cloning

• Cloning


  Producing genetically identical cells or organisms from the cell of an existing organism
• Cloning


  • Can occur naturally in some plants and animals, also artificial
• Vegetative propagation


  Production of plant clones from non-reproductive tissues e.g. roots, leaves, stems

  
• Cuttings


  1. Take a cutting using a stem 2-10cm from a stem

  2. Remove leaves from cutting

  3. Dip lower end in rooting powder

  4. Plant cutting into a pot containing a suitable growth medium

  5. Ensure a warm and moist environment
• Leaf cutting


  1. Remove complete leaf, score large veins on lower leaf, put on top of growth medium, broken veins facing down

  2. Plant elsewhere when it is strong enough and has formed its own roots
• Root cutting


  Very similar to stem cutting
• Tissue culture


  Used to clone plants that don't readily produce, are endangered or rare
• Tissue culture


  1. Cells are taken from original plant (stem and root tip/stem cells)

  2. Sterilisation to kill microorganisms

  3. Placed on a culture medium containing plant nutrients and growth hormones

  4. Cells will divide and grow into a small plant

  
• Tissue culture


  • Clones are genetically identical, so desired characteristics are preserved
  • Controlled environment, can be reproduced in any season
  • Requires less space, can mass produce quickly
• Tissue culture


  • Clones are genetically identical, so undesirable characteristics will remain
  • Clones have no genetic variability, a single disease could kill all of the population
  • High energy use, requires skilled workers, high production costs
  • Contamination by microorganisms can result in a complete loss of plants
• Therapeutic cloning


  Use of cloned cells, tissues or organs for the treatment of individuals
• Animal cloning


  Artificial embryo twinning, where an egg cell is extracted, fertilised, and the individual cells from the embryo are separated into separate petri dishes to develop into an embryo each
• Somatic cell nuclear transfer (SCNT)

  1. A somatic cell is taken from A, the nucleus is extracted

  2. An oocyte (immature egg cell) is taken from B, the nucleus is removed to form an enucleated oocyte

  3. The nucleus from A is inserted into the enucleated oocyte from B

  4. They are fused together and stimulated to divide, producing an embryo

  5. The embryo is implanted into a surrogate mother
• Animal cloning


  • Desirable characteristics are always passed on to clones
  • Undesirable characteristics are always passed on, infertile animals, susceptible to the same diseases
  • Endangered species -> biodiversity, development of new diseases, may not live as long, unethical, embryos as a stem cell source
• Clones occur naturally
• Cloning can be used for research, saving endangered animals, increasing animals with desired characteristics in agriculture, and producing useful substances from animals
• Cloning can be used to clone embryonic stem cells to replace damaged tissues