Table 2. Mutation rates in an S288c strain containing MLH1 and PMS1 gene combinations identical in amino acid sequence to those present in S288c, SK1, YJS5845, YJS5885, and YJM521.

MLH1-PMS1 genotype	Lys+ reversion rate (10−7), (95% C.I.)	Relative rate	(n)
S288c-S288c, compatible	4.1 (1.7–13.8)	1	13
S288c-SK1, incompatible	311 (111–919)a	75	16
YJM521c-YJM521k	92 (78.4–690)b	22	29
YJM521c-SK1	80 (47–182)b	19	15
mlh1Δ, pms1Δ	45,300 (13,170–126,800)a	10,970	10

EAY1365 (relevant genotype mlh1Δ::KanMX4, pms1Δ::KanMX4) was transformed with ARS-CEN plasmids containing the MLH1 and PMS1 genes obtained from the indicated strains and isolates. Independent cultures (n) were examined for reversion to Lys⁺. Median mutation rates are presented with 95% C.I.s, and relative mutation rates compared to the wild-type strain are shown. Data for S288c-S288c compatible, S288c-SK1 incompatible, and mlh1Δ, pms1Δ were reported previously (Bui et al. 2017). Note that MLH1 open reading frames in YJS5845c and YJS5885c are identical to S288c MLH1, and the PMS1 open reading frames in YJS5845k and YJS5885k are identical to SK1 PMS1 (Table S2).

^aSignificantly different from S288c-S288c (P < 0.001, Mann–Whitney U-test).

^bSignificantly different from S288c-S288c, compatible (P < 0.01, Mann–Whitney U-test).