Dr. Duane Carl Kraemer: The Transfer Scientist

"I remember going home and telling my parents that I had changed my mind from coming back to the farm to going on to [graduate] school," he says. Being born and raised in a Wisconsin dairy farm, the young Duane Carl Kraemer was expected to take care of the family business after finishing college. "My dad was disappointed because he built that farm for his children. He turned it into a poultry farm after we all left."

This change from farming to research not only changed a Wisconsin farm but also impacted the history of reproductive technologies.

"Dr. Kraemer is a true pioneer in his field of assisted reproduction in animals, in particular the field of embryo transfer," says Mark Westhusin from Texas A&M University. "He was the first person in the world to demonstrate successful embryo transfer in non-human primates, dogs, and cats by producing the first live offspring in these species using this procedure." Westhusin and Kraemer are long-time friends and current directors of the Reproductive Science Laboratory at Texas A&M University.

Kraemer was a student worker in different laboratories while studying for his bachelor's degree in Animal Husbandry at the University of Wisconsin. There, he became familiar with embryo transfer. "The laboratory where I worked was the place where the first cattle embryo transfers were done in 1951," he recalls.

Embryo transfer is one of the reproductive technologies that allow scientists to obtain more offspring from a genetically superior animal. An embryo-a fertilized ovum-is collected from one female (the donor) and transferred to another female (the recipient) to complete the gestation period. With normal reproduction a cow would give birth to 6 or 7 generations of cows during her lifetime; with embryo transfer the same number can be obtained in a shorter time.

Kraemer left Wisconsin and went to Texas A&M University for his master's degree. "When I got there, I was pleased and surprised to find Dr. R.O. Berry, who had done embryo transfers in sheep and goats in 1932, the year before I was born," Kraemer says. Dr. Berry greatly influenced Kraemer, and Kraemer gained more interest in the technology of embryo transfer. He ended up obtaining four degrees from Texas A&M: an M.S. in Physiology of Reproduction (1960); a B.S. in Veterinary Science (1965); a D.V.M. in Veterinary Medicine (1966); and a Ph.D. in Physiology of Reproduction (1966).

In 1966, Kraemer went to do research at the Southwest Foundation for Biomedical Research in San Antonio, Texas. The foundation had a large baboon colony for the purpose of developing a research model for diseases. "I went to the reproductive physiology lab and eventually did the first embryo transfer in a primate of any kind," Kraemer says. The first baboon embryo transfer was done in 1975, and published in Science in 1976.

Kraemer has in his office a black and white picture of him and the baboon offspring produced by that embryo transfer. He is holding the baboon in his hands, looking at it over a surgical mask. Photos of horses and bulls on every wall of his office show his passion for animals. "His commitment to his students, his work, science, and the public in general are unparalleled to anyone I have ever known," says Westhusin.
"'Completely unselfish' is one way you might describe him; 'totally giving' is another."

The phone on his desk rings and rings but he does not answer and continues to talk about his life.

"[After the baboon] we started doing embryo transfer in cattle at Texas A&M," Kraemer says. "We did the first embryo transfer in horses in the U.S., in cats, and dogs. And also, working with the Dallas zoo, we did the first embryo transfers in antelopes."
Embryo transfer is the basis for other reproductive technologies like in vitro fertilization, sperm injection, and cloning by nuclear transfer.

"One couldn't have done cloning in any form without doing embryo transfer," Kraemer says. "We specialize in adapting embryo transfer technologies to a variety of species. Then we apply in vitro fertilization and cloning to those species."

The transition between embryo transfer and cloning was gradual. In 1952, nuclear transfer experiments with a frog's adult cells produced viable embryos, which didn't develop beyond the tadpole stage. In 1986, Steen Willadsen at Cambridge, England, used nucleus transfer to produce sheep. He used embryo cells rather than adult cells. During that time, Kraemer helped some of his students to create a company-Granada Biosciences-that employed Willadsen to do nucleus transfer cloning. Granada produced hundreds of calves by nucleus transfer cloning during the '80s. In 1997, a group in Scotland used an adult cell from the mammary gland of a sheep, and produced offspring by nuclear transfer; Dolly became the first cloned mammal.

At that time Kraemer had done cloning with embryo cells and had initiated a study using adult tumor cells as possible cells for cloning. "But when Dolly was cloned," Kraemer says, "we changed from tumor cells to skin cells and produced 'Second Chance', the bull."

Cloning research at Texas A&M later generated controversy with the Missyplicity project-the effort to clone the dog Missy, with private funding from her multimillion-dollar owners. Missy died and her clone has not become a reality. "A dog is a very complex species to clone," Kraemer says.

However, Texas A&M researchers were able to clone a cat-called "CC" (for Carbon Copy). "The cloning of CC was more a sort of [an] adaptation since other mammals had been cloned before,'" Kraemer says. "It all depends on the attitude you have toward that."

In 1999, four Texas A&M faculty members involved in the Missyplicity project, Kraemer among them, co-founded of the company Genetic Savings and Clone-owned and licensed by the Texas A&M University to use the technology developed in the Missyplicity project. "We received many requests from pet owners who wanted to preserve cells from their animals so we transferred that to the private sector [creating the company]," Kraemer says.

Now, Genetic Savings and Clone is no longer a Texas A&M project. The company's headquarters moved to Sausalito, California, and will operate in Austin. Kraemer is still helping to develop their embryo transfer capabilities. "Eventually, they will be able to clone a dog," he says. "It can be done with the technology we developed, but it is quite inefficient." He would have liked to do more research with dogs and cats, but realizes it is time to move on.

"Dr. Kraemer has a true understanding of what it takes to be a good scientist," Westhusin says, "especially from the standpoint of patience and perseverance. He knows every experiment doesn't turn out as you would like, and even negative results are many times informative."

Kraemer is currently attempting to adapt the cloning technology to the dessert big horn sheep and the white tail deer. "Each species requires adaptations in the approach," he says. "Some species require a different medium to grow, or a different method for maturing the ova or obtaining them; the electrical current that is used to fuse is sometimes different and the timing of activation also."

Westhusin says he doesn't know any person in the world that has more experience using assisted reproductive technologies in so many different animal species than Duane Kraemer. One species, however, that Kraemer has never worked with is his own.

"The possibility of producing offspring in humans by nuclear transfer is not hard to imagine," Kraemer says. "It's the fetal wastage that occurs in the process of producing offspring in the other levels that makes me think it is not appropriate to do it in humans. If it were predictable in other animals, especially in the great apes, then it would be safer to try it with humans. I would like to do more research with the great apes."

At almost age 70, Kraemer still looks for new projects to work in. His laboratory is full of liquid hydrogen containers storing genetic material from endangered species for future cloning.

"I'm not sure he will ever retire," Westhusin says, "doing for others seems to keep him alive and full of spirit." If and when he does retire, Kraemer will have left his mark on the history of cloning and embryo transfer.