The day the world saw the first cloned sheep – level 3
22-02-1997
Dolly was a sheep born on July 5, 1996. At first sight, Dolly looked quite ordinary, but she wasn’t ordinary. She was an exact genetic clone of another adult sheep. She was created without the father ram, without the use of sperm.
She was created by scientists in Scotland. They used the following procedure.
They took an egg cell from one sheep and removed the nucleus. Then, they took the nucleus from the cell of another sheep and put it into the egg cell of the first sheep. They created an embryo from this special cell. They put the embryo into a third sheep, which carried it to the birth.
This method of cloning wasn’t much explored at that time. They had to make many failed attempts. In the end, there were 276 unsuccessful ones. Only the 277th attempt was successful, and a healthy sheep was born. It was named Dolly.
At first, her existence was kept secret for half a year due to possible complications, but then the scientists knew it was time to speak to the media.
On February 22, 1997, journalists from all over the United Kingdom gathered in the small Scottish town of Roslin where the scientists from the biological institute announced this success.
Difficult words: ordinary (normal), genetic clone (a copy of a living thing that is exactly the same), ram (a male sheep), cell (a very small part of a body), nucleus (the central part of a cell), embryo (a developing fetus or baby inside the mother’s body), attempt (an act of trying), gather (to meet as a group), announce (to say officially).
What was the success of the 277th attempt?
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