STEP 1: Spemann tied a single strand of hair into a noose and pinched off a region of cytoplasm from a single celled salamander embryo.

STEP 2: The part of the cell containing the nucleus grew normally, and developed into a multi-celled embryo. The region of picnhed cytoplam remained unchanged.

STEP 3: Spemann loosened the noose, and allowed a nucleus from one of the embryo cells to enter the isolated region of cytoplasm.

STEP 4: Spemann then severed the multi-celled embryo from the cytoplasm. The region of cytoplasm, which now contained a nucleus, began to develop into a normal embryo.

About this Diagram:

Hans Spemann performed this experiment, the first nuclear transfer in 1928. The fact that a nucleus from a matured embryo cell could direct the development of a complete organism proved that genetic information did not diminish as a cell developed. From these results, Spemann, in 1938, proposed the "fantastical experiment" of duplicating organisms from specialized cells.

Timeline: Spemann Performs First Nuclear Transfer (1928)
Profile: Hans Spemann

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