DNA evidence is the standard that most people rely on.  It clears the innocent and convicts the guilty.  But what happens when science can fake DNA results?  Scientists in Israel have now demonstrated that you can do just that.

The scientists fabricated blood and saliva samples containing DNA from a person other than the donor of the blood and saliva. They also showed that if they had access to a DNA profile in a database, they could construct a sample of DNA to match that profile without obtaining any tissue from that person.

“You can just engineer a crime scene,” said Dan Frumkin, lead author of the paper, which has been published online by the journal Forensic Science International: Genetics. “Any biology undergraduate could perform this.”

Dr. Frumkin is a founder of Nucleix, a company based in Tel Aviv that has developed a test to distinguish real DNA samples from fake ones that it hopes to sell to forensics laboratories.

The falsifying of DNA evidence is a serious issue.  It is much easier to plant DNA at a crime scene than fingerprints and you’re less likely to get caught planting that evidence.

From a pooled sample of many people’s DNA, the scientists cloned tiny DNA snippets representing the common variants at each spot, creating a library of such snippets. To prepare a DNA sample matching any profile, they just mixed the proper snippets together. They said that a library of 425 different DNA snippets would be enough to cover every conceivable profile.

Nucleix’s test to tell if a sample has been fabricated relies on the fact that amplified DNA — which would be used in either deception — is not methylated, meaning it lacks certain molecules that are attached to the DNA at specific points, usually to inactivate genes.

The use of the “chain of evidence” in of utmost importance here.  The integrity of the chain is relied upon to rule out any tampering, but what happens when the evidence has been tampered with before the police even arrive?  Can all police labs be equipped with the necessary tools to identify fake DNA?

While common criminals would probably just steal DNA from you to frame you and Dr. Frumkin is trying to sell you something, the entire matter should not be easily discarded.  While anyone with a little biology training can accomplish this task, we must remember that DNA is not the absolute answer in court cases.  It is fallible.  It can be planted.  It can be faked.  With this knowledge, DNA should remain a piece in a larger puzzle, but should not be relied upon to be the only piece.