1995: Dr. Ian Wilmut and Keith Campbell (U.K.) create the world's first cloned sheep, Megan and Morag, from differentiated embryo cells.  

            Ian Wilmut, Keith Campbell and their team of Roslin Institute cloned 2 lambs, Megan and Morag, from embryo-derived cells that had been cultured in the lab for several weeks.  Wilmut began the cloning research as a solution to improving the efficiency of gene insertion.  Traditional ways of genetically engineering animals was inefficient and ineffective. Very few animals sequenced the inserted genes into their genome, and fewer still expressed the gene in their cells. With cloning, it will be much easier to manipulate differentiated, genetically altered cells, and then clone them.

            Megan and Morag, two Welsh mountain sheep, were cloned using nuclear transfer with cells just past the embryonic stage.  The team knew that for cloning to work, the egg and the donor cell have to have their cell cycles synchronized.  To do so, Campbell starved the embryo cells so that both the egg cell and the donor cell are in the G0 state.  Afterwards, they fused the embryo cell with an enucleated egg by electricity.  Megan and Morag, predecessors to Dolly, were then born normally by 2 different surrogate mothers. 

Photo courtesy of the Roslin Institute