My cry of frustration echoed down the hall. My latest attempt to subclone five important PCR products had failed yet again. After two months of fruitless effort, I was at my wit's end until a colleague suggested I try the TOPO TA Cloning® Kit from Invitrogen.

"Look," he said, "all you need to do is to combine 1 microliter of your PCR reaction and 1 microliter of the pCR2.1-TOPO® vector, add 3 microliters of water, and wait 5 minutes. Then transform your competent cells. In the morning, you will have more white colonies than you will know what to do with." As proof, he showed me a petri dish with six blue colonies surrounded by hundreds of white ones.

I was sold on the spot. I promptly borrowed his TOPO TA Cloning kit and set about subcloning those pesky PCR products.

pCR2.1 Topo Map
A glorious sight...

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