Friday, December 28, 2007

Genetic fingerprinting

Forensic science
Physiological sciences
Forensic pathology · Forensic dentistry
Forensic anthropology · Forensic entomology
Social sciences
Forensic psychology · Forensic psychiatry
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Fingerprint analysis · Forensic Accounting
Ballistics · Bloodstain pattern analysis
DNA analysis · Forensic toxicology
Forensic footwear evidence
Questioned document examination
Explosion analysis
Cybertechnology in forensics
Information forensics · Computer forensics
Related disciplines
Forensic engineering
Fire investigation
Vehicular accident reconstruction
People in Forensics
Edmond Locard
Bill Bass
Related articles
Crime scene · CSI Effect
Trace evidence
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Genetic fingerprinting, DNA testing, DNA typing, and DNA profiling are techniques used to distinguish between individuals of the same species using only samples of their DNA. Its invention by Dr. Alec Jeffreys at the University of Leicester was announced in 1985. Two humans will have the vast majority of their DNA sequence in common. Genetic fingerprinting exploits highly variable repeating sequences called minisatellites. Two unrelated humans will be unlikely to have the same numbers of minisatellites at a given locus. In STR profiling, which is distinct from DNA fingerprinting, PCR is used to obtain enough DNA to then detect the number of repeats at several loci. It is possible to establish a match that is extremely unlikely to have arisen by coincidence, except in the case of identical twins, who will have identical genetic profiles.

Genetic fingerprinting is used in forensic science, to match suspects to samples of blood, hair, saliva or semen. It has also led to several exonerations of formerly convicted suspects. It is also used in such applications as identifying human remains, paternity testing, matching organ donors, studying populations of wild animals, and establishing the province or composition of foods. It has also been used to generate hypotheses on the pattern of the human diaspora in prehistoric times.

Testing is subject to the legal code of the jurisdiction in which it is performed. Usually the testing is voluntary, but it can be made compulsory by such instruments as a search warrant or court order. Several jurisdictions have also begun to assemble databases containing DNA information of convicts.

The United States maintains the largest DNA database in the world: The Combined DNA Index System, with over 4.5 million records as of 2007. The United Kingdom, maintains the National DNA Database (NDNAD), which is of similar size. The size of this database,and its rate of growth, is giving concern to civil liberties groups in the UK, where police have wide-ranging powers to take samples and retain them even in the event of acquittal.[1]