Nuclear transfer
' In nuclear transfer the DNA is removed from an unfertilized egg and the nucleus of a specially prepared body cell is introduced and the combination or " couplet" is triggered either by an electrical pulse, or the introduction of a chemical, to fuse them together and begin the process of development. Much is still to be known about what happens in this process and most attempts fail at the start.'
( From : http://www.ri.bbsrc.ac.uk/library/reseach/cloning/glossary.html )