Distal transformation in Drosophila leg imaginal disc fragments.

For an appendage to regenerate distal elements, it has been thought that the stump must contain a full set of circumferential positional information. We have shown that this rule is not binding for tarsus regeneration in the male foreleg imaginal disc of Drosophila melanogaster. Distal transformation was not restricted to fragments containing complete proximal segments, but was also observed in pieces with small or even substantial deficiencies that were not regenerated in their proximal segments.