When students take "Cut and Paste" too literally
17 December 2025
There are moments in teaching that test your faith in humanity. There are moments that make you question your communication skills. And then there are moments so spectacularly, beautifully wrong that you can only stand there in stunned silence, wondering if you've accidentally stumbled into an elaborate prank.
This is the story of one such moment.
The Setup
Picture this: It's a final year molecular biology practical. We're cloning the beta-galactosidase gene, the classic blue/white screening workhorse in molecular cloning since the dawn of time (or at least since the 1980s). The students have made it through the gauntlet: PCR amplification with restriction sites, double digest, agarose gel electrophoresis. They're in the home stretch. All that's left is the ceremonial gel excision, as it was done in the early 2000s: you venture with a gel full of ethidium bromide into the darkroom to carefully extract your precious DNA band from its agarose prison.
The academic in charge had explained this procedure. Clearly. In detail. With safety equipment demonstration and everything: "Put the gel on the transilluminator. Switch on the UV. Take a photo via the instant printer to document it. Then use a scalpel blade to excise the band and transfer it to a sterile tube. Finally, dispose the gel in the large bin with the EtBr waste."
The Last Group
As always happens with large practicals, one group was lagging behind. While everyone else enjoyed their well-earned break, this intrepid trio finally approached the finish line.
"What do we do now?" they asked.
The instructions were patiently repeated. Off they went to the darkroom. The rest of us waited, filling the time with excited chatting about the nearing weekend.
The Reveal
Eventually, they emerged. Triumphant. Beaming. Mission accomplished.
"Did it work? Show me the gel!"
What happened next will haunt the dreams of molecular biology educators everywhere.
They had, indeed, followed the instructions. They had put on gloves and face shield. They had placed the gel on the transilluminator. They had switched it on and taken a photo.
And then they had taken a scalpel blade and excised the band.
From the photograph!
There, in their sterile Eppendorf tube, sitting proudly where precious DNA should be, was a small rectangle of instant printer paper featuring a single band.
"What did you do with the gel?"
Please let them say it's still in the darkroom. Please let them say they just forgot it.
The proud response, full of confident knowledge that they had understood what to do:
"We put it in the ethidium bromide waste!"
Of course they did. Because why would you need the gel? You already got the band out. It's right there in the tube. Mission accomplished!
The academic in charge stood there in silence for quite some time. What do you even say? How do you begin to unpack the spectacular logic that led to this moment? The students had technically followed every instruction. They'd just ... imported the methodology from Microsoft Office rather than molecular biology.
Somewhere, a methaphorical "Ctrl+Z" was desperately being pressed. But unlike in Word, you can't undo throwing your gel in the EtBr waste.