White, Kenneth L. Department of Animal, Dairy, and Veterinary Sciences, Center for Integrated Biosystems, Utah State University, Logan, Utah.
Aston, Kenneth I. Department of Animal, Dairy, and Veterinary Sciences, Center for Integrated Biosystems, Utah State University, Logan, Utah.
Sessions, Benjamin R. Department of Animal, Dairy, and Veterinary Sciences, Center for Integrated Biosystems, Utah State University, Logan, Utah.
- Methods of manipulation and activation
- Status of SCNT technology
- Factors affecting SCNT efficiency
- Future outlook
- Links to Primary Literature
- Additional Readings
The procedure of cloning or nuclear transfer (NT) is defined as the transfer of a nucleus from one cell into another cell from which the nucleus has been removed. NT was first devised by the German Nobel laureate Hans Spemann in 1938, when he proposed an experiment involving the insertion of a nucleus into an enucleated oocyte, that is, an egg that has had its nucleus removed. The idea was not pursued, however, because Spemann did not have the equipment required to perform such an experiment. Robert Briggs and Thomas J. King were the first to utilize NT successfully in the production of live offspring from metazoan cells. They reported the successful production of Northern leopard frog (Rana pipiens) tadpoles via NT in 1952. Continued research by the same group later concluded that the developmental potential of NT embryos declined with increased embryonic cell age. In 1966, frog larval nuclei were used successfully to produce fertile Xenopus frogs and demonstrated proof in principle that somatic cells (any cells of an organism except the germ cells) from a variety of sources, including skin, lymphocytes, erythrocytes, leukocytes, and erythroblasts, were able to regress from a specialized or differentiated cell to a simpler, unspecialized cell and yield morphologically normal tadpoles; however, none of these tadpoles survived to adulthood. These results showed the potential of differentiated cells to derive numerous different cell types in a complex organism; the question remained, though, whether adult cells could be dedifferentiated or reprogrammed to a totipotent state (capable of differentiating into every type of cell found in an organism and of forming the entire organism) and consequently regain the ability to give rise to any cell type.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Its dedicated editorial team is led by Sagan Award winner John Rennie. Contributors include more than 9000 highly qualified scientists and 39 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 17,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information