In Defense Of Cloning

A University of Maryland professor who helped the FDA assess the potential dangers of selling meat and milk from cloned animals maintains that such food is safe

Q&a -- Carol L. Keefer

January 13, 2008|By Jonathan D. Rockoff | Jonathan D. Rockoff,Sun reporter

Washington -- Carol L. Keefer has played a significant behind-the-scenes role in the government's deliberations on whether to permit sales of meat and milk derived from clones. An associate professor at the University of Maryland, Keefer was one of three animal scientists who reviewed the Food and Drug Administration's research into the safety of such food last year.

The agency's tentative endorsement of the food's safety has been the subject of much hand-wringing among consumers, within the food industry and in Washington. Sen. Barbara A. Mikulski of Maryland, among others in Congress, is trying to block the FDA from making a final ruling that would pave the way for grocery shelves to carry meat and milk from cloned cows, pigs and goats and their offspring.

The cloning of farm animals is a hot-button issue for animal welfare advocates, who say the process leads to serious health defects. Mikulski and others say many consumers are uncomfortable with the prospect of eating meat or drinking milk from a cloned animal. If cloned foods are marketed, she wants them to be labeled to give consumers the option of avoiding them.

Still, the FDA is expected to issue a decision opening the door to selling cloned foods soon.

During an interview last week in her university office, across the hall from the labs where she studies animal reproduction, Keefer discussed the implications of FDA approval. She said cloning should not be confused with genetic engineering, in which the nature of the animal might be altered. She emphasized that the food wouldn't be genetically modified and said the food would be as safe to eat as food produced through existing means. She said she ate a steak from a clone in Japan.

Keefer has been looking into new technologies for breeding animals since she was a post-doctoral fellow at the Johns Hopkins University in the early 1980s, researching in vitro fertilization of rats. After leading a team of cloning researchers at a biotechnology firm in Montreal, she moved to College Park three years ago. She served as president of the International Embryo Transfer Society. How does cloning work?

This is just another advancement in reproduction, another method of reproducing an animal.

In this case, you might have a high-value animal that you would like another copy of. ... Well, if you breed him and look at the sons, they're not going to be identical to him because of the recombination of the DNA during fertilization. The way you make a copy of him is through cloning.

You need just one of his cells, which has a nucleus in it. The nucleus contains information on how to make him. We all have DNA in our nucleii which tells cells how to be a cell, how to make a new individual. (Actually, you need more than one cell due to the inefficiencies in the process.)

If you take the nucleus from one of his cells and put it into an unfertilized egg after you remove the DNA from that egg, then the egg cytoplasm - the material inside the egg - can utilize the information that's provided by the nucleus to start development of a new embryo. What happens after the transfer of the DNA from the nucleus of the cell you want to copy?

An oocyte is obtained - an unfertilized egg - and the DNA from that egg is replaced with the DNA from the animal that you're copying. This reconstructed embryo is activated; that is, it goes through the embryo development process - that means cells divide, it forms an embryo.

This embryo is then transferred into the reproductive tract of a surrogate, a recipient, where in some cases it will initiate a pregnancy. And the surrogate animal will hopefully carry that pregnancy to term. And then you have the offspring born.

So the clone itself undergoes the normal embryo/fetal development process inside what you might call the surrogate mother. The birth is normal. ...

The time during which the embryo is outside of a cow and being handled in a laboratory situation is approximately one week. Is it genetic engineering - transgenics?

It's not genetic engineering. No. The confusion arises because you can use the cloning process to make a transgenic animal. But in that case, ... other procedures become involved to alter the genome of the transgenic animal.

When you're talking about cloning to reproduce an animal, you're not altering the genetics that you're copying. You're just taking that copy of genetics from the animal that you're copying and using it, through this reproductive cloning process, to make a genetic copy of that animal. ...

The confusion arises, I think, because we use the same technique - somatic cell nuclear transfer - to either do reproductive cloning or to produce transgenic animals.

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