1. 1. PRESENTED BY Mr. SUMAN MANANDHAR I M.PHARM DATE: 26TH AUG 2014 TRANSGENIC ANIMALS & OTHER GENETICALLY PRONE ANIMALS
2. 2. CONTENTS: HISTORY INTRODUCTION PRODUCTION OF TRANSGENIC ANIMALS ADVANTAGES DISADVANTAGES DIFFERENT TRANSGENIC ANIMALS CONCERNS AND CONCLUSION
3. 3. HISTORY The first GMO(Genetically modified organism) was created in 1973 by Stanley N. Cohen and Herbert Boyer. The first transgenic animals were mice created by Rudolf Jaenisch in 1974.HE managed to insert foreign DNA into the early-stage mouse embryos.
4. 4. In mid-1974, scientists called for and observed a voluntary moratorium(delay or suspension of an activity or a law) on certain recombinant DNA experiments. One goal of the moratorium was to provide time for a conference that would evaluate the state of the new technology and the risks, if any, associated with it. That conference concluded that recombinant DNA research should proceed but under strict guidelines. Cont...
5. 5. DEFINITION: A transgenic animal is one that carries a foreign gene that has been deliberately inserted into its genome. Genetic material are altered using techniques in genetics generally known as recombinant DNA technology.
6. 6. PRODUCTION OF TRANSGENIC ANIMALS THE METHADOLOGY Step 1 Construction of a transgene Transgene is a segment of DNA containing a gene sequence that has been isolated from one organism and is introduced into a different organism. Transgene made of 3 parts: Promoter: a regulatory sequence that will determine where and when the transgene is active Gene to be expressed Termination sequence: a stop sequence
7. 7. Step 2 Introduction of foreign gene(transgene) into the animal 1. DNA microinjection 2. Embryonic stem cell-mediated gene transfer 3. Retrovirus-mediated gene transfer Microinjector
8. 8. A female animal is super ovulated and eggs are collected. The eggs are fertilized in vitro. The transgene containing solution is injected into the male pronucleus using a micropipette. Eggs with the transgenes are kept overnight in an incubator to develop to a 2 cell stage. The eggs are then implanted into the uterus of a pseudo - pregnant female (female which has been mated with a vasectomized male the previous night) i. MICROINJECTION METHOD
9. 9. Transgenic animals can be created by manipulating embryonic stem cells. ES cells are obtained from the inner cell mass of a blastocyst. Transgenic stem cells are grown in vitro. Then they are inserted into a blastocyst and implanted into a hosts uterus to grow normally. ii. EMBRYONIC STEM CELL METHOD
10. 10. BLASTOCYST MICROINJECTION
11. 11. #To increase the probability of expression, gene transfer is mediated by means of a carrier or vector, generally a virus. #Commonly used are Retroviruses because of their ability to infect host cells. iii. Retrovirus-mediated gene transfer.
12. 12. contd #Offspring derived from this method are chimeric, (single organism composed of genetically distinct cells.)i.e., not all cells carry the retrovirus. #Chimeras are then inbred fo r 1 0 to 20 generatio ns until ho mo zygo us transgenic animals are obtained and the transgene is present in every cell.
13. 13. Step 3: Screening for transgenic positives Transgenic progenies are screened by PCR(Polymerase chain reaction) to examine the site of incorporation of the gene Some transgenes may not be expressed if integrated into a transcriptionally inactive site. Step 4: Further animal breeding is done to obtain maximal expression. Heterozygous off springs are mated to form homozygous strains.
14. 14. Importance: Study gene function. Drug testing. Research into animal and human disease. Improve livestock animals. Use of animals as bioreactors. Gene pharming, to produce drug in their milk (e.g.: insulin, cancer drugs) and urine. Toxicity sensitive transgenic animals to test chemicals. Spider silk in milk of goat
15. 15. ADVANTAGES: Increased growth rate Increased disease resistance Increased muscle mass Increased nutritional quality Increased food conversion rate Improved wool quality Generate large quantities of human proteins in eggs, milk, blood or urine Decreased the number of animals used in such experimentation
16. 16. DISADVANTAGES: Breeding problem Multiple functions Some leads to mutagenicity and functional disorder Expensive Low survival rate Difficult procedure
17. 17. Rat Cow Pig Sheep Fish Goat Frog Transgenic animals produced Brinster's growth hormone mouse
18. 18. Some of transgenic rats: 1. Nude mouse: . A nude mouse is a laboratory mouse from a strain with a genetic mutation that causes a deteriorated or absent thymus, resulting in an inhibited immune system due to a greatly reduced number of T cells. . The phenotype, or main outward appearance of the mouse is a lack of body hair, which gives it the "nude" nickname. . Valuable to research because it can receive many different types of tissue and tumor grafts, as it mounts no rejection response.
19. 19. It is an animal model of essential (or primary) hypertension, used to study cardiovascular disease. It is the most studied model of hypertension measured as number of publications. The SHR strain was obtained during the 1960s by Okamoto and colleagues, who started breeding Wistar-Kyoto rats with high blood pressure. 2.Spontaneously hypertensive rat (SHR)
20. 20. A humanized mouse is a mouse carrying functioning human genes, cells, tissues, and/or organs. Humanized mice are commonly used as small animal models in biological and medical research for human therapeutics. Humanized mouse models represent powerful tools for studying hematopoiesis, inflammatory disease, viral host-pathogen interactions, and are helping to accelerate the development of novel therapies in HIV infection and oncology. 3. Humanized mouse
21. 21. CONCERNS Safety - have a potential human health impact in regards to: allergens, transfer of antibiotic resistance markers, and other unknown effects Potential environmental impact - Unintended transfer of modified genes through cross- pollination, unknown effects on other organisms in the environment, and loss of flora and fauna biodiversity Ethics- Are we tampering with nature by mixing genes among species? Does this create stress for the animal?
22. 22. CONCLUSION: The creation of transgenic animals has resulted in a shift from the use of higher-order species such as dogs to lower- order species such as mice . It holds great potential in many fields including agriculture, medicine and industry. With proper research and careful use the transgenic animals can go a long way in solving several problems for which science doesnt have a solution till now.
23. 23. BIBLIOGRAPHY http://www.wikipedia.org/ http://www.authorstream.com/Presentation/Parsi-472333-transgen http://www.slideshare.net/?ss http://people.ucalgary.ca/~browder/transgenic.html