Emergent cellular self-organization and mechanosensation initiate follicle pattern in the avian skin

Mechanics of follicle patterning in skin Studies of skin organogenesis have presupposed that a periodic molecular prepattern is responsible for the initiation of a periodic pattern of hair or feathers. To date, however, these initiating molecules have remained elusive. Using chicken skin as a model system, Shyer et al. found that the periodic spacing of feathers is triggered by mechanical rather than molecular events (see the Perspective by Grill). Furthermore, these mechanical events shape both the structure of prefeathers and their molecular identity. Science , this issue p. 811 ; see also p. 750