TABLE 2.

Spontaneous mutation rates of uve1 and pms1 null mutants

Genotype	Distribution of canavanine-resistant colo-nies/plate				Median no. of colonies/ 107 cells	Calculated mutation frequency (mean ± SE)
	0–2	3–34	35–86	>86
Wild type	18	16	2	0	2.5	1.5 × 10−7 ± 2.5 × 10−8
uve1::ura4+	4	14	8	10	34.5	9.7 × 10−7 ± 4.2 × 10−8
pms1::ura4+	0	8	10	18	86.5	2.0 × 10−6 ± 5.0 × 10−8