ABSTRACT
Dolly entered history as the first animal clone. Yet, in truth, the epoch making aspect of her birth was the fact that she heralded an entirely new approach to the genetic manipulation of complex animals. Molecular biologists have spent a good deal of time working out how genes are switched on and off in different cell types and how cells ensure that proteins are produced when and where they are required. The new technology allows novel gene combinations to be introduced into easily manipulatable tissue cultures of ‘normal’ cells, removal of their nuclei and injection into eggs from which the nucleus has been surgically removed. One of the major reasons is belief that it will be easier to tweak genes in a single cell in tissue culture than to inject them into millions of cells using somatic gene therapy. Researchers are investigating possibility of applying more extensive genetic manipulation to tissue cultured cells prior to using them in nuclear transfer.
