Phenotypic suppression caused by resonance with light-dark cycles indicates the presence of a 24-hours oscillator in yeast and suggests a new role of intrinsically disordered protein regions as internal mediators.

The mutual interaction between environment and life is a main topic of biological sciences. An interesting aspect of this interaction is the existence of biological rhythms spanning all the levels of organisms from bacteria to humans. On the other hand, the existence of a coupling between external oscillatory stimuli and adaptation and evolution rate of biological systems is a still unexplored issue. Here we give the demonstration of a substantial increase of heritable phenotypic changes in yeast, an organism lacking a photoreception system, when growing at 12 h light/dark cycles, with respect to both stable dark (or light) or non-12 + 12 h cycling. The model system was a yeast strain lacking a gene whose product is at the crossroad of many different physiological regulations, so ruling out any simple explanation in terms of increase in reverse gene mutations. The abundance of intrinsically disordered protein regions (IDPRs) in both deleted gene product and in its vast ensemble of interactors supports the hypothesis that resonance with the environmental cycle might be mediated by intrinsic disorder-driven interactions of protein molecules. This result opens to the speculation of the effect of environment/biological resonance phenomena in evolution and of the role of protein intrinsically disordered regions as internal mediators.Communicated by Ramaswamy H. Sarma.