Megan and Morag, two domestic sheep, were the first mammals to have been successfully cloned from differentiated cells.
The team at the Roslin Institute tried to make immortalized and undifferentiated embryonic stem cell lines in sheep, but failed.
Nuclear transfer was done, using electrical stimuli both to fuse the cultured cell with the enucleated egg and to kick start embryonic development.
The production of Megan and Morag demonstrated that viable sheep can be produced by nuclear transfer from cells which have been cultured in vitro.
The birth of Megan and Morag, a year before Dolly, with their huge beneficial potential, made relatively few headlines.