How is Cloning Done?

There are three different forms of cloning, gene cloning, reproductive cloning and therapeutic cloning. Each cloning method has a different purpose or specific outcome that is desired.

Brief Description of Each Cloning Method:

Reproductive cloning is the cloning of whole animals, which then become an exact replica of the Somatic Cell Donor as all 46 chromosomes have come from the one place, instead of two parents that each give 23 chromosomes to their offspring.

Gene cloning is when several copies are made of one gene, this is done by inserting one gene into a vector (cell carrier) which can be bacteria, yeast cells, viruses or plasmids, these are carried by bacteria in small DNA circles.

Therapeutic cloning is the process of creating embryonic stem cells which can then grow into a specific skin or tissue cell to replace damaged cells, this process aims at creating new stem cells with exact DNA replica from donor cells which can be useful when fighting disease or injury.

Detailed Description of Reproductive Cloning:

In the Reproductive cloning process there are two methods that could be used in order to create an identical replica of an animal. The first is Artificial Embryo Twinning which is very similar to the natural process of creating twins although it is made in a lab.

The method of Artificial Embryo Twinning is relatively simple, a fertilised egg is separated into two singular cells that are an exact replica of each other, these cells develop on their own in a Petri Dish until the embryos are large enough to be placed inside a surrogate in order to develop and grow. The two embryos are then born as two individuals, however are genetically identical.

The Second way to create a clone, is the Somatic Cell Nuclear Transfer (SCNT) method, this is a more difficult process but can be basically described by going into detail about each letter in SCNT.

A Somatic Cell is the cells that go through the mitosis process, in other words, any cell in the body excluding sex cells, otherwise known as germ cells, the sperm cells in males and the egg cells in females. Every Somatic Cell in the body has a paired set of chromosomes, whereas germ cells only have a singular chromosome in order to pair with another germ cell during natural reproduction.

In the Nucleus of a cell, the cells DNA is contained in a compartment which holds an animals chromosomes which can then be divided into genes that creates a genetic makeup that forms differences between each entity in an organism.

Transfer simply means to move one object to another place from the starting position. In the instance of cloning, transfer refers to the movement of a nucleus from an original somatic cell to a new egg cell after removing all DNA from the cell.

In the past, a sheep was cloned, this sheep’s name was Dolly, in order to create Dolly, scientists used the Somatic Cell Nuclear Transfer method. This is the process they used:

In order to create Dolly, a somatic cell from an adult female sheep was isolated from the udder, from there the nucleus was removed from the cell, with it all of the sheep’s DNA and genetic code. They then transferred the nucleus and DNA from the somatic cell into a sex cell, which was then chemically tweaked and developed into an embryo. By placing DNA from a somatic cell into an egg cell, the chromosomes acted as a naturally fertilised egg and developed enough that it could then be placed into a surrogate mother to develop and be born.

In order to fuse the DNA from the somatic cell and the egg cell, an electrical current is used to connect the two membranes from the two cells. This resulted in exact genetic clone of the adult female sheep where the somatic cell was extracted from.