Plasticity-led and mutation-led evolutions are different modes of the same developmental gene regulatory network

Area of Science:

• Evolutionary biology
• Developmental biology
• Systems biology

Background:

• Mutation-led evolution (MLE) is challenged by plasticity-led evolution (PLE), where environmental changes induce adaptive phenotypes later genetically accommodated.
• Developmental systems are typically robust to environmental and mutational changes, posing a question about transitions to adaptive plasticity.

Purpose of the Study:

• To investigate the evolutionary dynamics between MLE and PLE.
• To explore how developmental system robustness influences evolutionary pathways.
• To reconcile conflicting theories of evolution using a gene regulatory network model.

Main Methods:

• Constructed a gene regulatory network (GRN) model integrating development, hierarchical regulation, and environmental cues.
• Simulated the GRN model's evolution across varying magnitudes of environmental change.
• Analyzed phenotypic distributions and system susceptibility to perturbations.

Main Results:

• The GRN model exhibited PLE under large environmental changes and MLE under small environmental changes.
• The model showed a transition from robustness to susceptibility as environmental change magnitude increased.
• Phenotypic distributions became biased and aligned with environmental changes before robustness breakdown, facilitating adaptation.

Conclusions:

• The evolutionary transition from MLE to PLE is driven by a developmental shift from robust to susceptible states with increasing environmental change.
• Gene regulatory network models can integrate and reconcile mutation-led and plasticity-led evolution.
• Developmental system plasticity is a key factor in adaptive evolution under environmental stress.