Presentation on theme: "Chapter 7 Animal Biotechnology BTEC 3301. Dolly was created by agricultural research scientists, who were being funded to make the perfect sheep, for."— Presentation transcript:
Dolly was created by agricultural research scientists, who were being funded to make the perfect sheep, for the purposes of more efficient agricultural production. The name "Dolly" came from a suggestion by the stockmen who helped in the process, in honor of Dolly Parton, because the cloned cell was a mammary cell After the cloning was successfully demonstrated by Dolly creators, many other large mammals have been cloned, including horses and bulls. Dolly the sheep
Dolly who became the first famous adult cloned sheep was successfully cloned in 1996, (July 1996 to Feb 2003) was the first mammal to have been successfully cloned from adult cells. She was created at Roslin Institute Scotland and lived there until her death nearly seven years later. Dolly was put down on Feb 14 2003, due to complications from a lung infection. Refer: Fig7.7 for the process.
Animal biotechnology is the field to engineer transgenic animals, i.e., animals that carry genes from other species. The technology has already produced transgenic animals such as mice, rats, rabbits, pigs, sheep, and cows Transgenic Animals
A transgenic animal is one whose genome has been changed to carry genes from other species. For example, an embryo can have an extra, functioning gene from another source artificially introduced into it, or a gene introduced which can knock out the functioning of another particular gene in the embryo What is a transgenic animal?
Animals that have their DNA manipulated in this way are known as transgenic animals. Transgenic animals are useful as disease models and producers of substances for human welfare
Some transgenic animals are produced for specific economic traits. For example, transgenic cattle were created to produce milk containing particular human proteins, which may help in the treatment of human emphysema (A lung disease which involves damage to the air sacs (alveoli) in the lungs) Why are these animals being produced?
Other transgenic animals are produced as disease models (animals genetically manipulated to exhibit disease symptoms so that effective treatment can be studied The OncoMouse® or the Harvard mouse, carrying a gene that promotes the development of various human cancers
DNA microinjection: Introducing the transgene DNA directly into the zygote at an early stage of development. No vector required Retrovirus-mediated gene transfer: Infecting mouse embryo with a retrovirus which carry the new gene. Using virus as a vector. How are transgenic animals produced?
Embryonic stem cell-mediated gene transfer: The blastocyst (inner layer of a fertilized egg) is harvested and mixed with recombinant DNA and inserted back in the blastocyst Sperm-mediated transfer: Use of “Linker protein" to attach DNA to sperm which transfer the new DNA during fertilization. Gene gun: As described in Chapter 6.
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. Embryonic stem cell-mediated gene transfer:
The benefits of these animals to human welfare can be grouped into areas: Agriculture Medicine Industry Improving Agricultural Products with Transgenics
A) Breeding: Traditional cross breeding have been used for ages to create chickens, cows, pigs etc. Farmers have always used selective breeding to produce animals that exhibit desired traits (e.g., increased milk production, high growth rate). Traditional breeding is a time-consuming, difficult task. 1. Agricultural Applications
Researchers have now used gene transfer to improve the productivity of livestock. Now it is possible to develop traits in animals in a shorter time and with more precision. It also offers farmers an easy way to increase yields.
Scientists can improve the size of livestock genetically. Transgenic cows exist that produce more milk or milk with less lactose or cholesterol. Transgenic cows have been used to produce milk which are richer in proteins and lower in fat.
B) Quality Herman, a transgenic bull carries a human gene for Lactoferrin (gene responsible for higher iron content) Pigs and cattle that have more meat on them. Sheep that grow more wool. Eggs can be made healthier with high quality protein.
Animals can be engineered to be more nutritious, such as the Belgian Bull Bull Domesticated animals have been used to produce medically valuable proteins in their milk Goats have been engineered to produce spider silk for stronger materials. Transgenic Animals
C) Disease resistance Disease-resistant livestock is not a reality just yet. But there has been improvement in disease reduction in animals. The Foot- and- Mouth disease in England in 2000 led to destruction of herds of cattle, sheep and goat.
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. Transgenic disease protection promises a long term cost effective method of battling animal diseases.
A) Xenotransplantation Transplant organs may soon come from transgenic animals. Transgenic pigs may provide the transplant organs needed to alleviate the shortage of organs donor 2. Medical Applications
..Xenotransplantation Xenotransplantation is hampered by a pig protein that can cause donor rejection but research is underway to remove the pig protein and replace it with a human protein. Milk-producing transgenic animals are especially useful for medicines.
Biotechnology has improved medicines for animals, including vaccines used to prevent animal diseases such as foot and mouth, scours, brucellosis, shipping fever, feline leukemia, rabies, and infections affecting cultivated fish. There are new kits to diagnose the health of livestock Biotechnology in Animal Medicines, Vaccines, and Diagnostics
Blood Clotting factor in transgenic The Liver makes six blood clotting factors: I (fibrinogen), II (Prothrombin), IV, V, VI, and VII. Factor IV (calcium, Ca ionized and/or bound calcium) also required for the coagulation of blood in the process.,
B) 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. The first transgenic cow (Rosie ) produced human protein-enriched milk at 2.4 grams per liter.
This transgenic milk is a more nutritionally balanced product than natural milk and could be given to babies or the elderly with special nutritional or digestive needs. A transgenic cow exists that produces a substance to help human red cells grow.
Researchers at the University of Pennsylvania have used gene therapy to shorten the time it takes to breed large animals that produce therapeutic proteins in their milk. To get the goats to produce a specific protein: radiation was used to kill a portion of male goat germ cells and then a virus was used to insert the gene of interest (therapeutic proteins) in the remaining cells. Subsequently a predictable number of offspring will carry the gene and produce the desired protein in their milk (next figure)
Transgenic Goats to produce a therapeautic protein
C) 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. Finland produced a calf with a gene that makes the substance that promotes the growth of red cells in humans.
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. Biosteel is an extraordinary new product that may be soon used in bullet proof vests and in suture silk for stitching wounds. Animals have been used as “Bioreactors” to produce proteins. Genes for desired proteins are introduced via transgenics to the target cells. 3. Industrial Applications
: The target cells are cloned and several such cells are raised into adults. These adults may produce milk or eggs (due to the presence of introduced gene rich in desired protein). 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.
: Transgenic animals have been used to produce pharmaceutical protein: example a human gene called AT III has been transferred to goats. Goats milk contain this protein that prevents blood clotting (goats multiply faster than cows) “Hen bioreactor” eggs are used to enrich protein by recombinant DNA technology.
A cloned pig in Denmark, The University of Copenhagen, contains a gene responsible for Alzheimer's disease The cloned pigs were genetically modified to be a model for Alzheimer's
Ethical concern is ever increasing as the technology grows, including the issue of lab animal welfare These ethical issues include questions such as: Should there be universal protocols for transgenesis? Should such protocols demand that only the most promising research be permitted? What are the ethical concerns surrounding transgenesis?
Is human welfare the only consideration? What about the welfare of other life forms? Should scientists focus on in vitro (cultured in a lab) transgenic methods rather than, or before, using live animals to alleviate animal suffering?
Two research groups have been given permission to use hybrid human-animal embryos in research Dr. Lyle Armstrong, who is based at the North East England Stem Cell Institute (NESCI) and the Stem Cell Biology Laboratory Wolfson Centre for Age-Related Diseases, at King's College London.
Will transgenic animals radically change the direction of evolution, which may result in drastic consequences for nature and humans alike? Should patents be allowed on transgenic animals, which may hamper the free exchange of scientific research?
A summary of Animal Cloning : Although there has been limited success in cloning some animals, it's still seen as a viable technology. Ever since the announcement of the birth of Dolly three years ago, additional sheep, cows, goats, pigs and mice have been cloned. So far, most cloned animals die just before or after birth.
: There are still obvious problems as evidenced from the numerous deaths of cloned animals that occur just before or after birth. Cloning is a big first step. Genetic manipulation of cloned animals is the future direction of the cloning frontier.
: Cloning can produce genetically identical laboratory animals which can be used as models for human disease. No live dog clones have yet been reported, the company PerPETuate, Inc. (Connecticut) is freezing tissue from family pets for the future. Cells could be harvested from early embryos to provide cell and tissue replacement without the hazards of transplantation rejection.
: The cloning of human embryos for reproductive purposes is illegal at this time. Yet it is still important to examine the consequences and the likelihood of this scenario. The media may dream up and forecast robotic cloned armies of Hitler; however, identical twins illustrate that being genetically identical does not remove their humanness.
: At any rate, there have been significant difficulties with cloning primates, including an extremely low success rate and a high number of abnormalities. These results make it unacceptable to attempt human cloning at this moment in time. Cloning has opened many doors that could lead to remarkable medical advancements but, as with all new technologies, it will be accompanied by ethical and social dilemmas.
: Today's successes will pave the road to improving efficiencies and help add to the basic understanding of our cells. Even Dolly's creator, Ian Wilmut, is focusing less on sheep and more on understanding the mechanism of reprogramming our genetic material!.
What are Stem cells? Keep update with political issues on stem cells research including Christopher Reeves’ (Superman) idea of promoting stem cell research.
: Stem cells can be used to grow any organ. Stem cells have the capacity to develop into any type of cell in the body. And therefore, they have the potential to be used for almost anything, organ transplants, a cure for Parkinson's etc. Fetal stem cells, once harvested, cannot become embryos!.
: When a woman's egg is fertilized, the egg (or zygote) is totipotent -- it has the capacity to turn into any type of cell in the human body, including the placenta. About four days after fertilization the cells begin to specialize and form a blastocyst, which is a hollow sphere of cells with an inner cell mass in the center. The outer layer of cells becomes the placenta and other tissues necessary for the survival of the fetus
Inner cell mass - pluripotent, meaning they can become any cell type in an organism Blastocyst
: The inner cell mass goes on to form the fetus and eventually the baby. It is these inner cells that are so incredible because they go on to form all the tissues in the human body. If this inner cell mass was placed in a woman's uterus, it would not develop into a fetus and because of this some people claim that this cannot be considered an embryo
The controversy comes when the cells are harvested. Harvesting can be done by : obtaining cells from the embryos of terminated pregnancies getting them from embryos from in vitro fertilization clinics
The politics of stem cells In 1993, President Clinton banned federally funded research on stem cells and now President Bush has promised that he'll "not support research from aborted fetuses." The government's position reflects the views by others who oppose stem cell research. For example:
Religious groups and some politicians believe that it's unethical to harvest these cells because they believe it destroys the embryo. One Kansas senator went as far as to say that it's "Nazism," saying it's "illegal, immoral, and unnecessary."3
: Some religious groups also believe that "you are getting in the way of God's work. Adult stem cells have limited potential and may carry genetic mutations