Cellular Origami in Feather Shaft Morphogenesis

Wen-Tau Juan^1*, 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

During the bird flight, the flight feather is mechanically supported by a light and resilient shaft, a beam with a porous inner medulla enclosed by the dense outer cortex. How the composite feather shaft is developed and optimized has attracted much attention in bird adaptation. In this work, we applied a quantitative morphology field (QMorF) analysis to investigate the cellular origami in the medulla. The collective cellular folding in a cellular origami reflects the imposed stress field during the morphogenesis. The cross-species QMorF studies on flight feathers show that, for good flyers, the cellular-origami pattern evolves toward a homogeneous topology accompanied with the polarized cortex reinforcement. The spatial-temporal modulation of the keratin and adhesion molecule expressions contributes to the developmental origin of the observed cellular origami pattern. The variation of cellular origami among feather shafts is a vivid example of bio-architectural optimizations for different adaptive strategies in nature.

Keywords: cellular origami, feather shaft, morphogenesis, quantitative morphology field