TABLE 2.

Synergistic effects of pairs of mutations on sporulation efficiency

Genotype	Predicted sporulation efficiencyb	Actual sporulation efficiencyc	Synergistic effectd
WTa		1.0
yunB		0.5
ytvI		0.29
yhbH		0.25
ypjB		0.25
ytrI		0.14
ybaN		0.12
ytrH		0.11
yhbH ytvI	0.07	0.15	0.5
yhbH yunB	0.13	0.19	0.7
ytrH ytrI	0.02	0.05	0.4
ypjB yunB	0.13	0.12	1
yhbH ytrH	0.03	0.03	1
ypjB yhbH	0.06	0.04	1.5
yunB ytvI	0.15	0.13	1.2
yunB ybaN	0.06	0.02	3
yunB ytrH	0.06	0.02	3
ypjB ytrH	0.03	0.01	3
ytrI yhbH	0.07	0.018	4
yhbH ybaN	0.03	0.005	6
ytrI ytvI	0.04	0.003	13
ytvI ytrH	0.03	0.002	15
ytrI yunB	0.07	0.004	18
ytrI ypjB	0.04	0.002	20
ypjB ytvI	0.07	0.003	23
ypjB ybaN	0.03	0.001	30
ybaN ytvI	0.04	0.0008	50
ybaN ytrH	0.01	0.00006	167
ytrI ybaN	0.02	0.00003	667
ytrH ytrI ybaN	0.006	0.00006	100

^aWT (wild type) is strain PY79.

^bThe product of the sporulation efficiencies observed for the corresponding single mutants of the two indicated genes.

^cRatio of heat-resistant spores produced by the indicated mutant, after 30 h of culturing at 37°C, to those produced by the wild type. Values reported are the average of at least three experiments.

^dThe predicted sporulation efficiency divided by the observed sporulation efficiency.