B3h: CLONING

B3h: CLONING

GENE THERAPY
1. Altering a person's genes in an attempt to cure genetic disorders (scientists haven't got it to work properly yet but are working on it
2. TWO TYPES:
  1. Changing the genes in body cells, particularly cells that are most affected by the disorder This wouldn't affect the individual's gametes, so offspring could still inherit the genes
    1. e.g. cystic fibrosis affects the lungs, so therapy would target the lungs
  2. Changing genes in the gametes: every cell of any offspring will be affected by the gene therapy and won't suffer the disease.
    1. Currently illegal
    2. Might have unexpected consequences which cause new problems which would be inherited by all future generations
    3. Could lead to the creation of 'designer babies'
CLONING IS MAKING AN EXACT COPY OF ANOTHER ORGANISM
1. Dolly the sheep: nuclear transfer
  1. The nucleus of the desired animal's body cell is removed and inserted into a surrogate's egg cell
    1. The cell is given an electric shock to encourage mitosis as if it were a normal fertilised egg
      1. The dividing cell (now an embryo) was implanted into the uterus of the surrogate to develop
        The surrogate gives birth to a clone of the first animal
BENEFITS OF CLONING ANIMALS
1. Allows you to mass produce animals with desired characteristics
  1. Animals that produce medicines in their milk can be developed by genetic engineering and cloning
  2. Researchers have managed to transfer human genes (e.g. factor VIII for treating haemophilia) into cows and sheep
  3. Animals (like pigs) that have organs suitable for transplantation into humans could be developed by genetic engineering then cloning: which would ensure constant supply of organs for transplant
    1. Concerns: viruses
2. Human embryos could be produced by cloning adult body cells and then used to supply stem cells for stem cell therapy
  1. These cells would have identical genetic information as the patient, reducing the risk of infection
RISKS OF CLONING ANIMALS
1. Cloned animals might not be as healthy as normal ones
2. Cloning is a new science: might have consequences that we aren't yet aware of
HUMAN CLONING HAS ETHICAL ISSUES
1. There would be lots of surrogate pregnancies, probably with high rates of miscarriage and stillbirth
2. Clones of other mammals have been unhealthy and often die prematurely - human clones might too
3. Could be psychologically damaged knowing that it's just a clone of another human being
CLONING PLANTS
1. EASY
  1. Taking a cutting from a good plant and planting it
  2. Many plant cells keep their ability to differentiate
2. COMMERCIAL CLONING
  1. METHOD
    1. Choose the plant you want to clone based on characteristics
      1. Remove several pieces of small tissue (best results from fast-growing root and shoot tips)
        Grow tissue in a small medium containing nutrients and growth hormones. Done under aseptic conditions to prevent growth of microbes that could harm the plants
        As the tissues produce shoots and roots they can be moved to potting compost to carry on growing
  2. PROS
    1. You can be fairly sure of the characteristics - you'll only get good ones - doesn't waste time and money growing duds
    2. Possible to mass-produce plants that are hard to grow from seeds
  3. CONS
    1. If all the plants start to suffer from a disease or start doing badly because of change in environment, they'll all have the same problems
    2. Lack of genetic variation

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	Created by charl.mallon over 10 years ago