Blue colonies

Dr. Duncan Clark duncan at genesys.demon.co.uk
Tue Apr 22 09:36:24 EST 1997


In article <335C20DA.5440 at psuvm.psu.edu>, Zhiyong Zhao
<zxz4 at PSUVM.PSU.EDU> writes
>Hi, Rodney:
>
>Did you accidentally plate the cells on the plates containing X-gal and 
>IPTG? DH5 has a whole LacZ gene.


You don't need IPTG with DH5alpha and a pUC plasmid. The strain is lacI-
so lacZ is switched on continuously. Xgal plates alone would give blue
colonies.

Duncan 
-- 
The problem with being on the cutting edge is that you occasionally get 
sliced from time to time....

Duncan Clark
DNAmp Ltd.
TEl/FAX 01252376288
http://www.dnamp.com
http://www.genesys.demon.co.uk



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