R.D. Haigh rxh at
Tue Nov 25 05:29:05 EST 1997

Hi James
I believe the reason Amersham dropped pTTQ18 is because it contains 
two copies of part of lacZ either side of the plasmid such that when under 
pressure to make lots of DNA ie.when a large insert is introduced, you 
will see recombination and the formation of miniplasmid. Enough 
history - the plasmid was originally made in Leicester and I have 
checked the freezer and I have an old Eppendorf with its name on it. I'll 
transform some ASAP and get back to you if it is still alive.


    Richard Haigh                      
    Department of Microbiology        
    and Immunology,                        
    University of Leicester,
    University Road,        
    Leicester. LE1 9HN UK
    Phone: 0116 2523017 
    FAX  : 0116 2525030 
    Email: rxh at
    NB. remove nospam to Email  

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