In grad school we used single colony PCR to verify the presence of our plasmid. Set up a standard PCR master mix containing your Taq, oligonucleotides, primers, and appropriate buffer solution, but instead of adding purified template DNA, you can simply stab your individual colonies with your pipette tip and then pipette up and down into your reaction tubes. The bacteria sticking to the pipette should provide ample template, and pipetting up and down lyses the bacteria enough without requirement for a DNA purification step. Make sure you indicate on your plate which stab corresponds to which PCR tube-then any positive PCR reactions can be traced back to an individual bacterial colony, and you can grow up that colony and isolate your plasmid, now certain that the colony contains your plasmid and sequence of interest.
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