|
|
Article: A fantastical experiment: the science behind the controversial cloning of Dolly. (first cloning of mammal from adult nucleus)(Cover Story)
- Article from:
- Science News
- Article date:
- April 5, 1997
- Author:
CopyrightCOPYRIGHT 1997 Science Service, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
|
In 1938, just a few years before his death, the famous German embryologist Hans Spemann pondered a long-debated idea called nuclear equivalency. Spemann and his contemporaries knew that all animal cells contain a nucleus, the membrane-bound structure that houses a cell's genes.
During the earliest stages of life, when an embryo consists of fewer than a dozen or so cells, the genes inside every nucleus have their fullest potential. Each embryonic cell is, in the jargon of biologists, totipotent: It has the ability to give rise to cells that make up the eyes, the liver, the brain, or any other part of an adult animal.
Yet as an embryo develops, cells lose this ...