Fig 1. Segregants that carry ira2Δ2933 show different temperature sensitivities.

BY4716 (BY), 322134S (3S), and their recombinant offspring typically exhibit ‘smooth’ colony morphology. However, in the presence of the ira2Δ2933 frameshift mutation, some BYx3S segregants are capable of expressing an alternative, ‘rough’ colony phenotype. Examination of rough BYx3S ira2Δ2933 segregants at 21, 30, and 37°C revealed that these individuals largely express the phenotype in a temperature sensitive manner. For the most part, individuals exhibit the phenotype only at 21°C, only at 21°C and 30°C, or at all examined temperatures. We refer to these three classes as highly sensitive (HS), moderately sensitive (MS), and non-sensitive (NS) to temperature, respectively.