Cloning, Meaning, Types, Examples, Advantages, Disadvantages

Cloning is the process of producing genetically identical copies of organisms, cells and molecules. It is a new highly important technique in modern biotechnology, genetics and medicine. Dolly, the sheep’s birth in 1996, was the first mammal to be cloned from an adult somatic cell. This process brought global attention to the possibilities and dilemmas of cloning. While cloning has high potential in scientific research, agriculture, and regenerative medicine, it also raises profound ethical, social, and ecological questions, particularly when extended to humans and higher animals. In this article, we are going to cover cloning, its types, advantages as well as disadvantages. 

Cloning  

• Cloning refers to the process of creating an exact genetic replica of another entity. The process can be used for: 
  • Organisms (animals, plants as well as humans)
  • Cells (somatic and stem cells)
  • Molecules such as DNA (sequencing or genetic engineering)
• In molecular biology, fragments of DNA are inserted into carrier molecules called vectors, which can replicate within bacteria or host cells, producing many identical copies and each copy is called a clone.
• Reproductive cloning is the process of creating individuals with identical nuclear DNA. However, true genetic identity also requires similarity in mitochondrial DNA, which often varies. Importantly, cloned organisms are not always physically or behaviorally identical due to environmental and developmental influences. 

Cloning Types 

There are four types of cloning techniques: 

• Reproductive Cloning 
  • Reproductive cloning is the process of producing a genetically identical organism and can be used in the application of agriculture and species conservation. 
  • Example: Dolly the sheep (1996)
• Therapeutic Cloning
  • Therapeutic cloning means being focused on generating stem cells to develop tissues and organs for transplantation. This technique has the potential to treat degenerative diseases. 
  • Example: Parkinson’s disease, diabetes and organ failure
• Gene or molecular cloning 
  • Molecular cloning is the technique  that involves copying specific DNA sequences and genes and is used in genetic engineering, drug development and biotechnology. 
• Embryo Cloning
  • Embryo cloning also known as artificial twinning is the process that mimics natural twinning by splitting a fertilised embryo into two or more identical embryos. This technique is used in the process of animal breeding and early research. 

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Cloning Technique Advantages 

Practicing the cloning technique has the following advantages: 

• The process allows rapid multiplication of desired genes, organisms or traits. 
• The process facilitates DNA sequencing and large-scale protein production for pharmaceuticals. 
• Supports gene therapy, providing potential cures for genetic diseases like cystic fibrosis, hemophilia and cancer. 
• Improves agriculture output by transferring genes that are beneficial for the growth process like nitrogen fixing bacteria genes into crops. 
• Promotes species conservation through reproduction of endangered animals. 
• Provides stem cells for regenerative medicines and tissue replacement. 

Cloning Process Disadvantages 

The cloning technique has the following disadvantages: 

• There is a high failure rate as over 90% of attempts fail, making the success rate low. 
• There are many health issues found in clones like premature aging, genetic defects, immune deficiencies. For example, Dolly suffered from arthritis and died at a young age. 
• Human cloning attracts a lot of questions of identity, morality and religious objections to “playing God”. 
• Excessive cloning reduces genetic variability and increases vulnerability to diseases. 
• Cloning requires advanced infrastructure and technology, expertise and is economically unsustainable to scale. 
• Large- scale animal cloning can disrupt ecological balance. 
• Human clones face identity crisis and psychological stress. 

Human Cloning and the Ethical Dilemma

The debate over human cloning is one of the most controversial issues in bioethics.

• Scientific Concerns: There are extremely high failure rates and deformities in animal clones which suggest impracticality and risks for humans.
• Philosophical and Religious Concerns: Cloning violates natural laws, interferes with divine will, and reduces humans to objects of design.
• International Consensus: Most scientific bodies, religious institutions, and governments oppose reproductive human cloning, while therapeutic cloning for medical research is cautiously accepted under regulation.

Cloning Examples 

Some of the examples of cloning include: 

• Dolly the Sheep (1996): First mammal cloned from an adult somatic cell using Somatic Cell Nuclear Transfer (SCNT).
• Cc the Cat (2001): First cloned pet, though with different fur patterns from the donor cat.
• Snuppy the Dog (2005): First cloned dog, marking a breakthrough in pet cloning.
• Zhong Zhong and Hua Hua (2018): First cloned macaque monkeys, important for human disease research.
• Retro the Monkey (2024): Latest cloned primate, showcasing advancements in cloning technology.