Artificial cloning, animals

• Artificial twinning

  • After eggs is fertilised, it divides to form a ball of cells. Each individual cell is totipotent.
  • As cells divide, the embryo becomes a hollow ball of cells so embryo cant divide.
  • Early embryo is artificially split and two foetuses go on to develop from the halves of divided embryo.
  • Early embryo may be split into more than two pieces and results in a number of identical offspring.
  • Used in farming to produce maximum offspring from good dairy or beef cattle.
• 1. Cow with desirable traits, treated with hormones so releases more mature eggs.
  2. Ova may be fertilised naturally or by artificial insemination- early embryos are flushed out.
  3. Or mature eggs are removed and fertilised in lab.
  4. Totipotent cells of early embryo are split to produce many smaller embryos, each capable of fully growing.
  5. Grown in lab then implanted into a surrogate mother, each embryo is implanted into a different mother as single pregnancies carry fewer risks.
• Somatic cell nuclear transfer

  = Take the nucleus from an adult somatic (body) cell and transfer it to an enucleated egg cell.

  • An electric shock is used to fuse the egg and nucleus, stimulate the combined cell to divide, and form an embryo that's a clone of the original adult.
• Advantages

  • Artificial twinning enables high yield farm animals to produce more offspring than normal reproduction.
  • How successful a male animal is at passing on its genes can be determined, if successful more could be reared from frozen embryos.
  • SCNT enables GM embryo to be replicated, many embryos produced from one GM.
  • SCNT allows specific animals eg: pets and race horses to be cloned.
  • SCNT allows rare, endangered, extinct animals to be cloned.
• Disadvantages

  • SCNT is very inefficient, many eggs needed for a single clone.
  • Cloned animals embryo are often miscarried or produce malformed offspring.
  • Cloned animals have shortened life spans.
  • Unsuccessful at reproducing rare or extinct populations.
• Therapeutic cloning

  • Cloning somatic cells to make tissues or organs for medical purposes