CLONING TIMELINE 1938 -1999
1938: Hans Spemann, a German developmental Biologist, first suggests a nuclear transfer experiment to test the importance of the nucleus in early stage development. He was unable to complete the experiment.
Spemann H: Embryonic Development and Induction. New Haven, CT. Yale University Press. 1938
1950’s: Briggs and King report first nuclear transfer success in amphibians. Conclude that using an adult cell to clone is impossible.
1970’s: Developmental Biologist, John Gurdon, successfully cloned frogs using later stage cells. This experiment discounted the conclusion of Briggs and King and raised interest in the possibility of using adult cells in cloning experiments.
3/7/96: Announcement by Roslin Institute scientists of the successful production of two live sheep, named Megan and Morag, by transplanting nuclei from embryonic sheep cells.
K.H.S.Campell et al. “Sheep cloned by nuclear transfer from a cultured cell line.” Nature 1996: vol. 380: pg 64-66.
2/23/97: Announcement of the existence of Dolly the lamb, first clone of an adult mammal.I. Wilmut et al. “Viable offspring derived from fetal and adult mammalian cells.” Nature 1997; vol. 385: pg. 810-813
3/5/97: President Clinton bans federal funding of human cloning by issuing a five year moratorium.
1/21/98: Advanced Cell Technologies in Texas successfully clone transgenic calves, calves that have been genetically manipulated. The goal is to be able to clone calves that have been genetically altered to produce human pharmaceuticals in their milk.