DNA Evidence can be Fabricated


"DNA evidence, hair color and acting ability. One of these things ... can't be faked." (Miguel Garcia/Getty Images)

We've largely come to hold DNA evidence as the ultimate weapon in criminal investigation, as well as one killer obstacle on the road to the perfect crime. Humans are constantly spurting fluids, shedding skin flakes and dropping hairs. Just one genetic sample left in the wrong place is enough to cinch it. Right?

Well, not any more. According to a fascinating article in the New York Times, Israeli scientists have successfully demonstrated the ability to create a fake DNA sample in the laboratory. They took one person's blood and saliva sample and, with just a little scientific tinkering, gave it the DNA of another person altogether. What's more, they're pretty confident they could do the same with a DNA profile from a database.

Needles to say, this is rather disconcerting news. DNA profiling and the right to genetic privacy have been hot button issues for a while, and now here we are in 2009 staring the reality of fake DNA right in the face.

Granted, this isn't the sort of thing the average criminal is going to be able to pull off -- at least not yet. But the possibilities are still pretty scary. I don't think I need to run through the myriad of conspiracy theories this can kick off, nor the kinks this could introduce in to the legal system.

Let's run through how you fake DNA evidence instead:

  1. First, you're going to need an actual blood sample -- perhaps even your own.
  2. Next, you're going to want to spin that blood sample in a centrifuge to remove all the white blood cells (which contain DNA), leaving only red blood cells (which don't contain DNA).
  3. Then take your secondary DNA sample -- perhaps from a hair or blood sample taken from the individual you intend to frame.
  4. Inject this DNA into the red blood cells. Now you have a blood sample where all the DNA matches that of someone other than the original donor.

In an alternate method, the scientists were able to clone common DNA variant snippets. They claim that 425 of these snippets would be enough to manufacture any DNA profile out there. Nervous yet?

Of course, for those of you out there who look to episodes of "CSI Miami" or other such forensics fiction, you might have already thought this was possible -- so much on those shows exaggerates what's really possible on the forensic science end of an investigation.

I can't help but be reminded of the old beliefs that a witch could take a single sample of hair and use it to curse an innocent individual. Fast-forward a few millennia and it's not so fanciful an idea.

So what do you think? I know we have some true crime junkies and conspiracy theorists out there.

Thanks to HSW's own Rick Mayda for pointing this article out to me!

Know your DNA at HowStuffWorks.com: How DNA Works How DNA Computers Will Work How DNA Evidence Works How DNA Profiling Works Can a sewing machine stitch together DNA?