Figure 3.

Chromosome loss assay. (A) Schematic of chromosome loss assay. (B and C) The chromosome loss assay was performed with two independent transformants of both mutants and revertants, as described before (Sanyal et al. 2004). The numbers indicate the summation of colonies patched in independent experiments. Briefly, the strains were grown for ∼20 generations on YPDU medium at 30° under normoxic conditions. Subsequently, ∼1000 cells were plated on YPDU agar plates for each transformant and incubated at 30° for 2 days. The single colonies were patched on YPDU, SD minimal medium (SD) without arginine (CM−arg), and SD without histidine (CM−his). The chromosome loss rate was calculated by the number of colonies that were unable to grow on selective media divided by the total number of colonies grown on nonselective media.