A new paradigm for animal symmetry

Area of Science:

• Developmental biology
• Evolutionary biology
• Genetics

Background:

• Traditional views consider animal body plan symmetries (radial and bilateral) as fixed concepts.
• Recent advances reveal complex gene regulatory networks (GRNs) control morphogenesis.

Purpose of the Study:

• To propose a more flexible framework for understanding animal body plan symmetries.
• To integrate insights from GRNs and developmental timing into symmetry concepts.

Main Methods:

• Analysis of general principles in genetic regulation of morphogenesis.
• Examination of how developmental timing influences symmetry at different anatomical scales.

Main Results:

• The distinction between whole-body and fine-structure symmetry is a matter of developmental timing.
• Animal genomes possess the inherent capacity to express both radial and bilateral symmetries.

Conclusions:

• Symmetry expression is dynamically regulated by functional requirements of anatomical structures and the organism.
• The prevalence of radial and bilateral symmetry is a consequence of evolutionary necessity, not random chance.