Can Human beings be Cloned?
Cloning humans 'easier' than animals (1)
In the middle of the year 2001 a group of scientists said cloning humans might be easier than cloning animals. They were optimistic based on the research carried out into human genetics. However experts in Britain criticized their conclusions. An Italian fertility doctor, Dr. Severino Antinori announced his intention to clone humans, so that he can help infertile couples to have children. Many scientists were dismayed and scientists involved in animal cloning warned of the many practical problems in cloning. For example many clones die early or they are born with genetic deformities, and develop terminal illnesses such as cancer.
Scientists at Duke University Medical Center in North Carolina say the reason of all these problems may be one specific gene, which is responsible for controlling the way in which cells grow. When this gene is not working properly, cells can grow in an uncontrolled way to cause cancer tumors to develop.
In normal sexual reproduction a copy of this gene is passed from each parent to the offspring. But in many animals other than humans, one of these genes is turned off.
The cloning process affects the remaining active gene; it cannot work properly, and so the cloned embryo grows in an uncontrolled way.
For example, in sheep less than one embryo in 300 develops normally. Even the world's most famous sheep clone, Dolly, who died recently suffered from problems linked to this gene. Also she aged rapidly and was overweight.
Dr. Randy Jirtle of Duke University told that he and his colleagues found this genetic difference while looking at the evolution of genes. According to them this difference arose about 70 million years ago to help control the size of babies in the wombs of very early human ancestors. The researchers also say finding that the gene works in a different way in humans from animals such as rats and mice has raised questions about large areas of medical research. One example they say is that many drugs are rejected because they cause cancer in these animals. Medical Research should take a look at it t again.
The findings are published in the journal Human Molecular Genetics, but have been criticized in Britain. "It seems that a little knowledge is a dangerous thing, and the authors have allowed themselves to over-interpretate their interesting results," said Professor Ian Wilmut of the Roslin Institute, in Edinburgh, leader of the team, which cloned Dolly the sheep. "I hope that this will not be used to give encouragement to those who wish to clone humans," he said.
Dr John Parrington, a cloning expert at University College London, pointed out that more than one gene behaved in a way that might cause problems in a growing cloned human embryo. "You can't say, taking this information in isolation, that it's easier to clone primates and humans," he said.
Problems in Cloning People (2)
On April 11, 2003, Washington Post Staff Writer, Rick Weiss, reported "New research suggests that it may be a lot harder to clone people than to clone other animals, an unexpected scientific twist that could influence the escalating congressional debate over human cloning and embryo research."
Researchers Find Replicating Primates Is Harder Than for Other Mammals
"The new work by scientists in Pittsburgh provides an explanation for why hundreds of attempts to clone monkeys have all failed despite successes in several other mammals. The scientists said they suspect that similar roadblocks exist for all primates -- the evolutionary grouping that includes monkeys and humans."
In the light of this information, Congress could settle for less stringent restrictions on embryo cloning studies, which scientists favor. The newly discovered obstacle makes it more likely than ever that rogue scientists' recent claims to have created cloned babies were fraud.
But opponents of human embryo research were afraid that the new research not only identifies previously unrecognized hurdles to human cloning, but also points the way to overcoming those hurdles. They noted that the scientists could come up with a potential way to get around the problem.
"This report is bad news for the unethical charlatans who have been preying on people by claiming they are able to clone people's loved ones," said Gerald Schatten of the University of Pittsburgh School of Medicine, who led the new study in April 11, 2003 issue of the journal Science.
Scientists want to make cloned human embryos to get embryonic stem cells, which live inside early embryos and have the potential to cure a wide array of diseases. Many in Congress support a proposed ban on such research, however, in part because of fears that a cloned human embryo, once made, might be transferred to a woman's womb to develop into a cloned baby. But this will not be so easy. The team discovered a major roadblock to primate cloning by studying what went wrong in their more than 700 attempts to make cloned monkey embryos -- each of which failed spectacularly in the earliest stages of embryo development.
They started out using standard cloning methods, in which a single cell from the monkey to be cloned was fused to a monkey egg cell whose own DNA had been removed. In sheep, mice and other successfully cloned animals, substances inside the egg cell act upon the DNA in the fused cell, reprogramming the genes in a way that makes the cell "think" it is an embryo cell. That cell then begins to divide, one into two, then two into four, eventually forming a new embryo that is genetically identical to the animal that donated the original cell.
Although Schatten's monkey embryos looked normal on the outside, they always failed to develop after the first few cell divisions. Only on close inspection did the cause become apparent: Instead of each cell having a normal number of chromosomes -- the sausage-shaped collections of DNA found in every cell -- some cells had lots of chromosomes and others had few or none.
Schatten's group found that the spindle proteins and molecular motors in monkey egg cells are so closely bound to those cells' DNA that scientists had been inadvertently removing many of them when they extracted the eggs' DNA in the first stage of cloning. As a result, the "tightropes" became chaotic and chromosomes drifted unevenly to the daughter cells.
Similar studies on cloned human embryos in Britain suggest the same phenomenon is at work in humans, Schatten said.
Even if scientists overcome the chromosome problem, it is unlikely that cloned monkeys or humans would develop normally. Most cloned animals -- even those with normal numbers of chromosomes in their cells -- die in the womb or soon after birth because of other problems, which remain unsolvable today, they said.
Because cloned human embryonic stem cells have so much medical promise, scientists favor legislation that would allow them to make cloned human embryos and outlaw only the creation of cloned babies.
Cloning: The Time is Near (3)
Dr. Panayiotis M. Zavos, the former University of Kentucky fertility expert who is hard at work trying to develop techniques that will lead to the full, reproductive cloning of human beings, claims he created a cloned human embryo from the cell of a patient who wants a child and that it grew to eight to 10 cells before he froze it for further study. Writing an essay, ''Human Reproductive Cloning: The Time is Near.'' for the June issue of Reproductive BioMedicine Online, Panayiotis Zavos said ''our team of scientific and medical experts has created the first human cloned embryo for reproductive purposes.''
The Raelians, a religious group that believes humans are clones of extraterrestrial beings, made a similar claim last winter but offered no proof. Most scientists believe their claim to be a hoax.
The non-controversial cloning research is therapeutic cloning aimed at using a person's own cells to develop treatments for degenerative and fatal diseases.
(1) (http://news.bbc.co.uk/1/hi/sci/tech/1491056.stm) Wednesday, 15 August, 2001
(2) Rick Weiss, Washington Post Staff Writer, WASHINGTON POST. April 11, 2003.
(3) The Courier-Journal, April 11, 2003, Louisville, Kentucky
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