CGSC Strain#: 4241
Strain Designation: Ra-2      Source of Strain: M.C. Cappello
Other Designations: CSH60
Sex: Hfr    Point of Origin#: 48   Map Position: 88.40   Direction of Marker Transfer: Clockwise
Chromosomal Markers: glnV42(AS), λ^-, Sfa(att)4, malB28(λ^R)
Strain Comments:

• Ra-2 is a rather unstable Hfr, switching between Hfr Ra-2 and Hfr Ra-1. sfa-4 is a sex factor attachment site at the point of origin of Ra-1.
• Sfa(att)4-- is a sex factor attachment site at the point of origin of Ra-1.
• glnV42(AS) was formerly called supE42
• AS = amber(UAG) suppressor
• LamR = Lambda-resistant

References:

• Joset, F., B. Low, R. Krisch 1964. Induction by radiation of a new direction of chromosome transfer during conjugation in an Hfr strain of Escherichia coli. Biochem.Biophys.Res.Commun. 17:742-747
• Low, K.B. 1967. Inversion of transfer modes and sex factor-chromosome interactions in conjugation in Escherichia coli. J.Bacteriol. 93:98-106
• Low, K.B. 1968. Formation of merodiploids in matings with a class of Rec- recipient strains of Escherichia coli K12. Proc.Natl.Acad.Sci.USA 60:160-167
• Low, K.B. 1973. Rapid mapping of conditional and auxotrophic mutants of Escherichia coli K-12. J.Bacteriol. 113:798-812