Haunted pGEM (Ghost plasmid?)

Mounir Izallalen mounir at biota.rsvs.ulaval.ca
Mon Oct 6 09:16:23 EST 1997


Hi,
I cloned a 9KB EcorI fragment containing the Transposon Tn5 in pGEM and
selected for Kan resistant DH5  alpha. I used the qiagen mini-prep kit,
and once I digested the plasmid with EcoRI, I had 2 additional bands (8Kb
and 1.5Kb). I was quite puzzled. So I did a Southerne using the intenal
HindIII fragment of The Tn5 as a Probe, in order to verify if the 9Kb
or-and the 8Kb fragment contains the Tn5. Only the 9 Kb gave a
signal(good). I subconed this band  and got the same pattern, additional
bands.
So here is the question, am I dealing with these famous ghost bands
(Hengen, TIBS 1996) or does the Tn5 do these tricks, or is DH5 alpha or
pGEM well suited for this kind of cloning ?

Any comment or help will be appreciated.

Thanks
*****************************************
Mounir Izallalen                         
Recherche en Sc. de la vie et de la Sante
Pavillon C. E. Marchand
Universite Laval, Ste-Foy
Qc, G1K 7P4 CANADA
Tel(418) 656-2131 ext.6785
Fax(418) 656-7176
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