TABLE 1

Spontaneous can1 mutations in the pol3-Y708A strain and its rev3Δ derivative

	pol3-Y708A		pol3-Y708A rev3Δ
Mutation	No.	MR (×10⁻⁸)^b	No.	MR (×10⁻⁸)^b	Rate of Polζ-dependent mutations (×10⁻⁸)^c
Base substitutions
GC → AT	11	18	23	5.4	13
AT → GC	8	13	7	1.6	11
GC → TA	16	27	20	4.7	22
GC → CG	55	92	0	<0.23	92
AT → CG	7	12	0	<0.23	12
AT → TA	29	48	36	8.4	40
Total	126^a	210	86	20	190
Small indels
−1	8	13	4	0.93	12
−2	2	3.3	4	0.93	2.4
−3	0	<1.7	2	0.47	<1.3
−4	0	<1.7	2	0.47	<1.3
−5	0	<1.7	2	0.47	<1.3
+1	4	6.7	14	3.3	3.4
+2	0	<1.7	1	0.23	<1.5
+4	1	1.7	0	<0.23	≤1.7
Total	15	25	29	6.8	18
Large rearrangements (≥8 nucleotides)
Deletions between short direct repeats	15	25	92	21	4.0
Other deletions	0	<1.7	1	0.23	<1.5
Duplications	0	<1.7	1	0.23	<1.5
Complex mutations type I (≤6 nucleotides)^d	24	40	1	0.23	40
Complex mutations type II (≥7 nucleotides)^d	0	<1.7	4	0.93	<0.8
Total	180^a	300	214	50	250

↵a Two can1 mutants of the pol3-Y708A strain carried double base substitutions. The mutations were separated by 93 and 476 nucleotides in these mutants. These were counted as four individual base substitutions.
↵b 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 the corresponding strain determined by fluctuation analysis, 3 × 10⁻⁶ for the pol3-Y708A and 5 × 10⁻⁷ for the pol3-Y708A rev3Δ strain (Northam et al. 2006).
↵c Rate of Polζ-dependent mutations was calculated by subtracting the rate for the pol3-Y708A rev3Δ strain from the rate for the pol3-Y708A strain.
↵d Complex mutations type I are defined as replacements of one to six adjacent nucleotides with a different sequence no more than six nucleotides long. Complex mutations type II are defined as replacements where the original sequence or the new sequence or both are longer than six nucleotides.