Simple question that is hard to answer

peter via (by peter.ianakiev from
Thu Feb 22 14:58:18 EST 2007

On Feb 22, 11:53 am, "Tim Fitzwater" <tfitzwa... from> wrote:
> I studied plasmid copy number control (ColE 1) for 12 years, and since then have been cloning SELEX pools for the past 13 years.
> When you have two clones co-transformed into the same cell (same insert, same vector, same antibiotic resistance) they cannot co-exist in the same cell.  This is true even for high copy number pUC origin plasmids.
> SELEX pools containing an evolved 40 bp random region can contain distinct sequences or vary by 1 or more basepairs.  During the generations required to grow a colony and grow the first liquid culture prior to plasmid prep and sequencing, segregation occurs and most preps will contain a single sequence.
> Tim Fitzwater
> SomaLogic

Thanks Tim,
That is what I wanted to hear. You saved me some efforts. I also
suspected that, but planed to do experiment to find out. It is
interesting phenomena anyway.

More information about the Methods mailing list