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Animal cloning.

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Presentation on theme: "Animal cloning."— Presentation transcript:

1 Animal cloning

2 What is a Clone? Clone–a group of two or more individuals with identical genetic (nuclear) makeup, derived by asexual reproduction, from a single common parent or ancestor. Clones are NOT the exact copies

3 WHOLE ANIMAL CLONING

4 Methods of animal cloning
Nuclear transfer Embryo splitting Blastomere separation

5 Nuclear transfer Nucleus of an unfertilized egg is replaced with the nucleus of an donor cell.

6 Embryo splitting To split an embryo into pieces, each forming a new embryo (usually, it is to split a 2 to 8 celled embryo before the cells differentiate). It is actually a simple form of cloning

7 Blastomere separation
outer coating is removed from 4-celled embryo, causing separation of individual embryo cells (bastomeres), which are then cultured in vitro to develop embryo clones

8 Cloning by embryo splitting

9 Nuclear transfer using blastomers or cultured cells as nuclear donors

10 Somatic Cell Nuclear Transfer (SCNT or NTSC)

11 Chronology of advances in animal cloning
Hans Spemann(1938) proposed use of nuclear transfer to clone an organism.This idea originates from theoretical considerations of an experimental method which would allow to determine whether a loss of genetic material occurs during cell differentiation. If occurs –cloning would not be possible. frog Rena pipiens(1952) Robert Briggsand Thomas Kingcloned northern leopard frogsfirst animal cloning frog Xenopus leavis(1958, 1962) John B. Gurdonannounced that he had cloned South African frogs using the nucleus of fully differentiated adult intestinal cells. This demonstrated that cells' genetic potential do not diminish as the cell became specialized. carp(1963) controversial information sheep (1996) the first mammal cloned: Dolly mouse (1998) Wakayama, Perry and Yanagimachi50 mice from adult cells ( )

12 Dolly Dolly(July 5, 1996 –February 14, 2003) -the first mammal to be cloned from an adult somatic cell, using the process of nuclear transfer. She was cloned by Ian Wilmut, Keith Campbelland colleagues at the Roslin Institute in Edinburgh, Scotland 277 oocytes were fused with cultured mammary gland cells: of these 29 reached morula/blastula stage, and were transferred into surrogate mothers leading to 13 pregnancies, but only one live birth. During the Dolly`s lifetime, a lot of information on cloned organism development was collected. It was noticed that the age of the genetic material of cloned organisms is identical with the donor`s age. It means that biologically Dolly was 6 years old at her birth (age of the donor sheep). This causes that clone suffers from genetic disorders of mature/old-age donor and shows reduced disease resistance. At the age of five, Dolly developed arthritis. On February 14 , 2003 (at the age of 6 years and 7 months; the life-span for sheep: years) Dolly was euthanized because of a progressive lung disease. She was bred with a Welsh Mountain ram and produced six lambs in total. Dolly was named after the country western singer Dolly Parton.

13 Chronology of advances in animal cloning
Monkey Rhesus:from Tetra(female, 2000)embryo splitting

14 pig(5 piglets Millie, Christa, Alexis, Carrel, and Dotcom from one sow; Scotland-2000)

15 cow: Alpha andBeta (female,2001)

16 cat: CopyCat ”CC” a shorthaired calico (female, 2001)

17 Chronology of advances in animal cloning
mouse: in2002HochedlingerandJaenischcloned mice from T lymphocytes: They showed that the genome of cloned individuals contains the same rearrangement of T lymphocyte receptor as the original population of lymphocytes. This finding is commonly considered to be the strongest prove for organism cloning from differentiated cells. rabbit: (2003) in France and South Korea

18 Chronology of advances in animal cloning
mule: Idaho Gem(male, May 2003) and Utah Pioneer(male, July 2003) deer: Dewey(2003) horse: Prometeaan Arabian thoroughbred (female, 2003) rat: Ralph(male, 2003) fruit flies,Drosophila(2004) HUMAN (2004) Shin Yong Moon`s groupThey obtained pluripotent stem cells derived from cloned human blastocysts. dog: SnuppyAfghan hound (April 2005) wolf:grey wolves Snuwolfand Snuwolffy(2007), South Korea

19 Why develop cloning technology?
Potential applications of animal cloning Rapid multiplication of desired livestock Phenotypic evaluation and selection Animal conservation Transgenic applications Human cell‐based therapy

20 Potential applications of animal cloning
Rapid multiplication of desired livestock rapid spread of superior genotypes production of large number of preferred sires for natural breeding (alternative to artificial insemination) rapid response to market changes

21 A 3-year-old Friesian dairy cow, and her genetically identical cloned calves.

22 Potential applications of animal cloning
Cloning for phenotypic evaluation and selection to monitor effect of different environmental conditions on phenotypes of different lines of cloned animals enhance genetic progress by increasing the accuracy of selection

23 Potential applications of animal cloning
Animal conservation cryobanking of somatic cells from rare and endangered birds and animals “insurance policy” against further losses of diversity or possible extinction of wildlife to preserve endangered indigenous breeds of livestock adapted to particular environments Lady, the first surviving cow of the Enderby Island breed (a rare breed of New Zealand origin, adapted to the harsh sub antarctic environment), and Elsie her genetic duplicate.

24 Potential applications of animal cloning

25 Potential applications of animal cloning
Human cell-based therapy to treat disorders in tissues that neither repair nor replace themselves: diabetes, muscular dystrophy, spinal cord injury, certain cancers, various neurological disorders healthy cells from patient could be used to produce therapeutic tissue for transplantation: insulin-producing cells pancreatic cells for diabetes dopamine-producing nerve cells for Parkinson disease this may also be associated with gene therapy to correct a genetic defect in the somatic cells (e.g. muscular dystrophy)

26 Potential applications of animal cloning
Transgenic applications: cultured cells can be genetically modified in the lab the modifications can be checked prior to any animal work is conducted desired genetically modified cell lines may then be used in nuclear transfer nuclear transfer approach is more efficient than pronuclear injection method

27 Uses of animal cloning for transgenic applications
Pharmaceuticals production of medically important molecules in milk, e.g.:Human α-1 antytrypsin for emphysema and cystic fibrosis treatment Human antithrombin III to regulate blood clotting during surgery Nutraceuticals improved milk products, e.g.bovine milk proteins replaced with human equivalents different fatty acid profiles (CLA -conjugated linoleic acid isomers with anticancerogenic activity) Agricultural production traits genomics projects will identify target genes (influencing livestock production traits):to improve feed conversion efficiency, growth rate, muscle composition confer disease and pest resitance superior milk for cheese production increased casein and reduced β-lactoglobulin

28 Uses of animal cloning for transgenic applications
Xenotransplantation Shortages of human organs and tissues for transplantation Pigs are currently used for organ production Availability Similar anatomy, organ size and physiology Problematic: disease (need to generate pathogen-free herds) Modification of antigenes to reduce transplant rejection Inactivation of α-1,3-galactosyl transferase gene •Livestock as human genetic disease models Sheep as alternative to mice models could be generated as superior research models:Cystic fibrosis Huntington disease

29 Views on Cloning In the debate over cloning there are those that feel that advances gained from cloning outweigh any social dilemmas. There are those that feel that cloning is wrong on a fundamental moral level and would produce scientific and social problems.

30 Pros on Cloning Cloning will improve the overall quality of science and life. Cloning might produce greater understanding of the causes of miscarriages. Cloning experience may add to the increased understanding of genetics. Damage to nervous system could be treated through therapeutic cloning. Human cloning could be used for parents who risk passing a genetic defect to a child. Human cloning will allow a woman to have one set of identical twins.

31 Cons on Cloning Those that do not agree with cloning feel that is an affront to religious societies. Cloning may reduce genetic variability. Cloning may cause people to settle for the best existing animals. Cloning is currently an expensive process. There is a risk of disease transfer. Any research into human cloning would eventually need to be tested on humans. Human cloning might be used to create a “perfect human”. Human cloning might have a detrimental effect on family relationships

32 References Campbell, 1999, Nuclear transfer in farm animal species. Sem. Cell Develop. Biol., 10: 245‐252. Gurdon, 1986, Nuclear transplantation in eggs and oocytes, J. Cell science, Suppl. 4: 287‐318. •Stephens, 1995 Plant micropropagation using African Violet leaves •Vajta and Gjerris, 2006, Science and technology of farm animal cloning: State of the art, Animal Reproduction Science, 92: 211‐230. •Wells, 2002, Nuclear transfer from established cell lines, Encyclopedia of Life Sciences, Macmillan Publisher Group, New York, 13:327‐331. •Wilmut, 2003, Whole animal cloning, Encyclopedia of Life Sciences, Macmillan Publisher Group, New York •Wolf et al., 1998, Nuclear transfer in mammals: Recent developments and perspectives, J. Biotechnology, 65: 99‐110.

33 THANKS


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