Dynamical patterning modules: a "pattern language" for development and evolution of multicellular form.

Area of Science:

• Developmental Biology
• Evolutionary Biology
• Systems Biology

Background:

• The evolution of complex multicellular organisms (Metazoa) involved novel uses of pre-existing genetic and physical mechanisms.
• Understanding how diverse body plans arose from a conserved set of developmental genes is a key evolutionary question.

Purpose of the Study:

• To propose a framework, dynamical patterning modules (DPMs), explaining the origination and evolution of complex organismal forms.
• To investigate how conserved genetic toolkits and physical processes generate diverse metazoan body plans.

Main Methods:

• Conceptual analysis integrating developmental genetics, physical sciences, and evolutionary theory.
• Focus on the emergence of Metazoa and the role of gene-environment interactions.
• Modeling DPMs as a "pattern language" for body plan generation.

Main Results:

• DPMs, comprising developmental-genetic toolkit products and physical processes (cohesion, viscoelasticity, etc.), are proposed as fundamental units of morphogenesis.
• Pre-existing toolkit genes acquired new functions in multicellularity, enabling novel forms.
• DPMs, acting alone or in concert, can generate all metazoan body plans and organ forms.

Conclusions:

• Early multicellular organisms exhibited high phenotypic plasticity, exploring morphospace independently of strict selection pressures.
• Stabilizing selection shaped the developmental trajectories and stable phenotypes of modern organisms.
• This DPM framework resolves the molecular homology-analogy paradox by inverting the traditional view of genotype-phenotype evolution.