Table 1.
Mutation rate to sterility (αFR) in ancestral strains
| Straina | Clone | Mutation rate to αFR (×10−6 per generation) |
| DBY15104 (sste = 0.6%) | A | 2.68 (1.89–3.58, 95% confidence interval) |
| B | 2.50 (1.75–3.35) | |
| C | 2.17 (1.49–2.94) | |
| D | 2.19 (1.50–2.98) | |
| E | 2.30 (1.59–3.10) | |
| A–E combined | 2.37 (2.03–2.73) | |
| Average ± SD | 2.37 ± 0.22 | |
| DBY15105 (sste = 1.5%) | A | 2.85 (2.00–3.80) |
| B | 2.51 (1.74–3.37) | |
| C | 1.88 (1.26–2.59) | |
| D | 2.20 (1.53–2.96) | |
| E | 1.96 (1.31–2.71) | |
| A–E combined | 2.27 (1.94–2.62) | |
| Average ± SD | 2.28 ± 0.40 | |
| yGIL104 (Lang and Murray 2008) | 5.86 (5.46–6.28) | |
| DBY15084 (Lang et al. 2009) | 2.79 (2.24–3.38) |
a
The strains used in this experiment (DBY15104 and DBY15105) as well as the strain DBY15084 were derived from yGIL104. The silent mating cassette (HMLα) is present only in yGIL104. All of these strains can become resistant to αF by mutation; however, yGIL104 can also become resistant to αF by mating-type switching or by expression of the silent mating cassette. The rate of αF resistance in this strain is 5.86 × 10−6, suggesting that in HMLα strains, the rate of production of αF-resistant strains, by way of mating-type switching or by expression of the silent mating cassette, is ∼3.5 × 10−6.