What do you understand by Human Cloning:Another You?

The word “Clone” means, “Identical”, identical in all aspects. In biological point of view, two or more organisms are said to be clones of each other if they are morphologically, anatomically and more important, genetically identical. Clones have identical genome. Since the protein synthesis and metabolism is controlled by an organism’s genome, clones are identical in all aspects.

Cloning is done by nature in many lower level organisms like Monerans, Fungi, and in some eukaryotes. Cloning can be clearly observed during reproduction of these organisms by a process called “binary fission” in which a single cell grows and divides into two identical daughter cells. They are Clones. This can also be observed during “multiple fission” in some protozoans like plasmodium.

Cloning can be done artificially to produce genetically identical organisms. Several methods have been developed to clone an organism. The most applied method is “Somatic Cell Nuclear Transfer (SCNT)”. This method has been widely used to produce a large number of identical organisms. The first fully cloned animal was a sheep named Dolly. It was clone by SCNT technology.

Somatic Cell Nuclear Transfer, an egg from a female is taken and its nucleus is taken out and is disposed. Then, a cell from the body of same organism is taken; it must be a cell other than the reproductive cells. Any body cell other than the reproductive cell is called a Somatic Cell. The nucleus of this somatic cell is taken out carefully and it is inserted into the previously ‘enucleated’ cell. It is not just insertion; it is fused with the hollow egg using electricity. This fools the egg that is has been fertilized.

I will explain it with an example. Suppose we want to clone a cow named ‘A’. We will first request the cow to donate an egg. Since this has donated us an egg, it is called a ‘Donor’. Now that we’ve the egg, we will carefully suck out the nucleus from it and keep the ‘enucleated cell’ safely. After that, we will again go to the donor cow and take a cell from some other body part. These cells are diploid. Again pull out the nucleus and this time keep the nucleus safe. Now, carefully insert this nucleus into the previously enucleated cell and apply an electric current of suitable voltage.

That’s it! If we’ve done everything perfectly, the egg (which now pretends to be a zygote) should develop into an embryo and slowly into a cow which is clone of the donor cow!
Look at this picture, it describes the SCNT technology. This is how Dolly was cloned

Scientists have managed to clone a number of animals like sheep, cow, mice etc. But, their dream of cloning a human remained unfulfilled. There have been many attempts of cloning a human. It has become more of an ethical and social issue rather than a scientific advancement. Many scientists claimed that they have cloned a human. In 2004, a South-Korean scientist and his team claimed that they have successfully cloned 11 human embryos for the purpose of extracting stem cells; later it was confirmed that it was a false statement.

Scientists say that is in fact possible to clone a human by using the famous SCNT. A cell, which contains DNA, is taken from the person who is being cloned. Then the enucleated egg is fused together with the cloning subject's cell using electricity. This creates an embryo, which is implanted into a surrogate mother through in vitro fertilization. If the procedure is successful, then the surrogate mother will give birth to a baby that's a clone of the cloning subject at the end of a normal gestation period. Success rate is estimated to be about 2%.

The Process

Now, I state the steps involved in cloning a human in a brief way. The actual process is far more complex than what the steps here depict.

Step One:

Go fetch a human egg! Yes of course, you will need an unfertilized alive human egg. Scientists get them from the egg banks where the eggs are stored safely in an extremely cold environment, perhaps about -196 degree Celsius.

Step Two:

The next step is to obtain any body cell other that the reproductive cells from the individual to be cloned. These cells are called Somatic cells.

They are preferably obtained from soft tissues of the body where the cells are active and young.

Step Three:

After getting the somatic cell, the next step is to extract its nucleus carefully. After the nucleus is extracted, the remaining part of the cell is thrown away and the nucleus is kept safe for the following process.

Step Four:

Now we take the egg again and extract its nucleus. This time, we throw the nucleus away and keep the hollow cell with us. Yes! Throw the nucleus away. Only the enucleated cell is going to be part of the process.

Step Five:

Now we have all the raw material for the cloning process. In this step, the nucleus extracted from the somatic cell is carefully injected into the enucleated egg. This looks like a brand new cell! But the process will be incomplete without the next step.

Step Six:

To make the cell actually work, the cell has to be activated by using an electric spark. Then the nucleus fuses with the cell and forms a kind of pseudo zygote. This is the last step of human cloning. Since we have produced a zygote, the rest of the process follows the regular steps like embryogenesis, etc.

Further development of the zygote needs it to be implanted into the uterus of a surrogate mother. After complete growth, the individual will be an exact clone of the person from whom the somatic cell was extracted.