Extra bands on plasmid prep.

Martin Leach leach at bu.edu
Wed Jan 18 16:40:54 EST 1995


In article <pootanak-180195165111 at bi16.bc.edu>, pootanak at hermes.bc.edu
(Kusol Pootanakit) wrote:

> After I did the plasmid prep (by alkaline lysis--phenol/chloroform--ethanol
> extraction) and ran the gel, what I got was the plasmid band and and extra
> band that is around 9kb.  So I am wondering what could that 9kb band be.
> 
> thanks

What is the size if the plasmid you are working with?

If you perform alkaline lysis....and leave the alkali on the plasmid too
long...you will find an increasing amount of nicked plasmid...

you are probably looking at another plasmid confirmation...


BTW if it was very large...it would be bacterial genomic DNA contamination

Martin

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