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Cloning is the process of making an identical clone of a biological unit (such as a DNA sequence, cell, or organism) from which it was generated, usually using biotechnological means. Cloning is a method of reproduction used by many species, including aspen trees. J. B. S. Haldane coined the term “clone,” which is derived from the Ancient Greek word κλώv (klōn), which means “twig,” and alludes to the process of creating a new plant from a twig.
What is Cloning?
Cloning is a biological process that happens in nature when organisms such as bacteria, insects, or plants reproduce asexually and generate comparable populations of genetically identical individuals.
Cloning may be a term utilized in biotechnology to explain the procedures of creating copies of DNA fragments (molecular cloning), cells (cell cloning), or creatures (organism cloning). The manufacturing of numerous copies of a product, such as digital material or software, is sometimes referred to as duplication. But we’ll concentrate on cloning’s biological background.
Cloning is a sort of asexual reproduction that occurs naturally. Many species, including plants, fungi, and bacteria, employ this mode of reproduction. Various trees, such as hazel trees, blueberry bushes, and the American sweetgum, are examples of such creatures.
Natural Cloning Examples
Cloning can be done either naturally or artificially. The following are some examples of natural cloning:
- Vegetative reproduction of plants, such as the water hyacinth, which uses apomixis to produce numerous copies of genetically identical plants.
- Binary fission in bacteria.
- Parthenogenesis occurs in some species.
Artificial Cloning Examples
Artificial means also can be wont to create clones. These clones are created using biotechnological procedures. Artificial cloning is the process of making numerous duplicates via modification methods or biotechnology. It might be as a result of:
- Molecular cloning, which involves making copies of particular gene segments.
- Cellular cloning: in cell cultures, single-celled organisms with the exact genetic content of the original cell are created.
- Organism cloning, also referred to as cloning , is that the process of making a multicellular clone from one cell through vegetative cell nuclear transfer.
This is the procedure for making copies of biomolecules such as DNAs. It’s utilised to amplify a specific DNA segment that contains target genes. It is also used to make numerous copies of promoters, non-coding regions, and randomly fragmented DNA, in addition to genes (coding sequences). Fragmentation, Ligation, Transfection, and Screening or Selection are the general steps in molecular cloning.
The DNA strand is broken to extract the appropriate DNA segment in fragmentation. The DNA fragments are then bonded together to form the required sequence, which is subsequently followed by ligation. The freshly produced bits of DNA are introduced into the cell during transfection. After that, the transfected cells are grown. The cells containing the novel DNA are identified during the screening or selection process. Selection markers, PCR, restriction fragment analysis, and/or DNA sequencing might all be used to accomplish this.
Single Cell Cloning
Cloning a cell is the process of producing a large number of cells from a single cell. The procedure involves taking a sample and then inoculating it into the culture medium in single-celled organisms like bacteria and yeast cells.
How about cloning a multicellular organism’s cell?
This is a more complicated technique that requires the use of cloning cylinders (rings). The cloning cylinder (a sterile polystyrene ring) is dipped in grease and then put over an individual colony, where cloned cells can be generated and then collected for transfer into a fresh vessel.
Somatic-cell nuclear transfer is a type of cloning in which stem cells are cloned for study or treatment but not for reproduction. The stem cells are cloned and collected in order to research human diseases and, as a result, discover a treatment or better understand the disease’s pathobiology. This method has previously been utilised in agriculture and for cloning animals such as sheep, cattle, goats, and pigs. As a result, it’s viewed as a way to preserve endangered species from extinction.
The technique of producing a new multicellular creature that is genetically similar to another is known as organism cloning (also known as reproductive cloning). Cloning is an asexual mode of reproduction, as previously stated. The procedure does not include sex cells (gametes).
Because there is no requirement for a partner, the parent organism reproduces more quickly than sexually reproducing species. However, the downside of asexual methods, such as cloning, is that the species’ genetic diversity is reduced.
Because of the minimal genetic variation, the kids may be equally prone to environmental stresses to which their parents are exposed. They are thus at risk of extinction due to a certain environmental situation, particularly if one of their parents is vulnerable to it.
Reproductive Cloning in Bacteria
A clone has an equivalent genetic makeup as its parent. This is most common in bacteria that reproduce by binary fission. The general steps of binary fission are depicted in the diagram below. Steps in binary fission;
Bacteria reproduce through binary fission, as seen in the diagram. A chromosome that has been duplicated. Chromosomes segregate into 2-4). In the centre of the cell, a septum develops. Two cells have been generated.
Reproductive Cloning in Plants and Animals
Because apomixis (apomictic parthenogenesis) does not include meiosis, it generates complete clones of the mother. This is in contrast to automictic parthenogenesis, which involves meiosis and hence results in a child that is just a “half” clone of the mother.
Plants are more prone to apomixis. Plant cloning is also known as vegetative propagation. It occurs when a new plant develops from the vegetative portions of an existing plant. Here are several examples: Clones are generated in animals via asexual methods such as parthenogenesis and budding. Aphids, rotifers, nematodes, some lizards, snakes, birds, sharks, reptiles, and amphibians are examples of creatures that reproduce through parthenogenesis.
Some of them reproduce through parthenogenesis, either facultatively (meaning they may reproduce sexually as well) or obligately (meaning they have no other option for reproduction). Budding, on the other hand, is the development of an organism’s protrusion. This offshoot has the ability to develop into a new person and is genetically identical to the parent.
It could stay connected to the parent or eventually separate from it. Hydra, corals, echinoderm larvae, and certain acoel flatworms are examples of creatures that may reproduce through budding. This is an illustration of the budding process.
- Artificial cloning of domestic animals. Proc Natl Acad Sci U S A . 2015 Jul 21;112(29):8874-8.
- Animal cloning: problems and prospects. Rev Sci Tech . 2005 Apr;24(1):251-64.
- Cloning humans? Biological, ethical, and social considerations. Proc Natl Acad Sci U S A . 2015 Jul 21;112(29):8879-86.
- Figures are created with BioRender.com