insert-containing Bluescript still blue?

John Dixon jpcd0 at
Mon Jun 5 10:26:36 EST 1995

I am planning to clone a number of synthetic oligos back to back into a
bluescript vector. I was hoping that by careful planning (of size and lack
of stop codons) I could arrange it so that the first oligo insert causes a
frame shift giving white colonies, then the second insert restores the
correct reading frame so that the blue colonies would be the ones to pick,
and the third ... white...and the fourth... back to blue... etc etc

I think I saw a post recently about a frame shift mutation in Bluescript
which does not lead to white colonies, so can someone tell me if my plan
will be feasible?

Basically my question is:- are white colonies caused by the introduction
of stop codons preventing production of enough of lacZ protein for alpha
complementation or can the extra sequence in the polylinker screw up the
protein even if there is an open reading frame down to the end of the lacZ
(in the correct frame)?

Thanks for any suggestions, Johnny D

John Dixon                     Lab 44 (223) 334131
Wellcome/CRC Institute         Fax 44 (223) 334134
Dept Genetics
Cambridge University    
United Kingdom       e-m: jpcd0 at

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