetically inherited; half from a mother and the other half from the father. (Anjara, 2012) History of DNA

In 1950 graduate student Francis Crick and research fellow James Watson became interested in the research of DNA. Crick and Watson were not the only one’s studying DNA. In London Maurice Wilkins and Roseland Franklin were also studying DNA theories. In 1951 Franklin found that DNA could exist in two forms. By 1962 Watson and Crick won the Nobel Prize for physiology medicine. Franklin unfortunately was deceased and could not receive hers. Fred Sanger and his team developed many of the sequencing techniques continuing Franklin’s work. For 15 years Sanger and his collegues developed several and ever-improving methods to sequence DNA. This technique is still used today. (Bioinformatics, 2012). The DNA testing technique was first used in the late 1980’s. A Portland, Oregon man was convicted of raping and impregnating his 13year old daughter. Since the 80’s, DNA has been used widely in the court room. Even DNA from animals has been used. In one case a suspect was convicted for killing a couple and their dog. The blood from the dog was found on the suspects jacket. (ThinkQuest, 2012). Purpose of DNA Testing

There are many purposes for DNA testing. It can vary from catching criminal, freeing innocent offenders, identifying a dead body, and determining paternity. DNA testing is highly accurate. In one case, the odds that the match was incorrect were 350 million to 1. This makes DNA test the most accurate piece of evidence for a lawyer. (ThinkQuest, 2012). Types of DNA

DNA can be found in different places or in different objects. There is DNA in white blood cells, saliva, sweat, hair, semen, fingerprints, and fingernail clippings. DNA can be determined in any of these items. This is how criminals usually get caught. The use of DNA has become inseparable with investigation of violent and sexual crimes. DNA profiles can now be detected on swabs of steering wheels and be used as evidence in automobile theft. Types of DNA Testing

There are two types of DNA testing methods. The RFLP (restriction fragment length polymorphism) and the PCR (polymerase chain reaction); both very accurate, just conducted in different ways. The RFLP testing method, sometimes called DNA fingerprinting or profiling, is considered to be the most accurate. This test examines sequences of base pairs in a section of a DNA strand with high probability of being unique to the donor. Once a match is found there is no question that the donor was at the scene of the crime. The PCR testing method is not quite as accurate as the RFLP, but it takes less time to complete. The test can be performed within minutes of the crime scene samples which really help investigators who have very little physical evidence. The PCR test can test DNA no matter how old it is. This is because the PCR method involves copying the available DNA and analyzing only one specific gene. (ThinkQuest, 2012). Pros to DNA Testing

DNA profiling can be used to uniquely identify a person with good...
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