Cellular Origami in Feather Shaft Morphogenesis
Wen-Tau Juan1*, Hao Wu1, Wei-Ling Chang1, Yu-Kun Chiu2, Tse-Yu Lin2, Jih-Chiang Tsai2, Cheng-Ming Chuong3
1Integrative Stem Cell Center, China Medical University, Taichung, Taiwan
2Institute of Physics, Academia Sinica, Taipei, Taiwan
3Department of Pathology, University of Southern California, Los Angeles, CA, USA
* Presenter:Wen-Tau Juan, email:wtjuancmu@gmail.com
Hierarchical feather branches are supported by their light but resilient rachis, i.e., the shaft of the feather, to generate versatile functions. How to construct an optimized shaft according to the feather function is a mystery in bird evolution. A rachis is a composite beam with a porous medullary core surrounded by the dense cortex. Our QMorF (Quantitative Morphology Field) analyses on rachis medulla reveal patterned cellular origami, i.e., collective cellular foldings, leading to diverse rachis organizations. Analyzing flight feathers from different birds show a simplified trend of cellular origami accompanying the polarized cortex reinforcement toward higher flight performance. Emu, penguin, and hummingbird rachises exhibit distinct adaptive strategies. Special keratins and adhesion molecules are enriched in specific sub-regions during rachis morphogenesis to spatially modulate the intercellular coupling. The discovery reveals the feather shaft is not simply a weight-saving structure, but with diverse cellular-origami patterns optimized for adaptation to different eco-spaces. Our interdisciplinary work may inspire novel design for biomimetic composite materials.

Keywords: feather, rachis, QMorF (Quantitative Morphology Field), cellular origami, morphogenesis