The following are the opening comments and contents of a question and answer session in a press conference held by professor Hwang Woo-suk, Korea's world-renowned cloning scientist, at Seoul National University, on August 3. _ ED. Our canine cloning research is of great value because dogs share many physiological characteristics with human beings. Of course, the best cloning target en route to accelerating stem cell therapy for humans would be monkeys. But I don't think we can replicate a monkey with our current technologies, as University of Pittsburgh professor Gerald Schatten also claims. The most viable alternative is a dog, which has many physiological features in common with humans. Following this rationale, we embarked on a dog-cloning project in Aug. 2002 by setting up a special team. We will also be able to clone extinct species by studying the cloning of dogs. In the global history of cloning animals, our former team researchers were responsible for making the first copy of a cat in 2002 and first deer clone in 2003. With the success of dog cloning, we proved once again that we retain the best technologies and know-how as far as animal cloning is concerned. Questions and Answers Question: Exactly how close is a man to a dog Hwang: We have yet to reveal the closeness precisely. But we can say a dog is very close to a human in comparison to many other animals, including other domestic pets. Q: Do you have any reason to clone a male dog A: Thus far, scientists have mainly replicated female animals because they are believed to have more commercial value. In addition, cloning males has turned out to be more difficult. But with the pastfaced development of technologies, we addressed the gap between genders. Q: What is the key behind your attention-grabbing success Hwang: Most animals ovulate eggs, which can be used directly for cloning, or we can develop immature eggs in a test tube. But in the case of a dog, the animal ovulates very immature eggs and we have yet to establish technologies to nurture them in vitro (in the lab). That is the reason why geneticists from across the world have thus far failed to create a test-tube dog despite vigorous efforts and trials. In this climate, we optimized everything to extract proper dog eggs, which have matured enough inside dog oviducts, and leveraged our advanced nuclear transfer technologies for this unprecedented dog cloning. Q: You said your team transferred whole somatic cells, not their nuclei, without removing the cytoplasm that surrounds the nuclei. Cytoplasm does not affect the cloning process Hwang: When creating Dolly the sheep, the world's first cloned mammal, scientists transferred just nuclei. However, embryologists braced for the new way afterwards of inserting the whole somatic cells into eggs. We also compared the efficiency of the two routes and confirmed the new way works much better. So we follow the new way and so do other researchers in the world. Even Ian Wilmut, who cloned Dolly through the conventional format of getting rid of cytoplasm, now adopts the new way of transferring the somatic cells, or nuclei plus cytoplasm. Q: What is the implication of this research, for example, in relation to human stem cell research Hwang: We produced cloned dogs for a disease model, not only for animals but also for humans. If we grow stem cells from nuclear transferred embryos (of dogs), we will be able to apply this research to study the human stem cell clinic. With this trial, we achieved a very valuable and important target. Our next goal will be to establish dogs' embryonic stem cells through nuclear transfer. Schatten: Your question raises two important issues. One is reproduction and the other is stem cells from nuclear transfer. The brilliant work reported here demonstrates yet again reproductive cloning is inefficient and unsafe. So we call on the world to ban human reproductive cloning, which is also unethical. Human reproductive cloning that is unsafe is to be banned worldwide as it is banned here in Korea. Having said this, it is important to recognize the technology of nuclear transfer is amazingly invaluable in teaching us about root causes of diseases and potentially in revolutionizing medicine through the use of stem cells. We will responsibly develop stem cells in dogs and demonstrate that cloned stem cells in dogs are safe and efficient in dealing with dog diseases like diabetes and dementia. It will be a marvelous thing that the first beneficiary of stem cell medicine is our close companion, the dog. Q: What is the role of Gerald Schatten in this research Hwang: Schatten did not participate in the research conducted here in person although he himself is carrying out another experiment that we cannot disclose presently at our lab. Even though Schatten was not in Seoul to lead this dog cloning research, he was one of the most active participants because we always sent research data and processes to him for discussion and he gave us insight based on his cloning knowhow. This kind of help is sometimes more crucial than assisting in the lab through examining things via a microscope. I think our unique partnership will set a good model. Q: What was most difficult part of replicating dogs Can you enhance the efficiency of cloning through follow-up research Lee Byeong-chun (Hwang's colleague): We did not stimulate the ovulation of eggs through such ways as hormone injection. We extracted eggs from dogs after waiting for their ovulation. As a result, we had to check dogs around the clock. Currently, the development of technologies to obtain canine eggs via hormones is underway but none of them is viable at the moment. Without addressing the hitches in harvesting dog eggs, cloning efficiency will not improve dramatically. Q: Professor Hwang! Don't you plan to conduct cloning experiments with primate species like monkeys Hwang: I think it is stupid to attempt to produce monkey clones with our current level of technology. It is literally impossible. So we already gave up the mission. As far as I know, Schatten also shelved the monkey cloning. Instead, we will pursue efforts in accomplishing monkey stem cell research, which is of immense clinical value as a model to human beings. Q: I learned scientists should conduct pre-clinical tests with monkeys in order to apply therapeutic cloning research into actual use. So why did you jettison the monkey project and facilitate a dog program Hwang: No country stipulates that doctors should conduct monkey trials before human trials of stem cell research. Any animals will be used as far as they can prove to be efficient and safe in the therapy, the requirements for the government's go-ahead. Q: Who owns Tai (donor of somatic cells as a father of Snuppy) How many dogs contributed eggs Hwang: A U.S. citizen gave Tai to a Korean, who agreed with this research. We got 1,095 eggs from more than 200 dogs but none of them suffered from any problems related to the egg extraction. We lost only one dog in our three-year canine research and it is the cloned one that died of aspiration pneumonia 22 days after its birth. Q: Why did you select an Afghan Hound as a cloning target A: Because Tai has a perfect history well tracked by his former U.S. owner. In addition, we tried to avoid mixed-breed dogs, of which clones typically reveal little evidence of cloning in appearance. Q: Do you have a plan to clone more dogs In doing so, will you genetically engineer the dog cells for experiments Hwang: Please understand that I cannot say how many cloned puppies are waiting for birth. We will by no means genetically engineer the clones because we do not have an urgent reason to do so, and might increase the peril to replicated dogs. In the case of pigs, we have a crucial cause for them to be genetically changed: to transplant their organs to humans without causing negative immune responses. For mad cow disease-resistant calves, genetic overhaul is also a must to produce them. However, we do not have to do that with dogs. At least in our lab, genetic engineering will not be tried with dogs. Q: Do you conduct any research to create extinct animals Hwang: Let me give you a response later. There will be an opportunity to answer the question.