Human Cloning

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Human Cloning

Biological Aspects

True human cloning involves taking a somatic cell from a person and removing its nucleus. Then the nucleus of a fertilized egg cell is removed
and placed in the somatic cell. This is impossible in humans right now because the somatic cells are specialized and there are many genes that
have been switched off in them that we do not know how to turn them back on. This was done with frogs however. The eggs were implanted
with the nuclei from the intestinal lining of tadpoles. Most of these frogs died or grew into monsters. Of the ones that did grow normally they
were sterile.

Embryo splitting or blastomere separation is what is most commonly referred to as human cloning. Embryos in the early stages of development
start to divide into cells called blastomeres. The zona pellucida (a protective covering for the egg) is punctured or removed and the blastomeres
are separated from each other. Each blastomere is then covered with an artificial zona pellucida. Then each of the blastomeres starts dividing
and becomes an embryo. This was attempted by Hall and Stillman in 1993. They used embryos that contained too much genetic information
and got as far as 32-cell divisions in some the embryos. At this stage the embryo can be implanted in the womb.

Another technique is nuclear transplantation. In this process unspecialized embryonic cells are used and their nuclei are removed. An embryo
in the 32-cell division sta...

Submitted by: digitalessays
Date Submitted: 12-06-08 8:59am
Category: Science
Words: 1173
Pages: 4.69