always_rebel
18-08-2009, 10:31 PM
DNA evidence can be fabricated and planted at crime scenes, scientists warn
By Fiona Macrae
Scientists have shown it is possible to fake DNA evidence, undermining the credibility of the key forensic technique.
Using equipment found in labs up and down the country, they obliterated all traces of DNA from a blood sample and added someone else's genetic material in its place.
The swap was so successful that it fooled forensic scientists who do DNA fingerprinting for American courts.
Forensic evidence, often analysed in crime dramas such as CSI: Crime Scene Investigation (above), may not be the gold standard for such cases any more
It raises the possibility of samples of blood or saliva being planted at crime scenes, leading to the innocent being wrongly convicted and the guilty going free.
Israeli researcher Dan Frumkin said: 'If you can fake blood, saliva or any other tissue, you can engineer a crime scene.
'You have full control of the situation. Any biology undergraduate could perform this.'
Dr Frumkin's company, which has made a kit he claims can distinguish real DNA samples from fake ones, used two techniques to fabricate DNA evidence.
They then inserted the DNA into blood cells that had been purged of all genetic clues to their real owner.
The blood then contained the genetic fingerprint of the first person, the journal Forensic Science International: Genetics reports.
In theory, the blood could then be planted at the scene of a crime, misleading the police and leading to an innocent person being convicted.
Hair, chewing gum, cigarette butts and mugs and glasses could all provide the initial DNA sample.
DNA material can be gathered from an empty wine glass or cigarette butt
While it may seem easier to simply leave one of these at the scene, blood would be more believable and more likely to be spotted by the police, Dr Frumkin said.
The company has also developed a more complicated technique for use when their is no hair or chewing gum to be used.
This relies on prior knowledge of the DNA fingerprint - a 'bar code' containing the genetic code from just 20 set spots on a person's DNA.
The scientists built a 'library' made up of hundreds of DNA snippets covering all the possible genetic codes that crop up at the set points scrutinised by police.
To make a DNA sample matching a particular fingerprint, they just dipped into their library for the right combination of snippets and mixed them together in a test-tube.
The researchers believe that eventually the technology will be used by criminals, in the same way that credit card details are now commonly stolen to commit identity fraud.
They warned: 'Today, DNA evidence is key to the conviction or exoneration of suspects of various types of crime, from theft to rape and murder.
'However, the disturbing possibility that DNA evidence can be faked has been overlooked.
'DNA with any desired genetic profile can be easily synthesised using common and recently developed biological techniques, integrated into human tissues or applied to surfaces of objects, and then planted in crime scenes.'
British experts said that while the science was possible, it was highly unlikely any criminal would go to such lengths.
Dr Gill Tully, of the government-funded Forensic Science Service, said: 'You would need a full molecular biology lab, thousands of pounds worth of equipment and a fully competent molecular biology scientist or technician.
'The vast majority of people who may be involved in criminality would not have access to these materials.
'It seems a very complicated way to fabricate evidence. I can think of much easier defences to raise.'
Dr John Manlove, a forensic scientist and expert witness in court cases, said: 'Yes, it is scientifically possible but it is somebody going to an extreme.
'DNA is very important to a case but the investigations are not carried out on the basis of DNA alone.'
Read more: http://www.dailymail.co.uk/sciencetech/article-1207389/DNA-evidence-fabricated-planted-crime-scenes-scientists-warn.html#ixzz0OZCdo4P7
By Fiona Macrae
Scientists have shown it is possible to fake DNA evidence, undermining the credibility of the key forensic technique.
Using equipment found in labs up and down the country, they obliterated all traces of DNA from a blood sample and added someone else's genetic material in its place.
The swap was so successful that it fooled forensic scientists who do DNA fingerprinting for American courts.
Forensic evidence, often analysed in crime dramas such as CSI: Crime Scene Investigation (above), may not be the gold standard for such cases any more
It raises the possibility of samples of blood or saliva being planted at crime scenes, leading to the innocent being wrongly convicted and the guilty going free.
Israeli researcher Dan Frumkin said: 'If you can fake blood, saliva or any other tissue, you can engineer a crime scene.
'You have full control of the situation. Any biology undergraduate could perform this.'
Dr Frumkin's company, which has made a kit he claims can distinguish real DNA samples from fake ones, used two techniques to fabricate DNA evidence.
They then inserted the DNA into blood cells that had been purged of all genetic clues to their real owner.
The blood then contained the genetic fingerprint of the first person, the journal Forensic Science International: Genetics reports.
In theory, the blood could then be planted at the scene of a crime, misleading the police and leading to an innocent person being convicted.
Hair, chewing gum, cigarette butts and mugs and glasses could all provide the initial DNA sample.
DNA material can be gathered from an empty wine glass or cigarette butt
While it may seem easier to simply leave one of these at the scene, blood would be more believable and more likely to be spotted by the police, Dr Frumkin said.
The company has also developed a more complicated technique for use when their is no hair or chewing gum to be used.
This relies on prior knowledge of the DNA fingerprint - a 'bar code' containing the genetic code from just 20 set spots on a person's DNA.
The scientists built a 'library' made up of hundreds of DNA snippets covering all the possible genetic codes that crop up at the set points scrutinised by police.
To make a DNA sample matching a particular fingerprint, they just dipped into their library for the right combination of snippets and mixed them together in a test-tube.
The researchers believe that eventually the technology will be used by criminals, in the same way that credit card details are now commonly stolen to commit identity fraud.
They warned: 'Today, DNA evidence is key to the conviction or exoneration of suspects of various types of crime, from theft to rape and murder.
'However, the disturbing possibility that DNA evidence can be faked has been overlooked.
'DNA with any desired genetic profile can be easily synthesised using common and recently developed biological techniques, integrated into human tissues or applied to surfaces of objects, and then planted in crime scenes.'
British experts said that while the science was possible, it was highly unlikely any criminal would go to such lengths.
Dr Gill Tully, of the government-funded Forensic Science Service, said: 'You would need a full molecular biology lab, thousands of pounds worth of equipment and a fully competent molecular biology scientist or technician.
'The vast majority of people who may be involved in criminality would not have access to these materials.
'It seems a very complicated way to fabricate evidence. I can think of much easier defences to raise.'
Dr John Manlove, a forensic scientist and expert witness in court cases, said: 'Yes, it is scientifically possible but it is somebody going to an extreme.
'DNA is very important to a case but the investigations are not carried out on the basis of DNA alone.'
Read more: http://www.dailymail.co.uk/sciencetech/article-1207389/DNA-evidence-fabricated-planted-crime-scenes-scientists-warn.html#ixzz0OZCdo4P7