Genetic fingerprinting, DNA testing and DNA profiling are techniques used to distinguish between individuals of the same species using only samples of their DNA. Its invention by Sir 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 microsatellites. Two unrelated humans will be likely to have different numbers of microsatellites at a given locus. By using polymerase chain reaction to detect the number of repeats at several loci, it is possible to establish a match that is extremely unlikely to have arisen by coincidence. 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 studying populations of wild animals, paternity testing, identifying dead bodies, and establishing the province or composition of foods. It has also been used to generate hypotheses on the pattern of the human diaspora in prehistory 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 Kingdom currently has the most extensive DNA database in the world, with well over 2 million records as of 2005. 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. ==DNA fingerprinting process== DNA fingerprinting begins by extracting DNA from the cells in a sample of blood, saliva, semen, or other appropriate fluid or tissue. A common method is a mouth swab. Next, restriction fragment length polymorphism (RFLP) analysis is performed by using a restriction enzyme to cut the DNA into fragments which are separated into bands during agarose gel electrophoresis. Next, the bands of DNA are transferred via a technique called Southern blotting from the agarose gel to a nylon membrane. This is treated with a radioactively-labelled DNA probe which binds to certain and specific DNA sequences on the membrane. The excess DNA probe is washed off. An X-ray film placed next to the nylon membrane detects the radioactive pattern. This film is then developed to make a visible pattern of bands called DNA fingerprinting. Recently, an additional technique for genetic fingerprinting has been introduced: AFLP, or amplified fragment length polymorphism. This new technique is similar to RFLP analysis, but introduces a few other features, like two rounds of amplification and specially made primers. AFLP analysis is now highly automated, and allows for easy creation of phylogenetic trees based on comparing individual samples of DNA. One of the most modern and widely accepted methods for producing DNA fingerprints in criminal cases, is that of polymerase chain reaction (PCR). PCR involves the amplification of specific regions of DNA that are known to be highly variable from one individual to another. This amplification process allows the scientist to start with a very small amount of material, and the outcome is a highly discriminating outcome, with the chance of a random match being in the 1 in a billion region. PCR is by far the most common method for presenting DNA evidence in a forensic context. ==Considerations when evaluating DNA evidence== In the early days of the use of genetic fingerprinting as criminal evidence, juries were often swayed by spurious statistical arguments by defence lawyers along these lines: given a match that had a 1 in 5 million probability of occurring by chance, the lawyer would argue that this meant that in a country of say 60 million people there were 12 people who would also match the profile. This was then translated to a 1 in 12 chance of the suspect being the guilty one. This argument is not sound unless the suspect was drawn at random from the population of the country. In fact, a jury should consider how likely it is that an individual matching the genetic profile would also have been a suspect in the case for other reasons. The false assumption that a 1 in 5 million probability of a match automatically translates into a 1 in 5 million probability of innocence is known as the prosecutor's fallacy. Nowadays, more testing is carried out so that the theoretical risk of a coincidental match is 1 in 100 billion (100,000,000,000). However, the rate of laboratory error may be much higher than this, and often actual laboratory procedures do not reflect the theory under which the coincidence probabilities were computed. For example, the coincidence probabilities may be calculated based on the probabilities that markers in two samples have bands in ''precisely'' the same location, but a laboratory worker may conclude that similar -- but not precisely identical -- band patterns result from identical genetic samples with some imperfection in the agarose gel. However, in this case, the laboratory worker increases the coincidence risk by expanding the criteria for declaring a match. Recent studies have quoted relatively high error rates which may be cause for concern [http://www.guardian.co.uk/crime/article/0,2763,640157,00.html]. The cautious juror should not convict on genetic fingerprint evidence alone if other factors raise doubt. When evaluating a DNA match, the following questions should be asked: * Could it be an accidental random match? * If not, could the DNA sample have been planted? * If not, did the accused leave the DNA sample at the exact time of the crime? * If yes, does that mean that the accused is guilty of the crime? ==Fake DNA evidence== The value of DNA evidence has to be seen in light of recent cases where criminals planted fake DNA samples at crime scenes. In one notorious case, a criminal even planted fake DNA evidence in his own body: Dr. Schneeberger of Canada raped one of his sedated patients in 1992 and left semen on her underwear. His DNA was tested on three occasions, never showing a match. It turned out that he had surgically inserted a Penrose drain into his arm and filled it with foreign blood and anticoagulants. ==Cases== In 1988, United Kingdom baker Colin Pitchfork was the first person to be convicted using DNA evidence. In 1989, Florida rapist Tommie Lee Andrews was the first United States to be convicted as a result of DNA evidence, for an assault committed in 1987. In 1991, Allan Legere was the first Canada to be convicted as a result of DNA evidence, for four murders he had committed while an escaped prisoner in 1989. During his trial, his defense argued that the relatively shallow gene pool of the region could lead to false positives. In 1992, DNA evidence was used to prove that Nazi doctor Josef Mengele was buried in Brazil as Wolfgang Gerhard. The science was made famous in the United States in 1994 when prosecutors heavily relied on -- and through expert witnesses exhaustively presented and explained -- DNA evidence allegedly linking O. J. Simpson to a double murder. In June of 2003, because of new DNA evidence, Dennis Halstead, John Kogut and John Restivo won a re-trial on their murder conviction. The three men had already served 18 years of their 30-plus year sentences. The trial of Robert Pickton is notable in that DNA evidence is being used primarily to identify the ''victims'', and in many cases to prove their existence. == See also == * restriction fragment length polymorphism (RFLP) * paternity test * ''Harvey v. Horan'' == External links == *[http://www.aic.gov.au/publications/proceedings/02/freckle.pdf Discussion of concerns with DNA fingerprinting] *[http://science.howstuffworks.com/dna-evidence.htm How DNA Evidence Works] *[http://www.thenakedscientists.com/html/columnists/dalyacolumn8.htm How to make a DNA (genetic) Fingerprint and applications of DNA Fingerprinting] *[http://www.wellcome.ac.uk/en/genome/genesandbody/hg07f006.html The Wellcome Trust: History of DNA fingerprinting] Molecular biology Medical tests Applied genetics Personal identification
I don't understand how a 1 in 5 million chance translates into 30 people who would match the profile from a population of 60 million people. Wouldn't that be 12 people (and not 12 other people, 12 people in total)? Marisano ---- Agreed. I changed 30 to 12. User:Zashaw 02:06, 18 Aug 2003 (UTC) ----- This page seems redundant with DNA testing -- the articles should probably be merged, or, if there's a distinction between the articles, it should be made explicit. User:Zashaw 04:24, 18 Oct 2003 (UTC) So what are the advantages of this system ----- The second paragraph mentions PCR, the section on the DNA fingerprinting process doesn't. Which one is correct? Furthermore, what kinds of restriction enzymes/PCR primers are being used? User:AxelBoldt 16:21, 29 Jul 2004 (UTC) == Identifying a deceased person == Can someone explain in the article how a deceased person can be identified by genetic fingerprinting? I presume DNA is taken from a sample of a body part. Is it compared with a sample known to come from the putative person, before they died? Or is a comparison made against samples from blood relatives? If the latter, what are the principles involved? Is the situation the same as in a paternity test? User:Thincat 14:53, 24 Jan 2005 (UTC) It usually is compared against their parents / dental records / hospital samples and things like that. The procedure isn't fixed: the onus is on the law enforcement officers to use the sample to prove it in a number of ways. -- User:Natalinasmpf 02:10, 31 Mar 2005 (UTC) I UNDERSTAND COMPLETELY. And I poo on your eyes.
See other meanings of words starting from letter:
Words begining with Genetic_fingerprinting:
Genetic_fingerprinting
Genetic_fingerprinting
Genetic fingerprinting
Genetic fingerprinting, DNA testing and DNA profiling are techniques used to distinguish between individuals of the same species using only samples of their DNA. Its invention by Sir 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 microsatellites. Two unrelated humans will be likely to have different numbers of microsatellites at a given locus. By using polymerase chain reaction to detect the number of repeats at several loci, it is possible to establish a match that is extremely unlikely to have arisen by coincidence. 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 studying populations of wild animals, paternity testing, identifying dead bodies, and establishing the province or composition of foods. It has also been used to generate hypotheses on the pattern of the human diaspora in prehistory 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 Kingdom currently has the most extensive DNA database in the world, with well over 2 million records as of 2005. 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. ==DNA fingerprinting process== DNA fingerprinting begins by extracting DNA from the cells in a sample of blood, saliva, semen, or other appropriate fluid or tissue. A common method is a mouth swab. Next, restriction fragment length polymorphism (RFLP) analysis is performed by using a restriction enzyme to cut the DNA into fragments which are separated into bands during agarose gel electrophoresis. Next, the bands of DNA are transferred via a technique called Southern blotting from the agarose gel to a nylon membrane. This is treated with a radioactively-labelled DNA probe which binds to certain and specific DNA sequences on the membrane. The excess DNA probe is washed off. An X-ray film placed next to the nylon membrane detects the radioactive pattern. This film is then developed to make a visible pattern of bands called DNA fingerprinting. Recently, an additional technique for genetic fingerprinting has been introduced: AFLP, or amplified fragment length polymorphism. This new technique is similar to RFLP analysis, but introduces a few other features, like two rounds of amplification and specially made primers. AFLP analysis is now highly automated, and allows for easy creation of phylogenetic trees based on comparing individual samples of DNA. One of the most modern and widely accepted methods for producing DNA fingerprints in criminal cases, is that of polymerase chain reaction (PCR). PCR involves the amplification of specific regions of DNA that are known to be highly variable from one individual to another. This amplification process allows the scientist to start with a very small amount of material, and the outcome is a highly discriminating outcome, with the chance of a random match being in the 1 in a billion region. PCR is by far the most common method for presenting DNA evidence in a forensic context. ==Considerations when evaluating DNA evidence== In the early days of the use of genetic fingerprinting as criminal evidence, juries were often swayed by spurious statistical arguments by defence lawyers along these lines: given a match that had a 1 in 5 million probability of occurring by chance, the lawyer would argue that this meant that in a country of say 60 million people there were 12 people who would also match the profile. This was then translated to a 1 in 12 chance of the suspect being the guilty one. This argument is not sound unless the suspect was drawn at random from the population of the country. In fact, a jury should consider how likely it is that an individual matching the genetic profile would also have been a suspect in the case for other reasons. The false assumption that a 1 in 5 million probability of a match automatically translates into a 1 in 5 million probability of innocence is known as the prosecutor's fallacy. Nowadays, more testing is carried out so that the theoretical risk of a coincidental match is 1 in 100 billion (100,000,000,000). However, the rate of laboratory error may be much higher than this, and often actual laboratory procedures do not reflect the theory under which the coincidence probabilities were computed. For example, the coincidence probabilities may be calculated based on the probabilities that markers in two samples have bands in ''precisely'' the same location, but a laboratory worker may conclude that similar -- but not precisely identical -- band patterns result from identical genetic samples with some imperfection in the agarose gel. However, in this case, the laboratory worker increases the coincidence risk by expanding the criteria for declaring a match. Recent studies have quoted relatively high error rates which may be cause for concern [http://www.guardian.co.uk/crime/article/0,2763,640157,00.html]. The cautious juror should not convict on genetic fingerprint evidence alone if other factors raise doubt. When evaluating a DNA match, the following questions should be asked: * Could it be an accidental random match? * If not, could the DNA sample have been planted? * If not, did the accused leave the DNA sample at the exact time of the crime? * If yes, does that mean that the accused is guilty of the crime? ==Fake DNA evidence== The value of DNA evidence has to be seen in light of recent cases where criminals planted fake DNA samples at crime scenes. In one notorious case, a criminal even planted fake DNA evidence in his own body: Dr. Schneeberger of Canada raped one of his sedated patients in 1992 and left semen on her underwear. His DNA was tested on three occasions, never showing a match. It turned out that he had surgically inserted a Penrose drain into his arm and filled it with foreign blood and anticoagulants. ==Cases== In 1988, United Kingdom baker Colin Pitchfork was the first person to be convicted using DNA evidence. In 1989, Florida rapist Tommie Lee Andrews was the first United States to be convicted as a result of DNA evidence, for an assault committed in 1987. In 1991, Allan Legere was the first Canada to be convicted as a result of DNA evidence, for four murders he had committed while an escaped prisoner in 1989. During his trial, his defense argued that the relatively shallow gene pool of the region could lead to false positives. In 1992, DNA evidence was used to prove that Nazi doctor Josef Mengele was buried in Brazil as Wolfgang Gerhard. The science was made famous in the United States in 1994 when prosecutors heavily relied on -- and through expert witnesses exhaustively presented and explained -- DNA evidence allegedly linking O. J. Simpson to a double murder. In June of 2003, because of new DNA evidence, Dennis Halstead, John Kogut and John Restivo won a re-trial on their murder conviction. The three men had already served 18 years of their 30-plus year sentences. The trial of Robert Pickton is notable in that DNA evidence is being used primarily to identify the ''victims'', and in many cases to prove their existence. == See also == * restriction fragment length polymorphism (RFLP) * paternity test * ''Harvey v. Horan'' == External links == *[http://www.aic.gov.au/publications/proceedings/02/freckle.pdf Discussion of concerns with DNA fingerprinting] *[http://science.howstuffworks.com/dna-evidence.htm How DNA Evidence Works] *[http://www.thenakedscientists.com/html/columnists/dalyacolumn8.htm How to make a DNA (genetic) Fingerprint and applications of DNA Fingerprinting] *[http://www.wellcome.ac.uk/en/genome/genesandbody/hg07f006.html The Wellcome Trust: History of DNA fingerprinting] Molecular biology Medical tests Applied genetics Personal identification
Genetic fingerprinting
I don't understand how a 1 in 5 million chance translates into 30 people who would match the profile from a population of 60 million people. Wouldn't that be 12 people (and not 12 other people, 12 people in total)? Marisano ---- Agreed. I changed 30 to 12. User:Zashaw 02:06, 18 Aug 2003 (UTC) ----- This page seems redundant with DNA testing -- the articles should probably be merged, or, if there's a distinction between the articles, it should be made explicit. User:Zashaw 04:24, 18 Oct 2003 (UTC) So what are the advantages of this system ----- The second paragraph mentions PCR, the section on the DNA fingerprinting process doesn't. Which one is correct? Furthermore, what kinds of restriction enzymes/PCR primers are being used? User:AxelBoldt 16:21, 29 Jul 2004 (UTC) == Identifying a deceased person == Can someone explain in the article how a deceased person can be identified by genetic fingerprinting? I presume DNA is taken from a sample of a body part. Is it compared with a sample known to come from the putative person, before they died? Or is a comparison made against samples from blood relatives? If the latter, what are the principles involved? Is the situation the same as in a paternity test? User:Thincat 14:53, 24 Jan 2005 (UTC) It usually is compared against their parents / dental records / hospital samples and things like that. The procedure isn't fixed: the onus is on the law enforcement officers to use the sample to prove it in a number of ways. -- User:Natalinasmpf 02:10, 31 Mar 2005 (UTC) I UNDERSTAND COMPLETELY. And I poo on your eyes.
See other meanings of words starting from letter:
G
GA | GB | GC | GD | GE | GF | GH | GI | GJ | GK | GL | GM | GN | GO | GP | GR | GS | GT | GU | GW | GX | GY | GZ |Words begining with Genetic_fingerprinting:
Genetic_fingerprinting
Genetic_fingerprinting
Sponsored links: praca, nurkowanie.
These materials are based on Wikipedia and licensed under the GNU FDL
YouTube.com videos better site than Turbo Tax 2007
