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The possibility of human cloning has been a hot topic ever since, in February 1997, Dr. Wilmut and his research team at the Roslin Institute in Edinburgh, Scotland, created Dolly the clone sheep by somatic cell nuclear transfer (SCNT).
It was the first successful instance of using adult cells to clone a mammal. Previous cloning experiments had succeeded only using embryonic cells, and it was thought that after a certain stage in cell differentiation the DNA underwent a permanent change and cells became incapable of gene expression. The creation of Dolly proved that this wasn't so, that adult cells could be reprogrammed to go back and start all over again.
Since then several other animal species have been cloned with varying degrees of success and this opened the door to the possibility of cloning humans next. In November 2001, scientists from Advanced Cell Technology (ACT) produced the first cloned six-cell human embryo. Their later research has led them to create embryos up to the 16 stage cell; at this stage, theoretically, the embryos could be implanted into an uterus and could develop into a human fetus. ACT's interest, however, lies in therapeutic cloning; that is, in using cloning technology to produce stem cells which can be used to repair damaged cells, grow new organs and treat various health conditions. They say they don't intend to create human clones.
Others, like Dr. Severino Antinori and the Raelian sect's company Clonaid, have claimed to have already created human clones. So far, however, these claimants haven't put forward any concrete evidence and their claims are regarded with skepticism in the scientific community.
But, yes, humans can be cloned. And there are enough volunteers to give cloning a try. This, despite the obvious risks of cloning, as demonstrated by malformed or perennially-ill or short-lived animal clones.
So far technical, ethical, moral and political issues have kept scientists in check. Still, the technology could be perfected in coming years, and ethical and political dilemmas could be resolved by reducing margins of error and demonstrating the usefulness of cloning. Moral issues are flexible and always seem to subside when the personal element enters into the equation. For example, if cloning offered the only cure for you or your sick child, it would be hard to look at it as something 'morally repugnant'
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Human Cloning Process
Humans can be cloned using the SCNT process that was used to create Dolly. This is how SCNT works -
- Micromanipulators are used to remove the nuclei from embryonic cells or from adult stem cells.
- The nucleus is inserted into an enucleated egg. That is, an egg which has had its nucleus removed in preparation for this transfer purpose.
- The nucleus is stimulated with electricity to make it fuse with the egg.
- The renucleated egg is kept in a chemical solution.
- The new nucleus then guides normal development of the egg.
- After the embryo develops up to the sixteen-cell stage or further, it can be transferred into an uterus and, if all goes well, it can develop into a fetus.
- The fetus is carried full-term and a clone is born. It is genetically identical to the person whose cell nucleus had been used.
Another technique involves producing embryos by in-vitro fertilization and inserting nuclei from adult skin cells into them.
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Please also see the article 'What is Genetic Engineering? Get the Basics on Manipulating Genetic Material' here on Bright Hub.