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Humans 'nearly impossible' to clone: study Margaret Munro National Post Friday, April 11, 2003 It may be impossible to clone human beings with existing technology because of insurmountable molecular obstacles, a group of U.S. researchers said yesterday. "The chromosomes do not split properly," said Dr. Gerald Schatten, head of the research team at the University of Pittsburgh School of Medicine. "From the very first cell division, development is inappropriate in vital ways." Current techniques, which have been used to create a barnyard of cloned animals including Dolly the sheep, cows and goats, do not seem to work in primates, the team reports in the journal Science today. Dr. Schatten said it is almost as if someone drew a sharp line between primates and other animals, saying: "I'll let you clone cattle, mice, sheep, even rabbits and cats, but monkeys and people require something more." Still, Dr. Schatten and other researchers are unwilling to write off primate cloning forever. "Given enough time and materials, we may discover how to make it work," Dr. Schatten said. "It just doesn't work now." In December, Clonaid, a company founded by the Raelian religious sect, which believes space aliens created life on Earth, claimed to have produced the first human clone -- a 3.2-kilogram baby girl. The sect claims to have cloned several more babies, but has yet to provide proof. Scientists and ethicists around the world reacted to the Raelian announcement with disbelief and horror. Even when cloning works, the animals are often plagued with medical problems. Dolly the sheep, the first cloned animal created in 1996, developed arthritis and died prematurely in February. For every cloned animal that is born, many more are stillborn or have severe defects. The experiments in Pittsburgh show the obstacles to human cloning are huge. Not one of the 716 eggs from rhesus macaques, which the scientists tried to clone using state-of-the-art technology, produced a baby monkey. Few of the clones even developed to the 16-cell stage. "Our study suggests that reproductive cloning in primates -- human and non-human alike -- is going to be nearly impossible with current technologies," the Pittsburgh team said. The failure "demonstrates that neither the cloning process used to produce Dolly nor cloned mice work with a primate." The monkey failure is also seen as a setback for so-called "therapeutic" cloning, which many researchers dream of using to grow replacement parts and cells to treat diseases such as diabetes and Parkinson's disease. Therapeutic cloning would involve transferring new genetic material into human eggs. The resulting cloned embryo would not be used to produce a child but rather to produce cells and tissues that could be harvested. For therapeutic cloning to work, the cloned embryos must get through several cell divisions before the desired cells can be harvested -- a feat the monkey work indicates is going to be more difficult than expected. "This is complex biology, and just moving nuclei [which contain a cell's genetic material] around is not as simple as some people might suggest," said Dr. Alan Bernstein, president of the Canadian Institutes of Health Research. One cloning technique was reported to have produced a healthy cloned monkey a few years ago. No one has ever been able to repeat the experiment. The Pittsburgh team attempted to clone the monkeys using somatic cell nuclear transfer -- the technique used to clone sheep, goats, cows, pigs, mice, rabbits and Cc the cloned cat. The scientists harvested an unfertilized egg, pulled out its DNA genetic material and replaced it with new DNA from an adult cell of the animal to be cloned. The egg was then coaxed to grow using various stimulants. Although 33 embryos were transferred into surrogate mothers after initial cell division, no pregnancies were established. Although cell division continued in a superficially normal manner, the scientists found there were chromosomal problems within each individual cell. The Pittsburgh work indicates the hurdles to cloning primates begin the moment the cloned egg cell tries to divide and multiply. Dr. Christopher Navara, a member of the Pittsburgh team, said motor proteins that organize and move chromosomes around during cell division seem to be compromised or damaged when the DNA is pulled from the monkey eggs. "Sometimes they [the eggs] didn't even make it out of the first cell cycle; they'd just stop right there," Dr. Navara said. A few clones got to the 16-cell stage. "But we didn't see any past that," he said, all of which indicates that no one will be cloning humans any time soon. "Reproductive cloning is nowhere near as simple as the Raelians would have you believe," said Dr. Alan Leshner, chief executive officer of the American Association for the Advancement of Science. The association, and most scientists and ethicists, would like to see a ban on cloning of humans, or so-called reproductive cloning. As Dr. Navara puts it: "Everything we know about cloning in other animals suggests that human cloning is not safe, is not ethical and probably should be illegal." But many scientists believe human therapeutic cloning could have huge medical benefit and should not be ruled out completely. "There are clinical reasons for wanting to do it," Dr. Bernstein said. In order for researchers to be able to explore the potential of therapeutic cloning, they must be allowed to work with cells taken from human embryos. "There are some important experiments that we could and should be doing," Dr. Bernstein said. His agency, a main funder of Canadian university medical research, is keen to start funding work in the area but has been waiting more than a year for the federal government to pass legislation to spell out how human embryos can be used. Bill C-13, which was introduced last May, would make both human reproductive and therapeutic cloning illegal, along with attempted human-animal hybrids. The bill would also ban the creation of embryos for the purpose of research. It would, however, permit the use of surplus embryos for medical research until 14 days after conception. Canadian researchers have expressed interest in producing cells for research from the embryos. "It is important to get clarity," said Dr. Bernstein, who had hoped the legislation would pass before April 1. "There are a number of people at the starting line waiting to get going and patient groups who are very anxious to see that the work move forward," he said. Meanwhile, in Pittsburgh, the monkey cloners, though frustrated, are exploring ways to get around the hurdles nature seems to have placed in their way. Dr. Navara said they still hope to clone monkeys that could be used to test new disease treatments -- among them, therapeutic cloning. 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