TABLE 3

Rates of canavanine resistance in strains bearing conditional mlh1 mutations

26°35°
Relevant genotypeRate relative to wtAverageRate relative to wtAverage
Wild type0.74, 1.5, 0.741.00.51, 0.39, 2.11.0
mlh1Δ9.5, 20.2, 20.316.716.1, 11.3, 26.017.8
mlh1-T113A0.49, 0.79, 0.530.618.2, 4.4, 15.99.5
mlh1-I147T0.45, 0.44, 1.30.724.7, 18.0, 15.912.8
mlh1-F228S0.59, 1.0, 1.00.893.4, 4.4, 9.15.6
mlh1-I296S0.55, 0.76, 1.30.8517.6, 23.1, 28.723.1
  • EAY774 (mlh1Δ), was transformed with pEAA109 (MLH1 ARSH4 CEN6)-derived plasmids carrying the indicated mlh1 alleles or pRS415 (ARSH4 CEN6) and tested for resistance to canavanine. Forward mutation rates per generation were determined as described in materials and methods and are reported relative to EAY774 (mlh1Δ) transformed with pEAA109 (MLH1) at the respective temperature (4.8 × 10−7 at 26°, 2.6 × 10−7 at 35°). The forward mutation rate of each independent experiment is presented (median of seven cultures; Lea and Coulson 1949).