How PCR helps solve crimes.
Fellow Sleuths,
It’s been an interesting week in the world of crime-solving, stickers, and PCR. True, particularly regarding my conversation with Bob the Crime Scene Tech about Suspect Number Seven (Pairs).
You wouldn’t know Bob. He is the lab guy I work with regularly. You’ll meet him in Wrecks. Well, he came by with some news: he’d run PCR on a sticker we found on the aquarium floor. While PCR might sound like code for a new coffee blend, bear with me. It’ll all become clear.
Bob is a geek. I mean that in the nicest possible way. Skinny, cheerful. Loves his job. And he’s good at it too.
Stickers & DNA: How PCR helps solve crimes
What is PCR, a.k.a. polymerase chain reaction? I’m glad you’re asking. I did too. As a result, Bob stared at me like I’d just confessed I don’t believe in gravity. Apparently, I’m supposed to know how DNA copying works in criminal investigations. (Note to self: brush up on my crime scene vocabulary.)
PCR: DNA’s Copy Machine Helping Solve Crimes
PCR is science’s version of cloning on steroids. Imagine sending one tiny DNA strand to the gym and coming back to find a million beefed-up versions. That’s PCR.
In forensics, PCR heats and cools a DNA sample through a series of cycles, doubling it again and again until even the tiniest trace becomes enough to analyze. In plain terms: it turns a barely-there DNA speck into something database-ready.
The Sticker Clue
Anyway, the sticker we found on the floor of the Florida Aquarium had a few skin cells. Stickers like this one were also found on the face of the suspect. Why does that matter? Well, our sticker had only a few stray skin cells. Hardly enough to convict someone on its own.
Thanks to PCR, Bob now has enough DNA to run a full profile. And that’s how PCR helps solve crimes. Looks like the case is finally starting to peel away some answers.
So what does this sticker really tell us? A lot more than I expected. Could our sticker-wearing suspect—a kindergarten teacher who apparently treats facial stickers like a personality trait—be involved in something a lot stickier than classroom arts and crafts?
Next Steps
Bob’s running the newly amplified DNA through the system. We’ll know soon if it matches anyone in the database.
In the meantime, I’m on the lookout for rogue glitter trails and any suspiciously cheerful, star-shaped smiley faces.
Stay tuned, sleuths. In the strange world of Ned’s Notes, sometimes it only takes one tiny piece of evidence to crack a case wide open.
Also remember, in the world of crime, sometimes a small piece of evidence is all it takes to crack a case wide open.
Time—and DNA—will tell.
Finally, don’t forget to check your face for stickers.
— Ned
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