Table 2.

Rate of spontaneous mutation in haploid and diploid pol2P301R mutants

Canr mutationLys+ reversionHis+ reversion
PloidyGenotypeMutation rate (×10−8)aFold increaseMutation rate (×10−8)aFold increaseMutation rate (×10−8)aFold increase
n+15 (10–20)114 (11–16)10.57 (0.42–0.75)1
pol2P301R2,300 (1,800–2,800)150610 (450–710)44210 (160–250)370
pol2-444 (39–51)2.914 (11–15)13.3 (2.6–4.2)5.8
2n+/+19 (16–24)116 (14–18)10.87 (0.62–0.92)1
pol2P301R/+510 (430–680)2729 (23–53)1.825 (20–31)29
pol2-4/+41 (37–46)2.224b (19–29)0.8b3.3 (2.5–4.1)3.8
pol2P301R/pol2P301R14,000 (6,900–27,000)7404,100 (2,000–7,500)2801,400 (590–3,100)1,600
pol2-4/pol2-497 (73–110)5.122 (18–27)1.47.6 (5.7–8.6)8.7
  • aMutation rates are given as medians for at least nine cultures, with 95% CIs in parentheses.

  • bThe pol2-4/POL2 heterozygote contains two copies of the lys2-InsEA14 allele. All other diploids have one copy of lys2-InsEA14 and a nonrevertible mutation at the same position of the LYS2 gene in the homologous chromosome (Supplementary Table S2). The fold increase shown is the fold difference in the Lys+ reversion rate between the wild-type and pol2-4/POL2 diploids divided by two.