Nuclear Transplantation in Eggs and Oocytes

Nuclear transplantation involves the replacement of the nucleus of one cell with that of another. The original purpose of this technique was to test whether the nucleus of a somatic cell can replace the zygote nucleus of a fertilized egg, and so determine whether cell differentiation and morphogenesis are accompanied by stable changes in the genome. The need for such a test was evident since Weismann's (1892) germ-plasm hypothesis in which it was supposed that genetic determinants are segregated into different cells as development proceeds. The technique of nu clear transfer was first achieved in single-celled organisms, such as Acetabularia (Hammerling, 1934) and Amoeba (Comandon & De Fonbrune, 1939). The delayed--