The lambs originated by asexual means through a common ancestor making them clones. It was considered to be asexual reproduction because the creation of these lambs was not from the traditional union of sperm and egg. After this accomplishment, the scientists successfully cloned animals from a twenty-six day old fetus as well as an adult ewe. The famous Dolly was the result of the cells taken from the ewe. These amazing feats were performed using a method of cloning that is based on nuclear transfer.
Nuclear transfer involves a donor and a recipient cell.
The donor cell is the cell whose genetic information is to be copied, while the recipient cell has its genetic information removed. Once the recipient cell is free of its chromosomes, genetic information carriers, the donor cell is fused with the recipient. Researchers had to take into account the compatibility of these cells. To assure that the fusion was successful, the cells had to have coordinated cycles of DNA duplication and RNA production. This measure was taken to insure that the eggs would grow together once they were placed into the uterus of the surrogate mother.