||There are basically three techniques in cloning mammals. The three techniques are:
- Embryo twinning:
Once the egg is fertilized by sperm, the cell that is formed begins to divide. Once the cell begins to divide, the cells can be separated and implanted into the uterus of different mothers. If this procedure happens correctly, identical clones will be born from different mothers. This procedure can only work if the cells are separated before the cells begin to differentiate (begin to specialize).
- Nuclear transfer:
In nuclear transfer a donor cell and an egg cell (oocyte) are used. The first thing that must happen is the egg cell must have all the genetic material removed, then the cell is forced into a dormant stage in which the cell shuts down but doesn't die (this dormant stage is called Gap Zero stage). Next the donor cell's nucleus is put into the egg cell using the process of either cell fusion or transportation. The egg cell is then prompted to form an embryo, by using electric waves. Next the embryo is implanted into a mother. If this technique works correctly, then an exact copy of the donor cell will be born.
- Honolulu technique:
In the Honolulu technique, unfertilized eggs are used as the receiver of the donor nuclei. Once the nuclei are removed from receiver cells, the donor cell's nuclei are inserted into them. There is no culturing done on the cells. After one hour, the cell accepts the new nucleus. After five more hours, the egg cell is then placed in a chemical culture which jumpstarts the cell's growth, just like fertilization does in nature. In the culture is a substance that stops the formation of a second cell, which usually forms before fertilization. After the jumpstart, the cell develops into an embryo. This embryo can then be transplanted into a surrogate mother and then carried to term.