CGSC Strain#: 5006
Strain Designation: 2.320M12      Source of Strain: J.R. Beckwith
Other Designations: XA20
Sex: F- Chromosomal Markers: ΔlacZ57, lacI22, λ^-, rpsL135(strR), malT1(λ^R), xyl-7, mtlA2, thiE1
Strain Comments:

• ΔlacZ57-- is deletion M12 of Beckwith.
• lacI22 was formerly called lacI3
• lacI22 was formerly called lac_i3^-
• thiE1 was formerly called thi-1
• xyl-7 was formerly called xylA7
• LamR = Lambda-resistant
• strR = streptomycin resist.

References:

• BECKWITH, JR 1964. A DELETION ANALYSIS OF THE LAC OPERATOR REGION IN ESCHERICHIA COLI. J. Mol. Biol. 8:427-30.
• Newton, W.A., J.R. Beckwith, D. Zipser, S. Brenner 1965. Nonsense mutants and polarity in the lac operon of Escherichia coli. J.Mol.Biol. 14:290-296