Animal cloning how does it work

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.

The cause of death was unknown and the carcass was quickly cremated as it was decomposing. However, her early ageing may reflect that she was raised from the nucleus of a 6-year old sheep. Study of her cells also revealed that the very small amount of DNA outside the nucleus, in the mitochondria of the cells, is all inherited from the donor egg cell, not from the donor nucleus like the rest of her DNA.

So she is not a completely identical copy. This finding could be important for sex-linked diseases such as haemophilia, and certain neuromuscular, brain and kidney conditions that are passed on through the mother's side of the family only. Scientists are working on ways to improve the technology. For example, when two genetically identical cloned mice embryos are combined, the aggregate embryo is more likely to survive to birth.

Improvements in the culture medium may also help. Most of the ethical concerns about cloning relate to the possibility that it might be used to clone humans. There would be enormous technical difficulties. As the technology stands at present, it would have to involve women willing to donate perhaps hundreds of eggs, surrogate pregnancies with high rates of miscarriage and stillbirth, and the possibility of premature ageing and high cancer rates for any children so produced.

However, in South Korean scientists announced that they had cloned 30 human embryos, grown them in the laboratory until they were a hollow ball of cells, and produced a line of stem cells from them. Further ethical discussion was raised in when scientists succeeded in cloning mice from tissue that had been frozen for 16 years.

The Council of Europe has banned human cloning: in fact most countries have banned the use of cloning to produce human babies human reproductive cloning. However, there is one important medical aspect of cloning technology that could be applied to humans, which people may find less objectionable. This is therapeutic cloning or cell nucleus replacement for tissue engineering, in which tissues, rather than a baby, are created.

To clone a gene , researchers take DNA from a living creature and insert it into a carrier like bacteria or yeast. Every time that carrier reproduces, a new copy of the gene is made. Animals are cloned in one of two ways. The first is called embryo twinning. Scientists first split an embryo in half. Each part of the embryo develops into a unique animal, and the two animals share the same genes. The second method is called somatic cell nuclear transfer. Somatic cells are all the cells that make up an organism, but that are not sperm or egg cells.

Somatic cells, on the other hand, already contain two full sets of chromosomes. The egg develops into an embryo that contains the same genes as the cell donor. In , Scottish scientists cloned the first animal, a sheep they named Dolly. She was cloned using an udder cell taken from an adult sheep.

Since then, scientists have cloned cows, cats, deer, horses, and rabbits. They still have not cloned a human, though. 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. This process differs from other methods of artificial breeding, such as in vitro fertilization , in that it uses adult cells, instead of embryos. Follow Life's Little Mysteries on Twitter llmysteries.

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