#1Abstract: News of the cloned embryos immediately inflamed the debate over the ethics of human cloning. Advanced Cell Technology, a privately held company, is trying to patent its cloning technology as part oits for-profit ventures. But critics, particularly the Catholic church and anti-abortion groups, say such a business would immorally destroy thousands of human embryos. In parthenogenesis, an egg cell is treated with chemicals that cause it to start dividing into an embryo without fertilization by sperm. Advanced Cell Technology exposed 22 human eggs to those chemicals. After five days,six eggs had matured into blastocysts, a spherical structure that is a landmark in the early life of an embryo.
Scientists believe embryos created this way could mature long enough to be useful in medical treatment butwould be unable to grow to term. Both the cloned and parthenogenetically produced embryos had significant shortcomings. None developed stem cells, which can grow into any type of cell or tissue of the body. Advanced Cell Technology needs stem cells to produce medical treatments for patients. (Copyright, The Times Mirror Company; Los Angeles Times 2001 Allrights reserved)Full Text: A Massachusetts company announced Sunday that it had created cloned human embryos that were able to survive for several days, raising fears that someone could produce a cloned baby and rekindling debate on whether Congress should ban the procedure. Advanced Cell Technology Inc.
has no plans to produce cloned children, it said, but instead aims to use cloning to make new cells and tissues for people with diabetes, Parkinson’s disease and other ailments. The research, however, remains many steps short of what would be needed to create eithera cloned baby or human tissue for medical treatment. Still, it marks the first report in a scientific journal of a successful attempt to clone human life. A Korean team claimed in 1998 that it had produced a cloned human embryo, but the research was never published orconfirmed.
Michael West, chief executive of Advanced Cell Technology, said the work represented “the first halting steps” toward a new era of medicine in which disease would be cured by swapping a person’s faulty cells and tissues for new ones. “It looks like this is going to be possible, but this is obviously only a preliminary report,” West said in an interview. He said his team published early results because it wanted to remain “transparent” about its research amid the sweeping ethical debate over cloning. The research, which required no federal approval, appears in e- biomed: The Journal of Regenerative Medicine, a relatively new online publication. Scientific findings generally do not win credibility until they are published in a journal that subjects the data to review by other researchers. William Haseltine, editor of the journal and chairman of Human Genome Sciences Inc.
, a leading biotechnology company, said the cloning data were scrutinized by independent scientists with the same rigor that is used at traditionaljournals. News of the cloned embryos immediately inflamed the debate over the ethics of human cloning. Advanced Cell Technology, a privately held company, is trying to patent its cloning technology as part of its for-profit ventures. But critics, particularly the Catholic church and anti-abortion groups,say such a business would immorally destroy thousands of human embryos. “This corporation is creating human embryos for the sole purpose of killing them and harvesting their cells.
Unless Congress acts quickly, this corporation and others will be opening human embryo farms,” said Douglas Johnson of the National Right to Life Committee. Some critics say the company is hastening the arrival of cloned children, a prospect that they believe society has not fully considered or regulated. As the company continues to publish its research, these critics say, someone could eventually use it to create a cloned embryo and grow it to term in a surrogate mother. In a bipartisan vote in July, the House approved broad legislation that would criminalize cloning both as a way to produce children and as a medical tool. If the measure had already been law, West and his colleagues could be subject to jail terms of up to 10 years and $1 million in fines for the work they announced Sunday.
The Senate plans to take up the measure in February or March. Cloning critics said lawmakers should move sooner. “This is among the issues pushed to the back burner, or perhaps behind the stove entirely, by the events of Sept. 11,” said Richard Doerflinger, an official with the U. S.
Conference of Catholic Bishops, which opposes human cloning for any purpose. “The Senate has been acting as though thisis something way down the road that we can think about when we’re done with terrorism. . . . “But this announcement is a wake-up call that we have to deal with the ethical and social and legal ramifications of cloning right away.
” Prospects for the legislation are unclear in the Senate. Although there is widespread support for barring the cloning of children, some senators seem uncertain whether they want to outlaw a medical technique that might save lives. Senate Majority Leader Tom Daschle (D-S. D.
) said Sunday that he supported “cloning for research purposes. ” Still, he said the Advanced Cell Technology experiments were “disconcerting. ” “I think it’s going in the wrong direction,” Daschle said on “Fox News Sunday. ” The Senate sponsor of a broad anti-cloning measure, Sen. Sam Brownback (R-Kan. ), called for Congress to swiftly pass a six-month moratorium on all human cloning until the Senate can take up the issue more fully.
President Bush has criticized human cloning and praised the House ban. In its research, the Massachusetts company used two techniques to produce human embryos–cloning and a second process called parthenogenesis. In traditional reproduction, genes carried in the sperm and egg co-mingle to produce an offspring that has a unique mix of its parents’ qualities. Both of the Advanced Cell methods, by contrast, created embryos that were genetic copies of only one parent. The company obtained egg cells from seven female volunteers. It stripped the DNA from 19 egg cells and replaced it with genetic material from another person, also a volunteer solicited by the company.
The new genetic materialcame from either a skin cell or ovarian material called a cumulus cell. Seven of the eggs began to divide and grow. These early embryos were clones–offspring that carried genes from only one adult, the person who had donated the skin or cumulus cell. Two of them divided into four-celled embryos and one developed six cells before the growth stopped.
The growth occurred over a three- day period. West said the embryos were no longer viable and had been disassembled so that their cells could be studied. In parthenogenesis, an egg cell is treated with chemicals that cause it to start dividing into an embryo without fertilization by sperm. Advanced Cell Technology exposed 22 human eggs to those chemicals. After five days, six eggs had matured into blastocysts, a spherical structure that is a landmark in the early life of an embryo. Scientists believe embryos created this way could mature long enough to be useful in medical treatment but would be unable to grow to term.
Both the cloned and parthenogenetically produced embryos had significant shortcomings. None developed stem cells, which can grow into any type of cell or tissue of the body. Advanced Cell Technology needs stem cells to produce medical treatments for patients. A wide array of researchers is trying to understand how stem cells grow into other cell types, such as insulin-producing cells for diabetics. Researchers may face a significant hurdle even if they can produce tissues from stem cells for human transplant. The patients might reject the newtissue as a foreign substance.
Advanced Cell Technology and a small group of other private companies say cloning could produce tissues that match the genetic makeup of individual patients. This tissue might be more readily accepted by the patient’s body. “Our dream is that someday we could take a patient’s cell, skin cell,and give them back anything that they needed to cure disease,” West said Sunday on NBC’s “Meet the Press. “Some critics said Advanced Cell Technology’s work, so far, is a failure,not a triumph. “It seems that if you take eggs and don’t develop them beyondthree days, they don’t have success,” said Alexander Capron, a USC professorof law and medicine. He said the experiments also failed to show that cloned human embryos are free of genetic defects, a point that the company itself acknowledged.
Caption: PHOTO: “Our intention is not to create cloned human beings,” wrote Dr. Robert Lanza, a researcher with Advanced Cell Technology. ; PHOTOGRAPHER:ReutersCredit: TIMES STAFF WRITERReproduced with permission of the copyright owner. Further reproduction or distribution is prohibited without permission. =============================== End of Document ================================The following article has been sent by a user at SANTA BARBARA CITY COLLEGE via Proquest, an information service of the ProQuest CompanyThe First Clone ; Scientists have finally cloned a human embryo.
The breakthroughpromises cures for terrible diseases. Here’s the inside story:#2Abstract:Robert Lanza, Michael West, and Jose Cibelli have finally cloned a human embryo, and many claim that this scientific breakthrough could produce cures for diseases like diabetes and for the ravages of aging. Lanza, West, and Cibelli are profiled, and their belief in human therapeutic cloning is discussed. Copyright U.
S. News and World Report Dec 3, 2001Full Text: Physically, Judson Somerville didn’t feel a thing. When he took the cigar-cutter-like tool and clipped a chunk of skin cells from his right calf last April, there was no pain. The 40-year-old Texas physician hasbeen using a wheelchair for years, paralyzed from the chest down, the result of a terrible cycling accident.
But emotionally, that was another story. Cutting the skin from his calf, Somerville says, he felt the thrill ofbeing a sort of astronaut, a pioneer. By donating his skin cells, Somerville was volunteering for nothing less than service on the frontier of human cloning. Somerville did not make the decision lightly. As a conservative Republican, a longtime contributor to President Bush, Somerville knows how controversial cloning is for many of his political compatriots. Buthe is also a devout Episcopalian.
After consulting with his church leaders, Somerville concluded that being one of the first humans to be clonednot to produce a baby, which he would never do, but to create healthy new cells for ailing patients–would be one of the best things he could do for his fellow man. His decision wasn’t completely selfless, however. Neurons derived from his own cloned embryo could end Somerville’s paralysis. “My 14-year- old daughter doesn’t want me getting her wedding gown caught up in my wheelchair,” he says, laughing. “So when the day comes, she’s counting on me walking her down the aisle. ” Now, Somerville may be a step closer to that walk, and humanity is moving into uncharted medical and ethical territory.
Since the 1997 announcement of the cloned sheep Dolly, scientists around the world have been trying to duplicate and advance the work in a variety of species from mice to monkeys. Some have succeeded, but many more have been thwarted in their efforts. A few researchers had even set out to clone humans, without success. But this week, scientists at Advanced Cell Technology, a small biotechstart-up company in Worcester, Mass. , are announcing that they have done just that–successfully engineered the world’s first cloned human embryo. ACT is the only laboratory on U.
S. soil that has acknowledged working on human therapeutic cloning. But other than being called to testify before Congress on these issues, the company’s leadership and its scientists have not publicly elaborated on their human-cloning efforts–until now. Over the past 18 months, U. S.
News has reported from inside the ACT laboratory, with exclusive access to the cloning scientists and their laboratory work. In a highly technical paper in the Journal of Regenerative Medicine, the scientists now describe their laboratory success–the transfer of human DNA into human eggs and the growth of those eggs into six-cell embryos. What that scientific paper doesn’t describe, and what U. S. News documents here, is what went on in the hearts and minds of the people behind this achievement and the many setbacks and adjustments that preceded the final success. The accomplishment presents huge challenges to every premise of scientific, religious, and legal thought.
Given the intensity of last summer’s national debate over human embryonic stem cell research, ACT’s work is sure to become a lightning rod for conservative critics when the issue is taken up again in the months ahead. It will be condemned as an ethical abomination akin to playing God and described as the creation of embryos for spare parts. It will also be hailed as the hugest medical breakthrough of the past halfcentury–an accomplishment that could cure many diseases of aging and provides hope for people like Somerville. The story of ACT’s breakthrough is largely the story of three men, from very different backgrounds, who came together to stake their scientific careers on this controversial enterprise.
Here’s how, against the odds,they pushed the world into the age of cloning: The instigator Jose Cibelli’s ambitions started out simply enough. Raised on the Pampas of Argentina, the talented young researcher just wanted “to do something for the farmers. ” So after obtaining his degree in veterinary medicine, he married his high school sweetheart and headed to the University of Massachusetts-Amherstto get his Ph. D. There he quickly became a star student in the lab of James Robl, who was doing work on so-called transgenic animals–cattle, for example, with improved genetic properties that yield higher-quality meat or milk. By the summer of 1996, Cibelli was on the fast track to becoming a majorplayer in agricultural genetics.
But a Massachusetts Institute of Technology conference on cell therapies changed his life. Researchers there were presenting disappointing results in an experimental technique to cure Parkinson’s disease in humans. Young, healthy fetal cells were injected into the damaged parts of patients’ brains. But little long-term improvement had been seen. In the car on his way home that evening, Cibelli could not shake a nagging thought: Of course the cells didn’t work so well. They weren’t the patients’ own cells.
Working under Robl, Cibelli had already joined Advanced Cell Technology to focus on cloning prime specimens of cattle. If you could reproduce a cow’s cells, Cibelli reasoned, you could use the same method to endlessly multiply a given patient’s cells to replace any of those in the body that were worn out or diseased. In an instant, Cibelli saw “the future of medicine. ” Therapeutic cloning– for humans–became his calling.
There were obstacles, though. One was the scarcity of human eggs from women willing to donate them for experiments. But, Cibelli surmised, if you removed the DNA from a more readily available egg– say, from a cow’sit might be possible that the proteins and enzymes left would be the sameones that rejuvenate and multiply cells in humans. To find out, he scraped cells from the inside of his cheek.
He grew the cells in a culture, then inserted their DNA into a cow egg that had been rid of its bovine genetic code. Most researchers were skeptical. Cibelli had his own doubts, too. “But so often, people give up and declare something impossible after 800 tries,” he says. “When on the 900th try they would have figured out how to make it work.
” Cibelli kept at it. After implanting cow eggs with his own DNA over and over again, he and Robl were about to toss yet another petri dish full of failed cloning attempts when they spied a rudimentary embryo. It was a round ball containing a cluster of stem cells, the primordial body cells that are capable of becoming skin, liver, nerves–and every other cell in the body. The news spread fast in the biomedical community. Cibelli couldn’t reproduce the results, and he abandoned the use of cow eggs as a dead end. But the feat captured the attention of the man who would play a key role in making Cibelli’s dream a reality.
The visionary Michael West by his own admission, is “an absolute obsessive- compulsive”who views life as a mission. A self-described political conservative, he was in his early years a creationist, and he trained as a paleontologist with the goal of proving the Bible’s account of God’s design. But as hestudied the fossil record, instead of finding God’s divine plan, he found an endless account of disease and suffering. Out of that bleak vision he developed a new spiritual fervor: “If God is about love and life,” he says now, “then we should do everything we can to end suffering and death.
” So in his early 20s, West knew his holy grail: to conquer aging and death–a goal so stunning in its scope that many colleagues over the years have discounted him as a quixotic dreamer. “When I talk about ending aging, I’m not talking about some vain fountain of youth,” he explains. “I’m talking about ending the suffering of aging: macular degeneration, cancer, Alzheimer’s, heart disease. ” After getting his Ph.
D. in biology, West enrolled in medical school but was too impatient with the establishment to finish. Instead, he reincorporated his late father’s truck-leasing business as a biotech firm called Geron (Greek for “old man”), committed to ending the ravages of aging. Enchantedby findings that each body cell has an ever shortening fuse called a telomere that signals a cell to age and die, West poured all his energies into finding a way to keep extending the fuse to give a cell endless life. It took seven years, but his company did eventually identify telomerase, the enzyme that replenishes telomeres.
(And he ended up marrying the Geron scientist who cloned the gene for telomerase. ) Telomerase alone proved not to be enough to reverse aging, and West became fascinated with work on newly discovered stem cells. West immediately recognized that stem cells had the potential to rejuvenate aging bodies, and he quickly began funding scientists who ended up isolating the firsthuman stem c ells. But as Geron grew, its board became more and more uneasy with West’s controversial interests, and West despaired at the company’s lack of support for his vision. In early 1998, he left the company he had founded and lost access to the intellectual property he had created on telomerase and humanstem cells.
It wasn’t long, though, before West caught wind of Cibelli’s cloning feats, and he immediately seized on the concept as one far superior to producing “generic” stem cells. (Generic stem cells, derived from humanembryos, are the kind that President Bush agonized so publicly over last summer before deciding to fund limited research on the cells. ) But, West wondered, why would you treat patients with cells from an embryo donated from an in vitro fertilization clinic– with another person’s cellswhen you could give patients their very own cells? In a flash, West was in talks with Advanced Cell Technology–at that time an agricultural genetics companyand within the year became CEO, then owner of the venture. Both Cibelli and West knew from the start that they would need to race to form useful therapies before controversy overshadowed their efforts.
Because no new treatments can be given to humans without first being tested in animals, Cibelli and West needed someone with connections in the researchworld who could get those studies up and running right away. As it turned out, that person was working just a mile or so down the road. The activist Robert Lanza is the living embodiment of the character played by Matt Damon in the movie Good Will Hunting. Growing up underprivileged in Stoughton, Mass. , south of Boston, the young preteen caught the attention of Harvard Medical School researchers when he showed up on the university steps having successfully altered the genetics of chickens in his basement.
Over the next decade, he was to be “discovered” and taken under the wing of scientific giants such as psychologist B. F. Skinner, immunologist Jonas Salk, and heart transplant pioneer Christiaan Barnard. His mentors described himas a “genius,” a “renegade” thinker, even likening him to Einstein.
With a gift for enticing the world’s top inds, Lanza managed as a medical student to extract essays from the likes of C. Everett Koop, Boutros Boutros-Ghali, and Linus Pauling, which he compiled into a book sounding warning bells about the declining chances for health and survival of the species over the coming century. Lanza focused his laserlike intellect on transplant medicine and tissue engineering. For 20 years, he worked to cure diseases such as diabetes and leukemia through infusions of new cells and organs from donors. “But for 20 years, I hit my head against the same thing over and over again–rejection, rejection, rejection,” says Lanza.
Using strong drugs to prevent patients’ immune systems from attacking the foreign cells, Lanza says, the cure wasoften worse than the disease. “Even with the drugs, I watched too many children have first their fingers amputated, then their hands, then their arms. ” When Lanza discovered that it might be possible to clone a patient’s own cells, he felt that he finally had the solution he’d spent decades searching for, and in March 1999 he signed on as Advanced Cell Technology’s director of medical research. With characteristic chutzpah, his first act upon joining the company was to persuade 67 Nobel laureates to sign a letter to then President Clinton in support of human embryonic stem cell research. Like his newfound colleagues West and Cibelli, Lanza knew that human therapeutic cloning would haveto prove its ability to revolutionize medical care as fast as possible, before political and ethical controversies swamped the whole enterprise.
The controversy In the spring of 1999, ACT’s new troika sat down to discuss just how to venture into what’s arguably the most controversial area in medicinetoday. “We knew that we would have to fend off attacks,” recalls Lanza. “But we never imagined all the insanity that would come. ” Over the course of the next two years, the men would be called “mad scientists,” “baby killers,” and “monsters”; their names would be added to antiabortion “assassination”lists on the Web; the FBI would warn them of threats on their lives, and conservatives would push a bill through the House of Representatives declaring them federal criminals deserving of 10 years in prison and a $1 million fine. The source of the hysteria is a widespread misunderstanding of just what an early embryo is, according to West, Cibelli, and Lanza. “If you ask the average person, they will tell you it’s a tiny little person withbuggy eyes,” says West.
“But, in fact, these are just a few reproductive cells, not much different than eggs or sperm. They are the raw materials of life, but they are not a person. ” Most scientists agree. During the first 14 days after an egg is fertilized the group of cells is known as a “preimplantation embryo.
” In nature, themajority of these pass from the body without ever attaching to a woman’s uterus and developing further. If one truly believed that these were individual human lives being lost, argues Ronald Green, director of the Ethics Institute at Dartmouth and chairman of ACT’s bioethics committee, then this should be considered a huge public-health crisis, and there would be a massivemedical campaign launched to save these “lives. ” Moreover, these preimplantation embryos often split off to become two or more entities or, conversely, two groups of the cells sometimes merge together. And currently, there are an estimated 1 million of these early embryos left over worldwide fromin vitro fertilization procedures, poised to be discarded. Religious leaders have changed their minds many times over the years about when life begins.
Some religions say it begins at conception; somesay after 40 days of development; others say at the “quickening,” when fetal movement can be felt; and others say not until birth. An Episcopal bishop advised Judson Somerville that cloning his cells would not constitute creating a human being. “These are my cells being multiplied in a lab, not those of some other human being,” concludes Somerville. Still, the “pre-embryos,” as many call them, if implanted into a woman’s womb, do have the possibility of becoming a human being, which makes some ethicists uneasy about the idea of creating them in the first place.
“Many people do not consider embryos to be human beings, but they are also not just another cell or bit of tissue,” social critic Francis Fukuyama wrote in a recent Wall Street Journal essay. “Research cloning would get us accustomed to the idea that human life in its early stages should be treated like any other pharmaceutical product. ” Yet, because of advances in science, we are fast approaching a point when any given cell has the potential to be developed into a human being, given the right chemical tinkering. “Tocommit ourselves morally to protecting every living cell in the body would be insane,” counters Green. “Research advances are making all cells ’embryonic,’ ” adds Lanza. “But if you consider those cells a human life, then 100 souls are lost every time I sneeze.
” All three men are adamant that they are following the most moral path. “Three thousand Americans die every day of diseases that therapeutic cloning could treat,” says Lanza. “It would be wrong of us to abandon those people because we’re afraid of controversy. ” West is even more graphic about his beliefs. “I feel as if all my loved ones are trapped in a burning building, dying of diseases like diabetes and heart disease,” he says.
“I have the fire extinguisher– the therapeutic cloning technology–that can save them, but people are trying to take it out of my hands. ” And Cibelli is disgusted with the brouhaha. “Therapeutic cloning has to be done, and soon,” he says. “Patients are all waiting for the public to get over the hype and fearfulnessso that they have a chance to live. ” All three are equally insistent that cloning for reproductive purposes is completely unethical, because the risks to both child and mother are too great.
In fact, West considers the Raelian cult and other groups thatclaim to be working on cloning an actual human being to be his company’s worst enemies: Any success could scare the public enough to sink ACT’s efforts at providing new medical cures. The effortBecause of the hostile climate, it took nearly two years for Cibelli to even begin the experiments. During that time, the partners searched for members to serve on an ethics board and debated how to best go about getting donors for both body cells and human eggs. Should they ask ChristopherReeve to donate his cells’should Cibelli’s willing wife donate her eggs? The questions and concerns seemed endless.
One major turning point came in late September of 1999, when Cibelli met with Harvard professor Ann Kiessling, who agreed within five minutes to help set up a program to collect eggs from women. Another breakthrough came in mid-2000, when Dartmouth’s Green agreed to head ACT’s ethics advisory board. Under their leadership, very strict guidelines were set up for the collection of eggs and body cells, which finally began early this year. The pace was maddeningly slow.
While scientists working to clone cow eggs might have 1,400 to work with at a given time, and those working withmice could easily have 2,000 eggs on hand, the number of human eggs available to the lab was minuscule. The researchers hoped to collect about two dozeneggs a month from donors, but even that was an ambitious goal, and whenthe eggs did arrive, there were often only five or 10 to work with. With precious human eggs too few and far between, Cibelli spent his time between deliveries practicing the transfer of nuclear DNA from a half-dozen or so body cell donors into cow eggs just to perfect his technique. Often he would return to the lab late at night, after playing with his two daughters and putting them to bed, to work uninterrupted by daytime office demands.
That’s where he was at midnight on August 9, after President Bush announced that he would allow limited federal support for stem cell research but opposed human cloning even for research purposes. Driving his daughters home from a trip to choose a new puppy, he hadn’t quite heard over theburble of his girls’ banter Bush’s description of research cloning as “growing human beings for spare body parts. ” But transfixed at the microscope, Cibelli knew he was racing the clock to show therapeutic cloning’s benefits before the work was declared criminal. “It’s hard to describe why this work is so important, why I would go anywhere in the world to do it,” he mused.
“It’s just that there is nothing else in all of medical research that is anywhere near this promising. ” And that’s where he was at 3:15 a. m. on October 10, after removing the DNA from several human eggs, injecting them with DNA from body cells, and then tricking the eggs into thinking they had been fertilized so that they would begin the work of multiplying (graphic, Page 57).
But this time, Cibelli left the lab in a depressed mood. The eggs looked a little sickly, and he was convinced he had damaged them beyond repair. But when he called two days later from Michigan, his lab assistant gave him the news he hadbeen wanting to hear for almost five years: The eggs were cleaving into the world’s very first known human cloned embryos. The ramifications They were only clusters of four and six cells, but in them ACT’s scientists saw a revolution in medicine that will render many of today’s drugs and treatments obsolete. Essentially, cells yielded from human research cloning are the same stem cells that President Bush decided are promising enough to fund, only better.
Unlike existing stem cell lines, stem cells created through cloning would provide a patient with a fresh supply of cells with his or her own genetic code. Gone would be transplant failures and the need for immune-suppressing drugs. In the same way that antibiotics and vaccines rid the world of infectious plagues a half century ago, says Lanza, these cells could for the first time eradicate the chronic, degenerative diseases of our day, such as cancer, Alzheimer’s, and heart disease. “I watched diabetes destroy my mother, who got it at age 50, and then I came down with it 10 years sooner,” says Pablo Naumann, who has also donated body cells for ACT’s experiments.
“I really want to keep all my limbs intact and be a good father for my daughter as she grows up. ” Because body cells are rejuvenated by an egg’s proteins, therapeutic cloning would also tackle aging itself, replenishing the body with younger more vigorous cells than even the most healthy cells already in place. And because DNA removed from a body cell can be tinkered with before it is placed into an egg, Lanza hopes someday to add factors–genes for immune cells, for example, that would make a patient resistant to AIDS. To make these possibilities a reality in humans sooner, Lanza has forged partnerships with a number of prestigious labs to use therapeutic cloning to cure diseases in animals (box, Page 62). “We’ve already been able to turn cloned animal stem cells into large disks of bone, into beating heart cells, and whole dishes full of replacement neurons that could treat Parkinson’s disease,” says Lanza.
“We’ve also created new cartilage, skin, kidney, and heart tissue that was transplanted back into adult steers without rejection. This isn’t some futuristic dream. We are doing this right now. ” The dream has its detractors, and not just among politicians. Some biologists are set on avoiding moral issues by trying to coax adult stem cells back to an embryonic state.
Even James Thomson–one of the stem cell pioneers funded by West–believes that he may be able to tinker with the genetics of generic stem cells to make them less likely to be rejected, thus making DNA-specific matches unnecessary. But in the absence of a proven better alternative, to halt the work now, says West, would be like taking penicillin away from doctors in the last century. Indeed, many medical developments have been at least temporarily halted because of ethical qualms. Religious leaders found vaccines objectionable because they interfered with God’s plan for who should get sick, and in vitro fertilization was condemned in the 1970s by many of the same conservative ethicists who today oppose therapeutic cloning.
Organ transplants wereonce seen as objectionable. And recombinant DNA technology–the ability to create synthetic genes–was banned from top universities like Harvard and MIT for years, for fear that horrible and dangerous creatures would be produced. But much of the opposition melted when the technology was used to create a synthetic form of insulin to treat diabetics, and today recombinant DNA is used in virtually every research lab in the world. It’s still too early to say whether the United States will accept or reject therapeutic cloning. Cibelli and colleagues still have mountains of work ahead of them. It takes not just an embryo but the nurturing ofstem cells and the ability to transform those stem cells into specialized types before any clinical applications can be used in humans.
“I’m overjoyed, but I’m not getting drunk yet,” says Cibelli. “When I have neurons for Judson Somerville and islet cells for Pablo Naumann, that’s when I’ll celebrate. ” If history is any guide, that is also when the public attitudes will warm toward this new and intimidating medical technology. The art of cloning The idea behind cloning are simple: Remove DNA from an egg and replace it with the DNA from a body cell.
But actually getting that process to work is still as much a guessing game as an exact science, dependent on timing as well as technique. Here are some of the main challenges. THE STEPS; THE CHALLENGES (Step 1) Remove DNA from a human egg The Challenges (A) A human egg is very fragile. It can take hundreds of tries to extract the 2 meters of chromosomes with a microscopic needle without destroyingthe egg. (B) There is a tiny window of time–just a few hours–during which an egg can be prepared for cloning.
Then the egg loses its ability to repair and regenerate DNA. (C) If one too many drops of cellular material are accidentally removed along with the DNA, the egg can be rendered useless. (Step 2) Deliver new genes into the eggThe Challenges (A) No one knows which body cells are the most amenable to cloning. The easiest cells to get from donors–skin cells–are not ideal because they are very large and hard to work with. (B) Some scientists use an electric current to fuse an entire body cell into the egg cell, but the line between too little and too much current is perilously thin. (C) Other scientists take the genes out of the body cell and inject them into the egg, but the chromosomes are often damaged by the process.
(Step 3) Trick the egg into action The Challenges (A) No sperm is involved in cloning. So scientists must find another way to make the egg think it has been fertilized. (B) Some scientists use an electric current to make the egg grow. Othersuse a mixture of chemicals.
But it is all too easy to kill the egg witheither method. (C) There appears to be only about a four-hour period during which anegg will respond to activation signals. Prodding the egg before or afterthat doesn’t work. (4) Collect stem cells The Challenges(A) Dozens of nutrient mixtures have been developed to help embryoniccells proliferate, but no one yet knows which is best.
(B) Biologists disagree about how much oxygen the growing cells shouldbe exposed to in order to develop the healthiest stem cells. (C) Stem cells must be separated from the other cells without damageand kept alive until they become a self-sustaining colony. (5) Get the stem cells to specialize The Challenges (A) Any one of thousands of different “growth factors” may be involvedin spurring a stem cell to become a brain cell or a blood cell. (B) Even if the right chemicals are found, the stem cells may not respondunless the chemicals interact with the cells’ DNA in precisely the rightsequence. (C) The body has over 200 types of specialized cells, and the recipefor growing certain types may remain a mystery for years.
Source: Jose Cibelli, Advanced Cell Technology MILESTONES IN CLONING February 1997 The first cloning of a mammal, Dolly the sheep, from an adult body cell is announced. March 1997 President Clinton bans federal funding of human-cloning research. 1998-2000 Researchers clone mice, calves, goats, and pigs. A bull is “recloned”from a cloned bull. April 2000 Scientists find that cloning can restore body cells to a youthful state. October 2001 The first cloned human embryos are created at Advanced Cell Technology’slab in Worcester, Mass.
Source: Jose Cibelli, Advanced Cell Technologymedical research director believes that cloning could end transplant rejection. (JONATHAN SAUNDERS FOR USN&WR); Picture: Michael West. The head of ACTis an entrepreneur with a mission: to find cures for the ravages of aging. (JONATHAN SAUNDERS FOR USN&WR)Reproduced with permission of the copyright owner. Further reproduction or distribution is prohibited without permission. =============================== End of Document ================================#4Abstract:So far, though, it is a curiously one-sided debate.
As the Senate considers legislation to ban any kind of cloning, either for reproduction or research, there appears to be widespread agreement that making babies by cloning is wrong. Even the company that conducted the experiment, Advanced CellTechnology, has come out against human cloning Still, cloning provokes a visceral reaction, and some of the nation’s most respected ethicists, including Leon R. Kass, an adviser to President Bush, contend that it is an affront to humanity. At the same time, the people who speak the loudest in favor hardly do their cause a service. They include grieving parents who want to bring back dead children and several maverick scientists — including one who believes in extraterrestrial visitors — who insist on pushing ahead despite evidence from animal experiments showing that cloning is not safe. That view, however, is unlikely to hold sway with Congress.
In July, the House of Representatives approved, by a broad margin, a bill that would make any type of cloning, including so-called therapeutic cloning for research, a crime. President Bush supports the bill, and as the Senate prepares to consider it, the biotechnology industry has come out against human cloning, apparently calculating that in doing so, it can preserve its research. Copyright New York Times Company Dec 2, 2001Full Text:small group of bioethicists were having dinner about a month ago when, out of the blue, one of them gingerly raised the topic of reproductive cloning. ”I don’t know how to say this,” he said, according to someone who was present, ”but in my heart of hearts, I don’t think cloning is inherently wrong.
” After a few nervous glances, the diners went around the table, each offering a similar confession. None saw human cloning as intrinsically evil or immoral. Few would say so in public, however. As the person who related this story said, ”It’s a little bit like the McCarthy period. There’s nobody on theother side. ” Ever since the birth of Dolly the sheep in 1997, the specter of human cloning — the creation of babies that are genetic replicas of adults — has loomed large in the public psyche, like a creepy science fiction movieabout to become real life.
Last week, a Massachusetts biotechnology company announced it had createdthe world’s first cloned human embryos, not for reproduction, but to make tissues for treating disease. All the embryos died, but the debate over human cloning is once again alive. So far, though, it is a curiously one-sided debate. As the Senate considers legislation to ban any kind of cloning, either for reproduction or research, there appears to be widespread agreement that making babies by cloning is wrong.
Even the company that conducted the experiment, Advanced CellTechnology, has come out against human cloning. Nonetheless, some legitimate scientists, bioethicists and advocates for infertile people have quietly put forth a defense of human cloning that has all but been lost in the din. If cloning could be made safe ( a bigif), these proponents say, it could bring the joys of parenthood to infertile couples, single people and gay people — in short, anyone who cannot now have a genetically-related child. The technique will not upend society, they say; nobody will use cloning to mass-produce a man like Saddam Hussein.
But it could help a small number of people, giving them children who, like children everywhere, bear an uncanny resemblance to one parent or the other. ”The only purpose that cloning serves, and I think people should be allowed to do it for this reason, is to let infertile people have children,” said Lee M. Silver, a professor of molecular biology and public policy at Princeton University. ”Everybody is afraid that this child is going to be a replica of the person cloned, and that’s not true,” Dr. Silver added, ”because people are more than their genes.
” Still, cloning provokes a visceral reaction, and some of the nation’s most respected ethicists, including Leon R. Kass, an adviser to President Bush, contend that it is an affront to humanity. At the same time, the people who speak the loudest in favor hardly do their cause a service. They include grieving parents who want to bring back dead children and several maverick scientists — including one who believes in extraterrestrial visitors –who insist on pushing ahead despite evidence from animal experiments showingthat cloning is not safe. ”The lineup of people who want to clone somebody is a bunch of losers,” said Glenn R. McGee, an assistant professor of bioethics at the University of Pennsylvania who has edited a book on human cloning.
”If you eliminated them, this would be a very different debate. ”The irony is that the best candidates for human cloning are the people who have no intent of making a clone,” Professor McGee added. ”They just want a way to make a baby. ” Were the issue not so politically charged, some fertility specialists might be willing to help them, although most think the market for human cloning is small.
The American Society for Reproductive Medicine, which represents fertility doctors, is on record opposing human cloning. But John A. Robertson,a law professor at the University of Texas and the chairman of the society’s ethics committee, has outlined a careful argument in favor. As a first step, Professor Rbertson said, he would allow cloning for thesmall number of couples who suffer ”gametic infertility,” such as a man who can produce no sperm.
Instead of using an unrelated sperm donor, he said, scientists could create an embryo by inserting DNA from the man into his wife’s egg. The baby, carried by the woman, would be a genetic replica of her husband. BUT that first step would inevitably lead to a second and a third, raising questions about who else should be granted permission to clone. Single mothers? Old people? Gay people? Professor Robertson’s plan is to ”deal with that later,” but another ethicist, Prof.
Gregory Pence of the University of Alabama, would open the door to everyone. ”As far as I can see,” Professor Pence said, ”there is absolutely noConstitutional basis for the government to tell you how you can originate children. If you decide to replicate Uncle Harry because he was brilliant and funny and lived until 90, I don’t see why somebody shouldn’t be able to do it as long as it’s safe. ” That view, however, is unlikely to hold sway with Congress.
In July, the House of Representatives approved, by a broad margin, a bill that would make any type of cloning, including so-called therapeutic cloning for research, a crime. President Bush supports the bill, and as the Senate prepares to consider it, the biotechnology industry has come out against human cloning, apparently calculating that in doing so, it can preserve its research. At least one senator thinks this strategy will work. ”I predict that Congresswill ban reproductive cloning, and I’m all for it,” Tom Harkin, Democrat of Iowa, said. ”If senators felt comfortable that there was a good solid iron door against reproductive cloning, then I believe you will open the door for scientists to move ahead with these therapies.
” In any case, not many people really want to clone Uncle Harry, or even themselves. Pamela Madsen, executive director of the American Infertility Association, a patient advocacy group, said most couples prefer ”that magic mix of him and her” — even if the mix comes from donated egg or sperm. And for those who are not infertile, having babies is simply more fun, and cheaper, the old-fashioned way. Ms. Madsen’s group has issued a statement opposing human cloning, not for philosophical reasons, but on the groundthat it is not safe. But she wonders if, decades from now, those looking back on all the noise and passion of the cloning controversy will find it all silly.
”Ever since I have been a child, what was considered impossible or immoral or unimaginable by some has become a part of regular life,” she said. ”Think about when we first started to do blood transfusions, or organ transplants and, yes, Louise Brown” — the first baby born by in-vitro fertilization. ”Every time we have made a leap that has benefited mankind, it has always been with a loud voice behind us saying, ‘You’d better watch out. ‘ ” Captioned as: Girls using a mirror to perfect their form in a dance class in a poor Rio de Janeiro neighborhood.
(Associated Press) Reproduced with permission of the copyright owner. Further reproduction or distribution is prohibited without permission. =============================== End of Document ================================The following article has been sent by a user at SANTA BARBARA CITY COLLEGE via Proquest, an information service of the ProQuest CompanyHuman-Cloning Firm Received Federal Aid; Biotechnology: A $1. 8- milliongrant awarded before disclosure of the controversial research. Home EditionThe Los Angeles Times# 5SEE CORRECTION APPENDED; Biotech companies–A story in Thursday’s Business misstated the size of ImClone Systems’ potential stake in Advanced Cell Technology, which resulted in an erroneous estimate of Advanced Cell’s market value. ImClone may convert its $1-million investment for an equity stake of just more than 3%.
That would give Advanced Cell a market capitalizationof about $30. 7 million. The story also misidentified Miller Quarles. The retired Texas oilman was an early investor in Advanced Cell but does notown a controlling stake.
Under Michael West’s leadership, the company has pushed itself to the forefront of human cloning. But animal cloning remains its chief businessthough it has produced little, if any, profit. Advanced Cell made a considerable investment in the business this year when it acquired a Pennsylvania dairy breeding company. But dairy farmers are a tough sell; they want betteranimals, not clones, said John Meyer, chief executive of the Holstein Assn. USA.
What Advanced Cell may lack in business success it has in media savvy. It assured itself a splash with its human cloning experiment by simultaneously publishing an West and his co-authors on the Scientific American piece called their own account in Scientific American and granting an exclusive to U. S. News and World Report. To be sure no one missed the significance,work “the dawn of a new age in medicine” that showed “therapeutic cloningis within reach.
“Advanced Cell said it isn’t interested in helping couples clone offspring. The firm said it created clones to extract stem cells, which can turn into any type of tissue and can be used to treat diseases such as diabetes. In Scientific American, however, West and his co-authors left the door to reproductive cloning ajar, a decision likely to inflame controversy. Due to potential health risks, they wrote, reproductive cloning is “unwarranted at this time” and should be restricted “until the safety and ethical issuessurrounding it are resolved. “(Copyright, The Times Mirror Company; Los Angeles Times 2001 Allrightsreserved)Full Text:SEE CORRECTION APPENDED; Biotech companies–A story in Thursday’s Businessmisstated the size of ImClone Systems’ potential stake in Advanced Cell Technology, which resulted in an erroneous estimate of Advanced Cell’s market value. ImClone may convert its $1-million investment for an equity stake of just more than 3%.
That would give Advanced Cell a market capitalizationof about $30. 7 million. The story also misidentified Miller Quarles. The retired Texas oilman was an early investor in Advanced Cell but does not own a controlling stake.
The Massachusetts company condemned by the Bush administration for its efforts to clone a human embryo received a federal grant last month to conduct biotechnology research. Advanced Cell Technology’s human cloning experiments set off a national controversy this week that is renewing demands that Congress ban all cloning of human cells. But before the cloning experiment was disclosed, the company was awarded $1. 8 million under a Commerce Department program intended to accelerate research and development in private companies, said Michael Baum, a CommerceDepartment spokesman. The company said Wednesday that the grant would not be used for any human cloning research. Rather, the money is to fund experiments into reprogramming adult human cells in an effort to develop therapies for diseases.
Both the adult cell research and the human cloning experiments are part of an effort by the company–whose main revenue source has been cloning cows–to break into the business of disease therapy. Thus, the federal funding represents an important capital infusion for the small company. But researchers and industry officials say administering such grants and keeping salaries, equipment and other expenses separate is a difficult accounting chore. It is one reason some universities that receive federal funds have moved embryonic research off campus, avoiding any potential for conflicts with allowable work under such grants.
The Commerce Department issued the grant under its Advanced Technology Program. Baum said the terms of the grant specifically forbid the company from using the federal money to conduct research on human cloning. “We have audit procedures in place to make sure that doesn’t happen,” Baum said. The biotechnology start-up reignited a furor over cloning this week when an online science journal published an account of the company’s experiment. The article in e-Biomed: The Journal of Regenerative Medicine said that the company created only a few clones, that all died and none consistedof more than six cells. President Bush condemned the experiment and Sen.
Sam Brownback, a Kansas Republican, vowed to push for a six-month ban on human cloning while lawmakes consider legislation calling for a total ban. The House passed legislation banning human cloning in July, but it moved to the back burner after the Sept. 11 terrorist attacks. As a privately held company, Advanced Cell has disclosed little about its finances. According to information posted on its Internet site, it has $6 million available for agricultural research.
Also, the company disclosed in 1997 a five-year, $10-million collaboration with Genzyme Transgenics, a biotechnology company. But within the last six months, Advanced Cell sold a New York biotechnology company about a 7% stake for $1 million. The deal with ImClone Systems, which includes a research collaboration, gives Advanced Cell an estimated market value of $14. 3 million. ImClone Chief Executive Sam Waskal said Advanced Cell, like many start-ups, sold ImClone convertible preferred stock because it needed investment capital. “This is significant to them,” he said.
Advanced Cell wouldn’t comment on its finances. Michael West, president and chief executive, was in meetings and not available, a spokeswoman said. A vice president said he could not provide details, but reiterated that only private funds from venture capitalists and individual investors are used to support human cloning projects. “There were no research grants at all on this, obviously,” said Dr. Robert Lanza, vice president for medical and scientific development.
Details of the federal grant are posted on the Internet sites of the Commerce Department and Advanced Cell, but have attracted little notice. Founded in 1994, Advanced Cell is a spinoff of a chicken-breeding operation called Avian Farms. The company had hoped to bioengineer chickens using cloning techniques developed at the University of Massachusetts. West, who joined Advanced Cell in 1998, and New York venture capitalist iller Quarles took control of the company last year, after a Boston bank initiated foreclosure proceedings against some Avian Farms properties tocollect a $3-million debt. Terms of the transaction weren’t disclosed. Under West’s leadership, the company has pushed itself to the forefront of human cloning.
But animal cloning remains its chief businessthough it has produced little, if any, profit. Advanced Cell made a considerable investment in the business this year when it acquired a Pennsylvania dairy breeding company. But dairy farmers are a tough sell; they want betteranimals, not clones, said John Meyer, chief executive of the Holstein Assn. USA. What Advanced Cell may lack in business success it has in media savvy.
It assured itself a splash with its human cloning experiment by simultaneouslypublishing an account in Scientific American and granting an exclusive to U. S. News and World Report. To be sure no one missed the significance, West and his co-authors on the Scientific American piece called their own work “the dawn of a new age in medicine” that showed “therapeutic cloning is within reach. ” In the days since, Advanced Cell executives have made the rounds of morning talk shows and media events. According to his assistant, West has been booked solid for three days–raising questions among people in the scientific community as to whether the company hopes to use the publicity to attract investors.
Advanced Cell said it isn’t interested in helping couples clone offspring. The firm said it created clones to extract stem cells, which can turn into any type of tissue and can be used to treat diseases such as diabetes. In Scientific American, however, West and his co-authors left the door to reproductive cloning ajar, a decision likely to inflame controversy. Due to potential health risks, they wrote, reproductive cloning is “unwarranted at this time” and should be restricted “until the safety and ethical issues surrounding it are resolved. ” Research to be covered by the federal grant takes Advanced Cell down another scientific path. The company proposes to reprogram an adult cell, such as a skin cell, into a functioning nerve cell.
That cell could be used to treat such ailments as Parkinson’s disease, in which cells in the brain do not produce enough of the key neurological chemical dopamine. Baum, of the government’s Advanced Technology Program, said the company hopes to transform the cells by “dousing them with chemicals” in a process that does not involve cloning or the use of embryonic stem cell tissue,which, with limited exceptions, also is under a federal funding ban. Other companies and institutions are racing to understand how cells program themselves, so they can produce cell therapies without using embryos. Message No: 94915=============================== End of Document ================================#7Abstract:For Advanced Cell Technology, these uncertainties loom large. The company is betting that it can perfect human cloning, creating embryos not for reproductive purposes but as a source of stem cells.
Human embryonic stem cells could, in theory, grow into any of the body’s tissues and organs, and the company wants to provide them as replacement cells to patients suffering from any of a wide variety of diseases. The company tried to clone with two types of adult cells: skin cells and cumulus cells, which are cells that cling to human eggs. The researchers added skin cells to 11 eggs; none divided even once. They added cumulus cells to eight eggs; three divided once or twice, the others not at all.
Stem cells appear only after an embryo grows for about five days and, more important, forms a blastocyst, a sphere of cells with a ball of stem cells inside it. The Advanced Cell Technology embryos that were created by cloningwere not even close to that developmental stage. Copyright New York Times Company Nov 27, 2001Full Text:When Advanced Cell Technology, a small biotechnology company in Worcester, Mass. , announced on Sunday that it had taken the first steps in producing human embryos through cloning, it could not report lasting success; allthe embryos it created had died.
It could not even report that it had used groundbreaking techniques; itsmethods had already been used in animals. Some scientists even suggested that what the company was doing was notcloning at all. But if there is a future in human cloning, either for reproductive purposes or to create cell lines for use in treating diseases, people may one day say it started in Worcester. Despite the storm of protest that the company’s announcement has provoked, that would be just fine with Advanced Cell Technology. Its president, Dr. Michael D.
West, says the company feels pressure to keep the world informedabout what it is doing in so controversial a field. But he concedes that the desire to be the first to claim to have created a human embryo by cloning was a factor in the company’s decision to publish its results so far. Whatever the scientific significance of Dr. West’s announcement, its political significance was profound. President Bush denounced the work as immoral, and there were loud calls for Congress to outlaw it.
Page A12. Shadowing the raging dispute on whether such work should be outlawed is a major scientific question: Is the human-cloning attempt a milestone or a forgettable blunder? The answer, cloning experts say, is that it is impossibleto know. ork with animals has shown that cloning is something of an art. There are no rules or formulas.
Success, when it comes, can be unpredictable and nearly inexplicable. It could be that human cloning is extraordinarily difficult and that it will take years and thousands of attempts to make it work. Or it could be that a simple change in the laboratory procedure will turn failure into success. That has been the experience of scientists who work at cloning animals. For Advanced Cell Technology, these uncertainties loom large. The company is betting that it can perfect human cloning, creating embryos not for reproductive purposes but as a source of stem cells.
Human embryonic stem cells could, in theory, grow into any of the body’s tissues and organs, and the company wants to provide them as replacement cells to patientssuffering from any of a wide variety of disease s. The small company has a track record of achievement in the world of cloning animals; some of the leading cloning researchers are on its payroll. But it also has a track record of astute dealings with the news media. In interviews, Dr.
West acknowledged that scientists for the company had published their results in a little-known online publication — E-biomed: The Journal of Regenerative Medicine — because E-biomed had agreed to arrange for distribution to coincide with articles in Scientific Americanand U. S. News and World Report. Like many other small biotechnology concerns, privately held Advanced CellTechnology attracts investors with promise, not profits. And though Dr. West said the company had just completed a round of fund-raising, he noted that it would have continuing needs for money to finance its work.
”We’re going to require hundreds of millions in investments,” he said, ”before we become profitable. ” In the work reported on Sunday, the company’s scientists, led by Dr. Jose Cibelli, used a standard technique that involves taking the genetic material out of an unfertilized egg and inserting in its place the DNA of an adult cell. In theory, the egg then uses the genes from the adult cell to direct its development, turning into an embryo that is an exact genetic copy ofthe donor of the adult cell. The company tried to clone with two types of adult cells: skin cells and cumulus cells, which are cells that cling to human eggs. The researchers added skin cells to 11 eggs; none divided even once.
They added cumulus cells to eight eggs; three divided once or twice, the others not at all. Stem cells appear only after an embryo grows for about five days and, more important, forms a blastocyst, a sphere of cells with a ball of stem cells inside it. The Advanced Cell Technology embryos that were created by cloning were not even close to that developmental stage. Dr. Ronald M. Green, a Dartmouth professor who heads the company’s ethics board, says he prefers not even referring to the cells as embryos.
He would like to call them ”cleaving eggs,” he said. In fact, scientists say, eggs can divide a few times without making any use of their genes, so the fact that a few eggs divided a few times does not at all mean that the goal of the experiment — to add a new set of functioning genes to an egg — was even close. But cloning failures can suddenly turn to successes, as those who have cloned other species attest. That was the experience of Dr. Randall Prather, a cloning expert at the University of Missouri, in years of efforts to clone pigs. Over and over again, Dr.
Prather would start the cloning process, and then the cells, like those in the Advanced Cell Technology study, would simply die. Now he and others can clone pigs, but he does not know which changes in his laboratory procedures made the difference. All he can say, Dr. Prather remarked, is, ”Yeah, now it works.
”Cloning also depends on scientists’ having a delicate touch, experts said. One scientist now with Advanced Cell Technology, Dr. Tony Perry, who worked on mouse cloning experiments at the University of Hawaii, said it tookendless hours of practice to do the careful manipulations of microscopic cells involved in cloning. Some people develop a feel for the work, while others, no matter how hard they try, are never very good.
”It requires a kind of eye-hand coordination” and constant practice, Dr. Perry said, recalling months of practice, seven days a week, 10 hours a day. ”If you lapse in your practice for two weeks,” he said, ”you don’t return to point zero, but you’re a little bit rusty. ” There are also puzzling and unpredictable differences between species.
Dr. Ryuzo Yanagimachi, who cloned the mice with Dr. Teruhiko Wakayama, also now with Advanced Cell Technology, said about 2 to 3 percent of effortsto clone cattle resulted in the birth of a live animal. Most of the rest die very early: only about 20 percent of the embryo clones make it to the blastocyst stage.
With mice, Dr. Yanagimachi said, about 50 to 60 percent of the embryo clones make it to the blastocyst stage. But even more die afterward. In the end, he said, the same percentage of mouse cloning attempts succeed as cattlecloning attempWords/ Pages : 11,058 / 24
