Fig 2. Gene duplication as a force for trade-off resolution.

(A) Nonduplicated genes are forced to sacrifice expression responsiveness for precision because of the noise that accompanies responsiveness. Gene duplication can resolve this conflict by providing two genes with the same function at the protein level, one that is responsive and one that has a precise expression level. (B) Chapal and colleagues [25] provide a description of how the paralogs Msn2 and Msn4 cooperate to supply the cell with a precise but stable (Msn2) and responsive but noisy (Msn4) expression. Msn4 is hardly expressed during nonstress conditions but increases in expression as stress levels go up, whereas Msn2 remains constantly expressed at a low level. Panel A inspired from [26].