Q&A: The Stubborn Truth About Cloned Mules Scientists aren't cloning mules merely for the benefit of bettors; the research that produced them is also helping to shed light on human cancer research. Gordon Woods, part of the University of Idaho team that created the first cloned mules, now works on research that may lead to horse clones. NPR caught up with him earlier this week.

Q&A: The Stubborn Truth About Cloned Mules

Idaho Gem takes to the racetrack for a qualifying heat at the Winnemucca Futurity, June 3, 2006. University of Idaho/Phil Schofield hide caption

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University of Idaho/Phil Schofield

Dirk Vanderwall with Idaho Star and Ken White with Utah Pioneer. Click here to see all three mule clones. University of Idaho/Phil Schofield hide caption

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University of Idaho/Phil Schofield

Dirk Vanderwall of the University of Idaho with Idaho Star, Ken White of Utah State University with Utah Pioneer, and Gordon Woods of the University of Idaho with Idaho Gem. Standing far right is Don Jacklin, the man who funded the mule cloning research.

University of Idaho/Phil Schofield

It's race day. You've placed your bets. The mules (let's just say you've caught on to the fact that there are more than greyhounds and horses racing these days), come thundering around the track. You scream, you cheer. And as your mule blazes by, you can't help thinking he's certainly one of a kind. Or is he?

Born on May 4, 2003, Idaho Gem is the first cloned mule and the first-ever cloned member of the horse family. The result of a cell from a mule fetus and an egg from a horse, he is also the first-ever clone of a hybrid animal, which can't normally reproduce.

This summer, Idaho Gem and his genetic twin, Idaho Star, are stepping onto the racetrack and into the spotlight. They are participating in the professional mule-racing circuit, which draws thousands of fans -- and adding a new dimension to the old nature v. nurture debate.

But scientists aren't cloning mules merely for the benefit of bettors; the research that produced them is also helping to shed light on human cancer research. Gordon Woods, part of the University of Idaho team that created Idaho Gem and his twin, now works on horse clones. NPR asked him about the science of equine cloning.

Q: Why clone mules?

The person who funded the project, Don Jacklin, is a twin himself. He's the president of the American Mule Racing Association, and he wanted to bring the world's attention to racing mules. He wanted to race clones created from the same gene pool as his favorite mule, Taz, a champion racer. But my objective has always been on the research side. I've been involved in embryonic research of equines for many years. When cloning technology started to come through with Dolly in Scotland, the next logical step for us was to use cloning to learn what we could about embryo biology.

Q: What are the biggest misconceptions people have about animal cloning?

You go to the movies, say Star Wars or something, and you see the clones there and you think that it is this real easy thing to do. But cloning is a costly, expensive process.

Another misconception is that people think that if they have a pet dog, a perfect pet dog with a perfect personality, they think cloning will give them that exact dog. As others have noted, cloning is replication, not resurrection. If you know any identical twins, you see they are genetically the same, but their personalities can be miles apart.

Take our three cloned mules: Idaho Gem, the first cloned mule, is a little bit of a stinker. I mean, they are nice animals to be around overall, but he's a stinker. Utah Pioneer is standoffish. If you come to the fence, Gem and Star will want to be scratched and enjoy having their pictures taken. Pioneer won't. And Idaho Star -- he has a little-brother syndrome. If I watch their paddock from my window, I see the three of them and Star will come up and pester Gem and Pioneer.

Q: Idaho Gem's DNA came from a fetal cell culture first established at the university in 1998. For years, the team worked without success. What was the holdup?

Well, let's take a few steps back. What you first have to understand is that in vitro fertilization is very unsuccessful in horses. At first, we thought it was a matter of tweaking the technique. After a number of attempts, only two foals have ever been born using the in vitro technique. We invested years and failed miserably in our efforts. We even had someone who had an active, ongoing human in vitro fertilization clinic join our team, but we were still unsuccessful. We concluded it wasn't a matter of technique, but that the horse system is different from the human system.

Q: How so?

Well, you have to kind of visualize it. We would look at the horse oocyte, and we kept looking at cells that would not divide. If you look at cancer cells, they are constantly dividing. Horses have a markedly lower rate than humans of cancer mortality -- no prostate cancer, rare breast cancer -- and with skin cancer, they're amazing.

If you look at light-colored horses more than 15 years old, 80 percent have skin melanomas. But, here's what's interesting: In horses, the tumor will be there, but it won't rapidly divide and spread. We concluded there must be a chemical explanation for the proposed low cell activity in horses. We found that intracellular calcium -- that is, how much calcium is regulated into cells -- is different in humans and horses.

With our cloning project, we thought that if we increased the calcium in the cells, the cell activity would increase, and there would be more pregnancies in the horses implanted with clones. It was like we turned the light on in the room! We saw a seven-fold improvement! Calcium regulation was the key.

Q: So how does the cloning research relate to human health?

Picture it this way: You draw three circles. Think of the circle to the far left as a horse cell, the circle in the middle as a cell belonging to young, healthy humans, and the circle at the far right as the cell of an aged human, say, with prostate disease. You'll see that the circle on the far left has significantly lower calcium inside it and significantly higher calcium outside it. Although it is swimming in calcium, the horse cell has very tight regulation of what gets in.

If you look at a young, healthy human, there is more calcium inside. And if you looked at an aged person, there are elevated calcium levels inside the cell and much less outside.

When I tell people this, they think, "Oh! Should I decrease the calcium in my diet?" But it's not about the total amount of calcium; it's about how it's regulated. From a human standpoint, this sort of research could lead to a diagnostic aid that could monitor intracellular calcium levels in humans and provide clues into what role calcium plays in cancers.

Q: Do cloned animals have more health problems than other animals?

That may be species specific. I can speak to our three mules, who have been boringly normal. I mean, they have phenomenal personalities, but their health has been perfect. They are able to participate in the strenuous sport of racing -- that shows their tremendous health.

Q: What are the dangers of animal cloning?

I have to confess, I'm a glass-half-full kind of guy -- which you kind of have to be with all the lack of success that leads up to any success in the lab. I'm a veterinarian committed to animal health. If cloning produced unhealthy animals, that would be a cause for concern. Theoretically, cloning might narrow the gene pool if you were using it to do so. In reality, though, cloning gives us the opportunity to expand the gene pool.

Take, for example, endangered species…you could collect cells from individuals and preserve that gene set forever. Also, take superior athletes that are neutered: stallions at Olympic-type horse events. Here, you end up with mature, world-class champions who are not able to reproduce. Cloning enables you to make a genetic copy of that champion, and the clone could then pass on the genes. Cloning could allow us to make unwise decisions, but properly used, it could enable us to expand and preserve the gene pool of unique animals.