(Science: cell biology) change in determined state observed in experiments on drosophila imaginal discs.
These can be cultured for many generations in the abdomen of an adult, where they proliferate but do not differentiate. If transplanted into a larva, they differentiate after pupation according to the disc from which they were derived, they maintain their determination.
Occasionally the disc will differentiate into a structure appropriate to another disc. This is termed transdetermination. It is a rare event, involves a population of cells and certain changes are more common than others, e.g. Leg to wing is more frequent than wing to leg.