So, you thought that DNA evidence was foolproof? Think again.
Israeli scientists have discovered a way to prove that DNA evidence can be faked.
Long considered the most solid proof in any criminal court case, the biological goods can easily be planted at a crime scene, according to Dan Frumkin, lead author of a paper published in the online journal Forensic Science International: Genetics. "You can just engineer a crime scene," Frumkin contends. "Any biology undergraduate could perform this."
"This" is fabricating blood and saliva DNA samples. Frumkin's team was able to construct a DNA sample to match any profile in a database without having to take tissue from the person involved – if they had access to the database.
DNA is typically collected from things as simple as a strand of hair, a discarded drinking cup or cigarette butt or even a used toothbrush. The team used two methods to fabricate the DNA samples, one involving a real DNA sample, albeit small, which was then enlarged into a greater quantity by using whole genome amplification. This could then be planted in either blood or saliva.
In blood, red cells do not contain DNA, so the team removed white cells from a sample and planted their fabricated DNA in the blood instead.
In the second experiment, the team used a pooled sample of many people's DNA profiles that were stored in law enforcement databases. The scientists cloned tiny snippets of the DNA, created a library from the data, and simply mixed the elements together to match any profile required. According to Frumkin's team, such a "library" of 425 different DNA snippets could cover any possible profile.
Frumkin followed up the experiments by creating a test that could differentiate between a true DNA sample and a fake, using the fact that the amplified DNA used in either fabrication is not methylated -- it lacks specific molecules, and can thus be identified.
In order to market the test, Frumkin founded Nucleix, a Tel Aviv-based company that hopes to interest forensics laboratories in the product.
It's a good bet he will find a niche market.
Invasion of privacy is only one of the implications of his team's research. Planting of fabricated evidence at a crime scene is another, one that has the American Civil Liberties Union (ACLU) concerned.
"DNA is a lot easier to plant at a crime scene than fingerprints," Tania Simoncelli, ACLU science adviser told the San Francisco Sentinel. "We're creating a criminal justice system that is increasingly relying on this technology."