Mitalipov’s scientific competitor is a reclusive researcher named Jamie Thomson, and it so happens that the two share a bit of history: From 1989 to 1991, seven years before Mitalipov arrived, Thomson worked as a postdoc at the Oregon National Primate Research Center. Recognizing Thomson’s tremendous talents as a scientist, Don Wolf, the head of the primate center’s embryology research group at the time, attempted to convince OHSU to hire the postdoc permanently in 1991, but administrators, says Wolf, weren’t interested in keeping Thomson on.
“He was accomplished beyond his years,” says Wolf, still frustrated. “There was absolutely no question that he was going to be hugely successful in the future.”
Thomson became a scientific superstar in 1998, a heady time for the fledgling field that had been dubbed “bioengineering.” Two years earlier, an Edinburgh embryologist named Ian Wilmut had figured out how to clone an animal. Using a process called “somatic cell nuclear transfer”—the same process that Mitalipov would later refine in monkeys—Wilmut took an egg from a Scottish blackface ewe and swapped out its DNA with the DNA from a 6-year-old sheep of a different breed, a Finn Dorset. After zapping the egg with a jolt of electricity to initiate cell division, Wilmut implanted the newly formed embryo into another blackface ewe’s uterus. Five months later, a fuzzy, perfectly healthy little lamb was born, a baby clone of the adult Finn Dorset. Wilmut named the cloned lamb “Dolly.”
Dolly’s birth announcement on February 23, 1997, tapped into the public’s worst fears about cloning. It didn’t help that Wilmut’s work was funded by a biotech firm interested in bioengineering sheep to produce milk laden with a protein commonly used in pharmaceuticals. In interviews with the press, Wilmut attempted to dispel worries that Dolly was a prelude to human cloning.
“Why would you want to make another human being?” Wilmut asked Malcolm Ritter, an Associated Press science writer. “It would be ethically unacceptable.”
Nevertheless, the headlines that followed exuded an air of Aldous Huxley’s Brave New World, presaging legions of identical alphas and betas. In its lead story, the New York Times quoted Lee Silver, a Princeton biology professor, who declared, “It means all science fiction is true.”
In response, President Bill Clinton convened the National Bioethics Advisory Commission, which recommended imposing a five-year moratorium on government funding of human cloning research, a ban that George Bush extended once in office. It stands to this day.
As portentous a development as Dolly may have been, however, the truly revolutionary potential of cloning, from the perspective of medical science, wasn’t recognized until 1998, a year after Dolly’s birth was announced. That was when Thomson, by then a researcher at the University of Wisconsin-Madison, figured out how to harvest stem cells from human embryos left over from fertility treatments. Thomson was able to isolate and extract “pluripotent stem cells,” which are found in embryos only during the earliest stages of development and are capable of morphing into any manner of the body’s 200-odd different types of cells, from neurons and muscle tissue to blood and bone. By feeding a culture of these embryonic stem cells a precisely tailored chemical cocktail, Thomson could induce a process known as differentiation, triggering the embryonic cells to evolve into whatever type of cell he desired, be it liver cells for patients with liver disease or insulin-producing pancreatic cells for diabetics.
Pope John Paul II and other opponents denounced Thomson’s procedure as immoral because it involved the destruction of a human embryo—once the stem cells are harvested, the embryo is discarded. But scientists immediately recognized that Thomson’s discovery, married with Wilmut’s embryo-cloning technique, could revolutionize modern medicine.
The problem that such a coupling could solve was critical. Stem cell transplants had, in fact, been performed in leukemia patients for decades. The bone marrow stem cells used in such transplants are called “adult” stem cells. However, such stem cells, which are found in the parts of our body that constantly need regeneration (like bone marrow, skin and blood), have limited usefulness in medicine, because unlike the pluripotent stem cells that Thomson had harvested, adult stem cells have the potential to become only one thing. In other words, adult blood stem cells can only produce other blood stem cells.
Adult bone marrow stem cells from a healthy donor, when transplanted into a leukemia patient, will produce healthy bone marrow, potentially saving that patient’s life. But finding a donor with compatible DNA can be difficult, and even if a good donor is located, a patient’s immune system might reject the transplanted tissue, mistaking the bone marrow stem cells for foreign invaders.