The healing of an adult skin wound is a complex process requiring the collaborative efforts
of many different tissues and cell lineages. The behavior of each of the contributing cell …

Cell signaling plays a key role in the development of all multicellular organisms. Numerous
studies have established the importance of Hedgehog signaling in a wide variety of …

Vertebrate limb formation has been known to be initiated by a factor (s) secreted from the
lateral plate mesoderm. In this report, we provide evidence that a member of the fibroblast …

Avian feathers are a complex evolutionary novelty characterized by structural diversity and
hierarchical development. Here, I propose a functionally neutral model of the origin and …

Mammalian tooth forms are produced during development by folding of the enamel
epithelium but the molecular mechanisms involved in the formation and patterning of tooth …

Progress on the evolutionary origin and diversification of feathers has been hampered by
conceptual problems and by the lack of plesiomorphic feather fossils. Recently, both of these …

The formation of periodic patterns is fundamental in biology. Theoretical models describing
these phenomena have been proposed for feather patterning; however, no molecular …

Ventral cell fates in the central nervous system are induced by Sonic hedgehog, a homolog
of hedgehog, a secreted Drosophila protein. In the central nervous system, Sonic hedgehog …

Signaling molecules such as Activin, Sonic hedgehog, Nodal, Lefty, and Vg1 have been
found to be involved in determination of left-right (LR) asymmetry in the chick, mouse, or …

In the first part of this paper we review current knowledge regarding fish scales, focusing on
elasmoid scales, the only type found in two model species, the zebrafish and the medaka …