A case of adaptation through a mutation in a tandem duplication during experimental evolution in Escherichia coli

Table 3 Phenotypic traits of ancestral, evolved and reconstructed E. coli strains

Strains	Description	Yield^a	Acetate production^b	Fitness (Sh^-1)^c
Strains	Description	Yield^a	Acetate production^b	50:50	1:99
BW2952	Ancestor	1.00	-	1.00	1.00
BW4005.2	Derivative of evolved isolate BW4005	0.89 ± 0.02	+	−0.04 ± 0.01	0.06 ± 0.01
BW4005.C2	Derivative of BW4005 (DO)^d	0.74 ± 0.08	+	−0.09 ± 0.01	ND
BW4005.C3	Derivative of BW4005 (WT)^d	0.98 ± 0.03	-	−0.02 ± 0.01	ND
BW4005.C6	Derivative of BW4005 (HD)^d	0.83 ± 0.05	+	−0.04 ± 0.01	ND
BW6029	BW2952 yegS::bla	0.85± 0.03	+	−0.02 ± 0.01	0.09± 0.04
BW6030	BW2952 yegR::bla	1.01 ± 0.02	-	0.01 ± 0.01	−0.01 ± 0.01
BW6031	BW2952 ∆ogrK-yegS-yegR::bla	0.88 ± 0.02	+	−0.05 ± 0.01	0.11± 0.04

^aGrowth yields are shown relative to the ancestral strain BW2952 and were obtained from 24-hour glucose-limited chemostats by measuring the optical density of the cultures at 600 nm. Values are from three independent measurements.
^bAcetate production was tested with 24-hour chemostat cultures. +, acetate present at 2–5 mg l^-1; -, below the detection limit (< 0.15 mg l^-1). Data were from at least three independent biological repeats with less than 10% standard errors.
^cCompeting strains were mixed at 50:50 or 1:99 ratios after individual acclimation in the chemostat evolution conditions. Changes in the proportions of the competitors after 24 hours were used to calculate fitness values. Data presented are mean ± SEM from at least two independent experiments. ND, not determined.
^dSymbols are identical to the legend of Figure 3.

ISSN: 1471-2164