How Are Genetic Fingerprints Helpful in Forensics?
Forensics has mostly benefited from the developments in genetics. It analyzes small batches of genetic material which remains at the crime scene and is used to track down criminals who are behind it. Many cases have already been resolved with the use of genetic fingerprinting in forensic science. In fact, the use of this technology has revolutionized the investigation methodology of a crime.
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History
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The technique of genetic fingerprinting was invented by Alec Jeffreys of Leicester University. It is used especially for identification (as for forensic purposes) by extracting and identifying the base-pair pattern in an individual's DNA.
Technique
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The technique of genetic fingerprinting relies on the principle that repetitions of certain parts of DNA sequence vary amongst different people. This is known as genetic repetition. These repetitions can be arranged in such a manner so as to make it look like a bar code which is unique to each person. This is called as a multi-locus probe.
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First Application
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The original process was found incompetent to be used in forensics. So, Sir Alec and his team developed a variation of it and named it "genetic profiling". The first application was on a rape case where two girls were abducted, raped and murdered in Leicestershire. A man was arrested for this case, but he admitted to only one murder and not the other. So, the police decided to use this technology so that they could prove him guilty of both murders. But, once the test was conducted, it was found that he was innocent of both murders. Then, genetic profile of the entire males of that area was matched with samples obtained from the crime scene. At first, the test drew a blank until it was reported by someone that the sample provided by a man named Colin Pitchfork was actually his friend's. The case was thus closed.
Genetic Fingerprinting in Combination with PCR
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PCR or polymerase chain reaction is a method by which millions of samples of the same DNA sequence can be made in a very short period. For this, the DNA sequence is mixed with enzymes, nucleotides and primer and then, it undergoes regular heating and cooling to produce the samples. By combining this technique with genetic fingerprinting, the chances for finding the criminals increase many folds. Genetic fingerprinting can also be combined with techniques such as restriction fragment length polymorphism and amplified fragment length polymorphism to give better results.
Applications
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Genetic fingerprinting has aided in resolving a lot of criminal cases including murders, rapes and burglary. Also, it helps in excluding a suspect from a crime scene and has already proved its use in acquitting innocent people who were mistakenly arrested. Genetic fingerprinting is used to examine paternity claims and is used in such lawsuits.
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