Embryonic Avian Skin Explant Cultures: A Versatile Model for Investigating Tissue Patterning Mechanisms.

Avian skin explant cultures provide a powerful platform for studying the fundamental principles of tissue patterning during embryonic development. This ex vivo system retains the native properties of developing skin while enabling precise manipulation and live imaging to probe how biochemical and biophysical cues guide pattern formation across space and time. In this review, we highlight 3 major forms of embryonic explant culture and discuss how each has contributed to our understanding of morphogenetic processes such as feather bud initiation, spacing, orientation, elongation, and invagination during follicle formation. First, skin explant culture enables direct visualization of feather bud or scale formation and facilitate functional analysis through global or localized molecular treatments. Second, epithelial-mesenchymal recombination dissects tissue interactions by recombining epidermis and mesenchyme, revealing how inductive mesenchymal signals and epidermal competency define skin appendage identity and orientation. It can be further explored through heterotopic or heterochronic recombination. Third, skin reconstitution resets developmental programs by combining dissociated mesenchymal cells with intact epithelium, allowing the study of self-organization and the underlying rules governing periodic pattern initiation. Collectively, avian skin explant cultures serve as a versatile and accessible platform for uncovering how molecular, mechanical, and bioelectrical cues integrate to orchestrate complex tissue patterning.