Plasmid changes after transformation - (Jul/14/2005 )

hello.

These days, i am being in a trouble that my plasmids changed during the transformation.

First, i run the plasmid on the gel, and it is ok, just the size it is. then, i transform DH5@ with it, and after extract the plasmid from the transformed strains, it becomes 6 bands, which appears to be two different plasmids. and when i digest it, it comes two linar bands. So i think it is contaminated with other plasmid, and reselected the strains to find that all the strains are having the same plasmids----two different plasmids.

So i think something has happened to my plasmid. what is it? How can i get my target plasmid again?

I am looking forward for your comments.

Thanks.

boy

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you checked your DH5a's for having a plasmid before you transform them?

mike

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Thanks, Mike.

Maybe this is a good approach. i will check that. Thanks!

Boy

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