Cloning techniques

Abstract

Nuclear transfer involves transferring the complete genetic material (of the nucleus) from one cell into an unfertilized egg cell whose own nucleus has been removed. Cloning based on the nuclear transfer technology dates as far back as 1952, when Robert Briggs and Thomas King made frogs from tadpole cells. Nuclear transfer has been used in mammals as both a valuable tool for embryonic studies and as a method for the multiplication (cloning) of desired ('elite') embryos. Offspring have only been reported when early embryos, embryo-derived cells primary culture, or embryonic cells which had been cultured for several passages and then induced to quiescence by serum starvation were used as nuclear donors. The research carried out by Dr. Ian Wilmut and his associates is pioneering. This is the first time the complete genetic material (the nucleus) from an adult mammalian cell has been used in the development of a new individual. In this review, not only this new approach in cloning, but also the recent developments in the fields of genetic engineering, gene therapy and genome projects were summarized.