Morphogenetic effect of rotated skin cuffs on tail regeneration in Plethodon cinereus.

As an epimorphic system, the urodele tail has much in common with the urodele limb, relative to tissue components. In an effort to elucidate potentially similar functions of the skin during regeneration, two procedures which have been shown to be highly disruptive of limb morphogenesis were performed on the tail. In the first, cuffs of tail skin were rotated 180 degrees about the long axis of tails in Plethodon cinereus. Subsequent amputation through the rotated cuffs produced regenerates at a normal rate which were also normal in both internal architecture and skin gland distribution. In a second series, cuffs of tail skin were rotated 90 degrees about the dorso-ventral axis of the tail, such that the dorsal red stripe encircled the tail. Upon amputation through the middle of the cuff, the stump skin presented an exclusively dorsal surface which, nevertheless, had no effect upon the morphogenetic success of the regenerate. These data therefore indicate that a tissue, such as skin, may be inconsistent in its morphogenetic influence among epimorphic fields within the same organism. It is not clear whether these results reflect differences in field behavior or in absolute tissue potential determined by the field of origin. A tissue hierarchy of morphogenetic influence within and among epimorphic fields is suggested as a preliminary framework within which to coordinate such information.