Aug 18, 2009 01:45 PM in Biology

By Katherine Harmon – Scientific American

Researchers have demonstrated it’s possible to remove all the DNA from samples like blood and saliva, and replace it with genetic material from a different individual—even when the only source of this material is a used cigarette butt. Their methodology was good enough to fool a lab that does crime-scene DNA testing.

“DNA is a lot easier to plant at a crime scene than fingerprints”

Unlike finicky fingerprintsand frowned-upon fiber analysis, DNA evidence has been the most bulletproof evidence for forensic sciences in recent years. But staffers at a research firm in Israel have recently upended the presumed infallibility of this forensics golden child—by making it themselves.

Nucleix, a Tel-Aviv-based life sciences company, was able to create credible DNA evidence that could be used to finger the wrong person, proof that even genetic evidence can be manipulated (beyond planting a hair or used cigarette) just like other physical traces.

Fake DNA Evidence LAB

“You can just engineer a crime scene,” Nucleix founder Dan Frumkin told The New York Times. “The current forensic procedure fails to distinguish between such samples of blood, saliva, and touched surfaces with artificial DNA, and corresponding samples with in vivogenerated (natural) DNA,” Frumkin and co-authors wrote in a recent Forensic Science International: Genetics study that announced the technological achievement.

But, don’t worry, like a hacker taking down servers to sell cyber security services, Nucleix has a fix: a system that can detect the difference between natural and manufactured DNA. It looks for a lack of methylation; an addition of methyl groups to DNA occurs naturally in genetic code, but it isn’t found in Nucleix’s manipulated DNA.

To make the fake DNA, all the researchers needed was a small sample of the DNA they wanted to plant (such as that from hair or lingering in saliva left on a discarded coffee cup) and blood from a donor. Donor blood was centrifuged to separate DNA-containing white cells and DNA-free red cells. The researchers then expanded the filched DNA into a larger sample size via whole genome amplification and added it to the DNA-free red blood cells from the donor. Poof! Blood that matched the genetic profile of the person to be framed—not the donor—was created.

Nucleix was also able to replicate a deceptive double helix just by working off genetic profiles in a police database. Building a small collection of common genetic variations—425—for different genome points, they were able to drum up a fabricated sample.

“Any biology undergraduate could perform this,” Frumkin told the Times.

Of course, others are voicing doubts that many criminals could replicate such technical processes. “In my experience, the people that we arrest for murder, rape, robbery, child molestation, generally don’t have a very good foundation in molecular biology,” legal analyst Dean Johnson told San Francisco’s ABC News 7. But, notes Johnson, in a “real stretch,” attorneys could employ these findings to argue against the use of DNA evidence in court.

In the meantime, concern about disproportionate trust of DNA testing is mounting, notes American Civil Liberties Union science adviser Tania Simoncelli. “DNA is a lot easier to plant at a crime scene than fingerprints,” she told the Times. “We’re creating a criminal justice system that is increasingly relying on this fakeable  technology.”