On the evolution and development of morphological complexity: A view from gene regulatory networks

Area of Science:

• Evolutionary developmental biology
• Computational biology
• Systems biology

Background:

• Understanding the evolution of biological complexity is a central question in evolutionary biology.
• The relationship between genotype, phenotype, and the developmental processes linking them is crucial for understanding evolutionary trajectories.

Purpose of the Study:

• To investigate the evolutionary dynamics of morphological complexity.
• To determine how mutation rates and genotype-phenotype map (GPM) complexity influence the evolution of complex phenotypes.

Main Methods:

• Utilized EmbryoMaker, a mathematical model simulating gene networks, cell behaviors, signaling, and biophysics.
• Randomly wired gene networks to explore the development of diverse 3D morphologies.
• Analyzed the characteristics of networks generating simple versus complex morphologies.

Main Results:

• Networks producing complex morphologies are rarer, require fine-tuning, and are less robust to noise.
• Mutations in complex networks tend to decrease morphological complexity.
• Phenotypic complexity increases the complexity of the genotype-phenotype map (GPM).

Conclusions:

• The rate of morphological complexity evolution decreases over generations.
• Increasing phenotypic complexity leads to a decreased likelihood of mutations that enhance complexity.
• Complex GPMs and mutational asymmetry are inherent to developing complex, robust phenotypes.