Robustness: confronting lessons from physics and biology.

Area of Science:

• Cross-disciplinary science
• Theoretical biology
• Systems biology

Background:

• The concept of robustness is prevalent across diverse scientific disciplines, including engineering, control theory, dynamical systems, and biology.
• Key correlates of robustness include stability, resilience, and self-organisation, with origins in physics.

Purpose of the Study:

• To evaluate the applicability of physics-derived robustness concepts to biological systems.
• To determine if specific extensions or novel frameworks are necessary for understanding biological robustness.
• To clarify the diverse meanings of robustness based on the types of perturbations systems must withstand.

Main Methods:

• Comparative analysis of robustness definitions and mechanisms across scientific fields.
• Examination of underlying mechanisms for robust behaviors, distinguishing universal (e.g., symmetries, conservation laws) from biology-specific (e.g., feedback networks) ones.
• Investigation into the relationship between robustness and noise, including dynamic selection versus natural selection.

Main Results:

• The relevance of physics-based robustness notions to biology is debated, with potential need for extensions.
• Robustness definitions are critically dependent on the nature of perturbations.
• Mechanisms range from universal physical principles to biology-specific regulatory networks.
• The interplay between robustness and noise, and the distinction between dynamic and natural selection, are crucial.

Conclusions:

• Nested notions of robustness, applicable across different timescales and organizational levels, can reconcile the demands of robustness and adaptability in living systems.
• A nuanced understanding of robustness in biology requires integrating concepts from physics with biology-specific mechanisms.
• Future frameworks may need to accommodate the multi-layered nature of biological robustness.