Steen Willadsen

Steen Malte Willadsen (born 1943 in Copenhagen, Denmark) is a Danish biologist credited with being the first to clone a mammal using nuclear transfer.

Steen Willadsen
Born	1943 Copenhagen, Denmark
Alma mater	Royal Veterinary College of Copenhagen
Known for	The first cloning of a sheep.
Awards	Recipient of the Royal Agricultural Society of England's Gold Medal for Research, 1985, and the International Embryo Transfer Society's Pioneer Award, 2005[1]
Scientific career
Fields	embryologist

Willadsen graduated from the Royal Veterinary College of Copenhagen in 1969, and received a PhD in reproductive physiology there in 1973. In 1984, at the British Agricultural Research Council's Institute of Animal Physiology, Cambridge, he successfully used cells from early embryos to clone sheep by nuclear transfer.^[2][3] The procedure he developed was essentially identical to the one used to create Dolly the sheep, although nuclei from a mature sheep were used instead of sheep embryos. Prior to the nuclear transfer experiments, Willadsen had developed methods for freezing sheep and cow embryos,^[4] embryo manipulation methods for producing genetically identical animals (primarily identical twins in sheep, cattle, pigs, and horses),^[5] and for producing mammalian chimaeras, including interspecies chimaeras.^[6]

References

1. Reproduction, Fertility and Development 2005, 17
2. Willadsen, Steen M. (1986-03-06). "Nuclear transplantation in sheep embryos". Nature. 320 (6057): 63–65. doi:10.1038/320063a0. ISSN 1476-4687.
3. Willadsen, Steen M. (1989-01-15). "Cloning of sheep and cow embryos". Genome. 31 (2): 956–962. doi:10.1139/g89-167. ISSN 0831-2796.
4. Willadsen, Steen M. (January 1977). Elliott, Katherine; Whelan, Julie (eds.). "Factors affecting the survival of sheep embryos during deep-freezing and thawing". Novartis Foundation Symposia. 52: 175–201. doi:10.1002/9780470720332.ch9. ISBN 978-0-85708-010-3.
5. Willadsen, Steen M. (1979-01-25). "A method for culture of micromanipulated sheep embryos and its use to produce monozygotic twins". Nature. 277 (5694): 298–300. doi:10.1038/277298a0. ISSN 0028-0836.
6. Fehilly, Carole B.; Willadsen, Steen M.; Tucker, Elizabeth M. (1984-02-16). "Interspecific chimaerism between sheep and goat". Nature. 307 (5952): 634–636. doi:10.1038/307634a0. ISSN 0028-0836.

External links

• Thinkquest profile