Kan resistant plasmid growing in Amp

Kyle Legate legatekNOSPAM at hotmail.com
Wed Mar 2 17:39:26 EST 2005

Has anyone experienced this before? I can't find an explanation, and I 
would really like one. I am cloning in pEGFP-C1, which contains a Kan 
resistance cassette. I cut, ligated, plated, mini-prepped and 
maxiprepped, all using Amp by default because 90% of my plasmids encode 
Amp resistance. However, when I was making the data sheet for the new 
plasmid I discovered that it encodes Kan resistance, not Amp resistance.

How could this be? How could a Kan resistant plasmid be amplified in 
Amp-containing media?

I am sure I didn't accidentally use a Kan stock, and I am sure I have 
the correct product. I am not the only person who has experienced this; 
a colleague did the exact same thing (different Kan resistant plasmid) 
late last year.


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