E. coli XL1 vs. JM109 genotype

goyal at mbcl.rutgers.edu goyal at mbcl.rutgers.edu
Wed Feb 12 17:26:41 EST 1992

In article <.2 at Tony.Clementz.mikrbiol.lu.se>, @Tony.Clementz.mikrbiol.lu.se (Tony Clementz) writes:
> 	I'm looking for information regarding Escherichia coli strain XL1-
> Blue. The strain can be bought from Stratagen who lists the strains genotype 
> as identical to E. coli JM109 (except the F'). However working with both 
> strains has made it obvious that there must be some fundamental difference 
> between them. XL1 grows significantly slower than JM109 and is also more 
> prone to lyse. Colonies from XL1 also shows an unusual characteristic of 
> "sticking" to the agar. Does anybody have some information on it's genotype 
> in addition to the one listed in Stratagen's catalog or maybe information 
> about the "ancestor" to XL1.
    XL1-Blue: A high efficiency plasmid transforming recA E.coli strain with
beta-galactosidase selection. 1987 
W.O. Bullock, J.M. Fernandez and J.M. Short. Biotechinques. vol 5(4) 376-378

The genotype of E. coli XL1-Blue as given in this paper is
     recA, endA1, gyrA96, thi, hsdR17 (rk-,mk+), supE44, relA1, lambda-, lac-,
     [F', proAB, lacIqZdeltaM15, Tn10(tet)]

Good Luck

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