Tissue collections from sickle feathers used for RNA-seq. (a) Structures of a growing feather follicle. Six regions of tissue collected for RNA-seq are marked and labeled in red. Adopted and modified from (C. M. Chuong, Yeh, Jiang, & Widelitz, 2012). (b) Source of duplicate samples used for RNA-seq from the epithelial components including the upper follicle sheath (UFS), lower follicle sheath (LFS), collar epithelium (CE) and papillary ectoderm (PE). Source of duplicate samples from mesenchymal components including the pulp (PP) and dermal papilla (DP).