Expansion of a chromosomal repeat in Escherichia coli: roles of replication, repair, and recombination functions

Table 1 Expansion and survival tests

Genotype^a	Lac⁺ clone expansion test No. positive/no. tested	Survival on lactose minimal medium relative to wild type^b
wild type	28/28	1
recA	0/10	0.9 ± 0.1
recBCD	9/10	0.9 ± 0.1
ruvC	10/10	1.2 ± 0.4
recG	18/18	nd
ruvC recG	6/14	0.6 ± 0.2
red+	10/10	nd
red+ recA	8/10	nd
wild type single copy	0/10	nd

a. See the legend to Figure 4 for a description of the strains tested for expansion. For the survival test, the (lacIZ33Y)₂-cat duplication was replaced by a non-reverting lac deletion.
b. Means and standard errors are shown for three measurements. nd = not determined.

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