Figure 2. Tissue patterning in the developing skin.

A. A conceptual diagram illustrating tissue patterning during the development and regeneration of a prototypical amniote skin. Complex tissue patterns are established through De novo patterning and multiple steps in adaptive patterning. Regulatory patterning refers to the modifications of appendage phenotypes in adults to adapt to environmental changes. Regenerative patterning describes the reformation of tissue patterns after loss, as observed in wound regeneration or organoid morphogenesis of dissociated progenitor cells. B. Whole-mount in situ of β-Catenin in developing chicken embryo. C. Turing model and its molecular cellular mechanisms. D. In chickens, the reconstitution of skin explants shows feather bud formation simultaneously (in red circles), and feather density is dependent on dermal cell density (a-d). In vivo, under the influence of a global gradient, the formation process occurs in a propagatory manner (Inaba et al., 2019a). E, F. Roles of bio-electricity in feather bud morphogenesis. When short bud starts to elongate, it accompanied with an outward electric current and synchronized GCaMP6 activity (Li et al., 2018). External electric currents have effect on collective bud orientation which depends on the position of electrodes (Jiang et al., 2021). G. Assembly of dermal muscle network connect feather buds and is force dependent (Wu et al., 2019). H. The formation of the dermal vascular network depends on localized vasculogenesis within feather buds (Ou et al., 2024).