X-Gal and IPTG?

Duncan Clark blackhole at abuse.plus.com
Fri Feb 24 12:20:38 EST 2006

Historians believe that in newspost 
<1140797049.208999.90700 at e56g2000cwe.googlegroups.com> on Fri, 24 Feb 
2006, ali <atahery at gmail.com> penned the following literary masterpiece:
>I have seen that for some vectors we use both X-Gal and IPTG but for
>the others we just use X-Gal. Is it because of the strain or the

Could be both.

If the vector carries lacI then IPTG is required.

If the host carries lacI then again IPTG is needed.

i.e. pUC without lacI in DH5alpha or TOP10 (both lacI minus) only needs 

I love deadlines. I especially like the whooshing noise they make as
they go flying by.

Duncan Clark
GeneSys Ltd.

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