Introduction:


Cloning is a process of producing genetically identical organisms that already occur in nature. Cloning is asexual reproduction method. In nature microorganisms such as bacteria, and also plants reproduce asexually or by cloning method. Cloning in biotechnology is intentional cloning of an organism or molecular cloning of DNA fragments. In biotechnology scientists mainly use three types of cloning, known as reproductive cloning, therapeutic cloning and DNA cloning.

Types of Cloning in Biotechnology:

Reproductive Cloning:

Cloning which are used for producing the exact copy of an existing organism are called as reproductive cloning. Reproductive cloning is performed using a technique known as somatic cell nuclear transfer. During this procedure nucleus is extracted from a somatic cell. Somatic cell is any cell from the body other than the germ cell. Then the nucleus of the egg is also removed, the extracted nucleus is then transferred into enucleated egg. Egg starts to divide after receiving the external stimuli. Egg will divide and grow and finally will develop into an embryo. This embryo is then implanted into a gestational surrogate mother.

Reproductive cloning has some issues like; clones which are produced have shorter lifespan when compared with the parent species. Reproductive cloning also imposes the risk of losing genetic diversity of the nature.

Therapeutic Cloning:

Biotechnology cloning used for the purpose of medical treatment are known as therapeutic cloning. Therapeutic cloning is mainly used to grow organs, which can then be used to replace the non functional organs of a patient. It can also be used to generate the skin to treat burn victims, can be used to create nerve cells to treat patients suffering from nerve degenerative diseases. Therapeutic cloning like reproductive cloning is also done by using somatic cell nuclear transfer techniques. The main difference is that the dividing egg is used to extract stem cells. Extracted stem cells are then used to produce required organs, by growing them in the suitable media.

Therapeutic cloning plays a major role in medical treatment. Doctors with the help of therapeutic cloning technique can grow replacement organs for damaged body parts of the patients. These organs are genetically and immunologically same as the patient's own organ. Therefore it reduces the usage of immunosuppressant drugs and also the risk of organ rejection by the body.

DNA Cloning:

Biotechnology cloning techniques used to create many copies of DNA fragments are called as DNA cloning. This technique can be used to clone random fragment of DNA, specific sequence of DNA or can be used to clone entire gene sequence.

DNA cloning process comprises many steps; first the interested DNA fragment is extracted from the genome, by the help of restriction enzymes or can be synthesized chemically. Polymerase chain reaction or cloning vectors are used to produce multiple copies of DNA fragments. Then agarose gel electrophoresis and DNA sonication methods are also used for cloning DNA fragments.

DNA cloning is used in genetic engineering to create microorganisms, plants or animals with desirable features. DNA cloning is also used in DNA fingerprinting and also in gene sequencing.

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