The Irrelevancy of DNA

This work has been released into the public domain by its author, brian0918.

DNA has become an almost mythical molecule in the past 20 years. The Human Genome Project and the promises of personalized medicine and genetic testing companies like 23 and Me, give hope that we will find new treatments or cures for many tragic diseases, increase longevity and improve quality of life for millions of people. Hollywood has helped fuel our love affair with DNA with television shows like CSI and Dexter, which make DNA seem even more powerful than the police in catching bad guys.

What is often left out of the explanation is the fallibility of the police who collect the evidence and the scientists who analyze it. From the crime scene to the lab there are dozens of opportunities for contamination, damage or loss of specimens, either through carelessness, incompetency or maliciousness. Garbage in, garbage out: sloppy police work can easily invalidate or corrupt DNA evidence.

A suspect can be absolved if his DNA does not match any of the suspects’ DNA at the crime scene (assuming his attorney ever gets access to this evidence). However, even if his DNA does match the crime scene, if there were any breeches in security or protocol, he should also be released, since it is now unclear if his DNA got mixed in by mistake or in a deliberate frame-up.

These examples highlight just a few of the ways that DNA can “lie,” and result in an innocent person being punished.

A new report has found that the U.S. Justice Department (DOJ) has withheld critical evidence for decades that could have exonerated hundreds of prisoners and parolees. The defendants and their lawyers were not informed of flawed forensic work that could have led their acquittals. (See Democracy Now, 4/18/12) The DOJ investigated cases going back to 1995, but only focused on the work of one sloppy scientist, despite complaints that the problem was widespread and included numerous scientists. Further investigations will likely find many more people who should be exonerated.