For starters, we will give you a "recipe" from The BioFact Report, one of the more popular online Science journals:
How To Clone A Human Version 1.1
(Hey, this is NOT a joke! You must read on!)
Human stem cells of one tissue type, from the individual who will be cloned.
Human Tissue Culture Media:
Media in which these human cells will grow and divide.
Minimal Human Tissue Culture Media:
Media in which cells will stop dividing, and enter a state of "quiescence" without dying.
Incubator, Sterile Hood, Petri Dishes, Microscopes, and tools capable of removing and implanting cellular organelles, such as the nucleus, from one cell to another.
Unfertilized Human Egg Cells.
Human Egg Cell Growth Media:
Media where fertilized eggs will grow and divide.
Grow the human cells to be cloned until you have a good supply.
Transfer the cells to a minimal media.
This will allow the cells to live, but they stop dividing and enter a quiescence state. This is likely the step in which the cells will lose their differentiation, and revert to a more totipotent state.
Get an unfertilized human egg cell and remove the nucleus from this egg cell. Try to minimize damage done to this cell. Discard the nucleus.
Take one of the quiescent cells, in its entirely, and implant it inside the coat around the egg cell (known as the zona pellucida) next to the egg itself.
Electroshock the egg.
The electroshock induces the fusion of the two cells. You can tell when you have given sufficiently electroshock by just looking at the cells. This rebooting of the human genetic program is believed to be initiated by the replacement of donor cell protein signals by egg cell protein signals, but the electroshock might assist in moving those protein signals across the nuclear membrane as well. Electroporation is a common technique for moving DNA molecules through a cellular membrane.
Repeat the last three steps as necessary until you have enough
Expect a lot of them not to survive because of cellular damage and other mishaps. Allow the embryos to grow and divide a few times in the Human Egg Cell Growth Media.
Finally, implant the embryos in human mothers where they can be carried to term and born normally.
You may want to know...
In cloning, which human tissue (and type) to use is a very important question. Each of our cells has undergone considerable development and differentiation since we were first conceived. Each different cell type is likely to have undergone changes that prevents it from reverting to its original state as a fertilized egg cell.
Inducing quiescence may cause the cell to begin scavenging it's own proteins more rapidly than they can regenerate themselves. Steps of differentiation may have turned on certain cell functions and turned off others, but this starvation of the cell must reverse these steps of differentiation if cloning is going to work. Note: Quiescence of a cell is putting the cell in a state when it is so deprived of nutrients that it will no longer divide, but it is not so starved that it dies.
The above procedure was used in cloning Dolly the sheep. There is a Version 1.2 (unreleased as yet, but due to be published soon), with new information from the methods used in cloning reptiles and mice.
Does that give you a sense of excitement, or one of fear?
Cloning is causing waves of anticipation, and much concern. So, what exactly is cloning?
The Creation of Dolly
The first major breakthrough in cloning was in the creation of Dolly, the sheep. It all started sometime in 1996, when a group of determined researchers of the Roslin Institute near Edinburgh, Scotland, found a way to accomplish the seemingly impossible task of cloning animals.
Prior to Dolly, the cloning of cells from adult animals were all failures. After many years of research, scientists had concluded that the cells of mature animals were too specialized to be cloned. Consequently, these scientists began looking for simpler cells to duplicate (clone).
|Along came Ian Wilmut,
an embryologist. He and his colleagues took
some mammary-gland cells from an adult sheep and put these cells in a solution that
starved the cells of nutrients and it caused the cells to stop growing for a few days.
This process is known as "Quiescence of a cell".
Wilmut then fused each cell with an enucleated egg cell using a spark of electricity. The resulting cells were allowed to grow into embryos, which were then transplanted into surrogate mother ewes to complete their development.
Sounds quite easy, doesnt it? Not quite! Nearly 300 attempts at this technique resulted in failure! Some eggs did not accept mammary cell nuclei, many embryos died, quite a few lambs that were born were abnormal, and many more had unacceptable results.
Hah! But one sheep, apparently healthy, defied all the odds and survived the procedure. She was christened as Dolly and was born in July 1996.
Cloning The Hawaii Mouse
||After the success of Dolly, several more cloning accomplishments were
announced in 1997 and early 1998. However none of them could achieve what Ian Wilmut and
his colleagues achieved the creation of an animal clone from an adult body cell.
This led some scientists to question whether Dolly was in fact a clone of an adult sheep. This doubt was laid to rest in July 1998, when biologists at the University of Hawaii announced that they had created more than 50 mice using adult mice cells, and the cloning procedure used was different from the cloning procedure that produced Dolly.
There were 2 major differences between the Hawaii-mouse technique and the Dolly technique.
These cells were not growing: thus they could easily be reprogrammed inside enucleated cells, without the need to starve them in a special solution, as was necessary with the cells used in the Dolly procedure.
The technique of using a needle did less damage to the egg than electrical fusion, and it apparently increased the chances of the resulting cell developing into a healthy embryo.
Do you remember that there are many similarities between mouse and human (go read the section on Basics: History of DNA).
Therefore, scientists are particularly elated with the success of cloning the mouse, and it fuels the fundamental question "When can humans be cloned?".
Uses of Cloning
Researchers have said that the cloning of animals, especially the GM-Types (genetically modified in certain ways), could have a number uses for medical, agricultural and industrial purposes. However, the cloning of animals indicate that it is possible to clone THE ANIMAL of all animals: Humans.
Much of the public has expressed anger and disgust toward the prospect of human cloning. Some politicians have vowed to outlaw it. However, there are people in support of the idea of human cloning, seeing it as a way to help others, example: allowing infertile couples to have children.
The uses of cloning can be summarised (broadly) into two main catergories:
Transgenic animals (animals that have been engineered to carry genes from species other than their own) can be made to produce a wide variety of proteins that could be sold as drugs, as well as enzymes, that could be used to speed up industrial chemical reactions. Up to mid-1998, most genetically engineered proteins were being manufactured in Bioreactors. These are large steel vessels in which billions of GM micro-organisms produce proteins that are then extracted and purified.
Researchers involved in cloning envision other practical applications for their work. These include the creation of GM animals to provide organs for human organ transplants, the mass production of faster growing and leaner livestocks, and the decrease in number of endangered animals, or even the re-creation of extinct species of animals that once roamed our world. Jurassic Park? Hmmm.
Although human cloning would be much more difficult than animal cloning, geneticists foresee a number of practical applications for the cloning of humans. For instance, infertile couples, who do not wish to adopt, could use cloning to have children who are biologically related to them. There could also be the production of offsprings free of certain diseases, such as disorders affecting the eyes, brain, and muscles, potentially caused by flawed genes in the mitochondria (energy-producing structures in the cytoplasm).
How is this done? Simple!
Basically, if a woman was a carrier of a flawed gene, she can conceive a totally healthy offspring by having the nucleus of one of her body cells inserted into an enucleated egg cell from a woman without the flawed gene. The resulting embryo would then be implanted into the woman who donated the nucleus. She carries the baby to term and gives birth. Useful, isn't it?Advantages and Disadvantages
As with all medical advances, there will always be advantages and disadvantages. Many points have been raised against and in defence of Human Cloning. We present some below. What are your personal views? Let us know through our message board or email the DNA Team. (Click on Home button).
|AGAINST||IN DEFENCE OF|
|Cloning might lead to the creation of genetically engineered groups of people for specific purposes, such as warfare or slavery.||Cloning enable infertile couples to have children of their own.
|Cloning might lead to an attempt to
improve the human race in accordance with arbitrary, perhaps unacceptable, standards.
||Cloning give couples who are at risk of
producing a child with a genetic defect, the chance to produce a healthy child.
|Cloning could result in the introduction
of additional defects in to the human gene pool.
||Cloning could shed light on how genes work
and lead to the discovery of new treatments for many genetic diseases.
|Cloning of humans is unsafe. There are
just too many unknown factors that could adversely affect the offspring.
||A ban on cloning is unconstitutional. It
deprives the people of the right to reproduce and restrict the freedom of scientists.
|A clone may have a diminished sense of
||A clone would have as much as of a sense of individuality as does twins.|
|A clone may end up have fewer rights than other
people (who are not clones).
||A clone is not exactly a duplicate because environmental factors would mould
him or her into a unique individual.
|Doctors might specifically target the use
of clones as sources of organs, for human organ transplants.
||A clone would have all rights, the same
rights, as do each and every other person.
|Cloning is at odds with the traditional concept of family life.||Cloning is comparable in safety to a number of other medical procedures.|
|Cloning is against Gods Will
and there are certain aspects of human life that must be off-limits to science. The
cloning of a human is one.
||Objections to cloning are similar to
objections raised against previous scientific achievements, for example heart transplants
and test-tube babies, that later came to be widely accepted procedures.
Your Views ...?
Your Views ...?