DH5a vs XL1Blue

Rudi van de Wetering ReplyToButNoSpamR.vandewetering at czzorlnm.azn.nl
Fri Dec 1 06:11:04 EST 2000

> Xl1-Blue is a LacIq strain (and requires tetracycline for selection of the
> F'), whereas DH5alpha is not. That means that XL1-blue overexpresses the
> lacI protein, and thus represses the lacZalpha gene on plasmids like pUC19
> much better than Dh5alpha.

Thougth you also had to add Maltose for selection/expression of the F'  (at
least if you use LB). And that the F' is only important if you're gonna
infect them with a bacteriophage. Anyway, that is the only thing i use
XL-blue for.

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