Role of ancient duplicates in the metabolic switching in Saccharomyces cerevisiae

Abstract

Gene duplication events have been associated with increasing biological complexity throughout the tree of life, but also with illnesses, such as cancer. Early evolutionary theories indicated that duplicated genes could explore alternative functions due to the relaxation of selective constraints in one of the copies, as the other remains an ancestral-function backup. In unicellular eukaryotes like yeasts, it has been demonstrated that the fate and persistence of both duplicated copies in the genome depend on the duplication mechanism (whole-genome or small-scale events). Although it has been shown that smallscale duplicates tend to innovate and whole-genome duplicates specialize in ancestral functions, the implication of ancient duplicates¿ transcriptional plasticity and transcriptional divergence on environmental and metabolic responses remains largely obscure. Here we subject Saccharomyces cerevisiae to a metabolic switch by enforcing acute and chronic growth on a non-fermentative carbon source (ethanol) unrevealing the central role, the ancient duplicates have in metabolic shifts. In particular, the duplicates respond by transcriptional rewiring, depending on their transcriptional background. Our results shed light on the mechanisms that determine the role of duplicates, and on their continued evolvability.