Spatially and Temporally Distributed Complexity-A Refreshed Framework for the Study of GRN Evolution

Area of Science:

• Developmental Biology
• Evolutionary Biology
• Systems Biology

Background:

• Current interpretations of gene regulatory networks (GRNs) in development face limitations.
• These include inadequate understanding of genotype-phenotype links, zoocentrism, and assumptions of hierarchical organization in animal body plans.

Purpose of the Study:

• To constructively criticize prevailing assumptions in developmental biology regarding GRNs.
• To propose a more comprehensive framework for understanding developmental processes, genotype-phenotype relationships, and the evolution of complexity.

Main Methods:

• Critical analysis of existing paradigms in developmental biology.
• Exploration of transcriptomic transitions in unicellular organisms.
• Discussion of regulatory machinery dynamics and animal architecture.

Main Results:

• Developmental biology is often adultocentric; development is not solely egg-to-adult.
• Unicellular organisms exhibit transcriptomic changes relevant to GRN studies.
• A combinatorial, rather than hierarchical, approach better explains genotype-phenotype relationships.

Conclusions:

• Rethinking developmental biology requires moving beyond adultocentrism and zoocentrism.
• Incorporating unicellular development and combinatorial logic is crucial for understanding GRNs.
• Polyphenism and sequential unicellular phenotypes may be key to the origin of multicellularity and complex life cycles.