In 1979, University of Geneva Professor Karl Illmensee announced the success of a groundbreaking experiment: the cloning of mice from early embryos. Since 1952, scientists had repeatedly tried and failed to reproduce in mammals the experiments of Robert Briggs and Thomas King that had successfully cloned frogs. On this fateful day, Illmensee claimed he had successfully cloned three mice — long-awaited mammal clones brought to life. Since mice are so genetically similar to humans, this experiment represented moving one step closer to being able to clone humans.

Illmensee’s unprecedented work involved an incredibly complicated nuclear transplantation experiment. According to Illmensee’s 1981 paper, steps included breaking open an embryo cell, sucking out its nucleus and injecting it back into a newly fertilized egg whose genetic material had already been removed. The embryo was then implanted into a female mouse that was given hormones to induce pregnancy.

Illmensee’s experiment seemed practically impossible, but he had a reputation for “golden hands” and the ability to perform intricate experiments. Illmensee’s peer-reviewed paper was published in Cell, the leading journal of biology, in an issue that featured three cloned mice on the cover; Illmensee immediately received world renown. The New York Times printed a front page article titled “First Cloning of Mammals Produces 3 Mice” and other magazines predicted imminent human cloning, even starting to question the moral and religious implications of cloning.



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However, Illmensee’s exciting news soon began to sour. For the next five years, scientists repeatedly attempted to replicate Illmensee’s work without success. Illmensee responded that they just did not have the technical skill to carry out his experiments. Yet he avoided demonstrating his procedure to visiting researchers, claiming his pipettes were dirty or the needles too sticky.

In the fall of 1981, researcher Patricia Kahn joined Illmensee’s laboratory, hoping to learn the nuclear transplantation technique. Kahn soon realized that everyone in the lab was assigned a specific task and not informed about the overall steps. Nobody had learned the nuclear transplantation technique or even seen Illmensee perform one. When Kahn left a week later, Illmensee warned her of consequences if she reported derogatory information about his research.

Fellow researchers reported that Illmensee came in at night and on weekends when nobody else was in the laboratory and refused to show anyone his technique. One graduate student noticed that a broken pipette remained at Illmensee’s workbench for a week, even though Illmensee had claimed to have been working during this time and would have needed to replace the pipette to do his experiment. Even when the lab’s water purification system failed and the eggs should have died from contaminated water, Illmensee still claimed to successfully culture eggs.  A mouse geneticist soon noticed that Illmensee published pictures of mice from one of his experiments that did not have coat patterns that could have resulted from Illmensee’s work.

The evidence that Illmensee had committed scientific fraud was so great that members of his laboratory stood up during one of Illmensee’s presentations and announced that they could not accept his results, stunning the attending scientists. The University of Geneva launched an investigation that found that Illmensee had falsified his results and that his experiments were “scientifically worthless.”

Illmensee’s fraud impeded progress in the field of cloning for over a decade. Government funding for cloning research dried up...Illmensee’s failed experiments prompted many scientists to consider cloning a dead-end enterprise.

However, Illmensee denied all charges. Many scientists remained convinced that Illmensee had still successfully cloned the first mice, speculating that he was just sloppy in his record keeping. Finally, in 1984, biologist Davor Solter published a definitive paper demonstrating that nuclear transplantation does not develop mice to term, thereby strongly suggesting that Illmensee had not successfully cloned mice. Solter concluded that “the cloning of mammals by simple nuclear transfer is biologically impossible.” The news media reported around the world that the most impressive cloning of a mammal had been discredited.  Illmensee’s fraud impeded progress in the field of cloning for over a decade. Government funding for cloning research dried up, and the only cloning research left was done by veterinarians on barn animals for agricultural reasons. Illmensee’s failed experiments prompted many scientists to consider cloning a dead-end enterprise. Yet the allure of cloning did not completely die. In 1996, biologists still pursuing cloning were vindicated: researchers at the Roslin Institute in Scotland cloned Dolly the Sheep, the very real, very proven first mammalian clone.

Today, Karl Illmensee works at a fertility center in Greece.

Listed prominently in his biography profile sits the proud statement that his team was the world’s first to clone a mammal.

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