Saturday, 17 March 2012

5.19 Mammal Cloning

Describe the stages in the production of cloned mammals involving the introduction of a diploid nucleus from a mature cell into an enucleated egg cell, illustrated by Dolly the sheep

The original sheep in which the scientists take the genetic information from would have the same genes as its clone (Dolly).  This is done by:
  • Removing a diploid cell with the full set of genetic information. This nucleus contains all the genetic information to form a clone.
  •  At the same time, we need to obtain a cell, which has a tendency to divide, so another sheep would be injected with hormones to produce eggs, but we don't want the genetic information so we remove it (enucleation). 
  • So we take the cell with the genetic information that we do wish to copy and we take the egg cell which divides and we fuse them together and by doing so we combine the genetic information that we want with a cell that needs to divide
  • The combination of the two results in many cell divisions by mitosis and forms a ball of cells called the blastula, and this is essentially an embryonic sheep
  • This embryo is placed into another sheep - the surrogate sheep.
  • The embryo will grow into a foetus and then it will be born and this sheep that is born is called Dolly and it has the same sets of genetic information as the first sheep

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