Table 1.

Spontaneous can1 mutations in msh6Δ pol3-R696W yeast strains

Mutation	No. of detectable mutations	Mutation rate (×10−7)*	Percentage of total
Base substitutions
GC to AT	139	1,100	73
GC to TA	24	190	12
GC to CG	1	8.0	0.5
AT to GC	14	110	8
AT to CG	4	32	2
AT to TA	7	56	4
−1 frameshift	1	8.0	0.5
Total	190	1,500	100

The data are based on DNA sequence analysis of 189 independent Can^R mutants of msh6Δ pol3-R696W strains containing pPOL3. Fourteen mutants contained two different point mutations in the CAN1 gene. For these mutants, only mutations previously reported to produce a detectable Can^R phenotype are shown; the others were identified as likely hitchhiker mutations and were excluded from the mutation rate calculation. The location of mutations in the CAN1 sequence is shown in Fig. S1.

^*The rate for each type of mutation was calculated as follows: MR_i = (M_i/M_T) × MR, where M_i is the number of mutations of the particular type, M_T is the total number of mutations, and MR is the rate of Can^R mutation in msh6Δ pol3-R696W strains containing pPOL3 as determined by fluctuation analysis (1,500 × 10⁻⁷; Table S1).