Morphogenic accommodations for unidirectional airflow in the chicken lung

Unidirectional airflow in the avian lung enables gas exchange during both inhalation and exhalation. Stereo-seq spatial transcriptomics reveal a third, chicken-specific alveolar cell type expressing KRT14, hereby named luminal cells. Luminal, alveolar type 2, and alveolar type 1 cells sequentially occupy concentric zones radiating from the parabronchial lumen. Our study explores the evolutionary space of lung diversification and lays the foundation for functional analysis of species-specific genetic determinants. Overall design: E20 chicken lungs were harvested, and flash frozen in Tissue-Tek OCT medium in ethanol/dry ice bath, and then stored at -80°C until used for a Stereo-seq experiment. Cryo-sections were cut at the thickness of 10 µm and mounted on Stereo-seq permeabilization chips.