|
|
Human cloning: fact & fallacy
The announcement of the first human clone from Clonaid, a US-based company for human cloning, is widely seen as merely a claim yet to be verified, not a scientific truth. One needs to carefully look at the criticism from the experts of cloning to find out the reality behind this statement.
First of all, Clonaid presented no scientific proof to support their claim. No data and no details whatsoever was presented at the press conference held on Dec 27, 2002. Furthermore, despite their claim to be the first human cloning company in the world, Clonaid published not a single research paper in any research journal regarding human cloning - or even on mammalian cloning. That means Clonaid have no track record to prove this claim.
Worldwide scientific community has rejected this claim for various technical reasons. Rudolph Jaenisch, a cloning expert at the Whitehead Institute of MIT, says the claim is irresponsible and repugnant, and ignores the overwhelming scientific evidence from seven mammalian species cloned so far.
“It is not responsible at this stage to even consider the cloning of humans,” he said. Janeisch also said that even if a human clone appears healthy, it might not remain so once it gets older. He insisted that cloning a human at this point, without knowing more about why things go wrong, is “essentially using humans as guinea pigs, and one shouldn’t do this.”
Criticizing the human cloning announcement from Clonaid, a cloning expert at the University of Missouri, Dr Randall Prather said, “In animal work so far only about 1 to 5 per cent of cloning attempts succeed. That is, for every 100 eggs, one to five clones are born. Is it possible in humans? Potentially. Have we seen problems with cloning domestic animals? Yes. Do we understand what causes those problems? No. Therefore we shouldn’t do it.”
Dr Tanja Dominko, another expert and former primate cloning researcher at Oregon Regional Primate Research Centere, recalls that her team spent three years on monkey cloning and made more than 300 attempts with no success. She and her colleagues never got a single pregnancy. Instead, the cloning efforts produced extremely abnormal embryos, some with cells having no chromosomes; some with multiple nuclei (one cell had nine nuclei). About the the Clonaid claim, Dr Dominko promptly said, “I would be really, really surprised if it stands. I don’t believe it for a minute.”
Dr Jacques Cohen, the scientific director of assisted reproduction at St Barnabas Medical Centre in New Jersey, said, “If I did not know about the difficulty researchers had trying to clone monkeys, I would have thought that humans would be easy to clone because fertility experts have spent years perfecting techniques to handle human eggs in the laboratory and to grow human embryos for a few days in a lab. But the monkey work gave me a pause.”
Despite being optimistic, Dr Robert Lanza from Advanced Cell Technology (ACT) is not convinced: “I think that we should not dismiss them outright. I think that we do have the technology at present to clone human embryos and it may be a lot easier than many scientists think. But without any scientific data one has to be very, very skeptical. This is a group that has no scientific track record. They have never published a single scientific paper in this area; they have no research experience in this area. In fact, they have never even cloned a mouse or a rabbit. I have to say that I think this is appalling and scientifically irresponsible.” Dr Lanza got the fame when he cloned human embryos consisting of 6 to 8 cells back in late 2001.
Having mentioned the criticism from the science community, it is time to look at the technical reasons against human cloning.
Cloning embryo
The major problem in mammalian cloning is to obtain working egg cells. It becomes even more difficult in humans. An ordinary woman can produce 1-2 egg cells at a time. For in vitro fertilization (IVF) — commonly known as the procedure of “test tube babies” — a number of human egg cells are required. Using hormonal doses, a maximum of 12 to 15 eggs are produced at a time; later they are separated by surgery. Embryonic cloning by ACT, as mentioned above, involved 7 women to get 71 egg cells. Another crucial stage after obtaining egg cells is to successfully get a human embryo. ACT team could make only eight embryos out of 71 egg cells. Only two out of the eight embryos could reach the four-celled stage while only one of them could grow to the six-celled stage. It is important to mention here that the embryonic cloning effort from ACT only partially succeeded - even after third attempt. On the other hand, to be completely successful, an embryo must reach the blastocyst stage — that is, an embryonic stage consisting of 100 to 200 cells.
In the experiments of Dolly (the first successfully cloned mammal), only 29 successful embryos could be obtained out of 277 egg cells. Later, in the year 2000 (during the first cross-species cloning experiments resulting in the birth of a cloned gaur — Asian bull) only 42 healthy embryos could be obtained out of 692 egg cells.
So it is obvious that mammalian cloned embryos have an extremely low rate of success. General success rate remains only one per cent while the best ratio is 5 per cent (in mouse cloning).
Birth rate and death
After the successful cloning of embryo, the next thorny stage is the transfer of embryo in the uterus, having pregnancy and finally having a birth. Even in assisted reproduction (in vitro fertilization), most of the embryos are wasted during the process of transplantation.
The bleak picture emerges from the experiments of mammalian cloning. Most of the cloned pregnancies, soon or later, are aborted. A survey of mammalian cloning efforts reveals that, back in 1998, only 31 living mice were obtained out of 2468 embryos, which is by far the largest number of born-cloned mammals in any experiment. It makes the success rate only 1.3 per cent. Furthermore, 20 mice died when they were young. Similarly, in early 2001, cloned gaur died only two days after its birth. In March 2001, three cloned calves were born. First calf died only 12 days later, second one died after 15 days while the third calf (which was apparently healthy) could survive only a couple of days more than other two clones.
According to the mammalian cloning experts, early deaths of cloned mammals are very common. For the various reasons, they can’t survive longer.
Immune system and health
As we have seen above, despite the apparently good health conditions, a cloned mammal faces a number of complications such as problems in respiratory and blood circulation systems, weaknesses in immune system, kidney failure, immune deficiencies, retarded brain growth, etc.
Scientists have identified some genes that influence normal biological systems in mammals and cause the problems mentioned above. But there are other factors as well. For example, Telomeres (molecular caps on the tips of chromosomes, which become thinner and thinner as a mammal grows old) have a pivotal role in the process of aging. Dolly faced arthritis when she was only two years old, while the disease strikes a normal sheep at the age of about five to seven years - that is, at the old age from a sheep’s point of view. Put in easier words, one can say that Dolly was five years old at the time of her birth (because she was cloned from an adult sheep with the age of five years).
In the light of these facts, if Clonaid’s claim were correct, then the newly born baby girl would be 30 years old at the time of her birth - because she is a clone of a 30-year-old woman. And, if she lives to maturity - biologically speaking - she will actually be in her 50s despite having been born twenty years ago. It is also important to note that a genetic change in body cells may result in some unknown deficiency, or a horrible disease. What will happen in future, no one really knows at the moment!
Evolution suppression
It is said that cloning will give us more capable plants and animals in a greater quantity. In other words, cloning may give us a sort of “quality control” over the flora and fauna. But, on the other hand, it will also suppress the process of evolution. Every new living organism (from single-celled microbes to multi-cellular and complex mammals) produced through the natural means of reproduction contains different order of genes in it. Therefore, it may also have positive or negative characteristics as well. On the contrary, a clone will have very similar genes and characteristics to that of its original. It is now known that the new genetic makeup, resulting from the natural process of reproduction, also causes better brain-related abilities. These abilities are very important for the survival in the present age. One can easily conclude that cloning will stop the process of natural selection and resulting evolution.
Spreading epidemics
Last, but not the least, because of suppressed evolution, cloned humans will have a lesser potential to fight new diseases. Their immune system will be quite weak to stand attack from an ordinary ailment. The situation might get even worse with the developments in transgenic technology. (Using this technology, genes taken from one species are put in another, different species. For example, scientists are now trying to grow cows, sheep and goats that will contain certain human genes.) It may familiarize non-human proteins and viruses to human proteins and there is a great risk of new epidemics associated with transgenic technology. Normal humans have an adaptive immune system, which has a great potential to fight new diseases. But, as we have seen, cloned humans will certainly become a vulnerable target of such epidemics with, perhaps, no hope of survival.
Syed Salahuddin Qadri
Opening the Pandora’s box
On Feb 24, 1997, history was made when a group of scientists at Scotland’s Roslin Institute proclaimed successful reproduction of a sheep named Dolly using DNA from a single adult sheep cell. It may be true that history repeats itself but when it comes to technology there is no looking back, and the cloning of the first mammal initiated the race to create human clone. Today, the notion of cloning a living human raises fantastic thoughts for everyone.
This genetic engineering technology evades the intrinsic process of reproduction, in which the male sperm impregnates the female egg. Whereas the process of human cloning requires an embryo to be created by transplanting the DNA-containing nucleus of a man’s sperm into a woman’s ovum whose nucleus has been removed.
Although Las Vegas-based Clonaid’s claim of creating Eve, the world’s first cloned baby, is still knocking at the media doors to make history, it has already prompted furors from all corners. Unyielding to the wild commotion and the urgent demands for scientific proof, Clonaid is now trumpeting the success of its second clone and beginning the countdown to an expected third cloned baby later this month.
It appears that Clonaid is in race against the Italian fertility doctor Severino Antinori to produce the first baby clone. Earlier Dr Antinori had claimed that one of his patients would give birth to a baby clone in January.
Most leading scientists around the world have already said that they would not believe the claims until they have seen independent proof. So far, Clonaid has not supplied any proof for its claim and even the place of the supposed birth has been kept secret. Although, the company had promised to put forward the evidences in a week’s time which, so far, it has failed to provide, and has only been successful in gaining publicity for a cult which thinks that humans are aliens.
Dr Harry Griffin of the Roslin Institute in Scotland, where Dolly the sheep was produced, says: “Clonaid have made claims of two births, but of yet provided no evidence that either baby exists, no evidence from DNA tests, and as yet, therefore, there is no reason to believe this is anything other than a long, drawn out publicity stunt.”
Eastablished in 1997, Clonaid is linked to the Raelian religious sect which was founded in 1973 in France. The group believes that humans were created by extraterrestrial beings who had mastered genetic engineering. And it seems that the group’s desire to clone humans results from their belief that the human soul perishes when the body dies, and that the key to eternal life is not the soul but the recreation of individuals from their DNA.
The DNA to be cloned was taken from the mother’s skin cell, Clonaid said. Most scientists doubt Clonaid’s ability to clone a human and their motives, pointing to the company’s intention to charge around $200,000 for each cloned child.
According to Griffin the high success rate claims in its human cloning experiment defy years of research into cloning in other species, such as that of cattle, sheep, pigs, goats, mice, and rabbits.
The previous experiements to produce live birth with the embryos of these species have often failed. Mostly the clone died shortly after birth, or they developed serious health problems later in life, “and there’s no reason to believe that similar problems will not arise in the cloning of a child,” he says.
He further says, “I think its entirely unacceptable for groups like Clonaid to be gambling with the health of children,” he said.
Perhaps, the safe cloning technique is around the corner or it might take many years yet, time will tell. Even if there is a possibility, it will take a place as potentially the most valued and powerful technique in the history of future medicine. However, at present, the scientific truth is that even we do not know what we are doing, it is the only suffering that is outweighing the benefits.
If at all the cloning claims are authentic, what will be history’s view of Eve? Probably, it will also record compassion and sympathy for the innocent newborn. — Asif Noor Shoro
|
|
