TABLE 1.

Map locations and relative frequencies of the seven rrn operons in E. coli growing exponentially at 1.0 and at 2.5 doublings/h

GeneMap unitsDistance marrn genes/oriCb
μ= 1.0μ = 2.5
rrnA870.060.960.93
rrnB900.110.930.88
rrnC850.020.990.98
rrnD720.240.850.76
rrnE910.130.910.86
rrnF570.540.690.54
rrnH50.420.750.62
All 7 rrn/ori6.15.6
  • a m = relative distance of rrn operon from oriC as a fraction of the maximum distance (= length of half chromosome, from oriC to terC), set at 1.0.

  • b Number (X) of copies of rrn operons per oriC, X/oriC = 2mC (13) where C = time to replicate the chromosome from replication origin to terminus. At μ = 1.0 doublings/h, C = 60 min; at μ = 2.5 doublings/h, C = 40 min (13). τ = doubling time= 60/μ.