TABLE 2.

Motility rates of S⁺ ancestral, S⁻ evolved, and S⁺ rescued genotypes^a

Strain	Soft agar				Hard agar
	Motility rate (mm/day)	EC	Ancestor	% Rescue	Motility rate (mm/day)	EC	Ancestor	% Rescue
S ancestor	4.00				2.58
S2	0.33		***		0.97		***
S2/pDW79/+	1.31	***	***	27	2.25	***	**	80
S4	0.36		***		0.69		***
S4/pDW79/+	2.67	***	***	63	2.78	***	*	112
R ancestor	4.03				2.61
R2a	0.33		***		1.38		***
R2a/pSWU257/+	1.36	**	***	28	2.59	***	ns	98
R6	0.34		***		1.63		***
R6/pSWU257/+	3.98	***	ns	99	3.45	***	***	186

^aColumns labeled EC indicate statistical significance of the difference in motility rate between rescued (S⁺) and unrescued (S⁻) evolved clones. Columns labeled ancestor indicate significance of differences between all evolved genotypes (rescued and unrescued) and their ancestor. Significance levels are based on two-tailed t tests. ***, P < 0.001. **, P < 0.01. *, P < 0.05. ns, P > 0.05. The percent rescue columns show the extent of motility rate rescue as a percentage of the difference between the rates of unrescued evolved clones and their respective ancestors.