Transgenic animals are those whose genetic makeup has been altered to include a new gene, usually from a different species. These animals are often engineered to produce a specific product, like a protein, hormone, or antibody, in their milk, blood, or other bodily fluids.
Why are transgenic animals cloned?
* Consistent Product Quality: Cloning ensures that all offspring are genetically identical, guaranteeing consistency in the product they produce. This eliminates variability that could arise from breeding different individuals.
* Efficiency and Scalability: Cloning allows for the rapid production of numerous identical animals, increasing the efficiency of product yield. This is especially beneficial for products requiring high volume production.
* Preservation of Valuable Lines: Cloning allows researchers to preserve and replicate highly valuable transgenic lines, even if the original animal is no longer available.
* Minimizing Ethical Concerns: Cloning can reduce the number of animals needed to produce a specific product, minimizing the overall impact on animal welfare.
How does cloning work in this context?
1. Genetic Modification: A transgenic animal is created by inserting a gene of interest into its genome. This can be done through various methods, like microinjection or viral vectors.
2. Somatic Cell Nuclear Transfer (SCNT): A cell from the transgenic animal, usually a skin or ear cell, is taken and its nucleus, containing the desired gene, is extracted.
3. Enucleated Egg: An egg cell from a female animal of the same species is then taken and its nucleus is removed.
4. Nuclear Transfer: The nucleus from the transgenic cell is then transferred into the enucleated egg.
5. Activation and Development: The resulting egg is stimulated to start dividing and develop into an embryo.
6. Implantation: The embryo is implanted into a surrogate mother animal.
7. Birth: The surrogate mother gives birth to a cloned animal, genetically identical to the original transgenic animal, capable of producing the desired product.
Examples of Transgenic Cloned Animals:
* Genetically engineered goats: producing human proteins like antithrombin in their milk, used for treating blood clotting disorders.
* Transgenic cows: producing human growth hormone, which can be used for therapeutic purposes.
* Sheep producing α-1 antitrypsin: a protein that treats cystic fibrosis and other lung diseases.
Overall, cloning transgenic animals is a powerful tool for research, medicine, and agriculture. It ensures consistent product quality, increases efficiency, preserves valuable lines, and minimizes ethical concerns. However, the ethical considerations of cloning animals should be carefully evaluated and debated.
