Bacterial Chromosomes and PFGE

B.G.Macdonald bgm at
Fri Sep 2 07:49:43 EST 1994

lanoilb at (Brian_D Lanoil) reported that

  I am using a five step running system which separates DNA
molecules in the size range from approximately 350 kb to 5 Mb.  My
problem: when I run E. coli on the gel as a control, I see multiple
bands.  Since E. coli has only one chromosome and this particular strain
has no plasmids, I am at a loss to explain what the extra bands are.
There is one band which runs at the correct size of ~4.5 Mb, but all of
the others are _larger_.
An answer to this maybe:

You maybe seeing the chromosomes sticking together in dimers etc, this is most
likely.  Alternativly these bands maybe due to incomplete rounds of replication.

Hope this helps.


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