supercoiled DNA migration in agrose ?

Martin Kennedy cytogen at chmeds.ac.nz
Sun Dec 27 03:37:05 EST 1992


In article <1992Dec23.111137.24858 at wehi.edu.au>, chai_z at wehi.edu.au writes:
> 
> Hi,
> 
> 	Several batches of M13 RF DNA of mine have been cut by EcoRI or SmaI,
> etc. and then electrophoresized in agrose gel. Uncut DNA (supercoiled) of some
> batches migrated faster than the cut one (linear), while the others slower.
> Most likely, some batches of my DNA were nicked (open circular). Could any one
> tell me the correct agrose pattern of supercoiled, open circular and linear DNA?
> or tell me where to refer to?
> 
> Thanks in advance.
> 
> 
> Zhonglin Chai 


Some of your bands could be "miniphage" rather than various forms of cut/
uncut RF etc.  M13 throws off deleted derivatives (or miniphage) at a 
significant frequency.  They lack the multiple cloning and universal primer
site hence don't interfere with cloning or sequencing, but they can make it
hard to interpret M13 digestion patterns.

Cheers,

Martin



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