Table 1.

Mutation rates and frequencies under different conditions in E. coli ATCC 31343

Media	Time	Mutations	Viable cells	Mutation rates	Mutation frequencies
LB	1 day	leu+	1.31 × 109	1.91 × 10-10	2.65 × 10-9
LB	1 day	pro+	1.24 × 109	1.41 × 10-10	6.57 × 10-9
LB	1 day	lac+	1.26 × 109	2.45 × 10-10	9.86 × 10-9
MM+P	1 day	leu+	7.56 × 107	5.73 × 10-9	3.02 × 10-7
MM+L	1 day	pro+	4.89 × 107	3.07 × 10-9	2.78 × 10-7
CM(Lac)	1 day	lac+	8.34 × 107	3.60 × 10-9	2.90 × 10-7
MM+P	3 days	leu+	2.13 × 107	1.72 × 10-8	1.11 × 10-6
MM+L	3 days	pro+	1.09 × 107	4.06 × 10-8	1.79 × 10-6
CM(Lac)	3 days	lac+	3.61 × 107	1.47 × 10-8	1.18 × 10-6

The initial number of cells in the cultures were all 1.08 × 10⁸ cells/ml.