Today we will see how to make project on ' biology project on cloning for class 12' this project is only for class 12th student and this project is belongs to 'Biotechnology Principles' in this project we will cover following steps
➢ Introduction
➢ Cloning
• Natural cloning methods
♦️ Natural plant cloning
♦️ Natural animal cloning
♦️ Natural human cloning
• Artificial cloning methods
♦️ Embryo Cloning
♦️ Somatic Cell Nuclear Transfer (SCNT)
• Human cloning
♦️ Pros and cons of human cloning
➢ Conclusion
INTRODUCTION
In biology, cloning is the process of producing one or more genetically identical individuals. With whole individuals, it usually means the deliberate production of an identical copy. This was first achieved in mammals with the famous Dolly the Sheep. Human identical twins are natural clones. So are the off springs of asexual reproduction, and any Parthenogenetic reproduction which does not involve meiosis.
The laboratory copying of a molecule to produce exact copies is also called cloning.
Now let us see in detail about Cloning, its types, various methods of doing it, its pros and cons for humans as well as other beings and what it holds for us in the future.
CLONING
Types of ClonesThere are two types of Clones, namely Natural Clones and Artificial Clones.
Natural Clones
In asexual reproduction, a new individual is generated from a copy of a single cell from the parent organism. Natural clones, also known as identical twins, occur in humans and other mammals. These twins are produced when a fertilized egg splits, creating two or more embryos that carry almost identical DNA.
Many species can reproduce asexually and hence possess natural methods of cloning:
❖ All bacteria, majority of fungi and many species of protists reproduce asexually to produce genetic clones.
❖ While most plants reproduce sexually, they also possess methods of asexual reproduction (vegetative propagation).
❖ Certain animal species can also reproduce asexually, via a variety of different mechanisms.
Natural Animal Cloning Methods
Binary Fission
✓ The parent organism divides equally in two, as to produce two genetically identical daughter organisms.
✓ This method of cloning occurs in Planaria (flatworms) but is also common to bacteria and protists (e.g. euglena, amoeba).
Budding
✓ Cells split off the parent organism, generating a smaller daughter organism which eventually separates from the parent.
✓ This method of cloning occurs in Hydra but is also common to many species of yeast.
Fragmentation
✓ New organisms grow from a separated fragment of the parent organism.
✓ This method of cloning is common to starfish and certain species of annelid worms.
Parthenogenesis
✓ Embryos are formed from unfertilised ova (via the production of a diploid egg cells by the female).
✓ This method of cloning occurs in certain species of insect, fish, amphibians and reptiles.
Natural Plant Cloning Methods
Plants have the capacity for vegetative propagation, whereby small pieces can be induced to grow independently.
➢ This is because adult plants possess meristematic tissue capable of cellular differentiation (totipotent).
Virtually all types of roots and shoots are capable of vegetative propagation.
➢ Garlic and onion bulbs are modified plant leaves – all the bulbs in a group are genetically identical.
➢ Underground stems (e.g. potato tubers) can form new plants which are genetically identical to the parent plant.
➢ Certain plants can form horizontal stems called runners (or stolon) that grow roots and develop into clones.
Some plants (mainly algae, mosses and ferns) can reproduce asexually by producing spores.
❋ Spores are also produced by certain types of bacteria and fungi.
Natural Human Cloning
Even human beings can create genetic clones through natural means:
❋Identical twins (monozygotic) are created when a fertilised egg (zygote) splits into two identical cells, each forming an embryo.
❋ Non-identical twins (dizygotic) are created when an unfertilised egg splits into two cells and each is fertilised by a different sperm.
❋ Identical twins will be clones of one another (genetically identical), while non-identical twins will share 50% of the same DNA.
ARTIFICIAL CLONING
Artificial Cloning involves cloning an organism deliberately. It has many important commercial implications. It allows an individual animal with desirable features, such as a cow that produces a lot of milk, to be duplicated several times. The process is more complex in animals than in plants.
Embryo Cloning
At a very early stage, embryonic cells retain pluripotency (meaning they can divide and become any type of tissue).
✓ These cells will differentiate to form all the different tissues comprising the organism.
If these embryonic cells are separated artificially in the laboratory, each group of cells will form cloned organisms.
✓ This separation of embryonic cells can also occur naturally to give rise to identical (monozygotic) twins.
The separation of embryonic cells must happen early in the developmental cycle, ideally around the eighth cell stage (morula).
✓ The separated groups of cells are then implanted into the uterus of a surrogate to develop into genetically identical clones.
Somatic Cell Nuclear Transfer (SCNT)
involves Somatic Cell Nuclear Transfer (SCNT).
❖ This involves replacing the haploid nucleus of an unfertilised egg with a diploid nucleus from an adult donor.
❖ The advantage of this technique is that it is known what traits the clones will develop (they are genetically identical to the donor).
This method of using differentiated cells to generate cloned embryos can be used for two main purposes:
❖ Reproductive cloning: If the embryo is implanted into the uterus of a surrogate, a new cloned organism will develop.
❖ Therapeutic cloning: Embryonic cells can be induced to differentiate to create specific tissues or organs for transplantation.
HUMAN CLONING
Even after exorbitant advancement in cloning technology Human Cloning remains illegal globally, so it is out of reach of all scientists working in this field to experiment on humans (human trials).
This is because of lot of dangers it involves. Some scientists believe that it even jeopardises the existence of the entire human race.
Pros and Cons of Human Cloning
The pros or advantages of human cloning include:
• Infertility: Infertile people or same-sex couples could have children made from cloned cells.
• Organ replacement: A clone, like in the movie, "The Island," could be a source for transplant organs or tissue. (There are ethical issues that arise from this, however.)
• Genetic research: Cell cloning could assist scientists in gene editing and research.
• Selective human traits: After editing or removing bad genes, cloning could lead engineered humans for specific traits.
• Human development: Cloning could enhance and advance human development.
The cons or disadvantages of human cloning raise moral, ethical and safety issues:
• Reproductive cloning: The negatives of human cloning including the making of designer babies.
• Human cloning: Could be a violation of the clone's individual human rights.
• Embryonic cloning: Cellular degradation occurs when too many clones are made from embryos.
• Unique identities: Cloning raises the question of a moral or human right to an exclusive identity.
• Societal impacts: Human cloning could produce psychological distress for the clone and society.
CONCLUSION
Along with the endorsement of therapeutic cloning comes approval to use human embryonic cells for stem cell research. Despite objections based on ethics and morals, the potential benefits of this type of research cannot be overlooked. Research requires scientific testing of various ideas in order to acquire new knowledge. Experimentation involves many failed attempts before any success is achieved.
This same logic applies to cloning. That is why an immense number of embryos must be used before any new breakthrough is discovered. Unfortunately, many embryos must be sacrificed by scientists to reach the next level of knowledge, which will then be the stepping-stone for future research and experimentation.
With the discovery by Yamanaka in 2006 that mature cells can be reprogrammed to become pluripotent, it is possible that use of human embryonic cells will end, and the moral dilemma will be eliminated.
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