Table 1. Operon organization trends in E. coli relate to noise-minimizing transcriptional coupling patterns.

	Network module	Low noise configuration	Number of pairs	f a	f rand (μ ± σ)	Trend in E. coli b
A.	Linear metabolic pathway	Coupled	2471	0.038	0.0036±0.0011	Coupled (<<10−6)
B.	Redundant enzymes	Uncoupled	114	0	0.01±0.00094	Uncoupled (<<10−6)
C.	Metabolic branch point	Uncoupled	2036	0.0025	0.0047±0.0015	Uncoupled (0.071)
D.	Multiple gene regulators	Uncoupled	1368	0.0015	0.043±0.0054	Uncoupled (<<10−6)
E.	Physical interaction	Coupled	3938	0.35	0.0030±0.00073	Coupled (<<10−6)
F.	Covalent modification	Coupled	201	0.23	0.0047±0.0047	Coupled (<<10−6)

^aSame operon pair fraction.

^bNumbers represent p-value vs rand.