Dolly's "Father" awarded for "Century Experiment"

Ian Wilmut receives the highest German medicine prize

Clone sheep Dolly © Roslin Institute
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The "father" of the clone sheep Dolly, the physiologist Ian Wilmut of the Roslin Institute in the UK receives one of the highest medical prizes in Germany, the Paul Ehrlich and Ludwig Darmstaedter Prize 2005. Thus his groundbreaking experiments, which are to clone the first mammal from an adult cell.

In the justification of the Paul Ehrlich Foundation states: "In the context of their scientific work, Professor Ian Wilmut and his research team have transferred a nucleus of fully differentiated cells into previously seeded, unfertilized egg cells of a sheep. They have thereby gained a totipotent stem cell that, after planting in a conditioned female sheep, produced an embryo that developed into a normal sheep. These scientific experiments have fundamentally changed the visions in embryology. New limits in animal breeding and in human medicine will be the result. It is also beyond doubt for Wilmut that human reproductive cloning should be banned. "

The award, which will be presented on 14 March 2005 in the Frankfurt Paulskirche, is one of the highest and most internationally renowned awards in the Federal Republic of Germany in the field of medicine.

Detection of totipotency of adult cells

Until the birth of Dolly, all successful mammalian cloning had one thing in common: the donor nuclei came from very early embryos. There is a simple reason for this: with few exceptions, all cells of an adult organism have complete genetic information; but most of the genes are switched off, because the cell only uses the genes that are necessary for the special task of the respective tissue in the body. Ian Wilmut and his colleagues at Dolly have managed to restore the totipotency of their embryonic progenitor cells to such a differentiated cell.

The scientists gutted an egg and transplanted the nucleus of an udder cell from a pregnant sheep. display

The plasma of the enucleated ovum then reprogrammed the implanted genome so that it became totipotent again, that is, all genes were active again. The developing embryo in the test tube was implanted after six days of a surrogate mother who belonged to a different species than the nuclear donor. This ensured that the Lamb, who had finally been born, already indicated externally that it was not related to the animal that carried it out. Analyzes of the genetic material, the DNA, confirmed this result.

Dolly: One of 400

The effort involved in this experiment was considerable: More than 400 oocytes, taken from hormonally stimulated sheep, were gutted manually, provided with "donor cores" and 277 embryos were used in provisional mortars. Only 29 of these embryos were one week later in the physiologically expected stage of development and could be transplanted into a total of 13 definitive donors. In the end, a single healthy lamb was born - Dolly. Six years later, on April 10, 2003, the sheep had to be taken in for a lung disease, which actually occurs only in older animals. Whether his early death was related to his origins as a clone sheep is unclear.

Dolly was the result of a successful experiment that raised a multitude of scientific questions: what factors control cell differentiation during embryonic development? How can this differentiation be lifted under certain circumstances?

These questions are particularly interesting for cancer research, as tumor tissue is characterized by being different from its original genetic program and in part by recovering embryonic properties, such as the ability to divide.

"This made Dolly a very important breakthrough for basic research, especially for the future stem cell biology, " says Prof. Dr. med. Bernhard Fleckenstein, Head of the Institute for Clinical and Molecular Virology of the University of Erlangen-N rnberg, and Member of the Board of Trustees of the Paul Ehrlich Foundation.

(University of Frankfurt (Main), 24.11.2004 - NPO)