Size-Regulated Symmetry Breaking in Reaction-Diffusion Models of Developmental Transitions

Area of Science:

• Developmental biology
• Systems biology
• Theoretical biology

Background:

• Multicellular development involves self-organization and spontaneous symmetry breaking for pattern formation.
• Coordinating multiple, temporally ordered developmental transitions is a critical, yet less understood, aspect of development.

Purpose of the Study:

• To elucidate mechanisms coordinating reaction-diffusion-driven symmetry breaking with developmental timing.
• To propose system size-dependent patterning as a potential time-measuring principle in development.

Main Methods:

• Utilized a minimal mass-conserved substrate-depletion model for symmetry breaking.
• Simulated the model on growing domains to analyze different dynamic regimes.
• Investigated the dependence of patterning mode on system size.

Main Results:

• Identified three distinct behaviors: clock-like, timer-like, and switch-like dynamics.
• Demonstrated how system size can influence patterning mode, potentially serving as a time-measuring mechanism.
• Linked model behaviors to experimentally observed developmental timing.

Conclusions:

• Proposed a minimal conceptual framework for understanding developmental transition coordination.
• Highlighted the potential role of system size-dependent patterning in biological timekeeping.
• Provided a theoretical basis for interrogating developmental timing mechanisms.