Cloning.

Cloning understand the process by which reproduce identically two or more cells in a living organism. This process can occur naturally as well as artificially, thanks to the breakthrough of the human being to discover the composition of the human DNA chain from which you can perform cell reproduction.

The main element of which is party to perform any cloning process is the molecule that seeks to reproduce identically. It is impossible to carry out a cloning process if you do not have to repeat a subject since it can not be created from scratch. At the same time, it is important to know what the section of the field to play because it always seeks to establish cloning from a specific need (for example, in the case of any damaged tissue to be recomposed).

There are several types of cloning, all of which are used in scientific and healthcare. While some, such as molecular cloning, are used mainly for laboratory practice, chemical and medical analysis, there are others, such as cell cloning, which is mostly used to provide better quality health care to certain individuals. In this second group also enters therapeutic cloning.

When we talk about cloning, it is generally thought of controversial practices that could be aimed at the development of new individuals from DNA structures and other subjects living. However, as evidenced above, cloning techniques may be useful to humanity in many ways and not just in health but also in food engineering, development of chemicals, etc. In fact, cloning is already applied to humans if such a process means playing tissues, cells or damaged parts of the body and recomposed.

• Cloning in nature

Cloning is a natural form of reproduction used by many forms of life for over 50 millennia by plants, fungi, and bacteria, this is how clonal colonies reproduce some examples of these organisms are blueberry, hazelnut, Pando , Kentucky Cafetero, bayberry and American sweetgum.

• Molecular cloning

Molecular cloning is used in a wide variety of biological experiments and practical applications ranging from fingerprinting for protein production on a large scale.

In practice, in order to amplify any sequence in a living organism, the sequence to be cloned has to be linked to an origin of replication; It is a DNA sequence.

Transfection

The sequence formed within cells is introduced.

Selection

Finally, the cells that have been successfully transfected with the new DNA are selected.

• Cell cloning

Cloning a cell is to form a group of them from one. In the case of single-celled organisms like bacteria and yeast, this process is very simple, and only requires the inoculation of the right products.

However, in the case of cell cultures in multicellular organisms, cloning of cells is a difficult task, since these cells need very specific conditions of the medium.

A useful technique tissue culture used for cloning various cell lineages is the use of cloning rings (cylinders).

According to this technique, a group of unicellular cells that have been exposed to a mutagenic agent or a drug used to facilitate the selection are placed in a high dilution to create isolated colonies; each coming from a single cell and potentially clonally distinct.

In the first stage of growth, when the colonies have only a few cells; sterile polystyrene rings fat are immersed, and are placed on a single colony with a small amount of trypsin.

Cloned cells, are collected within the hoop and take a new container to continue to grow naturally.

• Cloning of organisms naturally

Cloning of an organism is to create a new organism with the same genetic information from an existing cell. It is a method of asexual reproduction, where fertilization does not occur. Generally speaking, there is only one parent involved. This form of reproduction is common in organisms like amoebas and other unicellular, although most plants and fungi also reproduce asexually.

obtaining identical twins naturally also included. It is considered as a spontaneous alteration during embryonic development, ignoring its cause, although a statistically significant correlation family.

• Reproductive cloning

It is necessary to distinguish between human reproductive cloning and other types of cloning because all human cloning is reproductive, as always a human embryo is produced. The difference really lies in the destination to be given to that embrión.4 This type of cloning is based on the creation of a genetically identical copy of a current or previous copy of a human or animal. It is technically possible, as has been achieved in animals, but has poor performance and carries certain risks, such as epigenetic problems (LOS syndrome: the clone grows much more, than the original animal) and senescence. This type of cloning is absolutely forbidden in humans, it has no therapeutic effect, apart from not being a perfected technique, human embryos may die in the process.

In 1996, he was cloned Dolly the sheep. It was the first mammal cloned from an adult derivative rather than using DNA from an embryo DNA. But though Dolly had a healthy appearance, questioned grow old before a normal sheep, ie the source (Dolly) he conveyed his old cell clone. 277 embryos were needed in addition to a live birth.

However, some have speculated that the death was an aggravating factor and it was Dolly who had a genetic six years old, the same age of the sheep that was cloned. A basis for this idea was the discovery of their short telomeres, which are usually the result of the aging process. However, the Roslin Institute has established that intensive health checks revealed no abnormalities in Dolly that could think of premature aging.

• Therapeutic cloning

Therapeutic cloning, an area in which much is being investigated at present, not to people or create cloned babies booking 5 but tissues and organs that can be transplanted the donor patient and thus cure disease.6 Different developments in international law and research allow cloning of certain animals and human tissues for medical research. This type of cloning involves fusing the nucleus of an adult cell (mother or differentiated) and an enucleated oocyte, which has been extracted the nucleus to create an embryo with which to work.

Of that embryo may be isolated embryonic stem cells compatible with the future recipient of the tissue. Stem cells are isolated from the inner cell mass of the embryo cloned once it reached the blastocyst stage. These stem cells have the same genetic background that the patient from whom the adult cell was taken and thus reproduce the same antigenic envelope, the structure of surface proteins of the cell, so it can avoid a reaction of rejection . Once you have extracted stem cells from the inner cell mass cells, the cloned embryo is destroyed.

In fact, in January 2008, it was announced that they had created five embryos cloned from human skin cells, in order to provide a viable source of embryonic stem cells for the treatment of diseases; Using the same technique that led to Dolly the sheep, scientists at the California company Stemagen Corporation, based in La Jolla, California, led by Andrew French, have used the skin cells of two adult males and eggs from three young women (20 to 24) who were undergoing treatment fertilidad.7 addition, in May 2013 the University of Oregon revealed that they had succeeded in obtaining human embryonic stem cells by cloning. The technique has major implications for regenerative medicine, as they could get stem cells from an embryo in blastocyst stage with which to regenerate body parts donor himself without risk of rejection during transplantation. In addition, in 2013 the cloning of a copy of laboratory mouse from a single drop of blood from the tail of the donor mouse, a fact that was a change in the landscape of animal cloning was achieved, as this has been the first time an animal has managed to clone without euthanize the donor animal, which is what was done until now on the cloning of animals such as in the case of Dolly the sheep

• Cloning of substitution

A fourth type of cloning would be called replacement cloning would be a combination of reproductive cloning and therapeutic cloning. In such cloning partial cloning of a tissue or part of a human necessary it would occur for a transplant.

• Cloning extinct and endangered

Cloning extinct species, has been a dream for many científicos.Uno of the targets for cloning was the woolly mammoth, but attempts to extract DNA from frozen mammoths have been unsuccessful, although a Russian-Japanese team is working on it.

In 2001, a cow named Bessie gave birth to a gaur (one Indian bison) cloned from Asia, an endangered species, but the calf died after two days.

In 2003, a banteng (a type of bull) was cloned successfully, in addition also were cloned three successful African wild animals from frozen embryos. These successes have given hope on the possibility that other extinct species can be cloned. Faced with this possibility; tissue samples of the last ibex (ibex) were quickly frozen after his death.

Researchers are also considering cloning endangered species such as the giant panda, ocelot, and cheetah.

In 2002, geneticists at the Australian Museum announced that they had replicated DNA Tasmanian Tiger, extinct 65 years ago with the polymerase chain reaction. However in 2005, they had to stop the project because the cells were not well preserved.

One of the obstacles in the attempt to clone extinct species is the need to maintain the DNA in perfect condition, very well preserved.