What type of organisms have been cloned

The nucleus contains nearly all the cell's genes. Then they injected the cell into an unfertilised egg cell which had had its nucleus removed, and made the cells fuse by using electrical pulses. The unfertilised egg cell came from a Scottish Blackface ewe. When the scientists had managed to fuse the nucleus from the adult white sheep cell with the egg cell from the black-faced sheep, they needed to make sure that the resulting cell would develop into an embryo. They cultured it for six or seven days to see if it divided and developed normally, before implanting it into a surrogate mother, another Scottish Blackface ewe.

Dolly had a white face. From cell fusions, 29 early embryos developed and were implanted into 13 surrogate mothers. But only one pregnancy went to full term, and the 6. The main reason that the scientists at Roslin wanted to be able to clone sheep and other large animals was connected with their research aimed at producing medicines in the milk of such animals. Researchers have managed to transfer human genes that produce useful proteins into sheep and cows, so that they can produce, for instance, the blood clotting agent factor IX to treat haemophilia or alphaantitrypsin to treat cystic fibrosis and other lung conditions.

Cloned animals could also be developed that would produce human antibodies against infectious diseases and even cancers. If this technique can be applied to mammalian cells and the cells cultured to produce cloned animals, these could then breed conventionally to form flocks of genetically engineered animals all producing medicines in their milk.

There are other medical and scientific reasons for the interest in cloning. It is already being used alongside genetic techniques in the development of animal organs for transplant into humans xenotransplantation. Combining such genetic techniques with cloning of pigs achieved for the first time in March would lead to a reliable supply of suitable donor organs.

However, there are still worries about virus transmission. The study of animal clones and cloned cells could lead to greater understanding of the development of the embryo and of ageing and age-related diseases. Cloned mice become obese, with related symptoms such as raised plasma insulin and leptin levels, though their offspring do not and are normal.

Cloning could be used to create better animal models of diseases, which could in turn lead to further progress in understanding and treating those diseases. It could even enhance biodiversity by ensuring the continuation of rare breeds and endangered species. Dolly, probably the most famous sheep in the world, lived a pampered existence at the Roslin Institute.

She mated and produced normal offspring in the normal way, showing that such cloned animals can reproduce. Born on 5 July , she was euthanased on 14 February , aged six and a half. Sheep can live to age 11 or 12, but Dolly suffered from arthritis in a hind leg joint and from sheep pulmonary adenomatosis, a virus-induced lung tumour to which sheep raised indoors are prone. On 2 February , Australia's first cloned sheep died unexpectedly at the age of two years and 10 months.

Have a look and if you think we have missed anything let us know on our Twitter or our Facebook page. And if you want to check out the data we used to create the graphic, you can find it here. Cloning timeline: Which animals and when? Share using Email. Fifteen years ago a sheep called Dolly arrived into our world and caused a sensation. A living, breathing and bleating sheep created from an adult cell, Dolly was not the first animal to be cloned, but she became the most famous.

In part, this is because it is difficult to produce a viable clone. In each attempt, there can be genetic mistakes that prevent the clone from surviving. It took scientists attempts to get Dolly right. There are also ethical concerns about cloning a human being. Researchers can use clones in many ways.

An embryo made by cloning can be turned into a stem cell factory. Stem cells are an early form of cells that can grow into many different types of cells and tissues. Scientists can turn them into nerve cells to fix a damaged spinal cord or insulin-making cells to treat diabetes. The cloning of animals has been used in a number of different applications. Animals have been cloned to have gene mutations that help scientists study diseases that develop in the animals. Livestock like cows and pigs have been cloned to produce more milk or meat.

In , a cat named CC was the first pet to be created through cloning. Cloning might one day bring back extinct species like the woolly mammoth or giant panda. The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited. Tyson Brown, National Geographic Society.

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