Adult frogs derived from the nuclei of single somatic cells.

Demonstration that somatic and germinal nuclei are genetically equivalent. Using somatic cell nuclear transfer (SCNT),  Gurdon (Nobel Prize 2012) transplanted cell nuclei from mature intestinal tadpole cells into enucleated eggs, which developed into normal tadpoles. This contradicted the textbook dogma that adult cells are irrevocably assigned to their specific functions and cannot assume new ones. The egg was able to reprogram the introduced nucleus and direct its genes to switch from the duties of an intestinal cell to those appropriate to a developing egg.