transgenic animals and its applications
TRANSCRIPT
TRANSGENIC ANIMALS AND ITS APPLICATIONS Done By
Gokul GawasDrizia Faleiro
Dvane Coutinho
OVERVIEW INTRODUCTION
METHODS USED TO PRODUCE TRANSGENIC ANIMALS
EXAMPLES
APPLICATION
ADVANTAGES AND DISADVANTAGES
SUMMARY
REFRENCES
INTRODUCTION Nowadays, breakthroughs in molecular biology are happening at an unprecedented rate. One of them is the ability to engineer transgenic animals.
Transgenic animals, i.e., engineered to carry genes from other species, have the potential to improve human welfare .
The first genetically modified organism was a bacteria created in 1973 by Stanley N. Cohen and Herbert Boyer.
These bacteria contained genetic information from a variety of different species.
The technology has now produced transgenic animals such as mice, rats, rabbits, pigs, sheep, and cows.
Although there are many ethical issues surrounding transgenesis, this presentation focuses on its applications in agriculture, medicine, and industry.
What are transgenic animals?Transgenic animals are the creations that involve the manipulation of DNA.
Technique of gene transfer is involved.
The foreign gene may be introduced in embryos at the first cell stage by a direct microinjection or via gametes.
Otherwise foreign gene may be introduced in cells that participating to the complete development of the animal in which gametes contain the foreign gene.
The first transgenic animals were mice created in 1974 by Rudolf Jaenisch, a professor of biology at Massachusetts Institute of Technology.
SUPERMOUSE
Transgenic mouse with the florescence genomehttp://www.whatisbiotechnology.org/assets/images/science/pages/transgenic.jpg
METHODS TO PRODUCE TRANSGENIC ANIMALS
TECNIQUE OF GENE TRANSFER
DNA Microinjection
Use of Transposons
Use of Lentiviral Vectors
Use of ICSIUse of Episomal Vectors
Use of Pluripotent Cells
Use of Cloning
Targeted Gene Integration
MethodsEven though there are many methods for producing transgenic animals, there are three basic methods used for producing them:
DNA microinjection
Retrovirus-mediated gene transfer
Embryonic stem cell-mediated gene transfer
DNA Microinjection The mouse was the first animal to undergo successful gene transfer using DNA microinjection.
This method involves:
• Transfer of a desired gene construct (of a single gene or a combination of genes that are recombined and then cloned) from another member of the same species or from a different species into the pronucleus of a reproductive cell.
• The manipulated cell, which first must be cultured in vitro (in a lab, not in a live animal) to develop to a specific embryonic phase, is then transferred to the recipient female.
Retrovirus-Mediated Gene Transfer
A retrovirus is a virus that carries its genetic material in the form of RNA rather than DNA.
This method involves:
• Retroviruses used as vectors to transfer genetic material into the host cell, resulting in a chimera, an organism consisting of tissues or parts of diverse genetic constitution
• Chimeras are inbred for as many as 20 generations until homozygous (carrying the desired transgene in every cell) transgenic offspring are born
The method was successfully used in 1974 when a simian virus was inserted into mice embryos, resulting in mice carrying this DNA.
Embryonic Stem Cell-Mediated Gene Transfer
This method involves:
• Isolation of totipotent stem cells (stem cells that can develop into any type of specialized cell) from embryos
• The desired gene is inserted into these cells
• Cells containing the desired DNA are incorporated into the host’s embryo, resulting in a chimeric animal
Unlike the other two methods, which require live transgenic offspring to test for the presence of the desired transgene, this method allows testing for transgenes at the cell stage.
EXAMPLESTRANSGENIC MOUSE
TRANSGENIC COW
TRANSGENIC PIG
TRANSGENIC MONKEY
TRANSGENIC RABBIT
TRANSGENIC FISH
The Glow fishhttps://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTB2UQ4BeSReBQXSUjU2Bj6wLC2XEH9t_QnVjIuWzUvBwtQlsxg
Transgenic Fish : Salmon with growth hormonehttps://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcRvFw5nCONCBjfu1rK8MyDRoyNGzYEMcxJcB_qGrMGwwWfUopoTUQ
Transgenic Animals
APPLICATIONS Why are transgenic animals created?In some cases these animals may be designed simply to be visually interesting, to study, to yield more meat, or to perform a specific task better.
GMOs are created and/or modified in the laboratory to amplify desired characteristics which are beneficial to mankind.
MedicineXenotransplantation Patients die every year for lack of a replacement heart, liver, or kidney. Transgenic pigs may provide the transplant organs needed to alleviate the shortfall.
Nutritional supplements and pharmaceuticals Products such as insulin, growth hormone, and blood anti-clotting factors may soon be or have already been obtained from the milk of transgenic cows, sheep, or goats. In 1997, the first transgenic cow, Rosie, produced human protein-enriched milk at 2.4 grams per litre.
Human gene therapy Human gene therapy involves adding a normal copy of a gene (transgene) to the genome of a person carrying defective copies of the gene. The potential for treatments for the 5,000 named genetic diseases is huge and transgenic animals could play a role.
AgricultureBreeding Farmers have always used selective breeding to produce animals that exhibit desired traits (e.g., increased milk production, high growth rate).Transgenesis made it possible to develop traits in animals in a shorter time and with more precision. In addition, it offers the farmer an easy way to increase yields.
Quality Transgenic cows exist that produce more milk or milk with less lactose or cholesterol, pigs and cattle that have more meat on them, and sheep that grow more wool.
Disease resistance Scientists are attempting to produce disease-resistant animals, such as influenza-resistant pigs, but a very limited number of genes are currently known to be responsible for resistance to diseases in farm animals.
IndustriesIn 2001, two scientists at Nexia Biotechnologies in Canada spliced spider genes into the cells of lactating goats. The goats began to manufacture silk along with their milk and secrete tiny silk strands from their body by the bucketful. By extracting polymer strands from the milk and weaving them into thread, the scientists can create a light, tough, flexible material that could be used in such applications as military uniforms, medical microsutures, and tennis racket strings.
Toxicity-sensitive transgenic animals have been produced for chemical safety testing.
Microorganisms have been engineered to produce a wide variety of proteins, which in turn can produce enzymes that can speed up industrial chemical reactions.
Goat with gene of spider silkhttp://cdn2-b.examiner.com/sites/default/files/styles/image_content_width/hash/8e/be/8ebee3815b6c1c4e1fd2f7cbbea49659.jpg?itok=pa0t0T6c
ADVANTAGESIncreased growth rate
Improved disease resistance.
Improved food conversion rate.
Increased muscle mass.
Improved nutritional value.
Improved wool quality
DISADVANTAGESInserted gene has multiple functions.
Breeding problems.
Sometimes leads to mutagenesis and functional disorder.
Low survival rate of transgenic animals.
SUMMARYoTransgenic animals, i.e., engineered to carry genes from other species, have the potential to improve human welfare
oMethods used to produce these animals are: DNA microinjection, Retrovirus-mediated gene transfer and Embryonic stem cell-mediated gene transfer.
o Some transgenic animals are produced for specific economic traits while some are produced as disease models.
o The creation of transgenic animals has resulted in a shift in the use of laboratory animals — from the use of higher-order species such as dogs to lower-order species such as mice
oTransgenic technology holds great potential in many fields, mainly in agriculture, medicine, and industry.
REFERENCES Methods to Generate Transgenic Animals. By Louis-Marie Houdebine. http://www.springer.com/978-3-540-85842-3 Pg.: 31-48
Endang Tri Margawati (January 2003). “Transgenic Animals: Their Benefits To Human Welfare” . Action bioscience . http://www.actionbioscience.org/biotechnology/margawati.html
http://www.whatisbiotechnology.org/science/transgenic
