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Basic understanding of how cloning is done

  1. May 10, 2006 #1
    I have a basic understanding of how cloning is done from here http://en.wikipedia.org/wiki/Cloning

    but hypothetically, if I wanted to clone myself, would it be enough to get the nucleus of any of my cells and put it into the host egg? I thought only the sperm cell can fertilise the egg. Or is the fertilisation in this case done articificially in which case only the DNA is important. But different cells in my body have slightly different DNA because the cells do different jobs and function differently? Does this fact not matter in cloning?

    Does the cell from me have to be diploid, haploid or dosen't matter? Why?
  2. jcsd
  3. May 10, 2006 #2


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    I think you misundestood the wikipedia explanation. The curent strategy is to remove the haploid nucleus from the egg and replaced with the diploid nucleus from a living cell. There's no need for fertilization.

    As far as DNA goes, every single cell has the same DNA, the difference in function is due to different gene expression. Certain genes are only expressed in specific type cells. For cloning, it appears that procedure reset gene expresssion to "after fertilization" state.
  4. May 10, 2006 #3

    So I can't inject one of my haploid nucleus (such as sperm cells)? Only a diploid nucleus is possible or needed in cloning?

    Could you also elobrate on this a little bit since I am weak on fundalmental biology but would love to improve on it.
    Last edited: May 10, 2006
  5. May 11, 2006 #4
    In principle every cell has the same genetic information as every other cell. The difference between say, a skin cell and a liver cell is in what part of this common genetic information it actually uses.

    So a skin cell technically has the DNA that codes for all the enzymes needed in the liver, it just doesn't use this DNA to make those enzymes. So in principle we can take the nucleus of any celll in the organism, insert it into an egg and get it to develop into a clone of the original orgainism.

    I think one of the problems with these techniques in practice, is that we don't really know how to "turn off" the pattern of gene expression. That is, just because we took the nucleus of a skin cell and inserted it into an egg, it may still behave like a skin cell in some ways.

    Another problem is mutation that occurs over the lifetime of the organism. A lot of the mechanisms we have to repair DNA damage only function in the germ line (the sperm/eggs) since these are the cells that will pass on their DNA to the next generation it makes sense that we would need these cells to be as free from mutation as possible. This is not so important for other cells. We find that skin cells tend to have a lot more mutations in their genome than germ cells would.

    This means that when we take the nucleus of a skin cell and insert it into an egg, the clone we end up making would be far more likely to have many (possibly lethal) mutations than we would see otherwise.
  6. May 12, 2006 #5


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    Correct. If you injected a haploid nucleus into an egg, that would be in vitro fertilization...you get the combination of sperm and egg DNA just as with natural fertilization (only you picked which sperm and egg), so produce an offspring, not a clone. To get a clone, you need to replace the haploid nucleus with the diploid nucleus from a somatic cell so that you have an exact genetic copy.
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