Clonig has been defined ( ア：a ) the production of a cell or organism with the ( イ：s ) nuclear genome as another ( ウ：c ) or organism. In other ( エ：w ), cloning is the production of one or more carbon copies of any given cell, or animal, ( オ：i ) a human. It was in fact the successful cloning of a sheep, the now famous ‘Dolly’ in 1997 ( カ：t ) represented a major breakthrough in the cloning arena.
The production of cloned animals ( キ：h ) stimulated much interest and anxiety worldwide, due to the implications this may have for human cloning. There are various potential uses of cloning techniques and a discussion ( ク：o ) these will help to identify ( ケ：b ) the scientific and ethical issues involved. From a scientific viewpoint, cloning opens up numerous potential research and therapeutic opportunities. For ( コ：e ), it may increase our understanding of the fundamental processes of cellular differentiation, thereby making possible its reversal, and hence providing a ( サ：m ) of controlling pathological and aging processes. Cloning technology also has the potential to improve the efficiency of production of transgenic livestock, ( シ：w ) could be used both for the production of organs or tissues for transplantation into humans, and ( ス：f ) the production of human proteins in cow’s or goat’s milk.