Did you know that Dolly, the wonder sheep, was named after the country and western singer Dolly Parton? This is because the DNA that she was cloned with came from a mammary cell.
So how was Dolly made (if made is really the right word)?
Scientists at the Roslin Institute in Edinburgh, Scotland took an egg from a Scottish blackface ewe and removed the nucleus from it. This left them with an enucleated egg. The nucleus is the bit in the cell that has the animal's DNA, which gives instructions as to how the cell should work.
The scientists also obtained a nucleus, which they got from a mammary gland cell of a Finn Dorset sheep. They then fused (joined) the enucleated egg and nucleus together by applying some electricity, which gave them an embryo.
The embryo was put into the uterus of a blackface ewe and allowed to grow like any other unborn baby sheep on a farm.
When Dolly was born there was an easy way to tell that she had different DNA to the blackface ewe that had given birth to her — Dolly didn't have a black face! They made a fuller check of Dolly and found that she was genetically the same as the Finn Dorset which 'donated' the nucleus. Dolly was therefore a clone.