Gene Clo Ning

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Gene Clo Ning

  1. 1. GENE CLONING
  2. 2. Cloning <ul><li>Different processes for duplicating biological material. </li></ul><ul><li>Diff types = technologies can be used for other purposes besides producing the genetic twin of another organism. </li></ul><ul><li>1. DNA cloning, </li></ul><ul><li>2. Reproductive cloning </li></ul><ul><li>3. Therapeutic cloning . </li></ul>
  3. 3. Recombinant DNA Technology or DNA Cloning <ul><li>1970s = common practice in MB labs today </li></ul><ul><li>“ Recombinant DNA technology,&quot; &quot;DNA cloning,&quot; &quot;molecular cloning“ or &quot;gene cloning” </li></ul><ul><li>Transfer of a DNA fragment of interest from one organism to a self-replicating genetic element eg. bacterial plasmid. </li></ul><ul><li>The DNA of interest can then be propagated in a foreign host cell. </li></ul><ul><li>Scientists studying a particular gene often use bacterial plasmids to generate multiple copies of the same gene. </li></ul>
  4. 4. Plasmids <ul><li>Self-replicating circular DNA molecules </li></ul><ul><li>HGP = Plasmids and other types of cloning vectors are used by researchers to copy genes to generate sufficient identical material for further study. </li></ul><ul><li>Can carry up to 20,000 bp of foreign DNA </li></ul>
  5. 5. How? <ul><li>DNA fragment containing the gene of interest is cut from chromosomal DNA using RE. </li></ul><ul><li>United with a plasmid that has been cut with the same RE. </li></ul><ul><li>Fragment of chromosomal DNA + cloning vector = &quot;recombinant DNA molecule.&quot; </li></ul><ul><li>The recombinant DNA can then be reproduced along with the host cell DNA. </li></ul>
  6. 6. Other cloning vectors <ul><li>Viruses </li></ul><ul><li>BACs = 100 – 300 kb </li></ul><ul><li>YACs. = 1 MB </li></ul><ul><li>Cosmids = up to 45 kb </li></ul>
  7. 7. Reproductive cloning <ul><li>Technology used to generate an animal that has the same nuclear DNA as another currently or previously existing animal. </li></ul><ul><li>Dolly. Roslin Institute. </li></ul><ul><li>Somatic cell nuclear transfer (SCNT), = transfer of GM from the nucleus of a donor adult cell to an egg whose nucleus, and GM has been removed. </li></ul><ul><li>The reconstructed egg containing the DNA from a donor cell must be treated with chemicals/ electric current to stimulate cell division. </li></ul><ul><li>Once the cloned embryo reaches a suitable stage, it is transferred to the uterus of a female host where it continues to develop until birth. </li></ul>
  8. 8. Dolly the sheep <ul><li>The first mammal to be cloned was put down by lethal injection Feb. 14, 2003. </li></ul><ul><li>Prior to her death, Dolly had been suffering from lung cancer and arthritis. </li></ul><ul><li>Studies showed that telomeres are shortened, a phenomenon that is associated with cellular aging </li></ul>
  9. 9. Reproductive cloning <ul><li>1952 = tadpole. </li></ul><ul><li>The possibility of human cloning, raised when Scottish scientists at Roslin Institute created Dolly ( Nature 385, 810-13, 1997), </li></ul><ul><li>Since Dolly, sheep, goats, cows, mice, pigs, cats, and rabbits all using nuclear transfer technology. </li></ul><ul><li>Attempts at cloning certain species such as monkeys, chickens, horses, and dogs, have been unsuccessful as some species </li></ul><ul><li>? some may be more resistant to somatic cell nuclear transfer than others. </li></ul><ul><li>Process can be traumatic </li></ul>
  10. 10. Therapeutic cloning <ul><li>Also called &quot;embryo cloning,&quot; production of human embryos for use in research. </li></ul><ul><li>Not to create cloned human beings, but to harvest stem cells that can be used to study human development and to treat disease. </li></ul><ul><li>Stem cells are extracted from the egg after it has divided for 5 days. </li></ul><ul><li>Many researchers hope that one day stem cells can be used to serve as replacement cells to treat heart disease, Alzheimer's, CA and other diseases </li></ul>
  11. 11. How to utilize recombinant tech? <ul><li>Gene therapy = Tx genetic conds by introducing virus vectors that carry corrected copies of faulty genes into the cells of a host organism </li></ul><ul><li>GMO/GAO = Genes from different organisms that improve taste nutritional value or provide resistance </li></ul><ul><li>Sequencing genomes = Knowledge. </li></ul>
  12. 12. How to utilize repro cloning <ul><li>Can be used to develop efficient ways to reproduce animals with special qualities . Eg. Mass production of , drug-producing animals or animals that have been genetically altered to serve as models for studying human disease. </li></ul><ul><li>Could be used to repopulate endangered animals or animals that are difficult to breed. Eg. In 2001, the first clone of an endangered wild animal was born, a wild ox called a gaur. The young gaur died from an infection about 48 hours after its birth. </li></ul><ul><li>In 2001, scientists in Italy reported the successful cloning of a healthy baby endangered wild sheep, now living in Sardinia. </li></ul>
  13. 13. How to utilize therapeu. cloning? <ul><li>. May produce whole organs/ healthy cells that can replace damaged cells. </li></ul><ul><li>Eg transplants = stem cells would be used to generate an organ or tissue that is a genetic match to the recipient. In theory, the cloned organ could then be transplanted into the patient without the risk of tissue rejection. </li></ul><ul><li>If organs could be generated from cloned human embryos = the need for organ donation could be reduced. </li></ul>
  14. 14. Problems of repro cloning <ul><li>Reproductive cloning is expensive and highly inefficient. </li></ul><ul><li>> 90% of cloning attempts fail to produce viable offspring. </li></ul><ul><li>> 100 nuclear transfer procedures could be required to produce one viable clone. </li></ul><ul><li>Cloned animals tend to have compromised immune function and higher rates of infection, tumor growth, and other disorders. </li></ul><ul><li>Japanese studies have shown that cloned mice live in poor health and die early. </li></ul><ul><li>1/3 calves born alive have died young, and many of them were abnormally large. </li></ul><ul><li>Don’t live long enough to generate good data. </li></ul><ul><li>In 2002, researchers at Cambridge reported that the genomes of cloned mice are compromised = certain of genes function abnormally. </li></ul>
  15. 15. <ul><li>Human cloning: </li></ul><ul><li>the most controversial debate of the decade.  </li></ul><ul><li>Aroused worldwide interest and concern </li></ul><ul><li>because of its scientific and ethical implications </li></ul><ul><li>Is it morally acceptable? </li></ul>
  16. 16. Certain questions to be raised <ul><li>Is self-engineering acceptable? </li></ul><ul><li>Will failures, eg. deformed offspring, be acceptable? </li></ul><ul><li>Will cloning lead to designer babies ? </li></ul><ul><li>Who is socially responsible for cloned humans? </li></ul><ul><li>Rights and legal protection? </li></ul>
  17. 17. <ul><li>95% public say no to cloning, </li></ul><ul><li>but 95% of scientists say yes </li></ul>
  18. 18. Reasons for cloning <ul><li>Provide valuable research </li></ul><ul><li>Answer to infertility? </li></ul>
  19. 19. Scenario 1 <ul><li>Scenario 1: A husband and wife who wish to have children but both are carriers of a lethal recessive gene. </li></ul><ul><li>“ Rather than risk the one in four chance of conceiving a child who will suffer a short and painful existence” </li></ul>
  20. 20. Scenario 2 <ul><li>Scenario 2 : Parents of a terminally ill child are told that only a BMT can save the child's life: </li></ul><ul><li>“ With no donor available, parents attempt to clone a human being from cells of the dying child. If successful, the new child could be a match for BMT” </li></ul>
  21. 21. Concerns of human cloning <ul><li>Act of human arrogance = Playing God </li></ul><ul><li>Safety concerns = Due to the inefficiency of animal cloning (1-2 viable offspring for every 100 experiments) and the lack of understanding about reproductive cloning = unethical to attempt to clone humans. </li></ul><ul><li>Technology only in animals, in men = possibility of mutation/ bio damage? </li></ul>
  22. 22. <ul><li>Individuality and Uniqueness = Fear that a clone would not be an “individual” but merely a carbon copy. </li></ul><ul><li>Would it have a soul? </li></ul><ul><li>Clone would be constantly compared = burdened with oppressive expectations . </li></ul><ul><li>???????????????????????????????? </li></ul>
  23. 23. <ul><li>THE END OF ML429 </li></ul><ul><li>STUDY HARD, PRAY HARD </li></ul><ul><li>I WISH YOU ALL THE VERY BEST IN YOUR EXAMS </li></ul>

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