OF MICE AND MEN July 23, 1998 The NewsHour with Jim Lehrer Transcript

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Using a new and simpler technique, scientists in Hawaii have successfully cloned over 50 mice. The technology may streamline efforts to clone other species. Following a report on the development of this new technique, co-author of the study, Cambridge University biology professor Tony Perry, discusses his findings.

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A RealAudio version of this segment is available. NEWSHOUR LINKS: February 24, 1998 Read an Online Forum on cloning . January 8, 1998 A Chicago physicist announces plans to clone humans. December 29, 1997 A year-end report on changes in reproductive technology. June 9, 1997 A presidential commission recommends a legislative ban on cloning. March 5, 1997 The bioethics of cloning. February 24, 1997: Scottish scientists clone a sheep. Browse the NewsHour's coverage of science OUTSIDE LINKS: Roslin Institute, Edinburgh, Scotland report on cloning sheep. TheGenetics and Public Issues Program at The National Center for Genome Resources (NCGR) discusses cloning. The University of Pennsylvania Center for Bioethics

JIM LEHRER: Phil Ponce has the cloning story.

PHIL PONCE: These mice represent yet another breakthrough in the science of cloning. Last October, they became the first mammals cloned in a year-- and all of them are genetically identical thanks to a new technique developed at the University of Hawaii.

A new cloning technique.

Scientists there took a egg cell from a female mouse and removed its DNA. DNA is what carries the genetic code that gives an individual unique characteristics. Then, they took cells--called cumulous cells-- from the ovaries of the mouse they wanted to clone. DNA from those cells was injected into the gutted egg cell. Chemicals were added to start cell division and embryo development in a laboratory dish. The embryo was then transferred to a surrogate mother mouse who gave birth to mice genetically identical to the one who donated the DNA.

Last year, a group of Scottish scientists created Dolly, the first mammal ever cloned. But some experts immediately questioned whether Dolly was truly a clone. This week, two separate studies confirmed that she was. Instead of ovary cells, Dolly's doctors used cells from a sheep's udder. They then used an electrical charge to fuse those cells with DNA from another sheep. Yesterday, Dolly's lead doctor reacted to the new development.

DR. IAN WILMUT, Geneticist: Our own observations provide all the confirmation that's necessary to prove beyond doubt that Dolly was from an adult cell, and now, using a very similar procedure, Professor Yanagimachi has produced mice from a different type of adult cell. And so this will all give us a great deal of confidence to begin more research.

PHIL PONCE: Since Dolly, there have been Rhesus monkey clones--done by scientists in Oregon. These monkeys were the first primates ever cloned. And earlier this month, scientists in Japan said they successfully cloned a cow.

Cloning's moral and ethical problems.

These breakthroughs have raised both moral and ethical concerns by the scientific community and the government about the potential for human cloning. President Clinton last year banned using federal funds for experiments with people, warning scientists against, as he put it, trying to play God.

PRESIDENT CLINTON: This new discovery raises the troubling prospect that it might someday be possible to clone human beings from our own genetic material. There is much about cloning that we still do not know. My own view is that human cloning would have to raise deep concerns, given our most cherished concepts of faith and humanity. Each human life is unique, born of a miracle that reaches beyond laboratory science. I believe we must respect this profound gift and resist the temptation to replicate ourselves.

PHIL PONCE: Congress drafted legislation restricting human cloning experiments but, so far, has passed no bills. The Federal Drug Administration has said it must approve any attempt to clone humans in the United States.

Joining us now is Tony Perry, a co-author of the cloning study and an embryologist at Cambridge University in England. He's currently a visiting fellow at the University of Hawaii. Welcome, Mr. Perry.

TONY PERRY, Embryologist: Thank you very much.

The new cloning technique: "highly reproducible."

PHIL PONCE: In your words, how would you describe the significance of what your team did?

TONY PERRY: Well, I think it's a new advanced technology for cloning, which has been developed in mice and which has many potential applications, positive applications, and which is highly reproducible. In fact, it's so reproducible that not only have clones been made but clones have been made from clones, and that's reported in today's paper in Nature, but since then clones have been made from the cloned clones, so that we have not only reproduced the technique but we've shown that it can be used repeatedly along down generations of clones.

PHIL PONCE: So this is a step beyond what happened with Dolly, where the Dolly experiment was somewhat difficult to replicate, is that what you're saying, that this is becoming more routine then?

TONY PERRY: Well, certainly, the Honolulu cloning that has been reported in nature is highly reproducible, and that's one of its cardinal features, yes.

PHIL PONCE: We described in our taped introductory piece some of the very basics of how it was done. How would you describe how it was done?

TONY PERRY: I think the description was very good. Essentially, an egg is taken and from that egg the genetic information is removed, so that you have a genetically empty egg. And then in the Honolulu training technology we removed with a very, very fine pipette, a very, very fine needle, whose tip diameter is only about five millionths of a meter, and the chromosomes, that is, the part of the cell that contains the genetic information from an adult cell, in this case we used cumulous cells, and those chromosomes—that genetic information is then injected using the pipette into the innucleated or genetically empty egg. That reconstituted cell is then allowed to develop for a short time in the incubator, in the test tube, if you like, following stimulation to start embryonic development using chemicals, as your report said, and then the embryo, once it's about three days old, is transferred to a surrogate mother that can carry the embryo to term, so that in a relatively high proportion of cases we have the birth of baby mice.

A step beyond Dolly.

PHIL PONCE: So how is that different from what happened in Dolly?

TONY PERRY: Well, it's different really because of the way that the genetic information is introduced into the cell. The Dolly method, or the method that was, in fact, developed by a man called Steen Willetson in about 1980—reported in 1986—that method takes a cell that is going to donate its genetic information and it places on the surface of the genetically empty egg and then causes these two cells to fuse—so they melt together and order the contexts of one cell mingle with the contents of the genetically empty egg, including, of course, the chromosomes from the incoming nucleus.

PHIL PONCE: And in the Dolly case is that fusion caused by electricity?

TONY PERRY: In the Dolly case it's caused by electricity, but in the case of the Honolulu cloning method we, first of all, extract the genetic information from the—as I said, in this case we're using cumulous cells, so there's another difference, slightly different cells. But the genetic information is extracted, it's removed, it's like a subcellular fractionation, if you like, and then—

PHIL PONCE: I won't ask you what that means.

TONY PERRY: Okay. Essentially it means we simply remove quite selectively and in a very controlled way the genetic information from that cell, and then we introduce it shortly afterwards into the egg that is genetically devoid of its genetic information.

"What we want to emphasize is what... can be applied for the benefit of people. And we don't want to squash that consideration with scare mongering."

What we want to emphasize is what's positive about the Honolulu cloning method or that can be applied for the benefit of people. And we don't want to squash that consideration with scare mongering

PHIL PONCE: So what are the implications of all this? Why is this a good thing, in your opinion?

TONY PERRY: Well, in my opinion it's got a great deal of many positive things. This new Honolulu planning technology has to offer human and veterinary medicine, and, indeed, farming, not least because of its reproducibility.

PHIL PONCE: What are some of the benefits for people as far as fighting disease or helping people with disabilities?

TONY PERRY: Okay. I think one of the relatively near term objectives will be to try and see if we can use—and I believe this is possible—to see if we can use the Honolulu cloning method to help the pharmaceutical industry, which relies to some extent on using mice as animal models of human diseases. And those mice are very, very useful models of human disease, because, like humans, they are mammals. There are many differences, of course, but there are some similarities as well, and because mice are relatively tractable model systems, we can actually use them to study disease processes and to test, for example, pharmacological or pharmaceutical agents, drugs, and accelerate the time at which those drugs will be available in—to patients in medical care and treatment. Now—

PHIL PONCE: And does it accelerate the process by which human cloning can come about?

TONY PERRY: Well, I'm a mouse developmental biologist. We concentrate on trying to understand the basic properties—basic characteristics of the process that we've been describing, which is essentially what is it, if you like, that allows embryonic development to be supported by, for example, a nucleus from a cumulous, but apparently not so well by the nucleus or the genetic information from some other cell types. Now, we're very interested in trying to understand and unravel the processes that underlie those differences and to find out, for example, whether their differences are real, and to try and develop the—and advance the Honolulu cloning technology so that, indeed, we can use other cell types to propagate mice from different types of adult cells.

PHIL PONCE: But what your team learns from mice, can the other team then apply and advance it to being a day closer when humans are cloned?

TONY PERRY: Well, what we're very interested in doing is to use a technique to and apply the technique to certain mammalian species, such as pigs and cattle and sheep, for use in human medicine, and, indeed, veterinary medicine and farming. What I would say—and I can see that you're getting a bit frustrated to think I'm hedging the question—is that that kind of development will require an enormous amount of experimentation. And we are collaborating and we're setting up collaborations with people who have a great deal of expertise, some of the best people who are out there, working, and who have the facilities to do the experiments that have been necessary to enable us to bring what was learned in mouse cloning to those species. And without considerable experimentation, it's really not possible, I think, to adapt what has been achieved in the mouse to other species. And that, of course, has implications if you want to consider developing the Honolulu cloning technique in certain other species. A great deal of experimentation has to go on in those other species before you can do that. What we want to emphasize is what's positive about the Honolulu cloning method or that can be applied for the benefit of people. And we don't want to squash that consideration with scare mongering and the prospect that the technique might be misused. We're very, very keen to bring out what is positive in that method.

PHIL PONCE: Mr. Perry, thank you very much.

TONY PERRY: Thank you.

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