Cloning

Cloning is producing a genetic twin of another organism. There are 3 kinds of cloning:  

·    Recombinant - the transfer of a DNA fragment of interest from one organism to a self-replicating genetic element.  Scientists call it a bacterial plasmid. 

Meaning that is taking one thing of something and putting it in something else.

·    Reproductive cloning is used to make an animal that has the same DNA as an animal that is living or extinct. This is how Dolly was made.

·    Therapeutic also called "embryo cloning". Therapeutic uses human embryos for research.

The goal of Therapeutic is not to create humans but to make stem cells. 
Scientists think that therapeutic cloning can be used to make tissues and organs for transplants. For example, liver, spleen, gallbladder, kidney, small and large intestines. 

In 1952, a tadpole was cloned.

The sheep Dolly was the first mammal cloned from the cell of an adult animal.

After Dolly, scientists have cloned some sheep, goats, cows, mice, pigs, cats, fishes and rabbits.

Some species such as monkeys, chickens, horses, and dogs, have been unsuccessful. They do not know why, but they think that some species are resistant to it.

• Cloning is good, because it allows to select the best and healthier donors. This is the way to remedy the problem of endangered species. Improving food supply. With cloning, infertile couples could have children, transplant patients could also have a benefit from cloning. Cloning, at long last, may be the key to understanding cancer, limbs for amputees may be able to be regenerated.
• On the other hand, cloning gives a false sense of security for animals (no habitat preservation), it could hamper efforts to conserve biodiversity habitats, problem of extinction is not reduced. One more disadvantages of cloning is losing gene diversity and loss of human identity. Cloning is “playing God”– it means that human cloning is out of the God’s permission and it transgresses nature.

         However, there are some risks of cloning. For example, reproductive cloning is expensive and does not work well. More than 90% of cloning attempts do not work. More than 100 nuclear transfer tries could be required to make one clone. So, in addition to low success rates, cloned animals have a higher rates of infection, tumour growth, and other disorders.