Genetically modified animals

Development of science from technology

1. GENETICALLY MODIFIED ANIMALS DONE BY M YESLIN PUSHAN

2. INTODUCTION Genetically modified animals  are animals that have been genetically modified for a variety of purposes including producing drugs, enhancing yields, increase resistance to disease, etc. The vast majority of genetically modified animals are at the research stage with the number close to entering the market remains small . Genetic modification of an animal involves altering its genetic material by adding, changing or removing certain DNA sequences in a way that does not occur naturally.

3. GM ANIMALS Genetic modification of an animal involves altering its genetic material by adding, changing or removing certain DNA sequences in a way that does not occur naturally. It aims to modify specific characteristics of an animal or introduce a new trait, such as disease resistance or enhanced growth. DNA is the genetic material of an organism and carries the instructions for all the characteristics that an organism inherits.

4. GM ANIMALS Changes introduced in an animal’s genetic make-up can therefore be transmitted to the next generation. While this technology has so far been used in plants for agriculture and in micro-organisms to produce enzymes, the potential application of genetic modification techniques to animals is also being researched. Several international organisations, including FAO/WHO and the United States Food and Drug Administration, have already published guidelines for the safety assessment of these animals and their derived products.

5. PROCESS OF GM AIMALS The process of genetically engineering mammals is a slow, tedious, and expensive process .   As with other genetically modified organisms (GMOs), first genetic engineers must isolated the gene they wish to insert into the host organism. This can be taken from a cell containing the gene  or artificially synthesised .   If the chosen gene or the donor organism's genome has been well studied it may already be accessible from a genetic library. The gene is then combined with other genetic elements, including a promoter and terminator region and usually a  selectable marker . A number of techniques are available for inserting the isolated gene into the host genome.

6. PROCESS OF GM AIMALS With animals DNA is generally inserted into using microinjection, where it can be injected through the cell's nuclear envelope directly into the nucleus, or through the use of viral vectors . The first transgenic animals were produced by injecting viral DNA into embryos and then implanting the embryos in females . It is necessary to ensure that the inserted DNA is present in the embryonic stem cells . The embryo would develop and it would be hoped that some of the genetic material would be incorporated into the reproductive cells. Then researchers would have to wait until the animal reached breeding age and then offspring would be screened for presence of the gene in every cell, using PCR, Southern hybridization, and DNA sequencing .

7. USAGE OF GM MAMMALS The majority of genetically modified mammals are used in research to investigate changes in phenotype when specific genes are altered. This can be used to discover the function of an unknown gene, any genetic interactions that occur or where the gene is expressed. Genetic modification can also produce mammals that are susceptible to certain compounds or stresses for testing in biomedical research. Some genetically modified mammals are used as models of human diseases and potential treatments and cures can first be tested on them.

8. GM PIGS The ability to genetically modify pigs has enabled scientists to create pigs that are beneficial to humans in ways that were previously unimaginable. The benefits to medicine include the production of pharmaceuticals, the provision of organs for xenotransplantation into humans, and the development of models of human diseases. The benefits to agriculture include resistance to disease, altering the carcass composition such that it is healthier to consume, improving the pig's resistance to heat stress, and protecting the environment. Additional types of genetic modifications will likely provide animals with characteristics that will benefit humans in currently unimagined ways.

9. GM COWS Scientists in both China and Argentina have genetically engineered cows to produce milk similar in composition to that made by humans. After modifying embryos, an Argentinian cow – Rosita Isa – was born that expressed milk containing proteins present in human milk but lacking in cow milk. However , there are a number of scientific, safety and taste issues that would have to be overcome before this replaces “mother’s milk” for infants.

10. GM GOATS BioSteel  is a trademark name for a high-strength based fiber material made of the recombinant spider silk-like protein extracted from the milk of transgenic goats, made by Nexia Biotechnologies. The company has successfully generated distinct lines of goats that produce in their milk recombinant versions of either the MaSpI or MaSpII dragline silk proteins, respectively. Nexia Biotechnologies, however, went bankrupt and is no longer company .

11. GM MICE Genetically modified mice are often used to study cellular and tissue-specific responses to disease ( cf  knockout mouse). This is possible since mice can be created with the same mutations that occur in human genetic disorders, the production of the human disease in these mice then allows treatments to be tested . The  oncomouse  is a type of laboratory mouse that has been  genetically modified developed by Philip Leder  and Timothy A. Stewart of Harvard University to carry a specific gene called an activated oncogene . Metabolic supermice  are the creation of a team of American scientists led by Richard Hanson, professor of biochemistry at Case Western Reserve University at Cleveland, Ohio .   The aim of the research was to gain a greater understanding of the PEPCK-C enzyme, which is present mainly in the liver and kidneys.

12. GM SHEEP Genome editing technology is being used at The Roslin Institute to increase the productivity of sheep bred for the meat industry. Naturally-occurring mutations that stop a gene called myostatin from functioning have shown that animals with these mutations have up to 20% more muscle mass compared to animals without the mutations. Animals with myostatin mutations convert feed to muscle more efficiently, reducing the amount of resources needed to produce meat. The meat from these animals is also of a higher quality and is healthier, containing less fat.

13. GM CHICKENS The Roslin Institute is working on GM chickens that contain an extra gene that interrupts the transmission of avian flu. Unlike a vaccination, the modification still protects the bird if the virus mutates . However, some farmers argue it is better to enforce good farming practices than create disease-free animals.

14. ADVANTAGES Higher growth rate in animals GM Salmon: Grows faster than regular salmon. Same age, but longer and heavier.  Improved disease resistance GM Chicken: Featherless and bird-flu resistant. Protected better against diseases. Increased muscle mass GM Super Cow: Larger than normal cow, there's more meat, greater product yield. Improved nutritional quality GM Enviro Pig: There are added nutrients and proteins which makes them healthier to eat. Tailor-made animals for desired traits GM Glow-in-the-Dark Cats: Jellyfish protein infused with GFP (Green fluorescent protein) and added to cats, fish, dogs, monkeys, etc . You can choose the traits for the specific animal. Increased genetic diversity By adding or changing traits, new genes are created. Results in a greater gene pool. More variety means more possible combinations.

15. DISADVANTAGES Unintended harm or breeding problems Animals may be too big for their legs, have shorter life spans, and there are low survival rates for transgenic aimals . Mutagenesis and function disorders Genetic mutations can occur which may reslt in diseases and disorders. Expensive and extensive The cost of equipment and animals is high. Also, it takes a while to find the right way to genetically modify the animal for whatever purpose. It doesnt happen over night. Unintended adverse effects Genes have more than one function. A gene in one animal may do certain jobs or not that the other one doesn't. This may cause problems in the genes that cannot fully carry out their function. Nature is complex Nature is an extremely complex inter-related chain consisting of many species linked in a food chain. Genetically modifying anmals may have irreversible effects with unknown consequences.

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