Wei-Ling Chang, Hao Wu, Yu-Kun Chiu, Shuo Wang,Ting-Xin Jiang, Zhong-Lai Luo, Yen-Cheng Lin, Ang Li, Jui-Ting Hsu, Heng-Li Huang, How-Jen Gu, Tse-Yu Lin, Shun-Min Yang, Tsung-Tse Lee, Yung-Chi Lai, Mingxing Lei, Ming-You Shie, Cheng-Te Yao, Yi-Wen Chen, J.C. Tsai, Shyh-Jou Shieh, Yeu-Kuang Hwu, Hsu-Chen Cheng, Pin-Chi Tang, Shih-Chieh Hung, Chih-Feng Chen, Michael Habib, Randall B. Widelitz, Ping Wu, Wen-Tau Juan & Cheng-Ming Chuong (2019)
The Making of a Flight Feather: Bio-architectural Principles and Adaptation.
Cell 179(6): P1409-1423.E17
A cortex/medulla composite beam organization allows rachides to adapt flexibly
Polarized adhesion and keratin _expression_ lead to hooklet barbules that form vanes
With-dermal papilla WNT signaling controls barbule shape along the feather P-D axis
3D feathers embedded in amber show primitive vanes formed by overlapping barbules
The evolution of flight in feathered dinosaurs and early birds over millions of years required flight feathers whose architecture features hierarchical branches. While barb-based feather forms were investigated, feather shafts and vanes are understudied. Here, we take a multi-disciplinary approach to study their molecular control and bio-architectural organizations. In rachidial ridges, epidermal progenitors generate cortex and medullary keratinocytes, guided by Bmp and transforming growth factor Î (TGF-Î) signaling that convert rachides into adaptable bilayer composite beams. In barb ridges, epidermal progenitors generate cylindrical, plate-, or hooklet-shaped barbule cells that form fluffy branches or pennaceous vanes, mediated by asymmetric cell junction and keratin _expression_. Transcriptome analyses and functional studies show anterior-posterior Wnt2b signaling within the dermal papilla controls barbule cell fates with spatiotemporal collinearity. Quantitative bio-physical analyses of feathers from birds with different flight characteristics and feathers in Burmese amber reveal how multi-dimensional functionality can be achieved and may inspire future composite material designs.