TABLE 1

A three-locus model

Locus typeSite countStrengthWild-type forward rateWild-type reverse rate
Environment A: base fitness = 1.0, base mutation factor = mb
AND fitnessαseuu
Additive fitnessγsduu
Multiplicative mutatormkmr00
Environment a: base fitness = 1.0 + se base mutation factor = mb
AND fitnessαseuu
Additive fitnessγsduu
Multiplicative mutatormkmr00
  • The genome contains three loci. The first locus produces environmentally sensitive selection and can be disabled by a mutation at any of α sites. The second locus allows for γ potential deleterious mutations, which have no environmental dependence. The third locus controls the mutation rate of the sites in the other two loci: it will range from umb to Embedded Image.