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  • Cloning
    • A group of genetically identical organisms formed from a single parent as a result of asexual reproduction or artificial means
      • Its purpose is to maintain genetic stock, to conserve rare breeds, to increase yield and to obtain desirable traits in organisms
    • Embryo Cloning
      • Low tech version of cloning
      • Mimics the natural process of creating identical twins
      • Made it possible for farmers to increase livestock numbers
      • In nature twins occur just after fertilisation in which the zygote divides into 2 embryos - the two embryonic cells came from the same zygote so are genetically identical
      • Artificial embryo twinning uses the same approach but in a petri dish
        • Fertilised zygote/egg divides by mitosis to form an embryo which then splits into 2 before differentiation producing a genetic clone of the original
        • Resulting embryos are placed in a SURROGATE mother where they are carried to term and delivered
    • Somatic Cell Nuclear Transplant Cloning
      • A somatic cell is any cell in the body other than the reproductive cells
      • 1. Somatic cell is isolated from the donor and cultured in a medium to stop division and the DNA is then removed
      • 2. Unfertilised egg is removed from the recipient and the DNA / nucleus is removed
        • Egg cell is ennucleated
      • 3. Donor and recipient cells fuse together - stimulated to divide to the 8 cell stage
      • 4. Developing embryo is placed into the uterus of the surrogate mother
      • The lamb born is genetically identical to the original donor sheep
    • Advantages
      • Potential benefits for the fields of medicine and agriculture
        • E.G. useful for the production of cells in quantity, such as cancer cells for research and monoclonal antibodies
      • Cloned sheep to produce milk with a specific protein for the clotting of blood
      • Makes copies of animals with desired agricultural traits
        • Lean meat or high milk production
      • Build populations of endangered or even extinct species
    • Disadvantages
      • Reproductive cloning is inefficient and expensive
      • Most cloned animal embryos cannot develop into healthy individuals
      • Adverse health effects including an increase in birth size and defective vital organs
      • Premature aging and problems with the immune system develop


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