DNA Discovery

[Paul Whybrow]

Crime writers, in particular, will be interested in a startling discovery about DNA, which has been shown to be highly mobile, migrating between objects in previously unimagined ways. Instead of DNA being undeniable evidence that a suspect committed a crime, it could just be that skin cells and bodily fluids were transferred by touching a door handle that hundreds of others later touch.

Framed for Murder By His Own DNA

This could potentially affect us all. Say, for example, that you sneeze while walking along a street. You can't see it, but some of your sputum attaches itself to a lamppost, which a passerby brushes against, picking up your DNA on her dress. She is murdered that night—your DNA is on her dress. So what, you say, "I'm not a criminal, no one has my DNA on file from a previous conviction." But unbeknownst to you, your cousin submitted a sample of their DNA to an ancestry tracing service which shares their data with law authorities, and there are enough similarities for you to be arrested! Have you got a provable alibi?

The Future of Crime-Fighting Is Family Tree Forensics

It's not as if the police are operating with a clean slate. A British forensic researcher, found DNA on three-quarters of crime scene tools he tested, including cameras, measuring tapes, and gloves, making any evidence discovered at a crime scene highly unreliable.

I predict that there will be hundreds of appeals against convictions based on DNA evidence, as a result of this revelation.

Only the Lone Ranger has silver bullets.

 

[Dan Payne]

This is terrible for law enforcement.

It's great for writers, though. Silver bullets are a pain when you want suspense or uncertainty in your story. How many times have we seen authors jumping through hoops to be sure their antagonist has not left DNA at the crime scene? And the possibility that a suspect's DNA could be found but not prove her culpability has narrative potential - at least for a short while until the idea isn't novel any more.

But I suspect the general expectation that DNA = incontrovertible proof is too deeply entrenched in the public psyche and it will take a long time before it fades, if it ever does, and so authors will keep on using it as a Voice of God plot device.

 

[Tim James]

I find it surprising that this persistence and transferability of trace DNA has not been noticed before now. Or maybe it has and those that use these techniques to "solve" cases have just "neglected to mention it."
Your DNA is left everywhere you go. Everything you touch, potentially will leave a trace. The body sheds skin fragments, hairs and other traces all the time. Admittedly not all of these contain viable full DNA strands, but saliva (yuk) often does, and as Paul said a sneeze, unchecked, spreads it everywhere, where it can then be transferred on by other "carriers".
On a side note, I would never use one of these ancestor searches that use a sample of your DNA. Firstly I'm not sure I want to know, and secondly you have no control over where the information will end up how that information will be used. Companies like Ancestry.com and 23andMe etc. are building up huge databases of people's DNA profiles. Call me paranoid, but big life insurance / medical insurance companies would love to get their hands on that data.
DNA is an index to every individual on the planet. Whether that will be a good thing or a bad thing in the future is uncertain.

 

[Steve C]

It's why I always wear gloves when I murder someone.