DNA evidence can be faked and planted at crime scenes, researchers find

This is going to be very tempting for crooked police. It shows again that just one piece of evidence should not normally be regarded as conclusive

Until now, DNA was considered the "gold standard" of criminal investigations: Hundreds of wrongly convicted individuals have been freed around the world after DNA analysis proved them innocent of their crimes; and many of the guilty have been brought to justice through DNA evidence as well. But the days of DNA's supremacy in the courtroom could soon come to an end, as researchers in Israel say it can be faked and planted at crime scenes, using basic DNA analysis techniques. "You can just engineer a crime scene," Dan Frumkin, lead author of the paper, told the New York Times. “Any biology undergraduate could perform this.”

The researchers, who published their results in the journal Forensic Science International: Genetics, say there are two basic ways to fake DNA evidence. One is to obtain a small sample of someone's DNA -- from saliva, or hair, or blood, for example -- and multiply it using a common procedure called whole genome amplification.

The second technique revolves around police genetic profiles. Typically, law enforcement keeps genetic information stored as a sequence of numbers corresponding to 13 spots on a person's genetic code. The researchers were able to clone snippets of DNA and insert it into the right spot in a DNA sample, thus changing the results. “DNA is a lot easier to plant at a crime scene than fingerprints,” Tania Simoncelli, a science adviser at the ACLU, told the Times. “We’re creating a criminal justice system that is increasingly relying on this technology.”

"This is potentially huge news in the world of criminal justice, which hasn’t yet even fully had the time to embrace DNA for all of its uses," CBS News legal analyst Andrew Cohen reports. "And I suspect it won’t be long before defense attorneys are using this study to undercut DNA analysis and conclusions in cases all over the country. ... This is potentially terrible news for prosecutors and police and the military and all sorts of industries that use DNA testing to confirm or find information." Cohen adds that this is "good news for crime dramas on television but not so much to the criminal justice system."

But John M. Butler, a geneticist at the National Institute of Standards and Technology, told the Times that these techniques are not something everyday criminals would be able to take advantage of. “I think your average criminal wouldn’t be able to do something like that,” he said.

The same techniques used to fake DNA at a crime scene could also be used to invade someone's privacy in serious ways. The Times writes:

Using some of the same techniques, it may be possible to scavenge anyone’s DNA from a discarded drinking cup or cigarette butt and turn it into a saliva sample that could be submitted to a genetic testing company that measures ancestry or the risk of getting various diseases. Celebrities might have to fear “genetic paparazzi,” said Gail H. Javitt of the Genetics and Public Policy Center at Johns Hopkins University.
Fortunately, it may be possible to tell when a DNA sample has been faked. According to the researchers, DNA that has been amplified lacks "methylation" -- certain molecules that are found attached to the DNA are missing in fabricated samples.

Thus, if investigators are careful, it may be possible to detect when there has been an attempt to fake DNA evidence.

Original report here



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