Zinder said: Either Dolly has mitochondria only from the egg, or her mitochondria are identical to those of the udder cell or her mitochondria are a mixture, with some from the egg and some from the udder cell. As an animal or person ages, their telomeres become progressively shorter, exposing the DNA to more damage.
Dolly had a massive scientific impact, especially through driving stem cell research and therapyWhitelaw told Live Science. She mated and produced normal offspring in the normal way, showing that such cloned animals can reproduce.
The adult udder cell's nucleus took over and directed the development of the egg, causing it to divide and grow into an embryo, then a fetus and a lamb. But since Dolly the sheep in became the first mammal to be cloned, replicating humans has increasingly become a matter of when, not if.
So when scientists working at the Roslin Institute in Scotland produced Dolly, the only lamb born from attempts, it was a major news story around the world. Dolly with Professor Sir Ian Wilmut, who led the research which produced her.
At present, cloning from embryonic cells and even old-fashioned animal breeding are still more efficient ways of producing large numbers of genetically-altered animals, notes William H.
Their first lamb, Bonnie, was born in Apriltwins Sally and Rosie were born the following year and triplets Lucy, Darcy and Cotton the year after. First has said informally that he had achieved some pregnancies in cattle but that none had gone to term.